Good morning all,
I took the bus out for a maintenance run this weekend to celebrate finishing the new subfloor throughout the bus and installing my drivers seat. I haven't driven the bus in quite a bit (1.5 Months) but I did start it up last weekend and let it run for about 45 minutes - hour. When driving this weekend, it seemed that it was really slow taking off from stopped. It would go slow through 1st and 2nd gear, pretty much skip 3rd gear, only heard it for about 5 second if that, then gets to 4th and seems to have more speed to it and gets on up to 50 MPH.
I was looking through some of the oldest posts just for browsing and saw one where someone mentioned that a customer complained about slow take off and the intake was clogged. Could this be my issue as well or does someone might know what the issue is?
Thank you,
Jonathan
How are your fuel filters? If intake plugged, you will get a lot of black smoke from exhaust. If filters plugged, you will see much less smoke on acceleration than you are accustomed to.
Fuel delay is probably sticking from lack of use or the fuel filters
I honestly don't even look to see the amount of smoke that comes out when accelerating. Just not something that I have been looking for when I drive it. as far as fuel filter, the one in the back that you can see the fuel level is still in good condition as far as I can tell (only a small portion up the filter is covered in fuel so its pretty new still?)
You're letting it idle for 45 minutes to an hour? That's not the best for the engine. It won't get up to temperature, even at fast idle (unless something's seriously wrong with the cooling system!), with the result it can wash unburnt fuel into the oil, or worse. Incomplete combustion can also leave carbon on the rings and valves. It's best to not start a big diesel unless you plan on getting it up to full operating temperature, and that takes at least fifteen minutes of hard driving. If you need to charge batteries, buy a battery charger, but leave the engine off unless you'll be driving it. It's better to not start a diesel at all for several months instead of idling it monthly: there are some RV owners in the RV yard where I keep my bus who do that every week or two. Ouch!
John
Thank you for that information John,
I was not aware that it does more harm than good to have them idle monthly. I don't start it up to charge the batteries, when I do want to start it, I charge the batteries in advanced. Ill keep that in mind and only start the bus when I plan to drive the bus.
Quote from: jraynor on August 06, 2018, 08:10:22 AM
Thank you for that information John,
I was not aware that it does more harm than good to have them idle monthly. I don't start it up to charge the batteries, when I do want to start it, I charge the batteries in advanced. Ill keep that in mind and only start the bus when I plan to drive the bus.
Setting the "idle" at 900-1000 rpm does no harm.
Quote from: eagle19952 on August 06, 2018, 09:07:06 AM
Setting the "idle" at 900-1000 rpm does no harm.
Only hard part is that I have no Tachometer. Im looking to get one so I can watch the RPMs but I just have a large speedometer and air pressure, then small hourmeter, fuel, temp and oil gauges. I plan to add a large size tach when I can find one.
Quote from: jraynor on August 06, 2018, 09:23:17 AM
Only hard part is that I have no Tachometer. Im looking to get one so I can watch the RPMs but I just have a large speedometer and air pressure, then small hourmeter, fuel, temp and oil gauges. I plan to add a large size tach when I can find one.
about 1/4 1/3 throttle :) just not "none" :)
I know of a few people that used to start their buses monthly without driving them and their mufflers got plugged up with oil. Same symptoms as your bus when they finally drove them. It just takes a while to blow the oil out
Worse if you have a catalytic muffler.
I remember someone mentioning idling was bad a while back and meant to ask about that. Because I remember as a kid going to the Greyhound terminal and they never shut those things off...8 or 10 Detroits rumbling was so cool to me...
But now Im gathering its just idling without getting to operating temp thats harmful?
Ive been starting mine every weekend to either move it into the shop(halfway all that fits), or to mow where its been sitting, or just to air it up...
So, if I take it a few spins around the section line each time it'll be ok?
Dieing to drive it anyway, and practice shifting thay funky 4 speed...
Thanks
Well. Idling Detroit's in the old days wasn't as bad for Greyhound since they were always on the move.
Do your air box drains go to the ground, back into the engine, or to a collection tank?
Here we go again with the religious observances of false prophets...
