BCM Community

My ECM on my 8V92TA DDEC II was replaced in June. Since then the engine smokes on acceleration, either with a very light touch or the pedal to the floor.  With the old ECM you couldn't make it smoke. Is there a way to program the ECM to stop the smoke? I was told that the reconditioned ECM is the latest version so i'm guessing it is different from the original. I took the bus to Interstate Detroit Diesel in Fargo, ND yesterday to have the engine checked and the technician said, after hooking up his diagnostic computer and a test drive that the smoke on acceleration is normal. He has 32 years working on DD engines so he should know them well. Anyone have thoughts on this?

Thanks, Sam

I'm guessing it's black smoke. It could be that with the latest software in the ECM the boost pressure sensor should have been changed to the newer style and I think there's more than one of those. I think Jim Sheppard had a related problem with the wrong pressure sensor, except he wasn't getting enough fuel. I hear that the series 60 folks install the old style DDEC II sensor for more power.

Ken

That's not normal for a DDEC Sam they burn clean you probably have a lazy turbo or the boost sensor is going bad is the HP setting the same as the old ECM  woops Ken had already posted sorry

good luck

Quote from: luvrbus on August 01, 2012, 08:55:11 AM
That's not normal for a DDEC Sam they burn clean you probably have a lazy turbo or the boost sensor is going bad is the HP setting the same as the old ECM  woops Ken had already posted sorry

good luck

My DDEC II 8v92 didn't black smoke at all, it was 475 HP. At night I could see maybe a little haze out the exhaust if someone were behind me. The other things Clifford mentioned are good possibilities too.

Ken

On the Series 60 there are at least two manifold pressure sensors.  On my original 60 Series 60, they used a GM MAP sensor (max pressure was about 25 PSI - not sure).  On the second engine, they used their own and it has a max of 40 PSI as I recall.  The DDEC uses a voltage from the sensor to determine fueling.  I think that voltage is 5V max and is proportional to the boost.  So, if the boost sensor and software do not match, the ECM will not fuel correctly.  I tried to use my old software/ECM with the new engine and the voltage from the DD pressure sensor was telling the ECM that the boost was something like 14 PSI when it was really 20PSI  - thus not enough fuel and no power.  The problem was dramatic, and I don't think that is the issue here.

DD should have downloaded the program from your old ECM and then installed it in your new ECM.  If your problem occurred right after the switch, it is obvious that they did not get your new ECM programmed correctly.  If the problem was not immediate, then we need to look at the issue further.

I think there is a possibility that DD might have your original software in their main computer (by engine serial number).  A good DD mechanic could compare the two programs and tell you if the new one is programmed correctly.  If your original ECM had the software changed (more HP for example), then there could be a problem.  If it was done by a DD facility, then the upgraded software should be on the main DD computer.  If it was done by a "backdoor" modification, then there is no way to get the software back unless you have the old ECM (doubtful).

Jim

Thanks for the responses. The program was downloaded from the old ECM to the reconditioned one at Interstate Detroit Diesel in Sioux Falls, SD so the program should be the same. Horsepower was 450 before the change and I don't think it was increased. Yesterday, the technician at Interstate Detroit Diesel in Fargo, ND, mentioned the boost sensor as a possibility  but ruled it out when he drove on the test drive and watched the computer screen. He also mentioned the injector response time being normal. This is all new to me, which is why I'm asking for help. Where would you suggest I take the issue from here? Should I ask to have the program checked to verify it matches the program removed from the old ECM? Again, any help is appreciated.

Thanks, Sam

If you have a boost gauge and pyometers are  the readings about the same as they were?? As Clifford pointed out you maybe losing a Turbo. If I remember  correctly boost pressure should be about 26 lbs under full load.

sorry triple post???

sorry triple post???

Hi Ken,

Thanks for your help. I don't have either turbo boost or pyrometer gauges. I talked to the service writer and have an appointment for 7:00 AM tomorrow for further testing. Hopefully they will determine what is wrong and fix it. Now that I know that smoking isn't normal I will be a little more persistent in getting a solution. I filled with fuel after leaving the shop yesterday and now know that I got the worst MPG since owing the bus, 5.15 MPG. I already knew that black smoke equals wasted fuel.

Thanks again, Sam

Sam,  it maybe a simple as a exhaust leak also, response time does not mean much if a injector is bad why didn't he cut out 1 injector at a time and check the smoke ? or did he 

They have a bypass on the blower I am not saying it has never been serviced but they are forgotten and stick open 

good luck

Hi luvrbus,

Thanks for your help.  There doesn't seem to be an exhaust leak. The power seems to be the same as before.  I think a n exhaust leak ahead of the turbo would cause a lose of power. I don't think he cut off each injector, one at a time and there is no noticeable miss. I will ask about the blower bypass being stuck open. Will the blower bypass being stuck open cause a lose of power too, besides smoking? I have no idea if the blower bypass has ever been serviced, I know that it has not in the about 17,000 miles I have owned the bus.

The engine only has 95,232 miles on it since new. The engine and transmission were both put in new when the bus was converted in the early to mid 1990s. I don't have much information about the bus since we bought it from the widow of the man that converted it. I wish I did have a better history of the bus.

Thanks for your help, it is greatly appreciated. Sam

Repeating myself, did the smoking start right after the ECM change?

