DTC 78 - Turbo Wastegate Solenoid Fault

[countrymidi]

I posted a thread week from the truck stalling on me.. It did the same yestersday too.. I'd gotten another FSD, but i was still waiting on the fuel calibration resistor to come in before i installed it.. well , I needed it badly to go ahead and try it without the resistor just to get the hay out of the field.i build a homemade cooler and put it all together and everything seems to be doing ok,, but only problem is now when i get it out on the hwy the "service engine soon" light is coming on and giving me a DTC 78 - Turbo Wastegate Solenoid Fault. Could this be happening because I dont have a calibration resistor installed yet or could this be something new? And could someone please tell me how to get the information about my truck to show up at the bottom of posts.? this is a 1994 chevy silverado 6.5L

[kevin77]

For the wastegate selenoid - you could have several issues:

1) vacuum pump is starting to go
2) vacuum leak
3) bad wastegate selenoid
4) wastegate stuck

The first thing to do is while the truck is running (idle) see if you can move the wastegate link on the turbo - if it is loose, you are not getting vacuum and you need to check the vacuum pump, lines etc. if it is tight, then you will probly need a new wastegate selenoid (the heat can affect them)

Also to add the description on the bottom of your posts, go to Quick links and click on signature.

Kevin