Do you idle your car for certain purposes?
Then idle the bus for the same.
Certain purposes.
The busnut who renders the coach undriveable is statistically putting the project in great peril.
No driving means no fun, and if there's no fun, the project hits the wall, and then we never hear from 'em again.
Everything goes to hell in a sitting coach. What worked when parked, doesn't after extended sitting.
Keep driving it, and it will keep driving.
Stop, and it will exponentially add to your repair problems.
The tired old whore lost her virginity long ago. This ain't no concourse worthy vehicle due this sort of idling fanaticism.
It's leaving the air system valves sitting that will cause more grief than most others.
My only issue with idling, is that you are spending fuel money and not going anywhere...
But when there's a reason, run the engine and carry on.
Happy coaching!
Buswarrior
Quote from: OKIE9ERS on August 06, 2018, 04:40:49 PM
I remember as a kid going to the Greyhound terminal and they never shut those things off...8 or 10 Detroits rumbling was so cool to me...
Chances are those Greyhounds were running at fast idle to keep the A/C running, not at low idle. Extended low idle in a 2 cycle is a no-no, and not healthy for the engine for reasons that have been well documented.
Quote from: eagle19952 on August 06, 2018, 04:03:09 PM
about 1/4 1/3 throttle :) just not "none" :)
So leaving the bus at fast idle when I'm doing work should provide a save idle?
Trust me, I love driving the thing around. Who doesn't love driving a 18 ton beast around town just because you can. I would drive it every weekend on my runs to lowes. It has plenty of space to put everything that I could possibly buy.
If oil has possibly clogged the muffler, how much driving should clear it out? I can use this as an excuse to go drive it to town this weekend so my wife wont be annoyed at me ::)
Yes, drive the bus on errands.
How are your driving skills going to improve/maintain without regular practice?
Why would you idle the bus "while doing work"?
If your wife thinks yer fooling around... you better get her better involved in this bus adventure... many a bus project and many a relationship have suffered in this hobby...
Happy coaching!
Buswarrior
I can't see oil clogging the muffler. You will see a fair amount of blue smoke from excess idling when you take it out for a drive, until it burns off. Then it should run clean with a little black smoke on heavy acceleration. Unless engine has issues, like worn out, etc.
Quote from: buswarrior on August 07, 2018, 06:06:00 AM
Why would you idle the bus "while doing work"?
Not necessarily while doing work, Just while I've been testing some functionalities like switches, lights, motors, air leaks, etc.
I had just "tied" off my baggage door air lines so I was making sure they didn't leak
His model of MCI should have a throttle delay it is not going to jump off the line till he gets the turbo boost
Yes, go ahead. Use fast idle and forget you ever read this thread, and the others like it.
Carry on, busnut, yer fine.
Happy coaching!
Buswarrior
Quote from: jraynor on August 07, 2018, 06:55:43 AM
Not necessarily while doing work, Just while I've been testing some functionalities like switches, lights, motors, air leaks, etc.
I had just "tied" off my baggage door air lines so I was making sure they didn't leak
On the topic of wanting to drive the bus some and do work on it and my recent bathroom , shower and plumbing projects I have a thought.
Charge up your tools, etc, pack a lunch, drive the bus to the back parking lot of Lowes or Menards and get to work. I swear over that few week process I burned hours driving there and back for a $1 fitting (5 mile drive normally). Maybe this speaks to my lack of planning, but how nice would it be to go in, get parts, maybe more than ya need, then return what you don't need all in one afternoon.
Quote from: neoneddy on August 07, 2018, 11:02:19 AM
On the topic of wanting to drive the bus some and do work on it and my recent bathroom , shower and plumbing projects I have a thought.
Charge up your tools, etc, pack a lunch, drive the bus to the back parking lot of Lowes or Menards and get to work. I swear over that few week process I burned hours driving there and back for a $1 fitting (5 mile drive normally). Maybe this speaks to my lack of planning, but how nice would it be to go in, get parts, maybe more than ya need, then return what you don't need all in one afternoon.