If there was a delay in the smoking problem, that points less to the ECM and more towards something else.

On the Series 60 there is a restrictor in the fuel return line.  If the 8V92 has that, is there a chance it is plugged?

Jim

Being the simple fellow that I like to think I am...

I'm always fond of going looking for leaking intake piping, on the pressure side. One loose hose clamp on any of those connections and you've got black smoke, and often a loss of power.

Anything that steals pressure after the turbo shows as black smoke.

happy coaching!
buswarrior

I don't think the black smoke started right after the ECM change, but not long after. At that time I was more concerned about whether the throttle problem was fixed and wasn't watching the exhaust closely. When at the shop Tuesday there were no codes stored, would there be with an exhaust or intake leak? I have had no noticeable loss of power. I am about to leave for my appointment this morning and will update later.

Thanks for the help, Sam

After over an hour waiting for my bus to be looked at this morning, the service adviser came to the bus and told me they are going to order another ECM, make sure it is programed correctly and install it. I have to be back at the shop at 8:30 tomorrow. We will see if that helps the smoking problem. Hopefully that will solve the problem.

Thanks, Sam

Sam, why did they replace the ECM in the first place, there may be something else going as suggested by others. Does it only smoke on take off or does it smoke all the time. Explane all the symptoms if you can and we will help the best we can. The problem with reprogramming the ECM is it has to be connected to the main frame at DDC and they need permission from the Germans to do that. I ran across that problem with a couple of ecm's I wanted up graded for a 12V92TA I am working on. I sent them to someone on this board to see what he could do with them.

Don

Don, the DD software will usually allow a 10 to 15% increase after that it get kinda of sticky with the Germans the DD 13 and DD 15 you don't do anything with those puppies not even the dealer will try lol  

Cole says you cannot do what you are after and he doesn't want to get involved with the state of Ca hope your guy can get it done

so much for engine manufactures. They sell a pruduct and then tell you to pound sand. I guess we can think the EPA and one world govment for this mess.

Don

Cole is giving classes at Luke Air Base here in Phoenix in mid Oct till the 1st of Nov it will be on the new stuff I don't if it would help us or not but if you want to go I'll try and get us in  

The new DDEC coming are going have GPS locator and other things like a touch screen for some actions I don't what all yet but it will probably do Sliver leaf an QuallCom in after all the old DDEC's are gone

Hi Don,

The ECM was replaced because I lost throttle intermittently. With the old ECM I couldn't make the engine smoke. Now it smokes black whether I use light or heavy throttle. Once up to speed, there is no visible smoke. But my fuel milage has gone down from 5.96 average over 6713 miles to 5.00 for the last 1832 miles since the ECM was replaced. I know driving conditions have an effect on mileage so that's why I average over the long term. There are no codes stored on the current ECM, but there were several on the old one. The engine runs smoothly and has the same power that it had before. The filter minder on the air cleaner shows 8 so I don't think that is the problem. The fuel filters were replaced Tuesday. What other information would be useful?

Thanks, Sam

Clifford, I would like to go to the class if Cole can arrange it. I would also like to meet Cole and pick his brain a little.

Sam, as ken suggested you need to put a boost gauge in even if you run it into the bedroom and have some one watch it as you run down the road as you would normally. I would also ask if the shop can check the throttle peddle operation it may have a bad rheostat in it, they should be able to check the output.

Don

A boost gauge and exhaust gas temperature gauge would be very useful for anyone operating a diesel engine might have any of the following questions. The gauges may not provide all of the answers, but they provide very useful information.

Why do I not have as much power now as previously?
Why is my engine over heating?
All of the sudden I have a lot of blue smoke, why?
Why is my engine is black smoking?
Why is my fuel mileage lower than previously?

Would most of you agree with that? What did I leave out?

I never leave home without the 2 Ken that was the first thing I installed on my wife's little motor home

We are back home. The ECM was changed at Interstate DD in Fargo Friday. No change in the black smoke so they put the other ECM back on and said that no other work on the engine is advised. I asked about exhaust leaks or a leak between the turbo and the blower, the mechanic said he checked that the first time I was at the shop and none were found. Smoked all the way home. I guess I am done with Interstate DD. I can't help wondering if it is still the ECM since the old ECM wouldn't let the engine ever smoke. If I remember correctly the original ECM was version 111 and both of the other ones are version 154. I think the only way I am going to know if the ECM is the problem is to find a version 111 and try it. I have no idea where to fine one, but will start looking at other things in the mean time. I ordered a new air filter today and will start there. The filter minder is only showing 9 with the current air filter, but Clifford has mentioned several times not to trust them. After that I will look at the turbo even though the mechanic said the boost pressure was normal. The power seems to be the same as it was before the ECM change except there seems to be better take off from a stop now. I noticed smoke also when in cruise when more power was needed to climb small hills.
I thought the hot weather might be a factor but it was cool when we started out this morning and had black smoke right away. If I can't find a solution to the smoking problem I will start looking for a different engine. I am really unhappy with all this smoke.

