Electrical Woes (EGR + Cruise...) [Archive] - Diesel Place : Chevrolet and GMC Diesel Truck Forums

: Electrical Woes (EGR + Cruise...)


thewoz
05-20-2006, 06:19 PM
:help::help:

Hi, all,

Some time ago, the EGR started to act up on my truck (valve not closing during accel, black smoke, etc). I disconnected the valve and everything was OK, except for the engine light being on.

About six months ago, the cruise control stopped working. (would not set, resume, nothing). I finally decided to take it in and have someone check out both problems.

The shop I took it to ran the diagnostic chart for the cruise, and decided to replace the PCM. They weren't sure what the EGR problem was, but since replacing the PCM was also indicated on the troubleshooting chart, I thought it would be worth a chance to change it and see if it fixed both problems (hey, if a PCM fault is causing one problem, maybe it's causing more than one, right?)

Well, I've got the truck back, and the EGR seems to be working fine. However, still no cruise. The tech drove the truck and said the cruise worked three times before it quit setting. They also said there was a code they hadn't seen before for the injection system (I don't know which code, I'll find out in a few days) that they thought might be interfering with the cruise not working. I'm gonna take the truck back next week and let them have another go at it.

Just to make things more complex, I took the truck out this morning, and the cruise set one time, then stopped working....?

Is this sounding familiar to anyone?? I'm at a loss as to what to look at next. (If the new code points to the FSD, I was thinking of purchasing a new one and mounting it on a cooler anyway...should I try this before spending any more cash on this problem??)

Any input or suggestions are greatly appreciated! Thanks!

---------------------------------
1998 GMC Sierra 6.5 Turbo Diesel, no mods, pyro, tranny temp

quantum mechanic
05-20-2006, 06:50 PM
Is the EGR still plugged?
What codes are you getting?

thewoz
05-20-2006, 07:17 PM
Nope, the EGR appears to be working fine, no black smoke or hesitation. (I took a drive with a vacuum gauge connected. The vac to the EGR modulated with engine load. Before, it was 15" all the time, no matter what the engine was doing.)

I'm not sure what the code is, it was a pretty hurried "Friday afternoon" pickup. (I know, not having the code doesn't help much..;-( )I'll know more once I can talk to the shop on Tuesday. All they said was they had a code "related to the injection system", which could stop the cruise control from working. (Actually, I have an ODBII code scanner, it shows no codes at all..?)