Now that is a good idea. But I have to power my floor fan to keep the temperature bearable. Florida heat isn't a joke. But I like your thinking. I was working on finishing the wiring for my air horn that I was installing and the darn ring terminal breaks off the hot side which I didn't need to modify. Did any of my ring terminals fit, No. What do I do, I cut the ring on the new terminal, make it a C, hook it on (C isn't big enough for it to slide off) and done. 25 minute drive to Lowes for a $.50 cent terminal. Ill replace it later lol
air locks on basement doors . I used a angle bracket 1' x 2" and slid them in between the plunger and the hole that locks go in . I left the air lines intact with the leaky cylinders on just in case I wanted to lock the bays . I added a air push valve to stop the flow of air so they did not leak any more . look in the pic at the far left of the air leveling valves
dave
Quote from: chessie4905 on August 06, 2018, 07:02:42 AM
How are your fuel filters? If intake plugged, you will get a lot of black smoke from exhaust. If filters plugged, you will see much less smoke on acceleration than you are accustomed to.
So I did some snooping around the engine today. Check the air filter and it's in good shape. I need to blow it out with air but just didn't yet. As for the fuel filters, mine has a full processor with the glass view done with the filter inside. It's only about 1/3 up the filter so that shouldn't be the issue. Talking with someone today they mentioned the turbo might be slagging and to check the cool side fin for wobbliness. Checked that out with a screwdriver pushing the bolt as there is a screen over the end preventing me from doing so by hand. It seems good. No wobble from the multiple angles I attempted. I do plan to maybe stick a camera down the intake vent from the side to verify no nests are found. Other than that, I may just take it for a good stroll one day and see if she improves
Take that old war horse out and RUN IT.
Find a long hill, several miles long, one that brings it to its knees, and go back down and climb it again...
Don't come back for at least 2 hours of highway driving, longer if you're having fun.
report back.
happy coaching!
buswarrior
Did you check for smashed exhaust under neath?
I've said it before, and I'll say it again-DO NOT BLOW OUT YOUR AIR FILTER! You can cause small holes in the paper that will let dirt into the engine. Just buy a new air filter element if it is questionable-they're relatively cheap compared to an engine overhaul. Good Luck, TomC
You could install a restriction gage on your air intake at engine to monitor filter. Most have a memory and reset after checking. Make sure to get one that is rated accurate. You need to note initial reading with new filter. Some will show some restriction, even with new filter due to particular air intake system in your coach.
Quote from: chessie4905 on August 07, 2018, 06:39:35 AM
I can't see oil clogging the muffler. You will see a fair amount of blue smoke from excess idling when you take it out for a drive, until it burns off. Then it should run clean with a little black smoke on heavy acceleration. Unless engine has issues, like worn out, etc.
Like I said earlier, I have seen oil clogging up a muffler several times. But when I asked about the air box drains, my message was hijacked by someone who is now on my new "ignore" list. I have also seen where mufflers have collapsed internally and caused power problems. I've been working on Detriots since the 1970's.
If you want to check for a clogged muffler, you could install a pressure gage in pipe before muffler and note pressure with engine against governor. Under load would be better. Would need some hose and have someone read it from bedroom.
Quote from: chessie4905 on August 12, 2018, 07:02:58 PM
If you want to check for a clogged muffler, you could install a pressure gage in pipe before muffler and note pressure with engine against governor. Under load would be better. Would need some hose and have someone read it from bedroom.
LOL it is a lot easier to check for a plugged muffler with a hand held IR temperature gun
But don't use one from Harbor Freight!lol ::)
Quote from: buswarrior on August 12, 2018, 06:35:31 AM
Take that old war horse out and RUN IT.
Find a long hill, several miles long, one that brings it to its knees, and go back down and climb it again...
