Hello, I am new to the deisel world and I have a 94 GMC SLE 4x4 6.5 turbo "F" 5-speed 3500, and I had 6 different codes flashing, 18,19,35,36,54,78, I took care of 2 of them and I know what is causing the code 78, my vac pump is shot. I replaced the crankshaft position sensor (19) and the code 36 went away, but my problem is does anyone know what a pump cam reference (18), injection pump time short (35), or a pcm fuel circiut (54) is? Any help would be highly appreciated, thanks.

I already gave you my answer in the other forum. However, I do not blame you for not wanting to listen to me. I would be in denial too if I got all those codes. Check your grounds. Replace your battery grounds. If that doesn’t do the trick, then your Injection Pump is TU. A bad PDM does not throw code, only causes stalling. A bad IP on the other hand throws 35, 36 and even 18.

Sorry Juancho, I do know that my injection pump is bad, but what does it mean (time short) and what does the other codes mean? Like the PCM fuel circiut, is that part of the ip going bad? And one more question, how good is a IP rebuild? Are they worth it? Thank you for your help Juancho. Oh yeah, and you say that the code 18 is part if the IP failure?

Hi 94 Dually,
Welcome to this site stroll up to FAQs I have listed the codes there 1st one is highest priority, we got some good IP folks that frequent here might be able to help out with specific codes. Does look though from what I see you are due for a replacement, have you done a thorough wiring and ground check intermittent wiring and poor grounds are usual bad actors for multiple codes.

Does anyone know where I can find a IP reasonable, or have one rebuilt reasonable? Any info would be really helpful.:help2:

PM Diesel-Pro and ask him if he still has a 4068 DS-4 for sale. Other than that you're looking at ~$900 usd