I am getting the check engine code...29 and 78... i just replaced the heads and head gaskets. It is also blowing some white smoke when it fires up. but after a few minutes it quiets down and never see it again. I belive that i have a slight diesel leak so i am goonna start there. any other suggestions would be great. thanks

29 is the glow plug relay. 78 is the waste gate solenoid.

check your grounds

i have a turbo master on the turbo...Do you mean the grounds for the relay? thanks again for the input

Then the 78 is over boost range. resist the MAP signal or upgrade the pcm to aftermarket.

thanks for the info...ended up being the ground. When i replaced the heads i guess i pinched the wire. now i got that figured out.

Alex one thing that works for me is adding an auxillary ground to the engine, I took a std batt cable with a ring lug at each end 1 to a frame bolt and the other to back of alternator mount, GM has horrible ground plane system, still need to keep a good eye on factory gnd wires but this added cable cured many ailments especially weak charging in my 90 GMC gasser tuck, I copied it over to my Diesel never had a problem with grounding on the Diesel.

Can't have too much ground on an efi engine.

Quantum What did you mean too much grounding on a diesel. I have figured out that the ground seems to be bad on the relay. I am gonna fix that first thing in the morning. Right now i have just a wire with gator clips on it to get by seems to be working fine. Hopefully this will cure the problem. Now i just need to find the "little" diesel leak and Check all my glow plugs. It smoke white when it first fires up. I am assuming that is the air in the lines.

A little white smoke at start-up is normal in cold weather. the harder the start and longer cranking usually indicate when the glows are failing.



Awhile back a pic of an EFI grounding harness surfaced. It was a coated 2"washer with 8-10 grounding cables coming off of it that get added to the engine accessories and battery grounds. It couldn't hurt to add somthing like it to create a bigger path back to the batteries from the engine and then tie in every ground on the harness.