Backfiring when Accelerating, but no SES light...
Thread Starter
Le Mans Master
Joined: Mar 2001
Posts: 9,464
Likes: 1
From: Modesto CA
Backfiring when Accelerating, but no SES light...
Well, tonight, when I took the vette out, it seemed a little odd at first (though a tire might be low) then, a few minutes later, when I went to accelerate, it didn't really want to accelerate, just backfire. I didn't get any SES lights, so I thought it might be because I was a little low on gas (3 bars left) so I filled up with some 91...still does it. It's not so bad, as to I CAN'T accelerate...it still accelerates, just backfires while doing it. Also, the worst backfiring it when initially accelerating from a stop.
Any ideas?
Also, when I disconnected the MAF Sensor, it didn't die, but the idle went up to about 1000-1200rpm and it was smoking (smelled like gas). I DID notice, however, that the sensor wires inside the MAF didn't glow when a friend shut the car off. (Aren't the supposed to glow red, meaning the Burn-off Relay is working properly?)
A while back, I got a Burn-off Relay SES Code, but it went away.
Any ideas?
Also, when I disconnected the MAF Sensor, it didn't die, but the idle went up to about 1000-1200rpm and it was smoking (smelled like gas). I DID notice, however, that the sensor wires inside the MAF didn't glow when a friend shut the car off. (Aren't the supposed to glow red, meaning the Burn-off Relay is working properly?)
A while back, I got a Burn-off Relay SES Code, but it went away.
Last edited by TIMSPEED; Feb 13, 2005 at 04:37 AM.
Melting Slicks
Joined: Dec 2004
Posts: 2,954
Likes: 2
From: Obama=death for America
If you got a burn off relay code, why not change the relay. It's cheap. It's about $12. Wouldn't it be nice if that solved your problem. Also, you could have a clogged fuel filter. When was the last time you changed it? Maybe your cat. is clogged?
Thread Starter
Le Mans Master
Joined: Mar 2001
Posts: 9,464
Likes: 1
From: Modesto CA
Originally Posted by 85 500 horse
If you got a burn off relay code, why not change the relay. It's cheap. It's about $12. Wouldn't it be nice if that solved your problem. Also, you could have a clogged fuel filter. When was the last time you changed it? Maybe your cat. is clogged?
Melting Slicks
Joined: Oct 2004
Posts: 2,510
Likes: 4
From: Austin Texas
Could be so many things. Doe's your '87 have Opti or otherwise? Could be a timing issue. Also, how does the car idle? Normal?
How does the car run at cruising speed, ie at 60mph steady..???
Here's a few things that comes to my mind:
- Fouled plug(s)
- Bad plug wire(s)
- Bad injector(s)
- Bad fuel regulator or pump
If your backfiring is taking place in your headers, this would indicate a rich condition in combustion chamber, which leads to incomplete burn during combustion cycle. The remaining "mixture" going thru the exhaust valve cotains enough fuel to re-ignite from your headers, which get really hot, and act as a "glow plug", causing backfire...
How does the car run at cruising speed, ie at 60mph steady..???
Here's a few things that comes to my mind:
- Fouled plug(s)
- Bad plug wire(s)
- Bad injector(s)
- Bad fuel regulator or pump
If your backfiring is taking place in your headers, this would indicate a rich condition in combustion chamber, which leads to incomplete burn during combustion cycle. The remaining "mixture" going thru the exhaust valve cotains enough fuel to re-ignite from your headers, which get really hot, and act as a "glow plug", causing backfire...
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Maybe dead burnoff relays. But dirty MAF wires would actually tend to lean it out.
Either way if it was getting too much fuel, your plugs are gonna be fouled.
Either way if it was getting too much fuel, your plugs are gonna be fouled.
Thread Starter
Le Mans Master
Joined: Mar 2001
Posts: 9,464
Likes: 1
From: Modesto CA
Well, I replaced both Power/Burnoff relays. NOW, it DOES visually make the MAF Sensor wires glow RED hot. ALso, when they glow, you can hear the relay "click". (Never heard that before) It SEEMED to idle better, and not backfire in the headers. I'll take it out for a test drive a little later, if not better, I'll replace the plugs, and then go from there...
