Once again I need to call on the collected wisdom of the list.
My 8V92TA (DDEC-II) is acting up again. I am noticing a increased amount of black smoke under load, especially moving from a dead stop. Subjectively, I am suffering a loss of power as well, with low acceleration off the line. And, under load, such as pulling a 6% or so grade, temperatures are skyrocketing, and I am having to stop periodically to let the engine cool down.
Turbo boost pressure and fuel delivery rates seem normal, and the cooling system looks normal (fans spinning, coolant level OK, etc.). Someone has already suggested dragging brakes, but I have temperature sensors in the wheels and all read normal.
Yesterday I replaced the air filter, on the chance that it was restricted. No change. I also have a reader (Silverleaf VMS200) on my DDEC -- there are no codes and no abnormal readings, as far as I can tell. Fuel filters were just changed, and my primary is a Davco FuelPro 380 so I can see that it is not restricted.
I am looking for suggestions on other things to check before I take it in to the shop for professional diagnosis.
Thanks.
-Sean
http://OurOdyssey.BlogSpot.com
Any chance your muffler has broken a baffle and is blocking some of the exhaust flow?
Sean,
Couple thoughts:
Bad fuel? Does occasionally happen. In running diesel engines since 91 I have had one really bad tank and the truck acted like what you describe. (I have had several with water in the fuel very upsetting for what one pays)
ULSD I've read all sorts of things being blamed on that so of course I'll add that to the list.
Injectors gumbed up....(probably not by the way you take care of your rig)
So maybe some injector cleaner additive then run as much as you can and get new fuel.
With everything you track (boost,fuel flow temp sensors every where) that just about leaves little to blame it on.
FWiW
Skip
Hi Sean,
Huh, I ain't sure I believe that I'm giving you advice after all, it seems everytime I read your posts I learn something I did not know! But then again I guess you comprehend a learn more from reading than I do (which is cool * great), where as I learn better (or more) by hands on learning experiences! Anyway I'm gonna see if some of my experiences I had with the "hot rod Setra's" I had will help ya!
On a DDEC controlled 8V92 there should be a boost pressure sensor, if my memory serves correct looking at the engine on the right side of the blower you should find what looks like a GM MAP sensor (trust me even though it looks like one and even has GM on it, it ain't a plain ol' map sensor! LOL! Don't ask, an I won't tell! LOL).I've seen them mounted on a bracket fastened to the blower, or valve cover, & I've seen 'em just laying in the valley on top of the manifold! It'll have a plug with wires going to it and a vacuum hose. The sensors do go bad, but more than once I've found that replacing a dry rotted or melted hose was all it needed. Before fixing this, my engines had the same symptoms as yours. After fixing this the only thing I couldn't pass was a fuel pump or a set of flashing blue light! By the way a DDD is the only place I've been able to find these for replacements! About $90+/- ! FWIW! HTH!
;D BK ;D
OK, lots of good ideas so far.
I did think about the possibility of bad fuel. We just put in 260 gallons at a cheap-charlie station, and it was ULSD to boot. I'm not certain, though, that I can say the problem only started after that fuel went in. I've been noticing progressively more black smoke over a few weeks now, and we only took on the fuel a few days ago. However, I won't rule it out (but it will be a while now before we burn through the roughly 200 gallons of that fuel still left in our tank).
My muffler is a spiral-type Cowl, so I don't think is has baffles that can break off in the traditional sense, but I will look into this possibility. We crush our exhaust pipe fairly regularly, as it is a low point in our low-clearance rear quarter, and I did think to check for this on Friday -- I don't see any obvious restriction. Getting the muffler out to check, though, will be a professional shop activity anyway -- I can't manhandle the massive Cowl and attached exhaust bits by myself, and the bus should really be on a lift.
As for the TBS (Turbo Boost Sensor), Bryce, I'm looking at the boost numbers coming from the DDEC (we don't have a separate gauge), and they look normal (running from zero to around 21-22psi under load), and I would think a bad or disconnected TBS would show up as extremely low boost readings. I'll try to check it, but it's very hard to get to on our engine, shoe-horned in, as it is, to the engine compartment.
Thanks, everyone, and keep the suggestions coming!
-Sean
http://OurOdyssey.BlogSpot.com
Sean,
Might have a bad injector, dumping fuel.
If you have the blower with the bypass valve, check that small rubber hose too. It collapses internally.
The purpose of the blower bypass valve is to allow the compressed air (boost) from the turbo to "bypass" the blower rotors and go directly to the airbox ,when the volume of air coming from the turbo is greater than what the blower can handle.
