2G: car not charging while running

GSTurbo1 · 05-07-2012, 10:03 PM

I recently bought a 98 clips that has a lot of aftermarket upgrades including turbo and NSDS computer system plus turbo timer. The car is not charging itself while running... if I run the headlights it dies within thirty minutes but will run for a couple of hours during day time. I had a shop owner inspect everything and he said my alt works but the computer is not telling it to charge... doesnt make since to me? He said that he jumped the blue wire coming out of the ecm to alt and it did not charge then he ground the blue wire to the frame it began to charge. Should I take it somewhere else? This just does not sound right. What is the blue wire coming out of ECM for? Should it be ground off?

TheEagle · 05-07-2012, 10:56 PM

Hes saying you have a fully functional charging system, but your cars ECM is saying don't charge even while using power. If that makes more sense. The thing to remember here its not literally hardwired from alt to battery like in older cars. The electronics do play a part.

Lots of things it could be. Maybe someone with more experience can help you out.

My biggest question is did he mean the battery was charging with wire grounded, or just there was flow through the wire. And how did he "jump" it.

luv2rallye · 05-08-2012, 04:27 AM

Quote:

Originally Posted by GSTurbo1

He said that he jumped the blue wire coming out of the ecm to alt and it did not charge then he ground the blue wire to the frame it began to charge.

You both are saying it close but incorrect. The alt blue wire (of the alt 4 wire connector) must be connected to +12v through the dash Charge light (you must have this load, do not connect directly to +12v) for the alt to put out. Grounding this wire causes the alt to not put out (actually a not putting out alt grounds this) and should make the charge light go on - test this (key on but engine not running) to see if your Charge light is not working which usually is the problem. This wire does not go to the ecm.

On a side note, on 2g's there also is a backup circuit (on the blue wire) through what Mitsu calls a generator relay (which is not really a relay) that connects to +12v in case the charge light fails. However this relay often gets damaged or burnt out on our models (it's next to the BCS) which then means when the charge light burns out the alt stops putting out.

Redslayer · 05-08-2012, 08:09 AM

Quote:

Originally Posted by luv2rallye

You both are saying it close but incorrect. The alt blue wire (of the alt 4 wire connector) must be connected to +12v through the dash Charge light (you must have this load, do not connect directly to +12v) for the alt to put out. Grounding this wire causes the alt to not put out (actually a not putting out alt grounds this) and should make the charge light go on - test this (key on but engine not running) to see if your Charge light is not working which usually is the problem. This wire does not go to the ecm.

On a side note, on 2g's there also is a backup circuit (on the blue wire) through what Mitsu calls a generator relay (which is not really a relay) that connects to +12v in case the charge light fails. However this relay often gets damaged or burnt out on our models (it's next to the BCS) which then means when the charge light burns out the alt stops putting out.

Lol, that's the most ridiculous thing I've ever heard. Why would they make the alternator rely on a light o.o *sigh* These cars are such a PITA lol.

GSTurbo1 · 05-08-2012, 08:41 AM

When you say charge light... you just mean the battery light that pops up on dash? Mine turns off after the battery gets low.

DSM1G90 · 05-08-2012, 10:44 AM

Quote:

Why would they make the alternator rely on a light o.o *sigh* These cars are such a PITA lol.

Prob goes through a relay that engages the charge light where the light is just a monitoring device of the current flow.

GSTurbo1 · 05-08-2012, 06:24 PM

update: well I stopped by a car shop today and he immediately noticed that my ECM was not even bolted into the engine compartment. He said that its not grounded if not bolted in, then he also noticed that my connections to battery were finger loose. So I'm in the process of cleaning all the connections to make sure everything is grounded off and connected correctly. Let you guys know tomorrow.

luv2rallye · 05-08-2012, 07:17 PM

Quote:

Originally Posted by GSTurbo1

When you say charge light... you just mean the battery light that pops up on dash? Mine turns off after the battery gets low.

