2G Spyder ECU - Alternator problem?

[ryan4269]

Starting and driving the car for 5 mins is fine and battery/alternator maintains 13.4 or so volts. However after 5 minutes or so the alternator is on full power, I can very noticeably hear and feel it rob power from the engine and the voltage then reads anywhere from 16-18v. When stopped in traffic for a few mins and idling it seems to kick back off. And voltage drops back to what it should be.

I don’t know much about how the alternators work on this car but could it be a problem with the ecu? Or does it all come down to the alternator?

 

[steve]

I'm sure that the alternator on the 2.4L NA Spyder has an internal regulator and pretty sure (pending checking the FSM) that if the ECU has any interaction with the alternator like the 2.0 Turbo cars it's to turn the alternator off to reduce emissions.

I check the sense wire from the alternator to the battery and start planning on replacing the alternator.

 

[ryan4269]

I'm sure that the alternator on the 2.4L NA Spyder has an internal regulator and pretty sure (pending checking the FSM) that if the ECU has any interaction with the alternator like the 2.0 Turbo cars it's to turn the alternator off to reduce emissions.

I check the sense wire from the alternator to the battery and start planning on replacing the alternator.

Thanks for the reply, so the connection between ecu and alternator only has the ability to lower the alternator load?

This is a 95gst ecu on a 97 n/a harness, turbo setup. Just finding it a little coincidental the alternator goes a couple weeks after turbo setup/swap

 

[99dsmer4g63]

Did you happen to get antifreeze or power steering fluid on it while swapping things? A little fluid kills these alternators quickly…ask me how I know. I wouldn’t suggest driving the car if your volts are actually that high. When my went out and starting having high voltage I noticed it in the driveway first from the high pitch electrical noise and then seen the voltage very high.
-Daniel

 

[ryan4269]

Did you happen to get antifreeze or power steering fluid on it while swapping things? A little fluid kills these alternators quickly…ask me how I know. I wouldn’t suggest driving the car if your volts are actually that high. When my went out and starting having high voltage I noticed it in the driveway first from the high pitch electrical noise and then seen the voltage very high.
-Daniel

Duude now that I think of it, one of the belts was developing a little squeak and I had this “belt care” spray laying around that I was gifted awhile ago. Turned out just making the squeal worse and I had to tighten up the tension. I definitely got a little in the alternator.

Could totally be it.. new alternator time? Damn

 

[ryan4269]

unplugging the pigtail connector on the alternator (believe it connects ecu and alt) has temporarily fixed my problem.

 

[steve]

Verify that the alternator is even working now. There are two wires on that connector that go to the ECU and the other two are to power the alternator up and sense the voltage at the battery.

Pulling that plug should keep the alternator from working.

 

[ryan4269]

Verify that the alternator is even working now. There are two wires on that connector that go to the ECU and the other two are to power the alternator up and sense the voltage at the battery.

Pulling that plug should keep the alternator from working.

Alternator appears to be working.. the voltage is on the low side but it’s maintaining it. I’ve driven it for a couple hours.