Backfire thru intake - 88 L98
Thread Starter
Racer
Joined: Feb 2001
Posts: 276
Likes: 0
From: Springboro OH
Backfire thru intake - 88 L98
I was out this afternoon, made a stop for about 1/2 hour got back in the car started it, ran ok for a second then it started to run rough. I pulled out of the parking space and it started to backfire and run real rough then it finally stalled. I started it up again, it ran rough, since I was in the road I feathered the gas to get to a cross street but then it started to run ok. The whole episode lasted about 5 min. Then about 10 miles later I smelled smoke so I pulled over and my AC compressor was smoking and quite turning (AC was on). I dont think the two are related but it seems wierd that this would happen around the same time. Any thoughts, anyone know what some reasons for a backfire would be?
Joe
Joe
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Re: Backfire thru intake - 88 L98 (joalyons)
The two don't seem related - engine backfire and the a/c compressor quitting.
As to the a/c, if you can turn the compressor bolt with a socket, then the clutch probably quit. If not, the compressor is probably seized. As to the engine, does it run ok now? Did it overheat while these problems were going on? Any smoke out of the exhaust?
As to the a/c, if you can turn the compressor bolt with a socket, then the clutch probably quit. If not, the compressor is probably seized. As to the engine, does it run ok now? Did it overheat while these problems were going on? Any smoke out of the exhaust?
Le Mans Master
Joined: Jul 2001
Posts: 8,183
Likes: 3
From: Santa Maria, CA
Re: Backfire thru intake - 88 L98 (joalyons)
Plug wires in good shape? or grounding out somewhere? That happened to mine once. A plug wire too close to exhaust manifold and burnt/grounded. But backfire thru the intake? A backfire in the muffler for example is like unspent fuel hitting the hot catalyst or hot pipes and igniting. Thru the intake might be like ignition of A/F while an intake valve is open :confused:
[Modified by 89 Paul in cal, 4:38 PM 10/24/2001]
[Modified by 89 Paul in cal, 4:38 PM 10/24/2001]
Thread Starter
Racer
Joined: Feb 2001
Posts: 276
Likes: 0
From: Springboro OH
Re: Backfire thru intake - 88 L98 (SunCr)
I checked the codes, there are non stored - all I got was a flashing 12. When I started the car it ran slightly rough and idled low, around 500 RPM. It appears the compressor seized, so do you think that could have caused the timming chain to jump a tooth?
Also the backfire was thru the intake.
[Modified by joalyons, 10:42 PM 10/24/2001]
Also the backfire was thru the intake.
[Modified by joalyons, 10:42 PM 10/24/2001]
Drifting
Joined: Nov 2000
Posts: 1,722
Likes: 0
From: Big D Tx
Cruise-In II Veteran
Re: Backfire thru intake - 88 L98 (joalyons)
are you sure it was an actuall backfire through the intake? those will be pretty damn loud, like a huge bang from a pistol. was it just a popping noise that you heard?
Pro
Joined: Jun 2001
Posts: 656
Likes: 0
From: Fort Worth TX
Re: Backfire thru intake - 88 L98 (88L98)
Mine did something like that ( not the A/C ) and it threw a code saying it was either the computer or the inition module it turned out to be the computer. At Auto Zone a replacement was $90 .
Thread Starter
Racer
Joined: Feb 2001
Posts: 276
Likes: 0
From: Springboro OH
Re: Backfire thru intake - 88 L98 (88L98)
It sure sounded like a backfire thru the intake, like something that would happen on a carb engine, if the timing was way off or the choke closed. Maybe Im wrong, but given how it ran (almost was not) it sounded and felt like it.
Update: I started the car this morning and it ran fine so I drove it to work to see how it ran when hot, at highway speeds, etc. It seems fine, there were no drivability issues, idled great, had plenty of power, etc. This is just crazy, I was thinking that maybe the timing chain jumped a tooth but I dont think that it would be running rough one time and ok the next. Is there a sensor that reads the air temp? Im thinking that since it was hot yesterday and cool this morning that might have made a difference.
Thanks again for the help,
Joe
Update: I started the car this morning and it ran fine so I drove it to work to see how it ran when hot, at highway speeds, etc. It seems fine, there were no drivability issues, idled great, had plenty of power, etc. This is just crazy, I was thinking that maybe the timing chain jumped a tooth but I dont think that it would be running rough one time and ok the next. Is there a sensor that reads the air temp? Im thinking that since it was hot yesterday and cool this morning that might have made a difference.
Thanks again for the help,
Joe
Race Director
Joined: Nov 2000
Posts: 10,340
Likes: 664
From: Beverly Hills (Pine Ridge) Florida
Re: Backfire thru intake - 88 L98 (joalyons)
Check your ignition timing. If the timing has not moved, then the timing chain has not jumped. Just went through this back firing problem in the intake. Turned out to be a bad runner gasket (at least on mine) letting in a lot of air (vacuum leak). Found it using the propane method. Mr. Gasket gaskets suck (literially)! Went with Fel-pro (had to "port" them to make them fit my oversized runners). The Mr. Gasket type are like paper and tear very easily. Fel-pro have a steel insert that prevents this type of blow-in (or blow-out).
Popping in the intake can also be caused by poor ignition wires, crossfire, etc.
Good luck,
Plasticman
Popping in the intake can also be caused by poor ignition wires, crossfire, etc.
Good luck,
Plasticman
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