Where would I look for a boost gauge and pyrometer? I had a Silver Leaf that showed boost pressure but I don't think it showed exhaust temperature. I may be wrong. I returned it because it wouldn't show road speed with the 111 version ECM I had at the time, which was the main reason I bought it. Can anyone tell me if it will tell me road speed with version 154 ECM? I would consider getting one again if it would. Then I would need to add a pyrometer.
Any further advise would be really appreciated. Thanks Sam

Sam, I am going to go out on a limb and say I bet you have a bad injector or two.  Sorry for all the trouble, It is not supposed to be like this. The new breed of mechanics don't know what to do if they can't find it on the computer or in the book (provided they can read and understand). They will tell you it can't be done.

Don

Sam, I suspect Ken will reply in a while.  However, the 111 and 154 you mention are software version and are not specific to you engine.  In addition to the software version, the ECM needs the data/tables that are specific to your engine.  Not worth trying to find an ECM with older software version, in my opinion.

A side benefit to the "new" ECM:  the VMSpc will now work ;D

Jim

Don, How do I determine if there are bad injectors? Can I do that myself or will I have to take the bus to a shop again? Or, should I just buy a set of injectors and have them installed? I used to be a pretty good mechanic with the mechanical engines, but am lost with electronics. I hate to pay over $100/hr for a shop to guess what is wrong. The 2 trips to Interstate DD last week cost over $500 and didn't accomplish anything. Your continued advise is welcome, thanks.

Jim, If I can get this engine straightened out I will give you a call about a VMSpc. I'm glad to hear it will work with the 154 version. I won't bother looking for an older ECM. Thanks for that advise.

I have a hard time with people like that why in the hell didn't he cut 1 injector out at a time and watch the smoke and eliminate  injector problems it only takes 1 bad injector and they will roll black smoke.

What was the boost pressure Sam did he say boost pressure can be ok even with a bad turbo response time is a factor with black smoke

Buying DDEC injectors are pricey almost 300 bucks each for a good rebuilt and reliable injectors

I learned that lesson the hard way I paid a e place seller 900 bucks for a so called rebuilt set in the boxes they are good paper weights lol Don has a good re builder but he is not cheap keep us posted 

I would not look for another engine DDEC's are like a mechanical engine it is all about the fuel to air ratio


good luck

J&J Injector Service in Portland, OR.  Best around.  They have plenty of cores so there is no waiting.  Speak with Darrel, the owner.

Thanks for all your help. Am I damaging the engine by continuing to drive the bus if I have bad injectors? We planned to go to a Midwest Bus Nuts rally this weekend near Dubuque, WI, 120 miles each way. Will I dilute the oil or score a cylinder by driving with a bad injector? I may be worried about nothing since the mechanic told me he wouldn't do any work on the engine because it runs so well. He told me the boost pressure was about 15 pounds the first time I was at the shop, but didn't put his computer on the engine during the second road test with the replacement ECM.

There is a Detroit Diesel shop at La Crosse, WI 10 miles from me if that is my only alternative to diagnose what the problem is. But with my recent past experience at DD in Fargo, ND I am reluctant to take it there. Will an independent shop likely have a computer for a DDEC II engine? There is a shop that is good with DD engines 80 miles away but I don't know if they have the right computer. C & J bus repair is 150 miles away and they have a good reputation. I will be making some phone calls today to see if I can get this engine fixed. The stress of this problem is adding to my already poor health situation so I hope I can find a fix soon.

Thanks, Sam

I don't think 15 lbs is enough boost. How bad and under what conditions is it black smoking? 1/4 throttle, full throttle?? Clifford is correct. They could have at least run a cylinder balance test, requires all the trouble of pushing 1 button with DDL. What I usually hear after someone has their Series 60 ECM replaced or reprogrammed at a dealer is that they don't have as much power. My contact at the Detroit Dealer says that's because the newer program has the latest emissions levels available for that engine. So I doubt if a new program will dump more fuel into your engine, it's not impossible. At this time I have no ECM programs from a 8V92, but I just called in a favor and should have my old ECM from my 475 HP 8V92 in my hands in a few days. Don't change engines yet. Give me a few days to get my old ECM and extract the program, then you can send me your ECM if you like and I can compare the tables that would cause excess fueling. In the mean time you could install a boost gauge, maybe you'll be lucky and there will be a  pipe plug between the turbo and the blower that you could remove for the boost gauge line, Clifford may know if it has a plug. Any name brand Boost gauge from ebay will work. I would get one that goes to 50 lbs. Boost pressure depends on a several factors, but you should mid 20's on a long hard pull, maybe 30 or so near sea level on really cold day. Any decent air pressure gauge will work, it would be better if it were 0 to 50 or 60 PSI. I recommend using 1/8 plastic line. I tried 1/4 in my 4104 and it made the response time of the gauge slow because of the volume required to fill the line. I notice my 88 Prevost had 1/8 from the factory. Don't worry about the EGT's yet, it's more work to install that gauge and the boost may tell you what you need to know.  I don't think there are many software levels for DDEC II. If my old ECM program looks better than what you currently have I can install the related portions of it into your ECM. I included a couple pictures of fuel maps I'm modifying for more fuel, of course the fuel maps can be modified for less fuel also. Before we change anything about your ECM program let's try and make sure all your related mechanical stuff is working correctly. What area of the country are you in?

