I have a very annoying intermittent problem. I will b driving down the road fine...then I will see my volt-meter reading 9 volts. Sometimes the car will try to stall and stutter, I will lose the radio for a second and then it will be fine. The volt-meter will read 9 for a couple of minutes to a half hour. During one of these episodes with the vol-meter I was driveing past an autozone and had them check the battery and the alternator. Both checked out fine and the battery read 13.4 via their tool, and still read 9 in the truck. On one occassion the car actually stalled and I had to wait 20 minutes before restarting it. It restarted all on its own, and was fine for a week. Please help if you can...it is very annoying.

 

just a thought,did you check your battery connection to make sure it is tight? batt post not covered with crap? or you might want to check your battery cables POS/NEG andsee if one of them has a frayed wire.mine did that a few months ago.i thought my battery connection was tight from the looks of it, i even grab it but apparently it wasNOT that tight. hope this helps.

 

I would also check for corrosion near your battery terminals... that will cause a crappy connection as well.

Also I have had it happen where the alt wasn't bolted down tightly and just the slightest jolt would send it off...check that too?

 

My thought - check BOTH ends of the battery cables. The problem may not be at the battery end. But unless you have an incredibly dirty battery terminal, it sounds unlikely to be the problem. if you had a loose cable at the starter end of the + cable, I wouldn't think it would show low voltage - I'd think it would show 12+V or almost nothing.

Frankly, this sounds to me like the voltage regulator in your alternator is going out, but hasn't given up the ghost yet...so the problem is intermittent. Or maybe - just maybe - the gauge itself has a problem.

Here's something to try: carry a voltmeter with you. When the gauge shows 9V, pull over, pop the hood and put the voltmeter across the battery contacts. If you are REALLY operating at 9V, it should show you that. If you don't get 9V, then something very odd indeed is happening. (Or maybe the gauge is bad.)

 

i agree with pilgrim on both the alternator and the gage. if i remember correctly (i could be wrong) but i think im right. the car actualy gets its signal from the gage on weather or not the voltage is right. so it uses the value of the gage to decide weather or not the alternator needs to run. could cause Alot of odd behavior if the gage is wrong. when i had my gage cluster out the alternator would not run, and the batterie ran down compeltely dispite that everything was working fine, just had the gage disconnected. i would check the gage.

 

I agree with the other guys, Ithink its the voltage regulator too. The best thing about it is that you can take the alternator to an auto electric shop and rebuild the alternator for a fraction of what I new one will cost. I had mine rebuilt last year and it cost me a whole $35.00. Most shops can test the voltage regulator on the spot.

 

I just replaced both fuseable links to the electrical mains. One from the battery to Alternator and another one that leads to the fuse box from the Alternator. Both were really bad (not blown just rotted beyond repair). The hardened rubber boots that cover these (factory set) where cracked and rotted to the point of exposing the wires. This was a pending electrical fire in my book.

Might want to check your fuseable links in those two spots. Just my 2 cents

 

I had the same problem with my 99 blazer and I ended up replacing the alternator and it still happened. It turned out it was the cable to the positive battery terminal so I just tighten the hell out of it and haven't had a problem since.