charging system problem...totally stumped

[pwmin]

PLEASE READ POST 19 IF NOTHING ELSE)

so, on sunday night, my GP quit charging. It would start charging again randomly and would sometimes way overcharge. I replaced the alternator and ran the car for at least an hour and it was still charging good. Then, this morning, I start it up and it's not charging...same thing. Does that sound like an ECM problem or does it have something to do w/ having a 96 engine and alt in a 91 or is there something else? I'm also running an Optima yellow top, all of which was done a long time before i experienced any weird problems. it has no inner fender splash guard to keep shit off of it, fwiw. Does anyone know what the internal differences are between the old style and new style alternators? I know the external differences.

i did recently upgrade all the wiring and added a 4ga wire from the alt to the charging post., so i doubt its that, but it could be. i'm going to recheck all of that.

the starter is going bad, too, but i doubt that has anything to do with it. as far as the starter goes, i can get one from say an 01 Impala 3.4 and it will work, right?

edit:
i'm thinking its probably a problem with the splice when the p/o (before luke) wired in the 96 engine.

and, nevermind on the starter....newer dohc's got their own revised started (mine still has the old style)

[gpse3400]

Upgrade the main wire? Could you tell me more about this?

[pwmin]

i ran 4 gauge stereo wire for the following:

-both battery cables (all of the wires arent necessary, i just did them all - 2 wires for each cable)
-ground from engine block to battery tray
-added 4ga wire w/ 125A fuse from alternator to charging post (kept little wire that goes from the starter to the alternator.

commonly known as "big3" or "big 5", etc.

[OldSkoolGP]

One thing I know is that the way a 96 alternator is wired vs. a 91 alternator is entirely different. What year alternator are you using now? And what year wiring are you using?

[gpse3400]

Thanks. I was looking for a way of fortifying the Charging system...I'm running the a new atlernator with the newer pressed in diodes but I still dont trust it.... You figure if I go bigger on the gauge from the alt to the starter you think that would make things better? Running a CS-130 '92

[pwmin]

One thing I know is that the way a 96 alternator is wired vs. a 91 alternator is entirely different. What year alternator are you using now? And what year wiring are you using?

the one that was in there was a 96 and the one thats in there now is a 96. its the 91 wiring w/ the 96 connector and pigtail spliced in. i'm thinking its a connection from where it was spliced. i dont think i looked at the splices but i did look at the others and they were just twisted and taped and fixed the ones i found. thats the problem getting a car someone else has modified. if i keep the car (may have to sell it) i'm def doing an obd2 swap as soon as i can. i've been running this car w/ the alternator and stuff as-is with no problem for almost a year and all of the sudden this stuff starts happening. therefore, i dont think it's wired wrong, but i def think theres a good possibility one of the splices is bad.

Thanks. I was looking for a way of fortifying the Charging system...I'm running the a new atlernator with the newer pressed in diodes but I still dont trust it.... You figure if I go bigger on the gauge from the alt to the starter you think that would make things better? Running a CS-130 '92

no prob. should def help.

[pwmin]

blown ignition fuse

must have just cracked and could still make contact sometimes...weird, huh? i just hope there isnt a short somewhere blowing the fuse. i'm driving it around a little around town before i take it commuting again to make sure its ok.

btw, i used a started from a 3x00 (01 Impy 3400) and it sounds so cool for some reason....guess i'm a nerd, lol. was smaller and lighter than the 3.4 starter. i was going use the 3.4 anyway, but the old starter had 9 teeth and the newer 3.4 one had 12 (3x00 had 9)

[pwmin]

New Update

new update: yesterday, car started doing the same thing and the fuse WAS NOT BLOWN. I checked out the schematics and that fuse is tied to a bunch of stuff, one being the ac compressor. i checked that out cuz the connector was always broken on the compressor side and sure enough, the one prong had broken off the compressor inside the connector and was dangling, probably causing a short. however, after fixing that, it is still acting funny.

the check gauges light will come on randomly with no change in how it charges. however, its charging weird, too. off idle, it will charge a little over 14V and then when you stop, it will go down to 13V or less. any ideas on what may be causing that? also, i started getting alternator noise last night.


anyone? i'm thinking this reman alt. i have is just bad.