I have also seen the same problem as BK has already mentioned.
Good luck.
Sammy 8)
As to the bypass blower, that's more a function of getting more efficiency. If the valve doesn't open, you'll still get just as much air, but because you're not equalizing the pressure on either side of the blower, you'll still be powering the blower which will take a few horsepower, but shouldn't create smoke. As you indicated, the turbo is showing 21psi. I would disconnect the exhaust piped before the muffler and take it for a ride. It'll be loud and since you won't be able to see the exhaust coming out of the normal pipe, have someone follow you to see if it still smokes. Usually when an injector goes, you'll get a knocking out of that cylinder. It is very unlikely that all injectors went at the same time. Also-boost senser might be it. Good Luck, TomC
Sean,
A thought crossed my mind but I'm not sure how applicable it is to your situation. If the ECU programming on your DD is anything like
what they have done to the PU deisiels. There has been many instances where:
1. The feul table has errors in it.
2. The current usage parameter sets are wrong.
3. The sensor code has a bug and isn't reacting to the sensor correctly.
4. The updated program has a bug. A lot of times the manufature will send out updates and when the shop uses the new
the client never knows.
I don't know if you have had any programming updates but with your handy reader you should be able to clear everything
back to factory default.
Just a thought.
Skip
OK,
I'm going to do the following, and see where it gets me:
1. Double-check the exhaust for any kind of restriction. Taking the muffler out will require a shop with a lift, so this will be a down-on-my-knees visual only.
2. Get the inspection cover over the turbo off, and make sure the intake has not come apart. That requires partial disassembly of my bedroom cabinetry and removal of the carpet, so I'll need to get to a place where I have some time to do it all in one shot -- can't be driving around with that stuff undone.
3. Look at the bypass valve, if I can get to it. Can someone help me to identify this? Is it attached to the blower, and what side/end of the engine is it on?
Getting any further into the motor, like taking the turbo off to see the blower, or worse, taking the blower off to see the aftercooler, is a major undertaking. If that needs to be done, I will likely take it back to Pedco, who did an in-frame on this engine 40,000 miles ago. (I'll have to sneak up on them, so they don't see me coming. My engine bay is *really* tight.)
Answering the questions that have come up: I don't think it's ECU programming, since that has not changed. Although the folks at Pacific Power did get into it, I declined to pay them the $500 they wanted for the update.
Thanks, everyone. I'll keep you posted here as to what I find.
-Sean
http://OurOdyssey.BlogSpot.com
Sean,
I'll put a bottle of Trilogy on an exhaust restriction. ;) I'm wondering if a plumbers camera could be inserted up the pipe. Hope it is something easy... like some kid stuffed something up the pipe. Good Luck.
Sean,
I really do hope it is one of the simpler suggestions.
Even simpler solution would be best.
I got to tell you paranoia is sometimes justified.....
" (they) did get into it, I declined to pay them the $500 they wanted for the update"
1. Get into it at any level is a cause for suspicion.
2. I don't know of any system that does a backup of current that can be reloaded.
Skip
I hope I'm out in my field wrong (wouldn't be the first or the last)
Quote from: Sean on July 15, 2007, 01:11:01 PM
Once again I need to call on the collected wisdom of the list.
My 8V92TA (DDEC-II) is acting up again. I am noticing a increased amount of black smoke under load, especially moving from a dead stop. Subjectively, I am suffering a loss of power as well, with low acceleration off the line. And, under load, such as pulling a 6% or so grade, temperatures are skyrocketing, and I am having to stop periodically to let the engine cool down.
Turbo boost pressure and fuel delivery rates seem normal, and the cooling system looks normal (fans spinning, coolant level OK, etc.). Someone has already suggested dragging brakes, but I have temperature sensors in the wheels and all read normal.
Yesterday I replaced the air filter, on the chance that it was restricted. No change. I also have a reader (Silverleaf VMS200) on my DDEC -- there are no codes and no abnormal readings, as far as I can tell. Fuel filters were just changed, and my primary is a Davco FuelPro 380 so I can see that it is not restricted.
I am looking for suggestions on other things to check before I take it in to the shop for professional diagnosis.
Thanks.
-Sean
http://OurOdyssey.BlogSpot.com
Hello my name is Ric I just joined so I am not sure how to put replies up but it could be your turbo I have a 92 series sitting on my shop floor with a small piece out of a piston and the piece went through the exhaust and took a good bite out of the exhaust side of the turbo. It still ran after that happened but the engine was lazy and it blew a fair bit of smoke. I am not saying your engine lost a piece of piston but it could be a faulty bearing in the turbo. I could get into other reasons but I don't have time. If you could help me figure out how to post this it would be appreciated as computers are not my thing. Hope I could help. Bye for now.