Don't come back for at least 2 hours of highway driving, longer if you're having fun.
report back.
happy coaching!
buswarrior
Ok everyone, I have an update from my drive today. I finally got to take the bus out today and I drove it for about 2 hours. No hills though as this is Florida not the smokies. I took it out on interstate 95 and had it running as fast as she would go. The bus got to a temperature of roughly 180. My thermostat only has ticks at 150 and 200 and it was just past middle between those two. She ran up to 75MPH and was really all it would do. As for smoke, very little if any smoke to begin with. After I got back I took her down the street and did some take offs. I get a small cloud of black smoke but only a little that you can still see through it. Wouldn't call it a cloud at all. I had one take off that was pretty quick but other than that, they were about the same. It seems to actually use all 4 gears this time which is good. It doesn't seem to skip 3rd.
As for the fuel filters, I have a fuel precessor so I can see how clogged my fuel filter is And it's less than half dirty. As for intake filter, box is clean and filter is in good shape. Tapped it with the handle end of the screwdriver lightly just to dump the lose dirt. I need to see if my model has the air flow indicator thingy that sits above the remote control box(the one with the rear start switch). I think mine has one but there's nothing connected to it?? That'll be for another day.
So what to check now? I'm wanting to look in for a tune up to see how that might help get some more power. No telling when it was last done
75 mph is about right on top end with a 6v92 and 3:73 gear,the throttle delay makes it slow on take off to prevent smoking,sounds like you have the typical CA 6v92TA engine 255 hp to 277 hp since it is running cool and not over heating as MCI intended it to do.You can bump the HP up to 350 if you want to fight the smoke and engine over heating that is your call,but it is best if left alone instead of opening a can of worms you will regret later JMO
Parlor buses in 1986 w/6V92TA ran 335HP. Now if it was a a NJ Transit bus it may have been a detuned bus @ 277 HP. You have to pull a valve cover and get the tag number off one of the injectors to see what you have.
I absolutely hate those temperature gages. Prefer something like this with more graduations.
https://www.vdo-instruments.com/instruments/by-series/singleviu/singleviu-2-1-16in-52mm-250-f-water-temperature-gauge-3341.html
You see a ton of MCI buses with 6v92TA @ 255 to 277 hp MCI didn't use high hp engines ,the standard setting on a MCI with a 8v92TA was only 365 hp in the C's ,lol bet you a quarter he has 9F70 or 9G75 injectors 8)
Most of your report sounds fine.
You knocked dust out of the air filter?
Go get a new one, it's done. As Tom YELLS, so shall I:
DON'T BLOW OUT an AIR FILTER.
If there's no smoking once she's rolling along, there's no tune up required.
1986, the 6V92 was positioned as a fuel economy choice against the 8V71. HP will be 277 from the factory.
Next project...
happy coaching!
buswarrior
Quote from: luvrbus on August 26, 2018, 04:14:18 PM
75 mph is about right on top end with a 6v92 and 3:73 gear,the throttle delay makes it slow on take off to prevent smoking,sounds like you have the typical CA 6v92TA engine 255 hp to 277 hp since it is running cool and not over heating as MCI intended it to do.You can bump the HP up to 350 if you want to fight the smoke and engine over heating that is your call,but it is best if left alone instead of opening a can of worms you will regret later JMO
How well would this bus pull hills though? If it keeps from overheating, then I'm happy. I'll take the slow start versus an overheating engine any day. I just thought I remembered the bus having a better take off than it does, but maybe not
Quote from: buswarrior on August 26, 2018, 05:31:11 PM
Most of your report sounds fine.
You knocked dust out of the air filter?
Go get a new one, it's done. As Tom YELLS, so shall I:
DON'T BLOW OUT an AIR FILTER.
If there's no smoking once she's rolling along, there's no tune up required.
1986, the 6V92 was positioned as a fuel economy choice against the 8V71. HP will be 277 from the factory.
Next project...
happy coaching!
buswarrior
Just some dirt that had gotten sucked to the filter. And that's one of my maintenance items, just not the highest priority. Oil change is the highest priority. I have the oil, now just to get the change done. Is it best to get the engine warm ( I don't like saying hot lol) then change the oil? I possibly see myself building some ramps in the near future to make doing the oil a bit easier
Quote from: jraynor on August 26, 2018, 07:45:51 PM
Just some dirt that had gotten sucked to the filter. just not the highest priority.
it should be.
