charging system problem...totally stumped

[pwmin]

myself, my dad and his business partner spent pretty much all day trying to figure this out. we pretty much "bench tested" the alternator on the car by running a jumper cable from the battery to the case and to power the wire that tells the alt to turn on and it still doesn't charge right (also unpowered the "check gauges" light). tried a different alternator (AC Delco reman) and it did the same thing. put the alt that was in there back in and its not charging at all. while putting the old alt back in, we thought maybe the clutch going out on the AC compressor might have something to do with it (causing drag and not allowing it to spin fast enough to charge properly), so we took that off.

one more thing: when we put a load on w/ a battery/alt tester, even 50A, the alt would not charge, where it should charge more due to the increased load.

this is making less and less sense the more we look into it. there's got to be something we're missing. any ideas?
how is the charging system supposed to act? when the car is running, it should run full charge all the time, right? (not like an OBDII car)

[pwmin]

i had all 3 alts tested and one was bad, so i used the newer good one w/ a different battery and only the original wiring. was working great and then started to drop charge until it wouldnt charge at all. then, i had it bench-tested and they said it was ok. checked the bottom of the charging post "assembly" and everything was tight and no corrosion.

[pwmin]

another update, lol.

hooked up the alt positive terminal and input signal to a battery along w/ negative to the case...all good. took out the input wire and added the factory plug...still good. added alt to post wire...bad, starter to alt wire...bad. changed the positive cable...still bad, changed negative...still bad. hooked the alt back up to the battery and charging good. :willynilly:

[pwmin]

Please Read! (dont have to read everything else)

When I have the wire from the battery to the charging post (or just connected to the wires at the bottom of the charging post) hooked up to another battery, it charges correctly. when i hook that back up to the battery in the car, the alternator cant keep up.

this next scenario is w/ everything hooked up like normal: With both fans running, the blower motor on high, and the headlights on, the alternator cant keep up. if i turn ANY one off, the alt still cant keep up, but if i turn ANY two off, its fine (keep in mind the wire that goes back to my amps is not hooked up and either are the terminals that feed the alarm that are normally on the charging post).

Since the fuel pump is tied heavily in the wires at the charging post, do you think it has something to do w/ the fuel pump drawing too much amperage? Or do you think the ECM or chip could be causing this or something else?

One more question about the chip. When you have it set up for a 180 t-stat, are both fans supposed to come on when the ECT hits 180?

A little update: uplugged the fuel pump and nothing changed, so its not the fuel pump drawing too much. Is there a possibility that the alternator was built for high output and something caused it to knock out something so it's not HO anymore, but charges like a regular 105A alt? Also, the alternator is reading 100A when you rev it up, but like 30A at idle.

Another update: checked everything w/ an inductive ammeter and nothing is drawing too much. alt is charging as designed, so it must have had an HO alt in it before. why a 105A alt cant keep up w/ a pretty much stock system, i have no idea. guess ill get another mr. alternator and hope it "fixes" it. IDK what else to do. only other thing that might help would be to run another battery and use the to go to the charging post. adding another battery to the stock one by just using jumper cables didnt help, but the other way did.

[gpse3400]

the CS-130 series is alittle flaky on output. as onlg as your charge ligt is not on it should be working properly.... FYI battery wire should go to the starter and from the starter to the battery. From the battery to the remote terminal and to the underhood relay center. IGN turns on the regulator... cold the alternator should be making around 14 volts and drop as it warms up at idle. Cruising it should be relativley steady.

[pwmin]

the CS-130 series is alittle flaky on output. as onlg as your charge ligt is not on it should be working properly.... FYI battery wire should go to the starter and from the starter to the battery. From the battery to the remote terminal and to the underhood relay center. IGN turns on the regulator... cold the alternator should be making around 14 volts and drop as it warms up at idle. Cruising it should be relativley steady.

my check gauges light (there is no battery light on a MTX car) comes on for a few minutes and then goes off for a few and will repeat.

i have the original wire from the starter to alt, i just added a wire from the alt to post and upgraded the wire from the battery to starter. when i added the wire, it increased the voltage by .2, but doesnt seem to be any different now with it on or off. i could help it by taking off my UDP, but it only dropped the voltage by .2. bottom line is i need an HO alt to keep up when the fans are on (even w/ my stereo off). it is chipped for a 180 t-stat so both fans come on at around 180. i may add some toggles for the time being to help out.

it sure doesnt put out what it used to and i never saw the check gauges light until it started putting out less voltage. the acd reman i have in there now is working better than the one that was in there.

[gpse3400]

I think you are having a feedback problem. I'd rewire it the way it was or send that one wire to the battery...I think you need to pick a one path and go with it. I have a 160 stat in my car and my fans come on early as well with a/c I dont have any issues...also the rated output is only for short bursts,kinda like an amp and speaker peak output. It mostly reiles on the battery to stabilze everything.

[pwmin]

ive been running it this way for quite a while now and never had any problems. believe me, i tried all combinations using only one of the charge wires and using both and it has the same problem. i'm thinking the light coming on is due to another problem since its not supposed to come on due to charging system failure unless it goes below 12V. it def never does that anymore. i may just have the cluster redone since it has a couple other small problems, too.

[gpse3400]

yeah the cluster is always fair game as well