Ric, welcome to the board and you made your post perfect.
Sounds like you are a DD mechanic. Tell us a little about yourself and what part of the country you are in. Again welcome.
Richard
Quote from: bounder39 on July 18, 2007, 07:58:07 PM
Quote from: Sean on July 15, 2007, 01:11:01 PM
Once again I need to call on the collected wisdom of the list.
My 8V92TA (DDEC-II) is acting up again. I am noticing a increased amount of black smoke under load, especially moving from a dead stop. Subjectively, I am suffering a loss of power as well, with low acceleration off the line. And, under load, such as pulling a 6% or so grade, temperatures are skyrocketing, and I am having to stop periodically to let the engine cool down.
Turbo boost pressure and fuel delivery rates seem normal, and the cooling system looks normal (fans spinning, coolant level OK, etc.). Someone has already suggested dragging brakes, but I have temperature sensors in the wheels and all read normal.
Yesterday I replaced the air filter, on the chance that it was restricted. No change. I also have a reader (Silverleaf VMS200) on my DDEC -- there are no codes and no abnormal readings, as far as I can tell. Fuel filters were just changed, and my primary is a Davco FuelPro 380 so I can see that it is not restricted.
I am looking for suggestions on other things to check before I take it in to the shop for professional diagnosis.
Thanks.
-Sean
http://OurOdyssey.BlogSpot.com
Hello my name is Ric I just joined so I am not sure how to put replies up but it could be your turbo I have a 92 series sitting on my shop floor with a small piece out of a piston and the piece went through the exhaust and took a good bite out of the exhaust side of the turbo. It still ran after that happened but the engine was lazy and it blew a fair bit of smoke. I am not saying your engine lost a piece of piston but it could be a faulty bearing in the turbo. I could get into other reasons but I don't have time. If you could help me figure out how to post this it would be appreciated as computers are not my thing. Hope I could help. Bye for now.
Ok guys, here is another tidbit that may provide a clue to Sean's mystery.
I had a catalytic converter on my car break up internally and a large piece rotated and blocked some of the flow. I didn't notice any drivability issues, smoke, noise, lack of performance (big v8) until the timing cover gasket failed. I was not happy as the engine had been rebuilt less than 20k miles prior.
A wise parts store man asked me why I needed the gasket. I grumbled about a poor rebuild. But he offered if this was the only problem with the engine, look at the cat. He was right on the mark. The resulting back pressure found the weakest place to blow.
(Note to self, always buy the large, quality cat not the 'universal' catalytic converter)
Long story but if Sean's exhaust had been smashed several times, over time, could the resulting back pressure have caused a gasket or something else to weaken producing the symptoms he currently has.
So my question to the brains here is: If the exhaust had such a restriction, what would that cause to fail? Fouled injectors? Rings?
Another long shot.
Hobie,
That's an interesting theory.
We've crushed the exhaust, to a significant restriction, only twice.
Once was before the in-frame, and it was repaired before the in-frame was finished.
The second time was crossing the Big Puddle (http://ourodyssey.blogspot.com/2007/02/big-puddle.html (http://ourodyssey.blogspot.com/2007/02/big-puddle.html)) earlier this year. We knew about that right away, and thus drove very gingerly to All Coach to have the exhaust fixed before we put any heavy loads on the engine. I guess it's possible we did some damage then, but I don't think we've seen symptoms until this past month or so.
Incidentally, I replaced the secondary fuel filter yesterday -- no change.
Does anyone know if a Davco FuelPro 380 can be "plugged" without the bowl filling most of the way?
-Sean
http://OurOdyssey.BlogSpot.com
Quote from: Hobie
Long story but if Sean's exhaust had been smashed several times, over time, could the resulting back pressure have caused a gasket or something else to weaken producing the symptoms he currently has.
So my question to the brains here is: If the exhaust had such a restriction, what would that cause to fail? Fouled injectors? Rings?
Another long shot.
And very possibly a good one! As to what I'm as clueless as the rest of the group!
Quote from: Sean
Incidentally, I replaced the secondary fuel filter yesterday -- no change.
Does anyone know if a Davco FuelPro 380 can be "plugged" without the bowl filling most of the way?
-Sean
Sean I'm not an expert on them, but I don't see how it really could as they are designed to fill up past the blockages. So if it was blocked I would think it'd fill all the way up! But stranger thinks have happened and maybe one of our more experienced members knows more about them than I do! FWIW!