Detroit's suffer less on old oil vs. a filter you can knock dirt out of...even talc dust is a horror show waiting to happen :)
Quote from: chessie4905 on August 26, 2018, 04:57:15 PM
I absolutely hate those temperature gages. Prefer something like this with more graduations.
https://www.vdo-instruments.com/instruments/by-series/singleviu/singleviu-2-1-16in-52mm-250-f-water-temperature-gauge-3341.html
Or even better resolution, less than $80, custom-made to order in USA: https://www.speedhut.com/gauge/G-WTR-01/1/Speedhut-Water-Temp-Gauge-120-260F
I think it's safe to assume that any original gauge is automatically suspect, unless it's known to be accurate. The engine temperature gauge is the single most important gauge for a 2-stroke bus.
John
Yes any of your favorite brand temperature gauge. I also dislike 90 degree 0 to 4000 rpm tachometers.
Quote from: Iceni John on August 26, 2018, 09:12:55 PM
Or even better resolution, less than $80, custom-made to order in USA: https://www.speedhut.com/gauge/G-WTR-01/1/Speedhut-Water-Temp-Gauge-120-260F
I think it's safe to assume that any original gauge is automatically suspect, unless it's known to be accurate. The engine temperature gauge is the single most important gauge for a 2-stroke bus.
John
Have you found any that offer the green color on the pointer? Be nice if it looked like the original.
The Eagle with the VDO gauges had the easiest to read gauges of any bus ,if I redo my dash I'll bite the bullet and install a Sliverleaf Glass dash since they have came way down in price
If you are saying your fuel filter is clear and 2/3 full, I think you are looking at a water separator, probably a Raycor. Your fuel filter wouldnt be clear, 1986...ummm....I think it would be a spin on type.
Quote from: opus on August 27, 2018, 09:19:40 AM
If you are saying your fuel filter is clear and 2/3 full, I think you are looking at a water separator, probably a Raycor. Your fuel filter wouldnt be clear, 1986...ummm....I think it would be a spin on type.
It says fuel processor on it. Looks like the photo below:
Ok, thats not what I was expecting. Unless you see others, that will be it for fuel filters.
That is a Davco 320
Quote from: opus on August 27, 2018, 09:35:17 AM
Ok, thats not what I was expecting. Unless you see others, that will be it for fuel filters.
Yeah I went looking for fuel filters and found this instead. Just a bonus that the bus came with it so I can see when it needs replacing. Next step would be to buy some replacement filters for it
Quote from: opus on August 27, 2018, 09:35:17 AM
Ok, thats not what I was expecting. Unless you see others, that will be it for fuel filters.
Maybe, or maybe not. I have a Racor 900FG water separator / fuel filter as the primary filter, and also a separate spin-on filter as the secondary filter after the fuel pump and DDEC cooler plate. The Racor filters to 2 microns, so I can't imagine much getting through to the other filter.
John
Just saw a 4108 with one of those "fuel processors" and it also had the two spin on fuel filters.
I'll try to trace the fuel lines when I can to see if there are any spin on or clamp style filters in the line
So yeah it's been awhile. School and work keeps me busy plus I've been working on the inside of the bus lately. Got all of the interior paneling out, insulation removed, rust cleaned and everything painted. So today I went out looking at the fuel lines. My conclusion, I only have the fuel prrocessor. Pictures are below. First shows where the lines come in and bolt to the bulkhead above the transmission, 2nd it is running to the fuel processor. 3rd is the fuel processor, last is the line to the govenor
There nothing wrong with your Davco system it works as good as the 2 filter system ,the throttle delay under the valve cover get wore out and the turbo need to spin faster to make up the air lost,so comes the slower take off lol a 5/16 th Allen wrench to remove the arm and off you go with a little more smoke of course
Quote from: luvrbus on November 14, 2018, 06:48:48 AM
There nothing wrong with your Davco system it works as good as the 2 filter system ,the throttle delay under the valve cover get wore out and the turbo need to spin faster to make up the air lost,so comes the slower take off lol a 5/16 th Allen wrench to remove the arm and off you go with a little more smoke of course
Is there an item to replace that would help the issue? I'm all for easy ways of fixing things but id rather have the bus stock versus a bunch of work arounds that can cause issues later. Like the fast idle stop arm, someone shortened this so that when the bus is on fast idle you can still press the gas and increase RPMs which is a no-no. One day ill order a new kit and replace it but for now ill just keep that in mind
You have to replace the throttle delay no rebuild parts for those a new one cost $785.00 if you can locate one and they are bitch to adjust some times,check your the nylon roller may have broken you can buy the roller
Quote from: luvrbus on November 14, 2018, 07:15:56 AM
You have to replace the throttle delay no rebuild parts for those a new one cost $785.00 if you can locate one and they are bitch to adjust some times,check your the nylon roller may have broken you can buy the roller
Ok thank you. I will add this to my list of things to work towards. I'll go dig through the DD manual I have and see what I can find about where this is located and such. What kind of seals do the valve covers have on them? Rubber or cork like? So that I can be prepared in case it rips or breaks looking into this
Valve covers use a reusable silicone gasket the 92 series you need a DD gauge to set the throttle delay too
If you need the throttle delay gauge pin tool, there are four for sale on eBay for $20 (eBay item number:271204440916).