Ken



https://www.dropbox.com/s/da2psman5zhqcve/Original%20Map.jpg (https://www.dropbox.com/s/da2psman5zhqcve/Original%20Map.jpg)

(https://photos-4.dropbox.com/thumb/AACstNKqUp8WT2Ck9xLyn_QW-mxnbhYsraV2toE6nIQA_g/76663175/jpeg/200x200/1/_/0/4/Original%20Map.jpg/da2psman5zhqcve/HGTgcBi8OJ/Original%20Map.jpg)

https://www.dropbox.com/s/q8rx6g401d7t1jc/More%20Fuel.jpg (https://www.dropbox.com/s/q8rx6g401d7t1jc/More%20Fuel.jpg)

(https://photos-3.dropbox.com/thumb/AAC8pq3onL8ZYx5gV72ajW38lOG2sBKmYWcpYVloq0AOiw/76663175/jpeg/200x200/1/_/0/4/More%20Fuel.jpg/q8rx6g401d7t1jc/D_N9Jyo0Ug/More%20Fuel.jpg)

Sam, I have heard folks talking about using an infrared gun to check exhaust manifold temperature at each cylinder.  I have not done that.  Not sure if you do it at idle, or just after a run on the bus for a few miles.

The data port of the DDEC II is different, but I would think C&J would have the adapter.  Most any diagnostic device should be able to run the cut-out test.

Jim

Sam,

Sorry about the stress my friend. I'm more than willing to come down in the next couple of days if that would help. I think Dan and JD at C&J coach would be able to find the source of your problems but I highly recommend Curt at Central truck in East Bethel as well.

Rick

A good device to run a cut out test is a called a screw driver if you remove the valve covers the ECM I don't think is his problem and Ken is right on with the boost numbers for the 8v92 DDEC the mechanical engines do fine with 15 lbs 

good luck

Luvrbus,

So you're leaning towards a failing turbo?. If that's the case he probably wants to get that off before it comes apart correct? So how can Sam troubleshoot it?

Sam, I think the best way to proceed is to take it someplace to have the injectors cut out, one by one, to see if you have a bad injector as Clifford said. If that's not the problem turn your attention to the turbo. I mean the first test must be a boost test correct? and it appears to have already failed that. Since the boost cannot be adjusted by the ECM that may be the first real sign of an issue that would cause the smoke. Worn seals etc.

Rick

Sam, we could do that in an afternoon if thats the case.

Boy-I sure like mechanical engines!

Most of the time it is a simple fix here is a example a friend has a 8v71 it was smoking bad I told he had a air problem for over a year  

People and dealers told him he needed a blower then injectors, overhaul you name it the best one was he has a N/A 8v71 and someone told him the after cooler was plugged

He did change the injectors still black smoke he was at Sonnies place guess what Sonnie found the emergency shut down had come apart and the gate was laying loose inside the housing he took it a tossed it no more smoke

Moral of the story don't get stressed be clam and do a little trouble shooting it doesn't take much to make these old 2 strokes happy DDEC or mechanical but paying 100 bucks a hour with no results will stress you Sam lol

good luck

Hi Sam , As Clifford mentioned , have you changed the  turbo boost sensor.  There is a program in the ECM that reduces the amount of fuel when accelerating. It shows up on the MPSI as smoke control. The ECM takes the throttle count and the boost pressure count and determines if the fuel should be cut back to eliminate smoke on acceleration. if your turbo is on its way out the ECM will deliver less fuel so it will still not smoke.. The turbo boost sensor has a direct affect on this calculation.  Try changing it and see what happens.     Cheers Gerry

Sam,
Don't worry about damageing your engine because of a little black smoke.  With out a throttle delay all non DD 8v92's smoke.  Some real bad, I know.  Most of the info here has been good.  I think the most important thing you can have with a turbo engine is a boost gauge.  I will give you more info than anything you can put on the engine.  Now would be the time to go back to the silver leaf.  It is showing you the same boost as the ecm is seeing.  If the boost sensor is telling the ecm you have boost and you don't it will make the engine smoke.  If you have a boost gauge and the silver leaf they should match.  Like Ken said just a 1/8 in tube. 
I would think they did a cut out test on your engine and from what the dealer told you I don't think you have a bad injector.  The 15 lbs of boost could be your problem and it could just be turbo lag.  If you can't get at least 26 lbs of boost you have a problem, but it won't damage your engine unless you let it heat up because of low power.  With low boost you won't be able to develop the power you should be getting.
Enjoy your coach until you get the boost info and quit spending money you don't need to spend.
Jack

Hi Guys,

I live in La Crescent, Minnesota (southeast corner) across the Mississippi river from La Crosse, WI. I calculated my fuel milage from Fargo, ND home and got only 4.43 MPG. That is down from a previous average of 5.96 MPG over 6732 miles prior to the ECM change and down from the 5.00 MPG since the ECM change up until Fargo. So the problem is getting worse and I won't be driving except to take it to a repair shop. I called the local DD dealer and they want $140/hr. to work on it, because it is an RV. I can get it worked on tomorrow afternoon but I think I will take a few days to think it over before making a decision on what to do.

Gerry, I have not changed the turbo boost sensor because the mechanic in Fargo said that was not the problem. If I need to change that where is it located. I don't have the book for the engine.

Rick, how much does Central Truck charge to work on a bus? I might take a chance on driving it to him if he is cheaper.

