QuestionThis is a really tough question with alot of detail. The subject vehicle has had this problem for over two years. It has the 6.5L diesel powertrain with dual batteries standard. I am the original owner and the vehicle is stock or has GM stock options added - not aftermarket modified in any way.
It started about the same two years time (not right away) that I converted the vehicle from the original 140A single generator to the factory dual 100A generators by ordering all the genuine GM parts involved from the dealer. It worked so we (Chev parts tech and I) think we ordered everything as needed. No change in PCM or other solid state electronics was done.
Sometime after that the vehicle exhibited the problem. When cold starting power will fluctuate for 5-6 seconds. Voltmeter would move up and down 2 volts, wait to start indicator would flash off and on, daytime running lamps would dim and return, etc. Then stabilizes and runs as designed from then on. Never any problems starting, driving etc. Never happens on warm or hot start. Vehicle has to be very cold (i.e., overnight or at least several hours sitting) to exhibit this.
Nobody could find the cause and I decided it could be a battery so I'd wait. Well this month both original Delco 78-6YR batteries finally got replaced when one of the CS-130D generators I added had to be replaced.
Still have the same problem.
Any ideas on the power flux cause? Would finally like to put this one down.
AnswerHello Ed,
I would say the fluctuation is due to the glow plugs cycling. They draw a lot of amps, and operate exactly when you say your problems are occurring.
I am just surprised you never had the fluctuation when the vehicle was new.
It is possible that there is a little bit of corrosion and resistance in some of the connections, which could make it worse.
I really doubt there is any problem with any of the glow plugs, such as an internal short, or it would miss some while warming up.
But every one of my fleet diesels,(currently over a dozen of them), both Chevy and Ford, fluctuates like that while warming up.
Here is another place to post your question, and you will get answers from numerous Chevy, and Burb owners... FREE.
www.chevytalk.org/
http://www.chevytalk.org/threads/dosearch.php
And speciffically this following search of that site.
http://www.chevytalk.org/threads/showflat.php?Cat=0&Board=UBB11&Number=1074141&S...
I log into that site as FixitFox, so may see you there.
Van
