an air leak in front of the mufflers
light backfiring while coasting
Thread Starter
Instructor
Joined: Apr 2011
Posts: 208
Likes: 0
From: Trophy Club Texas
light backfiring while coasting
My 1991 is backfiring when I let off the gas and coast down a hill. Or if I've been giving it a lot of gas and suddenly let off.
It does not backfire on accelleration.
I recently started getting a Code 23 (mat sensor) and plan to replace the sensor with the relocation kit.
I also get an EGR valve code only after driving the car for extended periods of time.
I think the code 23 could be causing my issue because it could be sending the wrong fuel/air mixture.
Any thoughts?
It does not backfire on accelleration.
I recently started getting a Code 23 (mat sensor) and plan to replace the sensor with the relocation kit.
I also get an EGR valve code only after driving the car for extended periods of time.
I think the code 23 could be causing my issue because it could be sending the wrong fuel/air mixture.
Any thoughts?
Thread Starter
Instructor
Joined: Apr 2011
Posts: 208
Likes: 0
From: Trophy Club Texas
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Instructor
Joined: Oct 2010
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Check your AIR pump selenoids. If they aren't functioning properly they'll be injecting air into the exhaust when your coasting and cause the back fires.
Mine was doing that and I just unplugged it, took care of the problem.
Mine was doing that and I just unplugged it, took care of the problem.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
I don't know about your year, but it may be similar. This is for '86 to '89 with 1227165 ECMs: The MAT sensor only determines when EGR is activated. That's ALL it does. It has no other function.
Check your EGR system.
Check your EGR system.
Le Mans Master
Joined: Jan 2006
Posts: 5,620
Likes: 206
From: Orlando FL
I would check to see if the EGR valve moves freely when you move it with your fingers.
I believe an EGR solenoid is used and I would check it to see if the coils resistance looks good.
I had a similar problem where the coil in the solenoid was good but the valve did not operate properly. I found the problem by externally putting 12 volts to the coil (it clicked) and blowing thru the valve portion. It did not close and open properly and then pieces of debris started to fall out after examining it for a while.
I believe an EGR solenoid is used and I would check it to see if the coils resistance looks good.
I had a similar problem where the coil in the solenoid was good but the valve did not operate properly. I found the problem by externally putting 12 volts to the coil (it clicked) and blowing thru the valve portion. It did not close and open properly and then pieces of debris started to fall out after examining it for a while.