Clifford, how would I cut out 1 cylinder at a time with a screw driver? I am willing to try that if you will tell me how. I suspect that I have at least 1 bad injector. I may also have other issues. I smelled the oil on the dip stick and there is no fuel smell. The oil level is the same as it was when checked in Fargo. So I don't think fuel is diluting the oil, if that matters.

Ken, thanks for the offer to check my ECM but I really don't think that is the problem now. The black smoke happens at any throttle setting but is worst at full throttle.

Don, when in September will you be in Minnesota? I am 4 miles south of I 90 if that would be your intended route. We have a full hookup place to park in front of my shop. We will be gone on a cruise to Alaska Sept. 6-16. Otherwise we will be home.

Jack, they did not do a cut out test on my engine. I was standing right by the mechanic the entire time he was working on it. He said he could do the cut out test but didn't because he was convinced that the black smoke was normal. Unfortunately I didn't know any better at the time.

Thanks for all the advise. After a break away from the bus I will decide what I'm going to do.

Quote from: Sam 4106 on August 07, 2012, 11:39:44 AMKen, thanks for the offer to check my ECM but I really don't think that is the problem now. The black smoke happens at any throttle setting but is worst at full throttle.

Sam, I too think it's unlikely an ECM problem. Maybe low boost pressure, faulty injector or boost pressure sensor, but the sensor should have set a code, but it's not totally impossible that it wouldn't.

Ken

Sam,

C&J is $105 an hour and Curt is $75 an hour. C&J uses Curt for all their major rebuilds (heads, cranks etc.) he is an excellent mechanic and has rebuilt literally hundreds if not thousands of two strokes. Great guy, I trust him implicitly with my bus. If I'm having work done that is exclusive to a bus as opposed to a truck like the complex air system that is in our MCI's then I turn to C&J otherwise I use Curt and his staff. If you want me to meet you and follow you or if you want to come stay with us for a day you are welcome. Bring your wife along as well. I'm sorry to hear that your health issues may be ongoing still. Keep your chin up my friend and I agree that it's unlikely to damage you engine unless you start seeing engine temps rise.

We are moving closer to you in a few weeks (Prescott WI)and we'll have to do a better job of staying in touch. Call me if you need help Sam.
six one two three eight five eight three nine seven

Rick

Sorry Sam the last three digits are seven three nine seven. Typing out numbers using letters is actually kind of weird.

Rick

Sam, before you do anything, I strongly recommend, as others have, that you install a boost pressure gauge.  

As I found out when I changed engines, the ECM can be getting a signal from the electronic sensor that is not the real boost.  In my case, it was a different style sensor from the one the ECM expected to see.  Once I saw that the mechanical gauge was over 20 and the ECM was seeing about 13, it was clear to me what was happening.

I did not go back through all of the posts, but Ken mentioned that you were only getting 15 pounds boost.  If that is on flat ground maybe that is acceptable, but on a hard hill with full power, you should be into the 20s.

A boost gauge is great for warning you of turbo issues, partially clogged fuel filters, dirty air filter, etc.  If the engine does not get sufficient air and fuel, it will not build good boost.

I would check your air filter and plumbing to make sure that something is not cutting down the supply.  It is pretty easy to pull the flexible hose off of most turbos to see if there is any significant play on the shaft.  

Jim

The boost pressure sensor has a hose on it that connects to the top of the blower to get the pressure reading from the engine.  Maybe this hose is loose or cracked, or the hose fitting on boost sensor is cracked, causing the sensor to read the boost lower than it really is, and that causes the ECM to overfuel the engine causing the smoking?  It's close enough to the ECM that the hose could have been hit and damaged when they R&Red the ECM...

http://miscpartsmanuals2.tpub.com/TM-9-2320-360-20-2/TM-9-2320-360-20-20306.htm (http://miscpartsmanuals2.tpub.com/TM-9-2320-360-20-2/TM-9-2320-360-20-20306.htm)

Easy and cheap to check.....

Thanks, Steve, I saw the boost pressure sensor this morning when I was looking for a place to hook up a boost pressure gauge. Could I put a tee in the line to the boost pressure sensor for a gauge? I have an appointment at the local DD shop but I think I am going to cancel it and do more on my own before paying $140/hr at a shop. If the boost pressure sensor isn't seeing enough boost why would the ECM be over fueling the engine? Or is it that the boost pressure sensor is showing boost that isn't there? How expensive is a boost pressure sensor and would it be practical to just replace it? I don't like throwing parts at a problem to see if that fixes it, but that may be an option in this case. If I have an injector problem, as some suspect, I will have to take the bus to a shop because I don't have the tools, nor am I physically able to do the work. I will be better off taking the bus to a shop if I can tell them specifically what is wrong. Please keep the ideas coming.

Thanks, Sam

Sam:

I had some trouble with a DT466 in an IH truck.  I knew it was fuel problem or an air problem or a sensor problem.  After much time and effort spent, I finally got an infared gun and shot each exhaust port after a long pull up a hill.  I just pulled onto the shoulder as soon as I could, put on the 4 ways and rolled the hood forward.  1&6 should be close to each other in temp, 2&5 should be close and 3&4 should be close.  My number 6 was way cooler than any others.  I replaced the injector and then each pair was close to each other.  I actually replaced 1 and 6. 

