RavageTheRoad

I've been noticing my volts dropping and engine stumbling at idle when I have too many accessories running. I always had a slight drop from my radiator fan, which I have wired to a switch, but it always goes right back up after a second or two. Now, when I'm idling and in gear, if I turn on the A/C, fan, and headlights, the volts drop very low and stay there. I couldn't get a reading with my meter as I have to be inside on the brake, but it goes about halfway between 8 and 13 on the gauge for whatever that is worth. And the engine barely stays alive and the car shakes fairly violently. No accessories on, the engine is smooth and volts are perfect, about 13.6. Is there a way I can test these to rule out one or the other? I don't have the income to get both and the car is my DD so I can't just take them to be tested either.

RavageTheRoad

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antares57

iTrader: (8)

Recently purchased a '91 Firebird Formula and had a similar problem. Autozone does free checks of the battery and alternator. Found out my battery was bad and my alternator was good. Might give them a try to narrow the problem. Good luck.

Jonesyfxr

iTrader: (2)

Clean all the grounds on the engine, you will notice a difference.

RavageTheRoad

I replaced the battery and can now run all accessories at once with minimal drop/engine stumble and volts recover right away. It still idles pretty rough though, I set the timing and it still seems low, I don't know where it is because my tach doesn't work, but it's definitely low. Any way to adjust the idle on a TBI? I don't care if it isn't perfect right now, I just need to bump it up 1-200 RPM and see how it feels.

Jonesyfxr

iTrader: (2)

Did you clean your grounds, they're EXTREMELY important on an older car. Just because you replaced the battery doesn't fix weak or nonexistent grounds.

RavageTheRoad

I actually did last week after I fried my ECM wiring new 02 sensor wire. I did end up moving the main ground to a hole in front of the block, for whatever reason I attached it to an exhaust manifold bolt after I did my swap last year. I'm not sure how to check ground strap condition, but the surfaces it attaches to are nice and clean. I believe that is all of them, correct? I'm pretty sure it's a fuel issue, someone dumped sugar in my tank about a month ago, it's probably starting to clog the fuel filter....

excessiveego

I had to add some grounds to get my electronics to work properly after my 88 sat for a year waiting to do an engine swap. My battery grounds to BOTH the fender and alternator bracket on the engine, and the block is grounded to the chassis at the firewall. Originally was just grounded block to firewall and battery to block.

I also added another ground from the instrument cluster to the firewall.

Before I added those grounds everything would act up when I used my windows or turned on the blower. Radio still gets bad static when using too many power accessories, but I can live with it.

Jonesyfxr

iTrader: (2)

I just added an adjustable cooling fan relay set up from Advance auto. I mounter it in the factory relay location and tapped into all the wiring right at the plug. I soldered and shrink wrapped all the connections and then I saw the factory fan ground n the core support. I removed it and to my surprise.....there was paint under it! What a ground no no! I pulled out the dremel and cleaned the area around the ring terminal. Now it's all done and works great. The temp doesn't get over 195 ish, according to factory temp gauge.

Grounds should be rust, paint and corrosion free. A good metal to metal contact!