If his problem is slow take off he needs to remove or back off the throttle delay, not set it to specs. IF that is the problem.
My vote is remove it they are nothing but trouble when they get a little wear,and you need a different gauge for different injectors ,they are a PITA for no more good than they do
If i remember,you have to plug the oil feed on the throttle delay if you want to run without it. Or if you can jam the piston all the way inside. Oil will com out from the small orifice.
So the original reason for these things was for less smoke and better MPG?
Quote from: jraynor on November 16, 2018, 05:01:06 PM
So the original reason for these things was for less smoke and better MPG?
Just less smoke on take off only when the turbo boost is up they are taken out of play by the boost pressure ,doesn't help any with fuel mileage I can tell.They are real pain on a steep grade to get the bus moving
We put one on the 4104 when we turbocharged it to cut the smoke on start out. It cut the smoke, but killed torque starting on a grade. Messed with it a lot till finally had it doing next to no delay. Especially bad in reverse with the high rear.
Quote from: luvrbus on November 16, 2018, 06:06:04 PM
Just less smoke on take off only when the turbo boost is up they are taken out of play by the boost pressure ,doesn't help any with fuel mileage I can tell.They are real pain on a steep grade to get the bus moving
Yeah mine is hard to move around the yard especially for the first time. But I think that has to do with the brakes kinda stick from sitting between moves. I mean there are times where it will get up and go from a stop, but not nearly as often. Is there potentially a pre-emptive take off from a start that allows more torque?
Also, I'm in Florida so I don't have any hills, so I don't really know what it is like going up a hill. I don't really want to find out that it crawls uphill. I'd like to fix the issue before it becomes one
The driver can be just as effective at reducing smoke, with just a little practice in right ankle modulation.
A skill you can be proud of yourself with, at every pull away.
The motivation to get good at this quickly? Clouds of black smoke attract enforcement attention, and lose you friends in your neighbourhood.
Read again... enforcement attention... the best busnut is an invisible busnut.
Flamboyant carelessness doesn't do the hobby any good...
With the throttle delay removed, then, in those couple of moments when you want everything you've got, you can get as much power as it is capable of making, smoke be damned.
The hair raising fear moments are supposed to rapidly stop, as you get more experience.
happy coaching!
buswarrior
LOL without the throttle delay it makes it nice to smoke out the Richard head fruit inspectors in CA too
and smoke out the toll booths ? oops sorry ! ;D
dave
Oh yeah, toll booths.
For the uninitiated, please idle slowly until the rear of the coach is ALL THE WAY CLEAR of that poor toll keeper...
Never you mind the following traffic, the toll keeper doesn't need that blast of exhaust.
That's showing some class, no matter what price point yer ride fits into.
Happy coaching!
Buswarrior
Yep Low Class and right now we don't need any more smoke.
You mean we're class A. Lol :)
Nope
Quote from: Dave5Cs on November 17, 2018, 03:13:04 PM
Yep Low Class and right now we don't need any more smoke.
