94 Lesabre running rough and backfiring

[Airsim14]

I have a 1994 Buick LeSabre that is running rough and backfiring. I changed the oil, oxygen sensor, spark plugs, and spark plug cables within the last 1000 miles.

The only thing I can think of that might be wrong is the timing.

A month ago, I filled up the tank and drove home. When i tried to start it again, it started up and died immediately. Eventually, I found that the vapor line to the fuel tank had rusted and broken in one spot. So I fixed it. It then started and would run for a couple seconds and die. I took the spark plugs out, and they were all black, so I cleaned them. It ran a little better, but not much. This morning I replaced the spark plug cables, and now it runs really rough, backfires and starts to shake really hard. but I am able to keep it running for a while if I hold the gas down.

Does this sound like timing or something else?

[DeltaP]

Sounds like misrouted secondary cables. Recheck them and then the timing.

[maxwedge]

As mentioned recheck wire routing/firing order, can't set timing all computer controlled. Disconnect the maf see how it runs when you recheck the plug wires.

[imidazol97]

Originally Posted by Airsim14

I took the spark plugs out, and they were all black, so I cleaned them. It ran a little better, but not much. ?

What would make the plugs black? Rich mixture if it was a dry black.

What oxygen sensor did you use. Some replacement brands have caused trouble. Do you have the original to put back in?

Also, don't bypass the possibiity of the computer being the problem.

[Tech II]

Anytime you have a misfire, this causes the engine to run rich, which will cause your plugs to be black, and also contaminate the O2 sensor, if you continue to run the vehicle with a misfire.....

First thing to do, is check coil output at the end of each wire with a spark tester.....If ok, then check fuel pressure, and see if fuel pressure holds....

[Airsim14]

I'm pretty sure the reason it was running rich is because the vapor line to the fuel tank was broken, and that messed everything up since I tried to run it so many times before I fixed it.

I took the O2 sensor out, and it was all. black. Is there any way to clean it?

Also, I tried to run it again this morning, and I heard a pop and there was a puff of smoke, the car died and I haven't been able to start it again.

I'm pretty sure this is the problem lol.






What is it? I can't seem to be able to push it back in.

[Airsim14]

Ok, I think that thing has something to do with the exhaust. I kind of put it back in, but it's not staying tight in there so I put a clamp on it to hold it in place until I get things figured out.

I also took the O2 sensor out to clean it last night, and soaked in gasoline to clean it. Not sure if that actually worked. Anyway, I started it up this morning without the O2 sensor, and it ran steady for a few seconds, so I think the timing must be fine. I think I also flooded the engine, so it's not starting right now with or without the O2 sensor.

If it doesn't work, then would I be right in guessing that the problem is the O2 sensor? If so, is there a better way to clean it, or do I have to buy a new one?

Thanks!

[imidazol97]

Originally Posted by Airsim14

Ok, I think that thing has something to do with the exhaust. I kind of put it back in, but it's not staying tight in there so I put a clamp on it to hold it in place until I get things figured out.

Trying to get picture

[DeltaP]

If it doesn't work, then would I be right in guessing that the problem is the O2 sensor? If so, is there a better way to clean it, or do I have to buy a new one?
__________________________________________________ __________________________________________________ ______________________
In a word.....No.

[Airsim14]

Thanks. The cloth that's on there has been there for years. I think it's supposed to be some kind of heat shield.

EDIT: I took the EGR valve (I think that's what you said it was) back out, and tried to run it. There is exhaust coming out the hole where the EGR valve goes, and I even had some coming out around the air filter(I don't have it on very tight).

Any idea why the exhaust is coming out the wrong end of the car? lol


EDIT 2: I did some research, and everyone seems to say timing is off, does that sound right?

[maxwedge]

Or the cat is blocked.

[Airsim14]

Ok, I can't figure out how to adjust the timing in my car. It seems that mine is different from most other cars. I tried to google it, but I didn't find anything helpful.

I don't think it's the cat.

Does anyone know how to adjust the timing or have a link to something that will tell me how to do it?


Thanks.

[aleekat]

Like Max said. Timing NON adjustable, computer controlled. I also leans towards a plugged cat.

I don't think it's the cat. How do you know?

[maxwedge]

Originally Posted by Airsim14

Ok, I can't figure out how to adjust the timing in my car. It seems that mine is different from most other cars. I tried to google it, but I didn't find anything helpful.

I don't think it's the cat.

Does anyone know how to adjust the timing or have a link to something that will tell me how to do it?


Thanks.

Did you read my post that it is non adjustable and computer controlled??

[Airsim14]

Yeah, I read the post, but for some reason I didn't see that part.

It's really cold right now, but I'll try to get the cat off tomorrow.