| Author | Message | ||
| Thomas Miller (Rmos50)
Registered Member Username: Rmos50 Post Number: 1 Registered: 6-2009 Posted From: 71.96.133.245 Rating: |
I have a 81 eagle with 6v92 and smokes. I have had the turbo rebuilt, drained fuel tanks, changed fuel filters twice and air filter. It doesn't smoke until its under a load, take off or uphill, once up to speed it clears up. I know its an air fuel problem but don't know what to do next. This bus has not been used regularly for 13 years, the guy I bought it from said he drove it 16 miles to town and back every two weeks. WHO KNOWS! He had it 3 of those 13 years. I drove it 450 miles when I bought it and had a black tornado following. I found the turbo had broken bands and the exhaust side turban was wore down so I had it rebuilt. Then I drained all the fuel (it was black) and cleaned the tanks and refilled, changed filters and added Lucas injector cleaner. Still have the tornado. I do air conditioning and this is beyond me. | ||
| Mark Karlsson (Flying_fishbowl)
Registered Member Username: Flying_fishbowl Post Number: 24 Registered: 2-2006 Posted From: 76.103.164.73 Rating: N/A |
Thomas: My guess would be you have a restriction upstream of your air filter or a plugged muffler. I would try to tap a vacuum gauge into the inlet duct to the turbo and see if you're pulling a strong vacuum under load. Or try disconnecting the air cleaner temporarily and drive it and see if the smoke goes away. Just make sure you don't have any rags or anything in the engine compartment that could get sucked into the turbo! I usually check exhaust back-pressure by drilling an 1/8-inch hole into the turbo exhaust pipe and stick an 1/8-inch piece of copper tubing into it, then shove some small vacuum hose onto it to run inside the coach and hook to a low pressure gauge. I hope this helps. Any other questions, you call email or call me at 707-258-2804, Pacific time. Mark Karlsson | ||
| Luvrbus (Luvrbus)
Registered Member Username: Luvrbus Post Number: 722 Registered: 8-2006 Posted From: 74.33.54.207 Rating: N/A |
Does your model 10 have the intake at sides or a snorkel on the cap. It could be several things so I would start with the air intake, then check the air box pressure. Then check the bypass valve if you have one.A friend had the same problem with his 10 and we found the aftercooler was pluged good luck | ||
| Thomas Miller (Rmos50)
Registered Member Username: Rmos50 Post Number: 2 Registered: 6-2009 Posted From: 71.96.133.245 Rating: N/A |
Tried it with the turbo intake hose off and same smoke. Where is the bypass valve? | ||
| Luvrbus (Luvrbus)
Registered Member Username: Luvrbus Post Number: 723 Registered: 8-2006 Posted From: 74.33.54.207 Rating: N/A |
Thomas,it is at the back of the blower with a 1/4 inch rubber hose.Can you post the model number of your turbo along with a/r number it may have too big of turbo.It would also help if we new the injectors you are using.Don Fairchild on this board can help you if you can post a little more info. good luck | ||
| Thomas Miller (Rmos50)
Registered Member Username: Rmos50 Post Number: 3 Registered: 6-2009 Posted From: 71.96.133.245 Rating: N/A |
The turbo is a Garrett 75 intake and 96 exhaust side. The motor has 77k miles on out of frame by Greyhound and I have no idea on the injectors used. There is a small black hose going to the top of the blower case, there is another hose about 3/8-1/2" going to a round object a little bigger than a silver dollar and about 2" tall beside the blower. What am I checking on this valve? and how? | ||
| Thomas Miller (Rmos50)
Registered Member Username: Rmos50 Post Number: 4 Registered: 6-2009 Posted From: 71.96.133.245 Rating: N/A |
Just took all the intake apart, screen is clear and of course, will be replaced. I'll tackle the exhaust tomorrow. Lots of rusty bolts there. The blower had a small black hose on top and one on the bottom. I don't mean to be stupid but, where are the injectors? They are not where I assumed they would be, on top between the intake and head. | ||
| Luvrbus (Luvrbus)
Registered Member Username: Luvrbus Post Number: 724 Registered: 8-2006 Posted From: 74.33.54.207 Rating: N/A |
Thomas, to check the valve remove the 2- 3/8 bolts holding the valve at the bottom then remove the valve. Check the slide on the inside of the valve it should slide from bottom to the top by pushing from the bottom.The injectors are located under valve covers on the the heads but you should have a build tag on the valve covers with all the information about the engine. (Message edited by luvrbus on July 04, 2009) | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 897 Registered: 8-2006 Posted From: 64.55.111.6 Rating: N/A |
