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1994 c3500hd black smoke ??

american hooking

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I have a 1994 Chevy C3500HD 6.5 turbo 5 speed roll back tow truck with about 130,000 miles on it.
My question is why would it all the sudden start to blow some black smoke while shifting especially with a load on it
will also do it sitting still if i stomp on fuel pedal. Seems to have also lost a little bit of power taking off also up a incline. You can hear the turbo spool up while shifting only smokes while shifting and when you stomp pedal while sitting still. Drives fine on the highway and while cruising down the road .
Has a brand new air filter
I have checked the wastegate actuator linkage while running and you can not move it at all. also checked the vacuum at waste gate and at pump. I put vacuum gauge on orange line at waste gate and got 25 in-HG i also checked line coming from waste gate actuator and got 15 in-HG.
Replaced the wastegate solenoid just in case and checked vacuum and got same readings.
I have also changed the turbo boost sensor. The exhaust is straight piped
Any help would be great im a small business owner with a new business i cant afford to keep throwing parts at this if it not going to fix the problem

Will it harm the engine to keep driving it like this???
 

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Any codes ?

service engine light would come on and go off sometimes stay on for 2 - 3 mins but would mostly just come on and off once in awhile
had it scanned and got code DTC 65 and DTC 35/36 codes were cleared and no light on for weeks still smoked with codes cleared recently light has come on a couple of times but has stayed off
 
I'd get a boost gauge on there so you can see what the boost is doing when you get smoke. The 65 is an APP code the 35/36 is the one to be worried about. Try dosing the fuel pretty heavy with some lubricant might buy you some time before you need a new IP
 
I'd get a boost gauge on there so you can see what the boost is doing when you get smoke. The 65 is an APP code the 35/36 is the one to be worried about. Try dosing the fuel pretty heavy with some lubricant might buy you some time before you need a new IP

ok thanks i run power service Diesel Kleen with cetane boost with twc 2 stroke oil every fill up
 
Sounds like you have maintained the truck really well.
The common causes seem to be eliminated.

May be something is weak, so having a boost gauge may help? having a loaded truck may have exposed those weaknesses.
May be just a batch of bad diesel?
Did you measure the fuel pressure?
 
A quart of 2-Stroke ashless oil to a tank of ULSD is definitely sufficient for lubricating the IP/injectors. That being said, you stated that it has 130,000 miles on it.

Has it had new (or rebuilt) injectors installed? 100K is considered the standard replacement interval and if original they are 30K past due and bad pattern/squirting can cause the black smoke under the circumstances you describe. It only takes one or two bad injectors to make noticable smoke.

Same with the IP, as 150K is considered the life expectancy for one and you're nearing that quickly. An IP wearing out can also produce the same symptoms.

While you are taking great Preventative Maintenance measures for the fuel system with the Diesel Kleen and the TC3 2-stroke each tank, unless it came with all of its maintenance records you really have no idea how/when it was serviced or what fuel treatments (if any) were used at fueling.

Since it appears that your turbo/wastegate/boost is operating fine, the smoking that has appeared under certain conditions leans towards an over fueling/incomplete combustion/fuel timing issue.
 
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