I never smoked out a fruit fly checker but sure wanted to at Vidal Junction one time
They must know I know you because they just wave me through, LOL :)
Quote from: Dave5Cs on November 17, 2018, 07:05:15 PM
They must know I know you because they just wave me through, LOL :)
I don't have CA plates lol,last year when I was bring my tractor back from Texas I had a little dirt on the tires and trailer,the inspector told me their washer was broken and needed to go back to Parker and wash it.I looked at him for a few seconds and said man I been in CA for over 20 miles if I go back to Parker that will be over 40 miles plus the return trip and AZ is only 50 miles give me a break.Nope go wash it so I went back to Parker and across to AZ.I think CA sends the screw ups to that location for punishment and they have a attitude about it, most of the time it's not bad though if I don't cop a attitude and you knowing me that can happen 8)
And that sign on your truck that says "I am here to mess with you, I am really from Tex-ASSSSSS"., LOL
I've been trying to remember the name of the upgrade from a "throttle delay", the piston type, and a "fuel modulator" used in the MUI 92 series The throttle delay works from an idle until the oil in the cylinder is pushed out by the little piston as the rack moves to deliver more fuel. Very slow take off.
The fuel modulator allows the rack to move to 3/4 of travel until the turbo boost releases a catch that let's the rack go to full fuel with no smoke.
I have the fuel modulator on my engine and it works great. No slow take-offs
Quote from: Geoff on November 19, 2018, 09:17:01 AM
I've been trying to remember the name of the upgrade from a "throttle delay", the piston type, and a "fuel modulator" used in the MUI 92 series The throttle delay works from an idle until the oil in the cylinder is pushed out by the little piston as the rack moves to deliver more fuel. Very slow take off.
The fuel modulator allows the rack to move to 3/4 of travel until the turbo boost releases a catch that let's the rack go to full fuel with no smoke.
I have the fuel modulator on my engine and it works great. No slow take-offs
Is it possible to convert to this? I drove the bus today and I could probably live with it. It just feels like it's struggling to go like something is holding it back
You can add the fuel modulator and get rid of the throttle delay, you just need to find one. I got mine off a junk engine.
Drill out the hole to SLIGHTLY larger size. Will need Cobalt or harder bit. Use number size bit since they size by smaller increments.
First you need to find out which you have you probably have the modulator with a turbo 6v92 engine look for a hose going from the air horn on top of the blower to the rear on the right side head
In looking back on this thread...
A newbie to buses thinks his bus pulls away slowly...
Before anything other than preventive maintenance is caught up, (air filter and go for a drive) maybe another busnut that is familiar with the crappy capabilities of a 1986 102A3 with 6V92 should take it for a spin???
The ones I drove brand new were not my favorite for pulling away...
Who lives in what part of Florida to take this for a spin?
happy coaching!
buswarrior
All the EPA highway 2 strokes beginning in 1984 had one of the other type fuel control,both are a real pain the modulator type you get a exhaust leak they don't work either,lol I have pile of both types I have removed over the years and the owners have learn how to use the right foot for smoke control and love not having either type
I like my fuel modulator. With the air throttle and auto transmission I just push on the accellerator pedal and go. No worries about smoke and having to regulate my foot pressure.
The military 8v92 came with the modulator and most were never hooked up,I have 2 that are under the valve covers that have never been in service our tax dollars at work
Quote from: luvrbus on November 20, 2018, 06:46:18 AM
The military 8v92 came with the modulator and most were never hooked up,I have 2 that are under the valve covers that have never been in service our tax dollars at work
I have worked on three military 8V92TA's and none of them had either a throttle delay or fuel modulator. And two of them were governed at 3,000 rpm's. They are exempt from the EPA regulations. I wonder if all those military engines are gone now, they were selling cheap.
All four 8v92 military engines I owned had the modulators the 2 I have left does also they have never been run ,both are rear mounted turbos 2100 rpm engines 475 hp 9G90 injectors ,they have 24v alternators driven from the blower gear and huge @$# air compressors,Jakes with Williams air throttles and electric shut downs