6.5 diesel ,no power

shafer2345 · 11-17-2007, 07:44 AM

Last week I bought a 1994 C2500 that had been setting for a couple of years. The previous owner started having engine problems and was told it was a turbo problem that would cost $1500 to fix so he parked it. The engine starts and seems to idle fine but if you start to excellerate it will only run about 30 mph and trails a lot of black smoke from the exhaust. This engine will also,immediately after an oil change, turn the oil very black,and nasty. Does this sound like a turbo problem? Or is there something else going on? I would appreciate any info. you could give me. Thanks.

mrjohnwayne · 11-17-2007, 06:21 PM

could very well be. if the turbo is not pushing enough air it will cause it to run rich and be very very sluggish

crabtruck · 11-19-2007, 06:07 PM

Welcome to the forum shafer2345.
Not a diesel expert, but you may want the oil analyzed for diesel.

mrjohnwayne · 11-19-2007, 08:32 PM

If you can somehow rig up a boost gauge. you should be able to tell if you are having air flow problems. that thing stock (don't hold me to it) should put out around 12 lbs boost +/- under heavy acceleration.

shafer2345 · 11-20-2007, 10:14 AM

Thanks for the info. Would a bad turbo cause the oil to look like black paint in just an hour? If so, how. What happens to the turbo to cause it to loose boost. Thanks again for all the info. as you can see, I don't know much about diesels.

mrjohnwayne · 11-20-2007, 11:32 AM

no the turbo should have nothing to do with the oil color. I would think it is just a dirty engine... How often the the owner maintain it?

as for the turbo loosing boost it could be several things. It could just be a simple leak somewhere at a connection, or it could be the bearing/thrust washer seizing up inside the turbo. if the oil turns black that quickly I would think it is something inside the turbo. if the owner did not service on a good regular schedule it could of had a hand in the turbo going out.

brokenbudget · 11-24-2007, 05:41 AM

this doesn't sound like a turbo problem at all. if the turbo was bad you would still have enough power to drive the thing. i would check the injector pump to see if its slipped out of time or the reg. diaghram is torn. how many miles are on it. the dirty oil is from all the excess fuel being dumped into the engine.

shafer2345 · 11-24-2007, 10:32 AM

The truck has 152,000 mi. A previous owner had a new pump put on, I believe due to a recall, around 100,000 mi.

brokenbudget · 11-24-2007, 12:01 PM

have the pump checked again. 50 000+ miles on a re-installed pump sounds about the time it would fail. chances are it was a rebuilt one, back in
94-ish the powertrain warrenty was only 50-60k-or 3 years, so it wasn't a gmc "certified new part".

shafer2345 · 11-24-2007, 08:36 PM

O K Thanks for the info.

11-17-2007, 07:44 AM	#1
shafer2345 Junior Member Join Date: Nov 2007 Posts: 4	6.5 diesel ,no power Last week I bought a 1994 C2500 that had been setting for a couple of years. The previous owner started having engine problems and was told it was a turbo problem that would cost $1500 to fix so he parked it. The engine starts and seems to idle fine but if you start to excellerate it will only run about 30 mph and trails a lot of black smoke from the exhaust. This engine will also,immediately after an oil change, turn the oil very black,and nasty. Does this sound like a turbo problem? Or is there something else going on? I would appreciate any info. you could give me. Thanks. Last edited by shafer2345; 11-17-2007 at 02:58 PM.

11-17-2007, 06:21 PM	#2
mrjohnwayne Senior Moderator Join Date: Apr 2005 Location: Texas Posts: 3,722	could very well be. if the turbo is not pushing enough air it will cause it to run rich and be very very sluggish __________________ John Wayne 2000 F-350 7.3L Powerstroke 4x4

11-19-2007, 08:32 PM	#4
mrjohnwayne Senior Moderator Join Date: Apr 2005 Location: Texas Posts: 3,722	If you can somehow rig up a boost gauge. you should be able to tell if you are having air flow problems. that thing stock (don't hold me to it) should put out around 12 lbs boost +/- under heavy acceleration. __________________ John Wayne 2000 F-350 7.3L Powerstroke 4x4

11-20-2007, 11:32 AM	#6
mrjohnwayne Senior Moderator Join Date: Apr 2005 Location: Texas Posts: 3,722	no the turbo should have nothing to do with the oil color. I would think it is just a dirty engine... How often the the owner maintain it? as for the turbo loosing boost it could be several things. It could just be a simple leak somewhere at a connection, or it could be the bearing/thrust washer seizing up inside the turbo. if the oil turns black that quickly I would think it is something inside the turbo. if the owner did not service on a good regular schedule it could of had a hand in the turbo going out. __________________ John Wayne 2000 F-350 7.3L Powerstroke 4x4

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11-19-2007, 06:07 PM	#3
crabtruck Senior Member Join Date: Jul 2007 Location: on your 9 Posts: 3,364	Welcome to the forum shafer2345. Not a diesel expert, but you may want the oil analyzed for diesel.

11-20-2007, 10:14 AM	#5
shafer2345 Junior Member Join Date: Nov 2007 Posts: 4	Thanks for the info. Would a bad turbo cause the oil to look like black paint in just an hour? If so, how. What happens to the turbo to cause it to loose boost. Thanks again for all the info. as you can see, I don't know much about diesels.

11-24-2007, 05:41 AM	#7
brokenbudget Full Member Join Date: Nov 2007 Posts: 22	this doesn't sound like a turbo problem at all. if the turbo was bad you would still have enough power to drive the thing. i would check the injector pump to see if its slipped out of time or the reg. diaghram is torn. how many miles are on it. the dirty oil is from all the excess fuel being dumped into the engine.

11-24-2007, 10:32 AM	#8
shafer2345 Junior Member Join Date: Nov 2007 Posts: 4	The truck has 152,000 mi. A previous owner had a new pump put on, I believe due to a recall, around 100,000 mi.

11-24-2007, 12:01 PM	#9
brokenbudget Full Member Join Date: Nov 2007 Posts: 22	have the pump checked again. 50 000+ miles on a re-installed pump sounds about the time it would fail. chances are it was a rebuilt one, back in 94-ish the powertrain warrenty was only 50-60k-or 3 years, so it wasn't a gmc "certified new part".

11-24-2007, 08:36 PM	#10
shafer2345 Junior Member Join Date: Nov 2007 Posts: 4	O K Thanks for the info.

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