Please be safe on the roadside...the way your posts are written, you read like a pretty smart guy, I am sure you will find a solution.

Josh

Sam, there are 2 plugs in the air horn (right under the turbo) to hook up a boost gauge and fwiw I have never heard anything but good about Curt not from this board but from people that have used him  

A DDEC can not read a over fueling injector it fuels according to the boost I have seen the 60 series smoking like a freight train also with a bad injector with 30 lbs of boost like Ken stated a bad sensor should flash a code


good luck

Sam, we used to troubleshoot low power DDEC engines by fooling the ECM by supplying air pressure to the turbo boost sensor. It fools the ECM into thinking it has lots of turbo boost and it will deliver more fuel, if the engine has lots of power we change the boost sensor. Lots of smoke on acceleration but it clears up as rpm picks up .

In your case it sounds like you are getting smoke all the time which would be air filter,  turbo or injectors.In the case of air filter or turbo you would experience low power. To cut out one cyl. without a MPSI reader is a pain in the @$#. you have to remove the rocker cover and disconnect the wires to that injector and then intall the cover and road test.    Cheers Gerry

Thanks, Rick for recommending Curt. I have an appointment with him at Central Truck on Monday. I spoke with him this morning and he is able and willing to work on the engine. Since his shop is about 175 miles from me he said I could stay in the bus if he has to order injector(s) so that will save me having to drive home and then back to pick up the bus. I think I will be in good hands at his shop.
I tried doing a little investigating this morning, but I injured both arms reaching into the turbo area so it just isn't feasible for me to try any further. I bleed very easily since my platelet count is so low, but the drug that causes low platelets is keeping me alive so I will continue taking it.
Thanks for all the suggestions and advise. The bus has good power and there were no codes stored when checked at Fargo. It just smokes a lot and is using more fuel than it used to. I will update after my trip to see Curt.
Thanks everyone, this group is great. Sam

Sam, I don't think it will be a boost sensor as usually when they go out they won't let the ecm fuel the engine much over 1200rpm. (it will go into limb home mode. Always an exception to everything). I will stay with a bad injector or two. BK. has offered a rebuilt DDEC II ECM if you need it at a reduced price if it turns out that is still the problem.

I will be out around your place sometime between the 10th and the 17th of Sept. That's as close as I can get right now. I will let you know as this gets closer and if you are around maybe we can get together for a glass of icetea.

Keep us posted on what Curt find to be the problem.

Thanks

Don

Hi Don,

The ECM has a 6 month warranty from Interstate DD but since they put another ECM on at Fargo and that didn't cure the smoke problem I think that the ECM is OK. Thanks for the offer BK. Very appreciated. From talking to Curt this morning I am quite confident that he will find and fix the problem, whatever it turns out to be.
We will be gone from Sept. 6 thru 16. I certainly would enjoy meeting you if you are in the area after the 16th.
Thanks, Sam

Sam,
Curt is an exceptional mechanic and an honest man. All the guys working there are top notch. Sometimes we go to big shops and they put the just-graduated hungover guy who started two weeks ago and didn't know what an impact wrench is in charge of mounting our tires. That does not happen at Central Truck, these guys are all really experienced and capable mechanics because Curt understands what's at stake with heavy equipment. He grew up on a farm working on tractors and I have actually watched him set liners, test injectors and his attention to detail is just great.

You are in good hands and I would be more than happy to come get you and spend the day with you if you don't feel like sitting in the bus all day. We are about 45 minutes away.

Good Luck Sam

RB

Hi Rick,

Curt asked me to be at his shop at 8:30 Monday morning so we will be coming up Sunday. He said we  could stay in the bus at the shop so that is the plan. We may have to stay over if he has to order injector(s) but he said he has some 6V92 engines that he can rob injectors from if they are the same. I gave him the serial and model numbers from my engine and maybe he already used that information to order injectors. I like to stay close to the bus while at the shop in the event there are questions or decisions that need to be made. If we have to stay over it would be nice to get together. I have your number and will give you a call if that can happen. We also have other bus friends in the area so if we have the chance we will visit them. One lady recently lost her husband and I'm sure she would enjoy visitors. Charlet may do some shopping on Monday since we will bring the car. If we can get together you will not have to pick us up.

On a side note, do you, or anyone else, reading this post think I will be doing further damage to the engine by driving it 175 miles to the shop?

Thanks again for recommending Curt, Sam.

What did Curt say about driving it?

Rick

Hi Rick,

The topic didn't come up in our short conversation and I didn't think to ask him. I didn't want to bother him with another phone call because I had decided to drive it to his shop anyway. Of course, Charlet wants to know, so I asked here to satisfy her. It didn't seem to bother the service writer or mechanic at Fargo because they thought the black smoke was normal. My concern then and now was/is could all that extra fuel cause me to score a cylinder or put an injector tip through a piston. It didn't happen in the 475 mile trip home so maybe that is not a valid concern. I guess I'll know when/if I get to the shop Monday.

