SES confusion...

[bhtooefr]

Turbo Wastegate Solenoid diagnosis?

The truck in question, a 1995 Silverado 6.5TD (my dad's truck), has the SES light come on under steady state driving. Acceleration or deceleration turns it off.

I then proceeded to try the paperclip trick from here (Google FTW):

http://dieselplace.com/forum/showthread.php?t=16399

I got DTC 78 (Turbo Wastegate Solenoid Fault), and cleared it.

Suggestions for troubleshooting?

I'm guessing check vacuum lines going to the turbo solenoid? Any specific procedures you guys recommend?

I'm somewhat familiar with the VW TDIs (which seem similar in operation to this), due to much reading on TDIClub, but know little about this truck.

 

[towcat]

this style wastegate is one of GM's more goofy ideas. check for a vacum leak with a vac tester first. betcha you have a bad diaphram on the gate itself. there's quite a few guys over at the dieselplace who have rigged up a spring loaded wastegate instead of the vac setup.

 

[Black dawg]

check for good vac at the wasgate sol, and check the see if the diaphram in the wastegae actuator holds vac. also make sure the vac line are in good shape if everything checks out the sol. is probably bad. Ive replaced around 15 of them.

 

[juicedcummins]

I just went through the same thing on the 95 here. After all the testing etc it ended up being the ECM. Easy to change and around $300.cdn.