Battery not charging(Not alt or belt)

drzero328 · Dec 2, 2012

Hey guys,

About a month ago my car died while driving it, I got a jump and managed to get home, barely. Since then I have taken the alternator out and had it bench tested and it said it was fine. I had the battery tested and its good also. I replaced the alternator belt and that still didnt resolve the issue.

If I jump the car it runs perfect the whole time the cables are on, as soon as I pull them off it rapidly dies, lights come on and go off and the engine starts to misfire or something and just dies. If I put a fully charged battery in it, it will run for about a day, not driving a lot, im assuming its just using what charge there was in the battery.

I am at a complete loss as to where to look next. From other posts i've read it sounds like it could be a fuse/relay? Where would these be located on a 1g? Could the alt have been not grounded properly? What about the battery?

Any and all help is much appreciated!

PrimerPLus · Dec 2, 2012

Where did you get your alternator tested? I do not trust the parts stores because they told me my alternator was fine in my f-150 and I could not figure out why my battery kept dieing. I took the alternator to the ford dealer and they tested it and failed all the tests LOL

. Replaced he alternator and had no issues. I bet you got a bad alternator. When was the last time it was changed?

Diamond Star Werks · Dec 2, 2012

Replace the alternator

MQTalon92 · Dec 2, 2012

1G cars seem to need to be well grounded so first check your grounds and battery terminals. Also check the fuses at the positive battery terminal. It wouldn't hurt to recheck your alternator at a different store to make sure it is ok. The wiring at the alternator plug may have gotten hot and lost connection with the alternator. I do believe the 1G cars get a signal from the problematic ECU. Check to see if the capicitors inside the ECU are leaking and may have shorted it out. Good luck, sometimes chasing electrical gremlems is time consuming.

DSMbabyy · Dec 2, 2012

MQTalon92 said:
1G cars seem to need to be well grounded so first check your grounds and battery terminals. Also check the fuses at the positive battery terminal. It wouldn't hurt to recheck your alternator at a different store to make sure it is ok. The wiring at the alternator plug may have gotten hot and lost connection with the alternator. I do believe the 1G cars get a signal from the problematic ECU. Check to see if the capicitors inside the ECU are leaking and may have shorted it out. Good luck, sometimes chasing electrical gremlems is time consuming.

Ive ran ito the same problem and found that my wiring got fried. If its struggling too much its get those wires hot!

Just like other people said, check out that alternator and wiring first. Check the easy shit first! Cause wiring problem can be a nightmare to diagnose. Check the alternator output with the beast running too.

steve · Dec 2, 2012

Sure sounds like the alternator isn't working in the car. Without voltage measurements while the engine is running the bench test results mean nothing other than the alternator should work.

Do you understand how an alternator works?

The alternator needs battery voltage applied to field coil at startup (L terminal). On the DSM that's the Black/White wire in the two wire connector (pin 2). You should see battery voltage at the connector when the ignition switch is on. The other yellow wire in the connector is the battery sense (S terminal).

The white wires bolted to the post (B+ terminal) are the output and run to the alternator fuse before reaching the battery. It's common for that fuse to be blown if you work on the alternator without disconnecting the battery. You should always see the same voltage at the B+ terminal as you see at the battery unless there is a blown fuse or a problem with the wires (excessive voltage drop).

The ground path is via the mounting hardware. Make sure the bottom pivot bolt is tight. If you ever pull the mounting bracket off the block you want to make sure it has a good clean connection to the block for the alternator ground path.

MQTalon92 said:
I do believe the 1G cars get a signal from the problematic ECU.

The ECU has nothing to do with the alternator on a 1G. On a 2G the ECU can switch the alternator on and off.

drzero328 · Dec 2, 2012

steve said:
Sure sounds like the alternator isn't working in the car. Without voltage measurements while the engine is running the bench test results mean nothing other than the alternator should work.

Do you understand how an alternator works?

The alternator needs battery voltage applied to field coil at startup (L terminal). On the DSM that's the Black/White wire in the two wire connector (pin 2). You should see battery voltage at the connector when the ignition switch is on. The other yellow wire in the connector is the battery sense (S terminal).

