strange electrical problem

[abrat6482]

I got this 85 blazer, and i'm having a problem. When you first start it everything is fine but the gages slowly change, the temp goes up to about 240,the volts go down to the top of the red marker, the fuel goes to empty, and the oil pressure goes to about 35psi. If the lights are on the lights get dim. and if you shut them off it all goes normal for a short time. Now the strange part is nothing bad happens. It doesn,t die, overheat,etc. has new battery and alternator is about 6 mo. old but bench tested good. PLEASE,PLEASE HELP ME!

[derblazer]

I check your alternator. I think it may be overcharging the system. I would do it soon you're likely to burn something out that you would like. I believe that there is a voltage regulator problem. I had the same problem on an old motorcycle once, not a pleasant experience.

[Fireplug]

Or a bad ground or grounds check battery for loose cables

[lieffer353]

I have that same problem but the with the gauges but also there seems to be a pulsating nose that comes from the speakers when the radio is on. Any help with this would be greatly apreciated.

[ricksza]

Originally Posted by abrat6482

I got this 85 blazer, and i'm having a problem. When you first start it everything is fine but the gages slowly change, the temp goes up to about 240,the volts go down to the top of the red marker, the fuel goes to empty, and the oil pressure goes to about 35psi. If the lights are on the lights get dim. and if you shut them off it all goes normal for a short time. Now the strange part is nothing bad happens. It doesn,t die, overheat,etc. has new battery and alternator is about 6 mo. old but bench tested good. PLEASE,PLEASE HELP ME!

It sounds like you're building high resistance in one of the ground wires. If you can find the problem, you might want to try to run a new redundant ground from the battery to the body.

[Rick Norwood]

Originally Posted by abrat6482

I got this 85 blazer, and i'm having a problem. When you first start it everything is fine but the gages slowly change, the temp goes up to about 240,the volts go down to the top of the red marker, the fuel goes to empty, and the oil pressure goes to about 35psi. If the lights are on the lights get dim. and if you shut them off it all goes normal for a short time. Now the strange part is nothing bad happens. It doesn,t die, overheat,etc. has new battery and alternator is about 6 mo. old but bench tested good. PLEASE,PLEASE HELP ME!

I'd check the Alterantor again. I replaced the alternator in an 82 Olds V6 that was bad right out of the box. The internal voltage regulator was either stuck open or stuck closed. I would drive down the road and the turn signals would barely flash, the lights were dim, the blower would blow slightly more than a whisper, and you couldn't hear the radio. Then without out warning, the lights would flare up, the radio would blast you out of the car, the blower sounded like a Hurricane, then everything would go dim again after a couple of minutes. The alternator tested good on the stand, but I demanded a replacement (Thanks to Autozone's Lifetime guarantee) and the problem was solved.