;D BK ;D
As I promised, I am posting an update here on our problems with low power, excess heat, and black smoke.
Today we visited W. W. Williams in North Las Vegas. Unsurprisingly, they are now down to only two technicians qualified on two-stroke products. We got Hank, who seems to really know his stuff. While I was standing around, the maintenance supervisor for Clark County Fire came over to chat with me about the coach (he was there to pick up a fire apparatus), and had good things to say about Hank's familiarity with 8V92's (which were very popular in fire apparatus prior to Series 60).
Hank could find nothing wrong with our coach, except for a dirty radiator. I have to confess to some embarrassment about not having noticed this myself (and no one here mentioned it either), and the price I paid for that gaff was to pay Williams over a C-note per hour to pressure-wash the radiator, which I could have done myself for free. And, while that may have accounted for some of the temperature issues, I don't think it fully explains the low power or excessive smoke.
Hank also tried disabling injectors one by one to see if the smoke changed at all, but it did not. Otherwise, his assessment was that the engine was mechanically sound. He did not feel there could be a turbo problem with the boost readings we had, nor did he think it could be the bypass valve without other symptoms.
I did have them pull an oil sample for analysis, which should come back tomorrow or maybe Thursday. That will, at least, tell me if I've sucked any dirt into the engine.
With no further diagnostics to run, they buttoned us back up and we escaped for less than $300. I feel a little better about continuing to drive it in this condition, but I don't think we've solved the problem. Before I spend any more money in the shop, though, I am going to try to burn through the last 170 gallons of this batch of fuel, and see if things improve after taking on a fresh load. It's possible that the fuel I've got now has the wrong cetane number, or some other non-obvious deficiency.
I'll post more if I learn anything from the oil sample, or if we get any closer to solving this.
-Sean
http://OurOdyssey.BlogSpot.com
Sean
I was wondering if the stuff they sell at Wal Mart called diesel kleen could help you. it is suppose to increase the cetane up to 6. it also reduces exhaust emissions.
Pete & Jean
Fantasy
Hey Sean,
If you're going to Vagas, you may want to try a garage in Parumph (sp ).
It's something like Paulson. I had some work done there a few years ago when I was passing thru and I thought they were great.
By the way the owner has converted a real nice Eagle.
He's a nice guy and is good with 2 strokes.
Hope this helps you
Frank
Make sure you're using the new ULSD. I was in Las Vegas last Dec and filled with normal sulfur Diesel with my Mercedes-Benz. Talk about smoke! After a couple of tanks of ULSD, it was back to its' normal amount of smoking. Good Luck, TomC
Tom, why would the amount of sulphur affect the amount of smoke?
Good question-actually, I don't know why, but I know at least it was a smokey tank of fuel I got there in Las Vegas. The car ran fine, just alot more black smoke. Maybe it was industrial Diesel rather than on road. Good Luck, TomC
I don't know ... 8v92 should love lots of sulfur. When we were down in Mexico my 8v92 just loved it ... yes it smoke more on take off but at running speed it didn't smoke. Maybe Mercedes has issues with high sulfur
Ron
And the answer is (drum roll, please): The engine is dirted out, for the second time in less than 100,000 miles.
More detail is on our blog at this post:
http://ourodyssey.blogspot.com/2007/07/good-bad-and-ugly.html (http://ourodyssey.blogspot.com/2007/07/good-bad-and-ugly.html)
(Read the sections labeled "The Bad" and "The Ugly").
The short story is that the oil sample came back, and it looks like we have dirt in the engine, as I was beginning to suspect. Our oil consumption has gone up, and the low power/white smoke on start/black smoke on load is consistent with blow-by past the rings.
We'll need eight new cylinder kits, a turbo, rod bearings, and any number of miscellaneous parts. I am guessing around $10,000 to get us back on the road.
We'll be going either to Stewart & Stevenson in Pueblo, if we can even make it that far, or back to Pedco, who in-framed our engine the last time it was dirted out.
I won't know until they start tearing into it where the problem occurred -- either something wore a hole in the intake, or the intake plumbing just came apart somehow. If you are curious, I will be posting follow-ups on our blog (not here).
-Sean
http://OurOdyssey.BlogSpot.com
Sean,
Bummer of an expense and it sounds like its not too good for your schedule either.
An idea for "next" time, and something I have been consdering myself is a by pass oil filter that will filter that kind of dirt out of the oil should your air filter or intake fail as yours must have. Seems like some relatively cheap insurance.