Yes the battery light. The light goes on when the alt is not working (putting out) - example is when you just turn the key to On but engine isn't started yet.

GSTurbo1 · 05-08-2012, 07:32 PM

so could the ecm not bolted in have something to do with it?

luv2rallye · 05-08-2012, 07:37 PM

Quote:

Originally Posted by Redslayer

Why would they make the alternator rely on a light o.o *sigh* These cars are such a PITA lol.

The light provides a path to get voltage to the alt's field coil to start the alt charging process. It also is an indication to the driver that the alt is not putting out. In parallel to the light is the "generator relay" (which is actually a diode in series with a resistor) to provide this voltage should the light burn out (so it's a backup to the light). Should both of these fail the alt gets no voltage on it's field coil.

mitch rich · 05-08-2012, 07:39 PM

My Car is doing the same thing. It will drain while driving even though its a new battery and alt. If I left the car with the battery charged and didn't start it for awhile it would start right up. So I'm not sure what it could be.

DSM1G90 · 05-09-2012, 01:42 AM

Once in a while, all of my idiot lights will just barely glow then go off .. and I replaced the ALT two years ago. My ALT dying again?

I did tthe VOM test voltage across the battery on motor idle and still doing the 13.8VDC output thing okey. Regulator in the ALT getting grumpy?

-DSM

luv2rallye · 05-09-2012, 08:03 AM

Quote:

Originally Posted by mitch rich

My Car is doing the same thing. It will drain while driving even though its a new battery and alt. If I left the car with the battery charged and didn't start it for awhile it would start right up. So I'm not sure what it could be.

Try doing this test: Car died on freeway... Electrical problems?

DSM1G90 · 05-10-2012, 01:58 AM

Yep, my ALT is not putting out the required voltage - just sitting at 12.1 VDC in idle and drops .5VDC when headlights and brights are on.

Oh wait: I knew how my ALT died - had to give a fellow worker a jump and his battery was completely dead since the goon left his headlights on. Vehicle was a 86 Chev PU with the 350. Battery much have been a good 10 yrs old, the way it looked and cabling was horribly nasty.

Unfortunately, it was so dead that even with a jump, that big V8 could just barely swing around, and the motor in my car was taking the toll with the idle really being pulled down - knowing that the ALT was really being worked to death. And we tried, tried and tried to get it going, but no avail. He finally called his father to come over to get the rig going - father just put in a new battery and the truck started immediately.

I think with all of this, that it fried the regulator in my ALT as the result.

GSTurbo1 · 06-01-2012, 08:40 AM

well turns out the regulator in the ECM is bad so instead of a new ECM we decided to put an external regulator directly on the alternator.

T is for TURBO · 06-01-2012, 09:06 AM

Quote:

Originally Posted by luv2rallye

On a side note, on 2g's there also is a backup circuit (on the blue wire) through what Mitsu calls a generator relay (which is not really a relay) that connects to +12v in case the charge light fails. However this relay often gets damaged or burnt out on our models (it's next to the BCS) which then means when the charge light burns out the alt stops putting out.

This is true, and another side note, if you do not have a working battery light or are missing the so called "generator relay" you can still bypass the problem by unplugging the alternator four wire plug, and "blip" the throttle to rev the car up to 2,500 to 3,000 rpm to manually excite the alternator. However, I do belive this causes the alt to run @ 14v at all time. You will get a CEL, but the car will charge

GSTurbo1 · 06-12-2012, 06:31 AM

Quote:

Originally Posted by T is for TURBO

This is true, and another side note, if you do not have a working battery light or are missing the so called "generator relay" you can still bypass the problem by unplugging the alternator four wire plug, and "blip" the throttle to rev the car up to 2,500 to 3,000 rpm to manually excite the alternator. However, I do belive this causes the alt to run @ 14v at all time. You will get a CEL, but the car will charge

Thats not bad to know, I just had a faulty reg. replaced in the alternator. About to get back on the road, I got my car for a steal... most shops could not figure the charging system out for the life of them.