Wish us luck. Sam

We went to Central Truck today to have Curt diagnose our smoking problem. He cut out the cylinders one at a time and didn't find any bad injectors. He did find a burned out exhaust manifold gasket so he replaced the gaskets for both manifolds. So, you guys that said to get a turbo boost gauge led me in the right direction. He removed a plug in the air horn and installed a fitting and 1/8" plastic line to the area of the rear electrical panel. I will complete the installation of the rest of the line and dash gauge when I get home. The turbo checked good. He also found an oil line to the air compressor leaking along with seeping oil from the water pump weep hole. They made a new oil line and rebuilt the water pump. Also adjusted the injectors, valves, and jake brakes. Had to replace one jake solenoid and put the wire back onto another. Since the engine was drained I elected to put in new antifreeze.

There is still a little smoke with pedal to the floor acceleration but Curt thought that might be because the Reconditioned ECM might be programed without the throttle delay that the old ECM had. We will see if my fuel milage returns to the level it was at before the ECM change.

We thought we had all the air bled out but we only made it a few miles before the low coolant sensor shut the engine down. Fortunately a man from a house near where we were on the side of the road came to our rescue. He used his Bobcat to pull the bus back to a side road to get us out of the traffic lane. That leveled the bus so I could get more antifreeze into the surge tank. That incident delayed our trip home long enough for the traffic on I35 to decrease enough so we had easy driving through the Twin Cities. We are spending the night at a casino near Red Wing, MN and will complete our trip home tomorrow baring any further problems.

Overall I would rate Central Truck A1. Curt was very diligent about checking things and let me watch and help with the little I could do. I learned a lot by watching and asking questions. Curt is a very pleasant man to be around and so were his helpers. If you need work done on your Detroit Diesel Central Truck is a good place to go. His rate is currently $80/hr, which is very fair as shop rates go in this area. I know I will return there as the need arises. Thank you RickB for recommending Curt, and thanks to all of you who responded to this thread.

Sorry for the long post, but I thought you would like to know the outcome from my trip to the shop. Thanks, Sam

Sam,

All good news. Still kind of puzzled as to what may have "fixed" your heavy smoking... For what it's worth, I think every DD smokes a bit at full throttle. I know mine does. Did Curt think that the valves or injectors were way out of adjustment and that adjusting them correctly was part of why it quit smoking so much?

Curt's a good man and I stay in touch with him enough to know that there are occasional lean times they go through. I'm always hoping that he doesn't ever experience enough lean times to go out of business. That would be a great loss indeed.

Sounds like you're back on track and that's a good thing my friend,

Rick

Sounds good. Things are looking up!

With regard to routing a line to the front for the boost gauge, I am doing the same thing in my 5C. Finding a way over the rear axle is not easy. I tried going through the tunnel with no success. I found an unused copper pipe that used to carry refrigerant for the old air conditioning. Today I will push an air line through it. I cut that copper pipe about half way into the front baggage bay so I can exit it with the air line. From there, I will go to the driver's side and up through the floor, then along the heater lines behind the couch, then through the electrical compartment to the left of the driver and under the dash. I am thinking of using hydraulic oil line from the air horn to the engine bulkhead, then plastic. I would be worried about engine heat on the plastic line.

I did that in my old Courier 96, and it works very well.

Good luck with it.

JC

Didn't chime in earlier. In feb my 8v92 blew a exhaust gasket . but symptoms were a little differant with only loss of power and fuel economy. That's why I did not say anything sooner. $16 dollar gasket and all was well. Sounds like you had a minor problem that led to fixing some other problems for you.  Sort of a blessing in the long run. sad the high dollar guy couldn't hear it from the seat? I heard mine. I was around heavy equipment all my life and can detect changes--funny I can not hear my wife sometimes.  Bob  

Rick, There was only one injector that was quite loose, the others were near spec and the valves needed minor adjustment. Curt thinks that the new ECM program is what is causing the remaining smoke because the throttle delay is different than the old ECM. I may send the ECM to Hard Headed Ken this winter to see if the throttle delay from the 111 version ECM can be put into the 154 version. It will be a while before I know if the fuel consumption returns to pre-ECM change levels. Thanks for your interest in this issue and your recommendation for Central Truck.

JC, thanks for the suggestion of using the former A/C pipe to route the boost line toward the front of the bus. If that line still goes to the former A/C compartment the rest of the way will be a piece of cake. There is an electrical conduit that runs to the front electrical panel from the A/C compartment. One way or another I will get the job done.

Bob, I wish you had suggested the possibility of a blown manifold gasket. That would have gotten me to looking in that direction. I welcome all ideas when I have problems with the bus. Hope your recovery is going well and you can return to your bus project soon.

Thanks, Sam

Sorry :;When mine blew there was no doubt. top speed dropped 7 mph and fuel mpg dropped right away. Did not fit your case problems  Will throw out there no matter how far out there it is.  Made temp road repair till I could get to place to fix and replaced that whole side.   Bob

Sam,you should have noticed a drop in power with a exhaust leak a fine 8v92 you have there if it didn't lose power with a exhaust leak most drop like a rock lol

Hi luvrbus,

The exhaust leak was probably too small to cause a big drop in power or maybe I was just not aware of it because we don't have big hills or mountains in Minnesota and North Dakota. The leak was on only one cylinder and just on the bottom of the manifold. I can see why it was missed at Fargo because the mechanic there didn't give as thorough of inspection as Curt did. I was really impressed with his attention to detail. I think I do have a good 8V92 since it has 96,000 miles since new. I am surprised I am having the problems because of the low milage, but maybe part of it is that the engine was built in 1990. I learned that from reading the information on the valve covers when they were off. I wish I had written all that information down when I had the opportunity.