Tom, Black smoke is caused by either a lack of air, or injector(s) not properly atomizing fuel. Turbos are driven entirely by exhaust gas. So, why don't we have enough air into the engine to properly burn the fuel? Problems could be as indicated above, bypass valve stuck closed, or the intercooler plugged. I don't feel the turbo is oversized, as the symptoms of that would be black smoke when you stepped on the throttle, which would clear up at full throttle and load. At this point, having checked the air cleaner, and the intake system in front of the turbo, look for leaks in both the exhaust piping, and the pressure side of the turbo, between the turbo and the engine. A bad exhaust manifold gasket, cracked manifold, or other exhust leaks, will let enough exhaust gas out before the turbo, to affect its drive, and consequently, output. The muffler and exhaust piping must also be completely open, and un-restricted to allow full exhaust gas flow. A burned TURBINE wheel indicates too much high temperature exhaust having gone through it, which is caused by too large injectors, improper timing, or a failed injector. The hot wheel is called the impeller, the cool side is the compressor. Last thing to look at is the injectors. An injector which is just squirting fuel into the cylinder, instead of atomizing it, will cause your problem. Detroits are different from the 4 cycles, each injector, known as a Mechanical Unit Injector is a complete unit, driven off its own cam lobe, between the exhaust valve lobes, with supply and return jumpers to rails. HTH, George | ||
| larry currier (Larryc)
Registered Member Username: Larryc Post Number: 244 Registered: 2-2007 Posted From: 64.12.116.203 Rating: N/A |
Whats the water temp? Since it cleans up once up to speed its acting like a truck engine with some get'er done injectors in it. Hows the power? Back in 81 some black smoke was just a trade off for HP. Now days everything gets small injectors and they run real clean. In 81, drivers would back out of the throttle pedal enough to make the smoke reduce, now they don't give the driver that option any longer, but you can spend a lot longer on the mountain. If you could put a boost gauge on it you would know for sure it is running right. Its possible you are low, but since it cleans up once your rolling makes me think it is just set up to pull. If its running cold its going to smoke. If its spent alot of time sitting and been idleing alot it may need to be blown out real well, that takes some miles against the governor with the water temps at 180. A few of us would kill for some big fat injectors, but its gonna smoke if thats whats going on. Its going to take some miles to get the oil and water up to running temperature, so be sure you aren't judging your situation to soon. | ||
| Mark Renner (Boomer)
Registered Member Username: Boomer Post Number: 170 Registered: 11-2006 Posted From: 206.58.200.38  Rating: N/A |
Could have a blown injector tip. That would explain constant black smoke. However, it also produces misfiring and rough running. Is that the case? If you had contaminated fuel, and water reached the injectors, it can and will blow a tip. Good luck | ||
| ned sanders (Uncle_ned)
Registered Member Username: Uncle_ned Post Number: 62 Registered: 5-2005 Posted From: 74.235.102.171 Rating: N/A |
I agree with Larry C. Sounds like someone has hopped up your 92. If it clears up on the road except under full throttle it has big injectors. The sign of this is the bigger turbo. a few words from another smoker. HP means smoke in a old 2 stroke. As long as it runs clean and does not over heat let it run. Place a guage in your intake and see if you are pulling to much vacume. uncle ned | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1555 Registered: 10-2003 Posted From: 71.58.110.9  Rating: N/A |
Does it run good otherwise? Yeah, I know, you don't have anything to compare it to. You could pull a valve cover and report back on the number on the injectors. If there is a problem, low air box pressure because the bypass on the blower is stuck open, bad blower, restriction orfice on return fuel line is too small or restricted. Checking air box pressure over the rpm range and fuel pressure from idle to governed speed would help in getting a correct diagnosis. This is a mechanical engine and not an electronic one? Could be that the fuel modulator on the rack was completely backed off. Does it start and idle smooth and not smoke after warmed up? | ||
| Thomas Miller (Rmos50)
Registered Member Username: Rmos50 Post Number: 5 Registered: 6-2009 Posted From: 71.96.133.245 Rating: N/A |
Just got back in town, lots of good information, thanks. This thing smokes on take off and under a load ie uphill, it starts and idles great. as I stated earlier, I drove it 450 miles home and had half of Texas honking at me due to smoke, so this is not a little smoke, my wife followed in the car and she thought it was on fire at times. It has no power on hills and running 60-65 it will slow down to 40-45 on a small grade, I had a 8v71 prior and it would run circles around this one. I am checking the exhaust and will get the injector information off the head if I can find it. Does anyone have a picture of this valve I'm checking? Again thanks so much for all your help. | ||