The white wires bolted to the post (B+ terminal) are the output and run to the alternator fuse before reaching the battery. It's common for that fuse to be blown if you work on the alternator without disconnecting the battery. You should always see the same voltage at the B+ terminal as you see at the battery unless there is a blown fuse or a problem with the wires (excessive voltage drop).

The ground path is via the mounting hardware. Make sure the bottom pivot bolt is tight. If you ever pull the mounting bracket off the block you want to make sure it has a good clean connection to the block for the alternator ground path.

The ECU has nothing to do with the alternator on a 1G. On a 2G the ECU can switch the alternator on and off.

I'm pretty sure this was the exact information I needed, Thank You! I will be making sure all those connections are clean and secure tonight, putting the alt back in and seeing if I can find a volt meter from a friend and test it that way, maybe i'll find a bad connection along the way and it will fix everything!

Eurogaps · Dec 2, 2012

drzero328 said:
Hey guys,

About a month ago my car died while driving it, I got a jump and managed to get home, barely. Since then I have taken the alternator out and had it bench tested and it said it was fine. I had the battery tested and its good also. I replaced the alternator belt and that still didnt resolve the issue.

If I jump the car it runs perfect the whole time the cables are on, as soon as I pull them off it rapidly dies, lights come on and go off and the engine starts to misfire or something and just dies. If I put a fully charged battery in it, it will run for about a day, not driving a lot, im assuming its just using what charge there was in the battery.

I am at a complete loss as to where to look next. From other posts i've read it sounds like it could be a fuse/relay? Where would these be located on a 1g? Could the alt have been not grounded properly? What about the battery?

Any and all help is much appreciated!

try this
1. check your batery terminals, not dirty or corroded, not loose
2. check the batery positive terminal, All cables must have good contact
3. start your engine with a charged batery when the engine are running, disconnect the positive battery terminal, if the engine continue running, the alternator are fine

try this and talk what happened

drzero328 said:
I'm pretty sure this was the exact information I needed, Thank You! I will be making sure all those connections are clean and secure tonight, putting the alt back in and seeing if I can find a volt meter from a friend and test it that way, maybe i'll find a bad connection along the way and it will fix everything!

voltmeter it better but if you don't have, try to do the i said

v8srslo · Dec 2, 2012

I had a couple alternators that bench tested fine but I know they were bad and told them to rebuild it anyways. My only failed when it got hot, put the rebuild one in and worked fine.they don't like heat at all.
It grounds to the block so that needs to be clean. Could add extra ground just to be sure. The charging cable could have high resistance if its oxidized it turns the copper wire green. Could test volts at the alternator output while revving and turn on as many electrical loads as possible. Volts at the batt should be very close or same to volts off alternator.

drzero328 · Dec 2, 2012

So I found the connector you were speaking of, coming off of the alternator connector is what looks like a yellow and blue cable, the yellow cable is attached to a bolt on the oil filter housing, where is the blue cable supposed to be attached? I did not disconnect it from anything when I pulled the alt out, so i'm guessing it wasnt attached to anything previously =/

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Diamond Star Werks · Dec 2, 2012

Pretty sure thats for your oil pressure sensor. It comes from the same loom as alternator wiring. Does your hauge work?

drzero328 · Dec 2, 2012

MJcanada said:
Pretty sure thats for your oil pressure sensor. It comes from the same loom as alternator wiring. Does your hauge work?

Hmm yup the gauge works

nuclearr · Dec 2, 2012

Where are you taking the alt to get tested. I had an alt from Pepboys first a bosh and the their brand (master pro I think) They all tested good on Pepboys newer machine.

I took them to my local Advance Auto that had an old machine that could not give print outs. The Advance machine showed perfect volts, how ever the alternators were giving out either 2-5 amps when they should be putting out 70 amps.

I was a nightmare warranting out the alts at Pepboys b/c they test good. I got the 3rd one in a year warrantied and never put it in.

SO I went and bought a Mitsu reman galant 90amp alt and have not had an issue since. I still have the unused Pepboys one sitting on the shelf.

Make sure where you are testing it gives you the amp out put as well as the voltage.

DSM1G90 · Dec 2, 2012

(Hope you're doing frequent oil changes due to that installed Microguard filter - made by FRAM)

That's the AC fan connector since your AC fan assembly is removed - it mounts next to the coolant radiator fan.

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Battery not charging(Not alt or belt)

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