[pwmin]

ANYONE?

another update: had the original alt. bench-tested and they said it was good, so i put it back in (got it down to 1/2-hour now by doing the belt from the bottom ). anyway, put it in and same thing: will charge for a while, then will drop down and only charge when you give it some gas. so, i pulled the wire i added running from the alt to the charging post and when it was acting up, there was only 13V at the alt., HOWEVER, the two wires that are at the connector were reading around 12V (12.1 and 12.4). that means that the alt is getting the proper signal, right? when i put the other wire back on, the reading didnt change. btw, check gauges light still is on, but goes off and comes back on randomly.

please, any input would be very helpful. i'm about the kick the shit out of this car, lol.

[gpse3400]

yeah I'd be going crazy right now too...the thing is you dont really know why its tripping th light...just for the hell of it i'd get another alternator used...hell if you can get a 3100 alternaotr to fit in tere temporarilly i'd do it...otherwise you are going to have to probe the plug harness and the power wire and see what you get...But I'm leaning more towared a bad alternator...I certianly wouldn't put it past it....

[pwmin]

well, i got the one alternator warrantied and put it in. i ran the car for close to an hour and all was good...charging at an acceptable level and no light. then, when i went to drive the car home, it started acting up again. son-of-a-bitch! I'm going to try a different battery in it tomorrow and see if that helps. from all I can figure, the alternator is getting the right signal to charge and all my connections are good, so I am really confused. i figured the alt was fine until it got hot, but a new one is doing the same thing. i doubt i would have 3 bad alternators. something else must be causing the alternator to go wacko. hopefully, a battery will fix it, but i doubt it. is there any way my harmonic balancer could cause this? a little bit of the rubber is messed up, so it may need to be replaced, but it doesnt seem too bad.

[gpse3400]

The damper wouldn't have anything to do with that...yeah check your batter connections and that remote terminal..i hear that likes to go bad too...

[pwmin]

The damper wouldn't have anything to do with that...yeah check your batter connections and that remote terminal..i hear that likes to go bad too...

didnt think so. im going to check that out. i think i may have a bad ground somewhere or bad fuseable link in the wire from the starter to alt. i'm going to check all of the wires for power loss. battery did nothing. alt noise has been randomly coming on and going away.

[Schurkey]

added 4ga wire w/ 125A fuse from alternator to charging post (kept little wire that goes from the starter to the alternator.

4-gauge wire as an alternator output is definitely over-engineered!!

Why would you fuse the alternator output? Since you've kept the alternator-to-starter wire, you're unlikely to do damage to the alternator if the fuse pops--but it seems like useless expense PLUS more sets of connections to corrode to me.

When I re-wired the alternator on one of my vehicles, I used fusible link wire in the recommended (4 gauge numbers higher, and about 6" long) size for the alternator output wires I was protecting. It's all crimped, soldered 'n' shrinkwrapped--most unlikely to turn green.

[pwmin]

4-gauge wire as an alternator output is definitely over-engineered!!

Why would you fuse the alternator output? Since you've kept the alternator-to-starter wire, you're unlikely to do damage to the alternator if the fuse pops--but it seems like useless expense PLUS more sets of connections to corrode to me.

When I re-wired the alternator on one of my vehicles, I used fusible link wire in the recommended (4 gauge numbers higher, and about 6" long) size for the alternator output wires I was protecting. It's all crimped, soldered 'n' shrinkwrapped--most unlikely to turn green.

it was extra wire i had laying around and it's always good to do anything that will help the system charge better esp. w/ an A/M stereo.

how does this help with my question, anyway?