| Thomas Miller (Rmos50)
Registered Member Username: Rmos50 Post Number: 6 Registered: 6-2009 Posted From: 71.96.133.245 Rating: N/A |
also, it does have a boost gauge on the dash and it didnt move on the trip home so I don't think it works, haven't tried it since having the turbo rebuilt. | ||
| Thomas Miller (Rmos50)
Registered Member Username: Rmos50 Post Number: 7 Registered: 6-2009 Posted From: 71.96.133.245 Rating: N/A |
sorry for all the also's, but you guys are requiring alot of info, the turbine wasn't burnt, the bands had broke and the body shifted causing the impeller to rub and wear down. hope all this helps. | ||
| Luvrbus (Luvrbus)
Registered Member Username: Luvrbus Post Number: 725 Registered: 8-2006 Posted From: 74.33.54.207 Rating: N/A |
Thomas, you have a air problem check for leaks on the exhaust system going to the turbo manifold, gaskets and piping a sticking bypass valve will cause black smoke on start up till the turbo spools up to speed.Check all of the air box covers below the head on the block for leaks or one missing,check the turbo for free spinning even rebuilt turbos sometimes are bad,disconnet your muffler and try that.take soap and water and check the gasket at the bottom of the blower.Any low pressure gauge can be used to check the boost pressure you should have 15# and above if you have that going into the engine and the rest checks out then it will probably be the after cooler under the blower.The numbers on your turbo sound about right for 300hp 6v92 turbo and what you are describing with hose and size is the bypass valve. good luck (Message edited by luvrbus on July 06, 2009) | ||
| Buswarrior (Buswarrior)
Registered Member Username: Buswarrior Post Number: 1648 Registered: 12-2000 Posted From: 76.68.134.58  Rating: N/A |
Power gone south and lots of smoke? My first target is always the pressure side of the intake. You aren't getting the right air into the engine. Hose clamp broken or stripped? It'll blow the pressure right by a snug fitting hose, giving you what you have. The pick-up for the boost gauge disconnected and open? Something rub a hole in a metal pipe out of sight? I am lazy and hate opening up things until I absolutely have to. happy coaching! buswarrior | ||
| Jack Campbell (Blue_goose)
Registered Member Username: Blue_goose Post Number: 130 Registered: 5-2007 Posted From: 71.100.201.35  Rating: N/A |
also, it does have a boost gauge on the dash and it didnt move on the trip home so I don't think it works, haven't tried it since having the turbo rebuilt. You need to get this gauge working and then you will find the problem. Jack | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1556 Registered: 10-2003 Posted From: 71.58.110.9 Rating: N/A |
Don't assume that the gage isn't working. The symtoms you describe, basically no boost, would cause your problem. You need to find the end of the boost gage line, assuming it is mechanical and apply a little air pressure to it. Don't use an unregulated air supply, you would ruin the gage. Good chance that it works fine and the problem is in the new turbo not able to spin or restricted intercooler, where those small particles of the impeller went, if it was the intake side impeller that wore down. If it was the exhaust side plugging up the muffler, I don't think the pieces would have been enough to restrict the exhaust enough to cause the intensity of your problem. The intercooler has small passages like a radiator's fins, and could get plugged by that debris enough to cause your problem. I would think that they checked that when the turbo was replaced, but who knows.... | ||
| Thomas Miller (Rmos50)
Registered Member Username: Rmos50 Post Number: 8 Registered: 6-2009 Posted From: 71.96.133.245 Rating: N/A |
I found the hose going to the boost gauge, wow first try, I blew into it and it moved on the dash and put into a vacuum and it went the other way. I blew on it pretty hard and it only moved 2 notches, along way fron 15, not even 5. I disconnected the exhaust at the turbine and am now waiting on the new gasket for the screen housing so I can try it. The new turbine is all blacked up as well as the inside of the exhaust pipe, I expected black but not this heavy soot buildup. Can not find any tags or markings on the head stating injectors size. The rebuild tag is on the block and states the date of rebuild and mechanic as well as some numbers I don't know about. ENGINE # D6VF069119C, ID STD, OD STD, MN BRG 010, ROD BRG 010. | ||
| Thomas Miller (Rmos50)
Registered Member Username: Rmos50 Post Number: 9 Registered: 6-2009 Posted From: 71.96.133.245 Rating: N/A |
