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Have a 98 Camaro V-6, once the car has been driven 15-20 minutes it will backfire, stall and the engine will stop running. It will restart ok, but not make it out of first gear before doing the same thing. Once the engine has cooled it will run ok until it gets hot again. My local tech. repaired 2 leaky gaskets that was causing antifreeze to leak. But this is a separate problem. Now he thinks the above problem is caused by a faulty crank shaft position sensor in the engine block. Has anyone else had this problem and is the crank sensor the correct fix? Thanks!
^ I would think it would throw a crankshaft code. Is it a M5 or A4 ?
08' L76 6.0L 4X4 Chevy EXT.Cab LTZ Vortec MAX with Snug top cover, Dynomax exhaust,Hptuners& K&N intake
96' Camaro M5 to A4 conversion, alot of mods . GT35R Turbo full suspension. Built engine
backfiring is usually a leak in the exhaust system (too much oxygen causes backfiring)...cracked manifold, cracked exhaust pipe, cracked muffler, cracked cat...crank position sensor usually causes car not to start at all....
backfiring is usually a leak in the exhaust system (too much oxygen causes backfiring)...cracked manifold, cracked exhaust pipe, cracked muffler, cracked cat...crank position sensor usually causes car not to start at all....
I do not believe you sir. Doesn't make sense. I could run open headers all day without backfiring.
To the OP- You can really drive it 15-20 minutes before it acts up like that? How's the cat?
There are typically two kinds of engine backfires, one is generated from the intake manifold of the engine, and the second is expelled from the exhaust pipe at the rear of the car.
Exhaust system backfires occur in engines that have an emission system malfunction, like an air injection system diverter valve problem, an exhaust leak, or when the catalytic converter has been removed.
A fuel injected engine may backfire if an intake leak is present (causing the engine to run lean), or a fuel injection component such as an air-flow sensor is defective.
Backfiring is usually the result of too much oxygen in the exhaust system. This causes a combustion in the exhaust system which results in backfire from the exhaust. Oxygen can enter the exhaust from leaks present in any component of the exhaust or from the air injection system if the vehicle is equipped with such a system.
Ok.. Read that crap. Our cars do not have an air injection system. If they do, then mine's hiding from me. Therefore, our catalytic converter and EGR valve is the other used option. Meaning if he's getting a backfire because air is in fact getting into his exhaust system to allow some sort of mixture capable of combustion, he's running too rich which has been caused by a different problem.
I can however, agree with you that if air is getting into the exhaust system before his O2 sensors it could create a lean read and his engine will try to compensate on the false cylinder combustion reads. To that extent I would agree.
I am willing to bet that the positive pressure of the exhaust would make the possibility of air entering any crack in the exhaust system, pretty hard pressed.
To the OP, just thought of something. Just to make sure all is kosher with the O2 sensors, disconnect the battery for like.. half an hour. Or something of the sorts. Unless you have HP tuners and you can just reset the fuel trims. Then disconnect the passenger o2 sensor. You don't have to remove it, just disconnect the wires to keep it in open loop. Then take it for a drive and see if the problems come back. If they do, I'd bet on.. a bad valve, crank shaft position sensor, or maybe camshaft position sensor.
Hey, excellent discussion guys. I'm printing it so my tech. can consider your ideas. I will say that my tech originally thought the intake manifold had a leak and was going to tear it apart and replace the gaskets when he found leaking gaskets for the thermostat and ? (can't remember the other part) and opted to replace those instead. Problem is it didn't solve the problem of stalls and backfires. I don't think the backfires are being generated in the exhaust system. I'm not that mechanically minded but when the problem get's started, it seems to run rich, like the engine is getting too much fuel, and that the engine needs to burn it and expend it somehow. It only reluctantly backfires a little, then starts stalling, cutting off. Sometimes it restarts, sometimes it does not. But the problem goes away after cooling 20 min.
Check for spark and for injector pulsing when it will not start. If one is not present or one is erratic I would suspect the Crank position sensor. They do not need to throw a code to be bad.
I would also check the ignition control module. When they are faulty they can start acting weird when hot, and they don't generate a code. I've had two of them go out on other cars, and the symptoms would appear when the engine was hot and/or under load. It can be tested at parts stores, call first to make sure they can do it. Have the coils checked too. But I'll bet it's the ignition control module.
I would also check the ignition control module. When they are faulty they can start acting weird when hot, and they don't generate a code. I've had two of them go out on other cars, and the symptoms would appear when the engine was hot and/or under load. It can be tested at parts stores, call first to make sure they can do it. Have the coils checked too. But I'll bet it's the ignition control module.
That would be for a "mis-fire", am I wrong? Unless the OP doesn't know the difference between a backfire and a misfire?
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Once engine is hot, backfires, stalls, stops
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