Hello all, here is my question. My grandpa just purchased a 94 c2500 with a 6.5 diesel and a 4l80 trans. He has trouble with it when he hooks up to his camper, it surges he says it feels like your moving along good at 55 up a hill and then the ses light comes on and then it starts smokin black and runs out of power. I have checked the computer for codes with a paper clip and all i come up with is a code 87 can anyone help? Also he has no trouble at all when he drives it without a load, and he says it has plenty of power when not under load.


thanks adam

Try changing the fuel filter.


Check the air filter.


Some more experienced 6.5 techs will be along soon to help you out more. Check the basics first.Edited by: Max Power

That is a code 78, not 87.


If you want it to not break again, get a turbomaster to replace the vacuum system. You can turn up the boost a little then too.


http://www.heathdiesel.com


If you just want to fix the vacuum system, it is probably a cracked line, a bad wastegate solenoid or bad vacuum pump.

Thanks for the replys so far but whatnot could you tell me what code 78 means is it something with the turbo or vacuum system? thanks again

Code 78 is for wastegate fault.


It is caused by no boost or too much boost. (black smoke means no boost)


If you have 8 bolt wheels then the vacuum system only runs the turbo wastgate and nothing else on the truck.

Hofz...,


Have you checked for vacuum?


Pull the vacuum line off the turbo with the engine running , it shoud be more than 15" Hg at idle.


It can be a stuck/ sticky wg flapper, lack of vacuum pull suffiecent to hold the wg closed tight, a stuck or sticky wg solenoid, lack of PCM signal to wg solenoid/ bad ground, or a bad vacuum pump.


http://www.dieselplace.com/forum/uploads/433_wgsolenoid.jpg

Hoff,


Go to the RPO post I put in and see what is on your trucks equipment update your sig to keep from having to repost time & again, & saves us from guessing about wrong thing when we don't know your config.


Does the truck only do this when pulling a heavy load, then I would suspect a fuel delivery problem 1st, check fuel filt, and lift pump/pwr.


As far as the boost code that may be a symptom not a cause if problem only happens when heavy loaded.


If problem/code is always present, then it may be a vacuum or WG solenoid problem, hand over hand vac lines until you come to the main one from vac pump mine is white nylon rest are black on solenoids, put vac gage there you should have around 18-22" at idle. During hand over hand verify no leaking lines/connectors.


If you have 18-22" there then plug back into solenoid and tee into line going to WG actuator on side of turbo, route hose into cab taking care to not pinch off hose, WG control vac out of solenoid as you are driving should modulate 15-22" to open & close WG as engine load requires more/less boost. If not and all rest is okay WG/Boost solenoid needs replacing.

That is a code 78, not 87.


If you want it to not break again, get a turbomaster to replace the vacuum system. You can turn up the boost a little then too.


http://www.heathdiesel.com


If you just want to fix the vacuum system, it is probably a cracked line, a bad wastegate solenoid or bad vacuum pump.





I vote for getting rid of vaccum system. Did it works good.

Thanks for all the help


I havent had time to mess with it just yet maybe i will tonight or tommorrow

My advise is to get rid of all vacuum devices use a turbomaster and install F intake gaskets and disable egr not epa legal but works wonders.