Pulled the bypass valve and it does move in and out with a spring action pushing it out. | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 900 Registered: 8-2006 Posted From: 76.171.79.185 Rating: N/A |
Tom, It sounds like your turbo gauge is working properly, and you aren't getting any boost! (It looks that way too!) 6 or 7 psi is all that most of us can blow. I think the ID tag means new liners and pistons, with a crank that has both the main and connecting rod bearing journals turned ten thousandths under. Any black trails around the exhaust manifolds or pipes? As BW says, look for pressure (clean) leaks also. From the amount of soot buildup, I'd be surprised if the turbo can turn at all... G | ||
| Larry Higuera (Larryh)
Registered Member Username: Larryh Post Number: 41 Registered: 6-2006 Posted From: 148.78.52.146 Rating: N/A |
Tom, I'm going to step out of the normal here as you do have a non normal problem. I had another shop bring me a truck having your same problem and heres what I found. Someone had replace the EXHAUST pipe and it was a double wall pipe and the inner pipe had collapsed inside and outside pipe looked fine. Dropped exhaust pipe and ran clean. Only way to see this was physically removing and and cleaning it inside and was able to see the restriction in the first bend of pipe. Only one ever seen in a 5 inch exhaust pipe and your engine will run cooler also. LarryH | ||
| Buswarrior (Buswarrior)
Registered Member Username: Buswarrior Post Number: 1649 Registered: 12-2000 Posted From: 76.69.142.155 Rating: N/A |
The soot is expected, all that smoke you were blowing passed through there. Does the turbo spin freely? To conduct the exhaust obstruction test, just loosen off and crack open the easiest to work on joint downstream of the turbo. That may be the one right at the turbo. Just separate the pipes a bit, you don't have to remove or otherwise yank them out, just get them cracked by somewhere 1/2 inch or more. If you are plugged, that'll provide more than enough difference to prove it. Turbo on that bolted to the top of the blower? Lots fewer places to leak pressure. As noted earlier, check all the access covers down the sides of the engine, it takes very little to let the pressure escape. happy coaching! buswarrior | ||
| Don Fairchild (Don_fairchild)
Registered Member Username: Don_fairchild Post Number: 28 Registered: 3-2007 Posted From: 66.17.9.74 Rating: N/A |
Tom; After you check with intake and exhaust off of the turbo and it still smokes, you need to pull the valve covers, put some rags over the top of the rockers start the engine and run each injector in to full fuel one at a time. Do this by holding the rack with one hand and pushing the injector fuel rod in wit the other. Do this to every injector and if you have a blown tip it will show up, if you don't find a bad injector then I agree with luvrbus you have a plugged after cooler. Don | ||
| Ralph Peters (Ralph7)
Registered Member Username: Ralph7 Post Number: 27 Registered: 3-2004 Posted From: 206.251.14.87 Rating: N/A |
On DD series 60 if you have a hole 1/8 in. or some pin holes in a air/ after cooler, results in low to no power. Same for the connector hoses. Any leak down stream of turbo is a very big deal. | ||
| Van (Van)
Registered Member Username: Van Post Number: 100 Registered: 7-2008 Posted From: 68.108.81.25  Rating: N/A |
Thomas,same similar problems when we brought the 89 home no boost ,and pletty of choo choo smoke check that connector hose .The burnt side was hidden from view under the clamp [IMG]http://i457.photobucket.com/albums/qq292/cwvanhagen/cedarrapidstrip08097.jpg[/IMG]sorry i'll try again (Message edited by van on July 07, 2009) (Message edited by van on July 07, 2009) | ||
| Van (Van)
Registered Member Username: Van Post Number: 101 Registered: 7-2008 Posted From: 68.108.81.25 Rating: N/A |
[IMG]http://i457.photobucket.com/albums/qq292/cwvanhagen/cedarrapidstrip08097.jpg[/IMG] | ||
| larry currier (Larryc)
Registered Member Username: Larryc Post Number: 245 Registered: 2-2007 Posted From: 64.12.116.203 Rating: N/A |
Thomas, If you are loosing your boost somewhere, the turbo will spool right up and start screaming at you. If its not then it will be pretty quiet, you can hold the RPM's around 1500. If there is any restriction in the exhaust, it won't spool up. If you lost an injector, it should be missing, does it vibrate sitting there at an idle? Sometimes if you loose an injector, the raw fuel will track its way out and you will see its wet under the exhaust port that has the problem. | ||
| Keith Wood (Ft6)
Registered Member Username: Ft6 Post Number: 124 Registered: 8-2008 Posted From: 75.209.114.218 Rating: N/A |
How about if it has only a little smoke at idle (after startup, building air), then thick dark grey smoke under load for the first half mile, then clear after that (even under load)? | ||
| Larry Higuera (Larryh)