Two years ago I had 125 ppm silicon in my oil, but no other wear metals. I change oil fairly often, but since I frequently go to the desert with bolwing sands, its not diffiuclt for sand to get in there. I have been losing some power lately although I have also been adding weight.
Jim,
You can filter the dirt out of the oil, but if it is getting past the air filter, the damage to turbo, blowers, liners, and rings is already being done. FWIW.
-Sean
(Who is on his third glass of Merlot, as a palliative.)
http://OurOdyssey.BlogSpot.com
Sean,
Such very bad news. Really, a bummer.
How could you have known that this was happening to your engine? I agree that finding sand in your oil would indicate dirt getting in there but not neccessarily via the intake. Oil analysis would have started a search even if it was a late one you would have been in the hunt maybe before terminal damage. Is there a sampling device, like fly paper or somthing, that would retain any dirt getting past the filter and intake couplings for evaluation?
Didn't the mech say your blower and general mechanical condition was "good"? How does that figure with blown rings and a worn blower?
Is there no way to set up a 5 gallon gas can of good fuel and rig it into the engine fuel system for a short test run? I did that with a gas powered rv to get it to a shop when the rust in the tanks overcame the fuel switching valve and the lines. used an electric pump to get the gas to the carb. It sat on the floor next to me and I am glad I didn't have a wreck and have a jerry can bouncing around. The things I have done in the name of science. Only save a few hundred dollars.
I hope you qare wrong about the overhaul and things come together for you in a cheaper fashion.
Best of luck
John
Sean - as I intimated at BNO - I think you got screwed by someone - no way this could happen in such a short period with your documented usage - somebody screwed up here - Whatever you do and whoever you take it to DON'T let this happen again - make them test and "certify" ALL the entire intake system this time - there is NO WAY I would have anticipated this outcome from your detailed descriptioms of prior maintenance and repairs - It sounds like incompetent service - Just plain STUPID - What the heck did you pay for? FWIW
(Cross-posted:)
Well, Niles, the last folks to even touch the intake system (other than filter changes, which I do myself) was Pedco. That was during the last in-frame.
When I talked with Pedco owner Virgil Cooley this evening to ask how this could have happened after his crew took pains to put it on correctly, he suggested that (1) something as simple as a braided hose might have fallen against the intake plumbing and abraded through it or (2) off-road driving (of which we have done some, but not much) might have worked a clamp loose, causing the intake to come apart.
The problem is that the whole intake system, other than the air cleaner housing, is buried in a very tight engine bay -- it's impossible to even see it without dismantling part of the bedroom and removing an access panel. Until we get in there, we won't know how it came apart.
If I take the coach back to Pedco to have the new work done, I would hope that Virgil will step up to the plate to cover at least part of it, if it looks at all like the problem was related to workmanship issues on the last rebuild. But, as you know, that can be very hard to determine.
If the intake hose is just loose, with the clamp dangling, is it because the mechanic that installed it didn't tighten the clamp properly, or is it because the air cleaner bounced around in its mount when I plowed through "the big puddle"? It will likely be impossible to say.
In any case, it's a good bet that if I don't take it back to Pedco, there won't be any possibility for any credit, so that's one factor weighing in favor of going back there. OTOH, if I felt certain that this was a screw-up on their part, then I would be foolish to want to go back there to have them do it again.
Anyone else here feel the same way Niles does?
-Sean
http://OurOdyssey.BlogSpot.com
Although devastating and frustrating, I think after this amount of time and miles it falls more under an on going maintanence issue. Or just the luck of the draw with the way its configured. Pending more information when you get it apart.
If it happened within several or even 9 months, I might be pointing my finger more.
Pedco has such a great reputation, I would not hesitate to take it back. I also suspect that if Virgil thinks he contributed in any way that he will cut you a deal.
I'd put that by pass filter on anyway. I have to believe that the dirt cycling through over 1,000's of miles is much worse than if it got filtered out in the first 50. You're right, the dirt would do some damage as it went through, but it still seems like its cheap insurance. ( said by a man that does not have one -yet)
Woo ... I can't believe this happen again Sean. Is there no way to redesign the intake (relocate the airfilter) so you can see the plumbing from the filter to the turbo? Sounds like a design flaw. Hop all works out for you.
Ron
Well, Considering the Damege you did to the tail pipe on the "Off Road" jaunt. and the "Tight" space you say its in, Id guess it wouldnt take much "Off Raod" bounceing around to knock something Loose.
Bummer though. But I hope it wont be as bad as they Quoted..
Paul..