Dear Fellow Thirdgeners:

I built a sweet 355 TPI (mass air) and stuck it where my ‘87 2.8 MPFI used to be; for convenience, I had the 2.8's wiring harness modified to work with the TPI.

I have the late model single-wire style (or small) alternator. A plug from the wiring harness goes into the top of the alternator and a very thick gauge wire, which screws into an extension coming out of the rear of the alternator, runs straight to the top positive post of my battery (the battery has both top and front posts and the car's cables are attached to the front posts only)

I usually let the car sit for weeks at a time since it’s not ready to drive yet. However, when I do drive it and it's under load (higher RPMs), my battery gauge indicates below 12 amps. In fact the higher I rev it in gear (it's a 5 speed), the lower the battery gauge seems to go. One day, after I hadn't driven it for a while, I took it down the freeway for a few miles hoping to recharge the battery and when I got back, it wouldn't restart because the battery had died.

The battery is the biggest and best DieHard (Sears) I could have bought; I've had it tested and recharged and everything is A-Okay; I had the charging system tested and it came back A-Okay; and I even took the alternator out and had it tested separately and it also checked out.

So I'm officially stumped. One of my cooling fans seems to always be on when the car is running, is that normal and could that be causing a drain? What’s strange is the car starts right up after sitting for weeks, so I don't think I have an open short anywhere. Would this be caused by a week battery that's been sitting for a while or been discharged a bit?

Anyone have any experience with this or any thoughts?

 

Is it a factory alternator, or a summit replacement? According to my Helm manual the factory CS130 on my car has *two* wires. Not one. One goes to a dummy light in the dash, and the other goes to the battery. And you can make it a three wire by connecting the wires to the extra port.

You might also consider doing the big three upgrade. Large gauge battery to alt cable, large gauge battery to ground cable, and large gauge engine to ground cable. That might fix your problems, and all else fails, wouldn't hurt anything.

 

Thanks for your response. It's a factory alt. It's got one whether pack connector at the top and I believe there’s 3 wires to it; it also has a large gauge cable that’s screwed into the back of the alt and runs straight to the battery. I can't figure it out. I just had the battery recharged today and when I drove it, the gauge in the instrument panel goes below 12 amps whenever I push it. I checked the battery with a voltmeter before starting it and it was at 12 Amps and then when I started the car it read 14.75 Amps. So the alt should be charging the battery right? However, I don't know if it is.

I do have large injectors (Accel 30 pounders), as well as a high flow Welbro in-tank pump with an adjustable fuel pressure regulator that’s probably set too high. Could that combination be sucking up the juice? There's no stereo in the car and I don't have underdrive pulleys, so I can't figure it out. Also, the cables to the battery from the car and the alt are all large gauge too.

I just don't get it!

 

i know this is a realy stupid question but is the alt spinning in the rite direction?