Indy GTA

I've done a search and I'm still stumped as to why I'm not getting the voltage I was getting before.
I used to get 14.5 volts on my instument gauge at all times even with the headlights on(even the foglights). Now I start out with 13.5v and end up with less than 13v at times sometimes lower. I know that the fans are taking away some voltage because it gets progressively worse as the car warms up. The lights also dim now.
I've checked the battery, 12.8v on the multimeter. I've installed a new alternator yesterday and had it checked before I took it home (15v). I cleaned the connections at the starter, firewall, battery, alternator and engine block. I checked the ohms and found no resistance in the cables and some of the wires(fusible links) around the battery. I also checked the chg/fan fuse(o.k.).
Is there anything I could have missed? I just want it to go back to the way it was. Also sometimes I can't get the headlights to come up. I just changed the actuator motor bushings recently so I know that isn't the problem.
This just started recently and I would greatly appreciate any help.
This is on an 88 GTA with a tpi 350 and the only mod is an ADS chip(not my doing) that came with the car. I've also replaced the ignition module, fuel pump relay and ECM since I've bought it in Jan. of this year if this helps any. Everytime I fix one thing on it something else goes wrong.
Thanks for any and all input!

89IROCZ28

iTrader: (14)

I've got a similar topic going.

Check the voltage at the battery to see if it's actually being charged when the engine is running. Basically, anything over the reading when the engine isn't running will charge it, but it should be up around 14.5. If you have that you can be certain the battery is being charged and it's just a gauge problem like I have.

If your reading is lower then either: 1) the alternator isn't putting out what it should (volts or amps); 2) there is a huge electrical demand (lights, fans, high powered amp, etc.) in your car; 3) a pooir electrical connection between the alternator & battery; or 4) a short in the wiring (unlikely b/c you would be blowing fuses/fusible links or cooking some wires).

If you find something out regarding correcting low gauge readings let me know.

Thanks

Indy GTA

Thanks!
I'll check the alt. when it's running and see what the voltage output is. I haven't tried that yet. I'll charge the battery and see what else happens. I don't think it's the gauge itself because my lights also loose power and dim along with the low voltage reading. But then again I've been known to be wrong. It just happened Thurs. It ran fine. I went into the bar, shot some pool, went out to leave and the problem came up and has has stayed with me. It has never done this before. Granted I don't drive it much but I also have to put it in neutral to keep the voltage up to 13 volts.
If I find out anything I'll keep you posted about this low voltage problem. This way if it happens to anyone else this way, they'll know how to correct it.

89IROCZ28

iTrader: (14)

Yeah, it doesn't sound like you're having a gauge problem since everything is being affected.

Unless you really know the circuit, troubleshooting using resistance can be misleading. See if you can isolate the problem by connecting the black (-) lead from your voltmeter to the battery negative post. Then using the red (+) voltmeter lead follow each of the wires from the battery to each connection you encounter along the way. You should read the same voltage at each point as you do at the positive battery post. If you get a lower voltage at some point the problem lies between that point and the last good reading - usually a bad connection.

After re-reading your description of the problem, I suspect a main wire, main wire connection, or fusible link is the problem.

Hope this helps.

Indy GTA

Thanks 89IROCZ28.
I'm now beginning to believe that my problem is outside temperature related. I went outside to play with the car around 7:30 p.m. last night after the thunderstorms blew through. Went and started the car and I had no problems. It ran between 14 and 14.5 volts and I turned on the lights and no drain on the voltage gauge. No dim in the lights either. The outdoor temp dropped from 85* to around 70*. I didn't touch it after that.
Something is not grounding itself until it contracts in the cooler weather. This is very interesting. I'll try to find out more and fill you in.

Indy GTA

Just thought that I'd post what happened in case it happens to someone else. My problem had to do with the computer chip. I've had problems with it in the past and I soldered a bad connection. Problem went away. The temp. gets warm outside then my problems come back. I went ahead and got a factory chip, replaced it and my voltage problem went away. Now my headlights come up when they should and the car starts up right away. I thought that I also had a problem with my crank sensor because it took a couple of cranks to get it started. Hope this helps. Darn ADS superchip. Hope this helps anyone else if they ever run into this problem.

89IROCZ28

iTrader: (14)

Indy GTA - Good catch! That had to be a tough one to run down. Thanks for posting the solution.

Indy GTA

Yes it was a hard one to track because it wasn't throwing any codes. My neighbor works for a GM dealership and told me about problems with the pins on the chip not connecting as they get older. He got me a stock prom and the problem was solved. Now I just fixed another problem with the car. I went to change the thermostat back to a 195* (because of the new chip) and broke off the aft bolt holding the housing on. Nothing that any easy out couldn't fix though. Now I just need to get new gaskets for the plenum. The car is old and I knew there would be problems. This car wasn't taken care of concerning the engine. It still has the factory clamps holding the hoses on and some of the hoses have been there since it's birth.

89IROCZ28

iTrader: (14)

I know what you mean about problems with the pins on the ECM chips.

I purchased a custom programmed chip from another TGO member and when I pulled the OEM chip just about every pin broke. I couldn't believe it! There I was holding a custom chip that I had no idea how or if it was going to work and my original chip is in pieces - completely unusable.

Fortunately, the custom chip worked great and I was able to get the .bin file for the OEM chip & had a couple spares burned at work. Unbelievably, the same chip used in the ECM was used in some older industrial controllers we manufactured.

Bummer about the thermo housing bolt - if it isn't one thing, it's another! Glad to hear it was an easy fix.