Alternator issue? Charging issue? Gah.

[Baddog]

So a couple days ago the SS suddenly would start to sputter out and sometimes die at idle when the radiator fans would kick on. So I decided to test the alternator. With the blower motor on and lights on (HID's) it's putting out 12.5-13 volts at idle. Turn more things on, Wipers, dome light, etc. and the voltage DROPS lower. Revving it up doesn't help. With everything off at idle its around 13.1-13.5 doesn't move when you rev it either.

So I figured well the alternator isn't good. Battery is new and I had that tested. Good Battery. 100% charge (hmmm).

Replaced both battery terminals awhile ago. Can't see any issues with the wiring.

Battery light on the dash works when in the "ON" Position.

I replaced the alternator by the way and nothing changed. Any ideas?

I am assuming the stalling is due to a power loss somewhere or something.

[rallyak]

Check an clean all grounds.

[FundamentalyConfused]

Check this link and see if there's a wiring diagram for your car. http://www.main.experiencetherave.com/s ... FSM_Scans/

It should be in there, there was a zip file for my 90' n/a.

[Legacy777]

Yeah, check that all the grounds are good and check the voltage drop from the alternator post to the positive lead on the battery, and then to the fuse box distribution. You're looking for anywhere in the chain that there is a significant drop in voltage. This could signify a bad component.

[Baddog]

Fixed a couple grounds. All is well in the charging department. However. I am still having the stall issue at idle. Only happens when the car is fully warmed up and you've been driving it for 10-15 minutes. Will stall and sometimes just shut off. Other times it will catch it self. I have smoke tested it. There are no leaks.

[Legacy777]

Another thing you could check or clean is the MAF sensor. Just make sure to use MAF sensor specific cleaner and be gentle

[Baddog]

Not sure how I keep forgetting to post this. But i forgot to mention the speedo no longer works again. Replaced the sensor on the transmission and that fixed it. But then we did an top mount install and tucked wires under the dog bone. Speedo stopped working again. Pull the cable out of the sheath and looks fine. When I felt up behind the dash I believe it fell out I just can't get it back on.

Question is could this cause the issue? 5 speed.

[Legacy777]

I don't think so, but anything is possible. I'd definitely recommend getting the speedo cable installed again before troubleshooting further.

[Baddog]

Tested it with a known good MAF. No change.

This is a very awkward situation here.

[Baddog]

Fixed the speedo about an hour ago. Put it into D-Check mode. Got a code 32 and 35. Oxygen Sensor and Purge solenoid.

Replaced the Oxygen sensor. This made the car idle more steadily when it wants to idle properly. Purge Solenoid I know won't cause any of these issues. I will replace that when the top mount and TD04 goes on.

Car no longer back fires either. That's nice. However the random erratic idle is still there at times. I am running out of ideas here.

[Legacy777]

The ECU still does some interesting stuff with a code 35. So work on that and then see if you still have issues.

[Baddog]

Okay I will keep this updated.

Thanks

[Baddog]

So, code 35 is fixed. Fixed it when we did the tmic and td04. The issue is still there. I replaced the coolant temp sensor a couple months back so I don't think it's that. Car has a low cold start idle. 1k–1.1k. When warmed up idles at 700-750. It only idles irraticlly and dies maybe once a day maybe twice.

Any other ideas? Motor is sealed tight. No leaks or anything.

[Legacy777]

Ok, so are there any other codes stored or that come up during the active diagnostic?

So are you still seeing the voltage drop issues or is it just the poor idle and engine dieing now? Forgive me if you already mentioned this, but have you investigated the IAC valve?

[Baddog]

Sorry for the delay.

No stored codes while in D-Check mode. Drove it around and got no codes, got those fixed.

Thought it was a weak alternator so I switched over the the 2nd gen alternator. Idle is 14.1 amps and then when the secondary fan kicks on when you turn on "defrost" it drops to 12.4-12.6.

These numbers are consistent at the battery and at the alternator.

Keep in mind the stalling issue doesn't happen every time the secondary fan kicks on. However about half the time it does cause it to start stalling out.

Not sure if that would be the IACV because of the randomness. How do I check it?

[Legacy777]

You can check the resistance of the solenoids in the IAC valve top. Instructions are in this scan.

http://www.main.experiencetherave.com/s ... C_Diag.zip

[Baddog]

Sorry for these long delays.

IAC checked out okay. So I went ahead and took an old grounding kit I had laying around from Paranoid Fabrications and "reinforced" all the stock grounds. Cleaned up the mounting locations and the terminals. So far it has been fine.