Registered Member Username: Larryh Post Number: 43 Registered: 6-2006 Posted From: 148.78.52.145 Rating: N/A |
Keith That is all common to a diesel engine but you can inspect air filter with a light inside and see if you can see light on outside of filter. element removed from cannister Larry | ||
| Thomas Miller (Rmos50)
Registered Member Username: Rmos50 Post Number: 10 Registered: 6-2009 Posted From: 71.96.133.245 Rating: N/A |
I replaced the gasket/screen on the intake and disconnected the exhaust at the first joint past the exhaust turbine of the turbo. The boost gauge does work and goes a little past the 5 mark (nothing prior). I can only get up to 45 mph on this short road but this is more power than its had before. The black tornado is still there so I will pull the covers and attempt the injector check or the after cooler blockage??? You said push the injector rod in to full fuel and if its bad it will show up, how will I know? also, how do you check for a blocked aftercooler? I checked the water temp and it was around 180, and no, it does not smoke sitting at idle, just on takeoff and acceleration to reach speed limit and climbing hills. | ||
| Larry & Lynne Dixon (Larry_d)
Registered Member Username: Larry_d Post Number: 217 Registered: 7-2005 Posted From: 71.111.185.149  Rating: N/A |
Tom The 8v71 in my 4905 has about 25K on out of frame rebuild, was told by past owner the injectors were large. Don't know number. The engine smokes black on take off and hills if you put your foot to it. I can regulate the black smoke with the amount of throttle, which on hills backing off until no smoke will keep engine cooler. Just thot this mite help. | ||
| JC Alacoque (Jc_alacoque)
Registered Member Username: Jc_alacoque Post Number: 82 Registered: 7-2006 Posted From: 72.45.68.242 Rating: N/A |
I recently had to pressure test my charge air plumbing. I duct taped a tin can over each end of the pipes. I drilled a hole in the bottom of one of the cans and threaded a Schrader valve in it. Spray soapy water on the aftercooler, and pump air pressure through the valve. It doesn't take much to make bubbles if you have a hole. A bad injector will smoke at full fuel on your test if you try them one at a time. Keep us posted. JC | ||
| Bill Gerrie (Bill_gerrie)
Registered Member Username: Bill_gerrie Post Number: 281 Registered: 3-2006 Posted From: 216.198.139.38 Rating: N/A |
Tom Everything you describe indicates large injectors. The aftercooler can only be checked by removing the turbo and the blower. It is located directly under the blower. If it was blocked the engine would smoke all the time not just on acceleration or pulling. Check the numbers on the injectors and you should find something like 7G75 or 9B80. | ||
| Luvrbus (Luvrbus)
Registered Member Username: Luvrbus Post Number: 735 Registered: 8-2006 Posted From: 74.33.54.207 Rating: N/A |
Tom, a easy check for you do is make sure the engine stop cylinder on top of govenor housing is not stuck and has clearance.As for as big injectors if set up right with air to fuel ratio they smoke very little I have a 8v92 with 9g90 and get very little smoke. good luck | ||
| Cullen Newsom (Cullennewsom)
Registered Member Username: Cullennewsom Post Number: 104 Registered: 2-2009 Posted From: 98.201.161.214  Rating: N/A |
Tom, what's the status? I'm curious as my 6V92 is also somewhat less than tip-top. | ||
| Justin Griffith (Justin25taylor)
Registered Member Username: Justin25taylor Post Number: 51 Registered: 4-2007 Posted From: 70.243.82.19 Rating: N/A |
Tom, Where are you located? I am in Texas and could let you drive my Eagle 10 with 6v92. It too smokes a bit when taking off and climbing due to oversize injectors. I hindsight the bigger injectors were not the best idea, but I can live with just backing my foot off to keep smoke to a minimum. Best, Justin | ||
| Thomas Miller (Rmos50)
Registered Member Username: Rmos50 Post Number: 11 Registered: 6-2009 Posted From: 71.96.133.245 Rating: |
Here is the update, I got with Don Fairchild and he walked me through things to check and we found a broken valve bridge guide on one of the heads, had to drill it out and replace (broke the bit first thing so it took 17 more bits and 20+ hours to get it out). Put it back together and it runs so much better. I have a major exhaust leak on the manifold on the same cylinder as the repair was made and I'm replacing the gasket tomorrow. I'm already running 7-10 boost easy and expect more after leak is fixed. This leak didn't show up prior due to the broken part which works the exhaust valve for that cylinder. I highly recommend Don if you have an issue you can't figure out. | ||
| Cullen Newsom (Cullennewsom)
Registered Member Username: Cullennewsom Post Number: 130 Registered: 2-2009 Posted From: 98.201.161.214 Rating: N/A |
Thanks for the update Tom. Glad to hear that you're running again. |
