GMC Repair: 99 Gmc Jimmy SLT 4.3 V6 - Instrument Panel Lights & Crank, No Start, engine cranks, gmc jimmy

Question
Hi,

I also have a 1999 Gmc Jimmy SLT with a weird indicator light/no start condition, very similar to another person who contacted you. Sometimes (cold or warm outside temp) the car will crank, but not start. IF/when the engine cranks and starts, sometimes the fuel gauge and temp gauge will not function, and the ABS, Battery, High Beam, Low Fuel and  Security Indicators all stay lit. After running/driving a while, the other lights go out and the Battery and Security  Indicator Lights stay lit and all gauges operate normally. When this occurs, if I turn the motor off, then restart, the Indicator lights go out, gauges function normally, and the Jimmy functions normally!

I have noticed that if the car cranks but doesn't start, using a jumper battery/jumpstart device allows the car to start and run, but very sluggishly for about ten minutes, then all seems well (sometimes with the indicator light/gauge condition mentionrd earlier, sometimes not) I have replaced the battery twice in the past two years, and each time this seemed to make everything ok for a while, which leads me to suspect the cahrging system. I have also learned that letting the car sit for about a month or so seems to allow the battery to discharge almost completely.

I'm not quite sure what I'm dealing with here. Is this a common problem, and if so, is there (hopefully) a common fix? Is it something I can handle by myself (I'm mechanically and electronically capable)

Any directions, guides to same, or technical information would be greatly appreciated. Sorry for the length of this 'question', and Thanks in advance!

Answer
Hi
I would check the Alternator output with a meter. SHOULD be 13-15vdc output.
Thats first.
I would check ALL the power and grounds. Power going to starter and alternator.
Grounds from battery remove them, clean and properly torqued.
If you want, please follow post back and check the PRIVATE box, please.
First check that alternator output.
The battery running down in 30 days MAY be normal, depending on the reserve capacity of battery.
Post back, I'll TRY to explain how to check that too.
Pawl