Alternator ECU electrical problem 1G

[Rally1]

On start the engine idle surges to 2k, up and down every second.

Common on 1G DSM was the fact that the capacitors in the ECU tended to leak. So I replaced the ECU with another used one that had the caps replaced. The problem still exists.

The interior lights and headlight will flicker rapidly when the car is on, if i give it gas (RPMs over 2k) they lights are solid.

With the car off (ie just on Batt.) there is no flickering.

I am guessing alternator. It is an "upgraded" alternator, rebuilt to put out 90A rather than 70A.

If I put a meter on the battery with the car on the voltage sits at 14.2V, even though the lights flicker, the number doesn't change. And i tested it with a digital VOM and an analog one so i could see the needle swing (it didnt).

Does it sound like alternator, or does it sound like a voltage regulator or something else?

Need more info, just let me know.

 

[Defiant]

Sounds like grounding corrosion; I think yours is regulated by the ECU, not at the alternator. That output is right where it's supposed to be.

 

[Rally1]

So i got another bad ECU? Or does the grounding issue ---> the ECU having a bad reading?

By grounding corrosion, do I need to ground the battery better? I seem to remember trying that a while back. Or do i need to ground something else?

I can tear whatever appart i need to, it's not my daily driver. As long as my WRX doesn't break down .

 

[Rally1]

any clarification of grounding corrosion

 

[Defiant]

Be patient, I'm not often around in daylight.

Yeah, check the battery grounds, and the ground connection on the ECU itself.

 

[Rally1]

No such luck, any other ideas? TIA.

 

[Rally1]

I have done this: http://www.vfaq.com/mods/BISS-1G.html

I tested the ISC, and it checks out good.

Had the battery and alternator tested at Kragen (Autozone like store) and both passed. When I asked him the test told him how many Amps it was putting out, he said 14Volts

I want to test the output of the alternator, but I dont have a meter that will read over 10A. I have the shop manual, and it has ways to test it, but not without a meter that will go to 100A.

Just checked the belts tighness again, and looked good, tightened it a little more to be sure.

If/when I do the timing belt, would that be a good time to replace the alternator anyway? Or perhaps when it is out I can have it tested?

I also cleaned on the B+ connector on the alt.

At night my Talon looks like a strobe light, not a good look

 

[wishihadatalon]

our alts. are weird. mine died then i put a new one in and 3 lights on my dash wouldn't go away so then i got another one and it was finally right. it was a long and stressful process

 

[Rally1]

bump!

 

[Rally1]

As mentioned above had the alternator tested in the car: Passed

I took out the alternator, and took it to AutoZone, it passed on their machine.
I took it to Kragen, it failed. They didn't have the alternator in stock.
Went to another Kragen, had it tested again, failed again.
Bought new 90A alternator, had them test new unit in the store, passed.
Installed alternator.
Problem solved.


While the old alternator put out 14.5V it wasn't putting out enough current (Amps), it was putting out just enough to charge the battery, no more. Voltage isn't everything, and the only (easy) way to test load it to remove the alternator and have it tested.