1995 lesabre backfires and quits after starter is released.

99.99% sure that vehicle is not OBDII.

Take the money you would have spent on an ODBII code reader and buy a new battery. Sound like it's in rough shape.

Steve

The main problem is that it Will start but will only run as long as the switch is held in the start position, let it back to run and the engine quits, if I force the issue it will sometimes backfire too. Well guess its the process of discovery, when the weather warms up now its about -3 below zero. our is the back yard. Thanks for the reply, Tom A

Check the Ignition fuse in the fuse box. If it is blown it can do this. What the problem comes from is the run circuit is being broken when the key comes back from the start position. It could also be a bad ignition switch.

Steve,

You are correct. The 1995 LeSabre is what is called a "transistion vehicle" AKA OBD 1.5 - OBDI electrical interface (12-pin plug) but PCM outputs OBDII codes. Damn few "civilian" model scanners will work properly with these cars (my '94 Regal is also so afflicted).

Backfire makes me think bad spark timing or possibly crossfire

Regards, Bill Bowen Sacramento, CA

Very possible How old are the plug wires? If original, or more than about 5 years, change them.

Thanks for the reply, The plug wires are 2 years old [about 11,000 miles] It doesnt backfire all the time. just when the battery gets low. So far I have checked the fuses, their good. Checked the ign switch by using The dash lights, they dim when the switch is turned to 'start' the engine starts runs fine, then when I release the switch to the run position the engine dies immediately. If I keep hitting the key to start it will sometimes backfire. The battery is about 5 years old and I am off to get another one today but I doubt that will make any difference, But Hey! it cant hurt. I got a Dodge truck so i'm not without wheels anyway. I would be interested in how to test the ignition switch more that just seeing the dash lights dim when the starter is engaged. Anyway off to the battery buying for now Thanks again Tom A. Shure wish I had a warm area to work in, its -3 today.

>

Turning the ignition switch to start doesn't check the run position. The problem you have is being caused by the power to the ignition being cut off when you allow the key to return to the run position. The occasional backfire is because of the loss of power allowing the fuel to build up in the engine. Then when you try to start it that fuel gets ignited and you get a backfire.

Go under the hood and see if you have voltage to the coil pack (pink wire) with the key ON (not start). If you don't trace the power lead back till you find power. You will find power at the tan/black wire when the key is turned to start. You have checked ALL the fuses correct. There is one in the relay center as well as the fuse panel.

I'd think it was the ignition switch myself. About the only way I can think of to test it would be to remove it. The dash lights dimming is not a valid test. They're going to dim from the load of the starter.

Ok, Got new battery in- same problem. Also checked all the MAX fuses on the firewall panel, They are all good. Guess all thats left is wire tracing and removing the ign switch. Also tried 2 different security keys just to see if that would change anything- Nada. Got to look up how to remove the ignition switch somewhere. The weather hasn't got above 0 yet today, Dammed if I know why I still live here in this climate. Oh Well, bundel up and get back at it. Thanks again for the replys Tom A

Does the car run at all? While running, are any dummy lights on?

If it doesn't run, turn the ignition key on and watch the warning lights. After the car is done it's bulb check, what lights are still on?

Steve

No- it only runs for about 1-2 secs while the switch is in the start position. I just realized that even if I hold the switch in the start position the engine still dies in 1-3 seconds. Little hard on the starter tho. After bulb check oil, volt, temp, check, and seat belt lights stay on. If I try the start, only the volt and temp and seatbelt light stay on after. All the lights go out when the engine does it's short little run. Does that mean something? Well back at it I guess. Tom A

Yes. Your battery light should not be on after a bulb check.

First, check the "ENG EMIS" fuse in the Underhood Electrical Centre #1, it's the one on the passenger side.

If it's okay, disconnect the alternator connector. Not the big wire going to the battery, the little plug. Turn the ignition to the "RUN" position. Does the battery light come on? If not, replace the alternator.

Steve

I think you are correct, I will get to power tracing this weekend when it warms up. I will answer when I find the problem. Thanks again, Tom.

This 1995 lesabre does not work that way. All the bulbs come on when the key is turned to run and "Stay on" untill the key is turned to the start and back. "Battery, temp, oil, and engine check come on and stay on," Security and air bag are intermitten. They [security, air bag] flash and go out seems like when they feel like it.

I got a question, Would a code reader [of any kind] shed any light on this no run condition? Thanks Tom A

Code reader only works if the check engine light came on and there is a code stored.

Unfortunately, I'm going from memory because I no longer have a GM in my possession, but the VOLT light should come on and go out after a few seconds after switching to the "run" position and definatly after starting. I'm reading through the service manual and it doesn't state this fact, but I'm

99% sure that's how I remember it. Anyone with an early 90s GM can verify: does the battery light go out a few seconds after switching to "run?"

Steve

Only if the engine is actually running and turning the alternator.