Curt has a rebuilt 8V92 MTU engine in an MCI cradle if you know of anyone looking for one.

Thanks for all your help, Sam

I got the boost pressure gauge hooked up today. The test drive up the steepest hill in the area, 3rd gear (HT740), engine at 2100 RPM, 22 pounds of boost. Air temp was 70 degrees F. with no wind. The air filter minder is showing 9. I think I will install the new air filter, that came in today, and test again tomorrow. Hard headed Ken called me yesterday and advised me to be sure I don't have another mechanical issue before sending him my ECM to check the fuel maps. Is 22 pounds boost enough to rule out other mechanical issues? He also mentioned the blower bypass and I am not sure how to check that or exactly where it is located. Will someone please help on that question? I found a 1 1/2" cylinder, with a flange and two bolts holding it on top of the blower housing in front (flywheel end of engine)of the turbo horn , with a 1/2" or so hose going from the side of the cylinder to the side of the blower housing above the blower rotors. Is that the blower bypass valve? If so, can I just unbolt the flange and check its operation? It should be fairly easy to reach with the air cleaner out of the way. Are there any special cautions I need to be aware of and what should I be checking when I get the cylinder off?

I hope with these questions answered I can relax and stop worrying about the black smoke on acceleration.

Thanks gain for all the help that has already been given, you people are the best. Sam

Yep 22 lbs is enough for a 8v92 on level ground no hard pull around 8 to 10 lbs and what you are describing is the bypass valve check the hose those are supposed to be a silicone hose not regular rubber I hope you have the serviceable type by pass (has a 1/2 or 1/4 in square head in the top cap) if not it will cost you about 75 bucks

Post some photos so we can see if yours is a full bypass or a mini bypass valve ok check for wear on the plunger if signs of excess wear replace it  

good luck

Hi Clifford,

I have the bypass valve out and it doesn't have the square head on top. The top is flat with two pins on opposite sides that hold the top plug in. So, I believe I have the non serviceable type. When I talked to Ken, he described his bypass valve to be about 3" in diameter and mine is a little less than 1 1/2" in diameter so I guess I have a mini bypass valve. The plunger is smooth and doesn't appear to be worn. It seems that the plunger is normally extended by the internal spring, so I am not understanding how the valve is supposed to work. How do I tell if it needs to be replaced? I guess I could replace the O-ring and reinstall the valve and see if it has made a difference with the black smoke, but I would like to only put things back together once.

Thanks, Sam

Sam here's a link to that part of the service manual. Take a look at section 3.4.1 page 3 it explains the operation.

Clifford if the bypass valve is not working how would that affect boost pressure or would it?  I tend to think is would be higher because the pressure can't get around the blower.

I'd don't think the manual said this, but  I used a hand vacuum pump to see if vacuum would pull the plunger up.  

Is that correct Clifford?

Maybe about 2 inches in diameter.

http://www.mediafire.com/view/?qveq05rys244dj8 (http://www.mediafire.com/view/?qveq05rys244dj8)

Hi Ken,

Thanks for your phone call and your continued help. I don't know how to open the information in the link you sent since I'm not very computer literate. Could you email that page to me? If not I will try to get my wife to make the link work when she gets home. The part number on the bypass valve is 8927187 if that is helpful. I would like to post a picture, as Clifford asked, but I don't know how to take a picture or post one, sorry. The bypass valve was a little hard to remove. It seemed like maybe something was stuck. Without knowing how the valve works, I don't know for sure. With all the help I am getting I think I am getting closer to eliminating the black smoke and I am learning something about my engine. I still enjoy learning even if I will never use the new knowledge.

Thanks, Sam

Sam,
The file is too large to email. Click on the link, then in the upper left corner there should be a small green down load button, click that and another window should come up with a larger green down load button near the bottom. Click that and the file should down load to you computer. If it the asks where to save it choose desktop(the page your computer opens to when it starts). If it doesn't ask it will most likely be saved to your down loads folder. Then just go the down loaded file and click it. It's a PDF file, most any computer will open it.

Ken

Hi Ken,

My wife got the link downloaded for me and I read the page. Now I understand how the mini bypass valve works and know that there is nothing wrong with it. Do I need to clean the passage on the engine that the plunger slides in, and if so, how would I do that?  If the plunger was stuck would it likely have been in the closed, open, or partially open position? My thought is that it would have been open or partially open and allowing the blower pressure to recirculate. Therefore causing black smoke at lower RPM, I hope this solves the problem.

Thanks, Sam

I visited friends with my wife yesterday so I didn't test drive the bus. So, I took the bus for a test drive this morning, with new air filter and cleaned mini bypass valve, and still have heavy black smoke on pedal to the floor acceleration but with light pedal acceleration, only a small puff of smoke at the shifts. I still have 22 pounds of boost on the hill so I don't think the old air filter was dirty enough to cause a problem. I do think the bypass valve was stuck open or partially open. I could be wrong! Anyway, I think I will call it good enough until winter when I will ask Ken to compare fuel maps between my ECM and his '88 8V92TA DDEC II ECM. How often do I need to check the mini bypass valve, or do I just watch for black smoking again?

Thanks Ken and everyone else for guiding me through this ordeal, Sam