92 Dies when turning on headlights!!!

1992 Buick Lesabre
130k miles
3800 Engine

OK, I know this sounds strange but my Father drives this car and he called me over to check out a problem he was having.

At first, I immediately noticed the awful noise coming from the alternator. That noise, along with the sparks flying out of it lead me to believe it was going bad. I replaced the alternator and thought all was well when the car would just stall at low idle.

The second issue occured when the head lights were turned on. If the car was at a low idle when the headlights were turned on the dash would flash and the car would shut down.

The only code I'm pulling is from an older issue with the A/C. Code 66.

I cleaned the MAF carefully and that has helped the car stop stalling from a normal idle but the issue with turning on the headlights still remains.

Anyone have any idea why turning on the headlights would lead to a short that would shut down the car? However, I can keep it running as long as I have the car running at a higher rpm first.

:screwy:

It still sounds like an alternator or battery problem. A lot of autopart stores will check them both for free.

I took the car back up to Autozone and had them test both the battery and the alternator. They both checked ok.

The car will only stall from a low rpm. It usually happens when adding a load to the vehicle like turning on the headlights or turning on the fan blower or hitting the brake pedal.

It's as if the computer does not respond to the additional load and it is too much for the vehicle and it stalls.

update:

After running the car to full temp the HVAC controls work normally. Until warm however the controls are non-responsive.

I am suspecting a leaky vacuum line.

Anyone know where to get a schematic of the vacuum lines for a 92 Lesabre?

Thanks.

Here's an update. I pulled the battery out and tested. It only read 10.9 volts. My charger said it had less than a 50% charge. I charged it to 100%, recleaned the MAF senser with electronics cleaner and put it back together.

The car hasn't stalled since.

I don't think the parts store people really know how to use their equipment.

...on to the next issue

You may have a problem with the positive battery terminals. If corroded under the insulation, your charging system will be erratic at best and the battery voltage will eventually drop again. It is imparitative that the terminals are corrosion free and perfectly clean & tight, to carry the load demand at this connection.
Read post 10, in This Thread (http://www.automotiveforums.com/vbulletin/showthread.php?t=671413)for more info.

You may have a problem with the positive battery terminals. If corroded under the insulation, your charging system will be erratic at best and the battery voltage will eventually drop again. It is imparitative that the terminals are corrosion free and perfectly clean & tight, to carry the load demand at this connection.
Read post 10, in This Thread (http://www.automotiveforums.com/vbulletin/showthread.php?t=671413)for more info.

I suspected just that. The terminals did not appear too bad from the surface but once I checked the mated surfaces between the terminal and the battery it was almost entirely corroded. I took a wire brush and cleaned them up.

Thanks...

> 3 echo 9<
BTW, thank you for your 'follow-ups', for they certainly help those who are trying to assist in resolving your issue

AHH!

Today's my lucky day. This will be the second time I type this post, this time I'll make it shorter.

I had the same problem withthe same car. I also couldn't passMARTA and it took me hours to find a place with a diagnostic scanner that could test my car (all others only went back as far as '95). The scanner they used, although supposedly only worked on '96s and back, DID give me some results that seemed to correspond with suggestions I had heard before, but the manual was very vague, and even the guy who ran the test said he didn't know what to tell me. He told me to try the website for Haynes Manual, but it is currently under construction.

My numbers were:

21
41
85
86

For anyone who might tell me what they mean, and even better, how to fix it.

What year is your Lesabre? Those last two codes aren't in my Haynes book.

21 is TPS sensor or circuit - voltage high

41 Cam sensor circuit (3.8L engine) or Cylinder select error - MEM-CAL or ECM problem.

I don't show the others.

Did you pull the other codes or did someone else?

I would first check that your charging system is functioning correctly. After the car has set over night I would check the battery. Mine was low and throwing everything off. It even fooled the Autozone people because the new alternator I put on charged the battery a bit. Leaving it over night allowed the charge to bleed off and gave me a true reading.

good luck