Small backfire through intake - '94 LT1
Thread Starter
Teching In
Joined: Mar 2010
Posts: 4
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Small backfire through intake - '94 LT1 Hi! New guy from Kentucky here.
I have been looking at buying a friend's '94 Camaro Z28, but it has one small problem that worries me. When you stomp the gas it hesitates for a second, backfires through the intake, then takes off like a rocket.
The backfire isn't persistent, which is what confuses me. It idles fine, and runs great after it takes off. I'm assuming that it is a timing issue, because it wouldn't backfire through the intake unless an intake valve was open and premature detonation was occurring in one of the cylinders, right? Just an assumption, though. I've kind of ruled out the Opti-Spark being a problem, because of the smooth idle and it has plenty of high-end power.
- The car only has 96,000 miles, but is it possible that the timing chain has developed enough slack to advance timing for a few seconds when you stomp the gas, and then return to normal when it takes off?
- Is there anything on these engines that electronically advances and retards timing?
- MAF sensor?
- Any other ideas?
Any help is greatly appreciated!
I have been looking at buying a friend's '94 Camaro Z28, but it has one small problem that worries me. When you stomp the gas it hesitates for a second, backfires through the intake, then takes off like a rocket.
The backfire isn't persistent, which is what confuses me. It idles fine, and runs great after it takes off. I'm assuming that it is a timing issue, because it wouldn't backfire through the intake unless an intake valve was open and premature detonation was occurring in one of the cylinders, right? Just an assumption, though. I've kind of ruled out the Opti-Spark being a problem, because of the smooth idle and it has plenty of high-end power.
- The car only has 96,000 miles, but is it possible that the timing chain has developed enough slack to advance timing for a few seconds when you stomp the gas, and then return to normal when it takes off?
- Is there anything on these engines that electronically advances and retards timing?
- MAF sensor?
- Any other ideas?
Any help is greatly appreciated!
TECH Enthusiast
Joined: Mar 2009
Posts: 680
Likes: 7
From: Clearwater
bump for figuring this out
my friends 94 auto did it for over 100k miles and we never figured it out. another friend with a 94 m6 did it too on nitrous and blew out the MAF. my 95 m6 has never done it on the old motor or the new one as well as another friends 95 auto. kinda wierd that it was only happening for 94s.
my friends 94 auto did it for over 100k miles and we never figured it out. another friend with a 94 m6 did it too on nitrous and blew out the MAF. my 95 m6 has never done it on the old motor or the new one as well as another friends 95 auto. kinda wierd that it was only happening for 94s.
Thread Starter
Teching In
Joined: Mar 2010
Posts: 4
Likes: 0
bump for figuring this out
my friends 94 auto did it for over 100k miles and we never figured it out. another friend with a 94 m6 did it too on nitrous and blew out the MAF. my 95 m6 has never done it on the old motor or the new one as well as another friends 95 auto. kinda wierd that it was only happening for 94s.
my friends 94 auto did it for over 100k miles and we never figured it out. another friend with a 94 m6 did it too on nitrous and blew out the MAF. my 95 m6 has never done it on the old motor or the new one as well as another friends 95 auto. kinda wierd that it was only happening for 94s.
I'm going to hook up a multimeter to the MAF sensor and see what the voltage readings are tomorrow.
Could it be a intake valve slightly bent, staying open alittle letting compression blow out the intake?
I bent a valve in my 93' before and it ran smooth, but had alittle backfiring out the intake, it didn't miss, I just noticed it was down on alittle power then what I was used to with it.
I bent a valve in my 93' before and it ran smooth, but had alittle backfiring out the intake, it didn't miss, I just noticed it was down on alittle power then what I was used to with it.
Thread Starter
Teching In
Joined: Mar 2010
Posts: 4
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These are all good possibilities. I'll start with the MAF and the O2 sensors before I start pulling off valve covers and/or heads.
I hate everything that comes with buying a used car haha.
VERY nice GTO, by the way!
I hate everything that comes with buying a used car haha.
VERY nice GTO, by the way!
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Hi! New guy from Kentucky here.
I have been looking at buying a friend's '94 Camaro Z28, but it has one small problem that worries me. When you stomp the gas it hesitates for a second, backfires through the intake, then takes off like a rocket.
The backfire isn't persistent, which is what confuses me. It idles fine, and runs great after it takes off. I'm assuming that it is a timing issue, because it wouldn't backfire through the intake unless an intake valve was open and premature detonation was occurring in one of the cylinders, right? Just an assumption, though. I've kind of ruled out the Opti-Spark being a problem, because of the smooth idle and it has plenty of high-end power.
- The car only has 96,000 miles, but is it possible that the timing chain has developed enough slack to advance timing for a few seconds when you stomp the gas, and then return to normal when it takes off?
- Is there anything on these engines that electronically advances and retards timing?
- MAF sensor?
- Any other ideas?
Any help is greatly appreciated!
I have been looking at buying a friend's '94 Camaro Z28, but it has one small problem that worries me. When you stomp the gas it hesitates for a second, backfires through the intake, then takes off like a rocket.
The backfire isn't persistent, which is what confuses me. It idles fine, and runs great after it takes off. I'm assuming that it is a timing issue, because it wouldn't backfire through the intake unless an intake valve was open and premature detonation was occurring in one of the cylinders, right? Just an assumption, though. I've kind of ruled out the Opti-Spark being a problem, because of the smooth idle and it has plenty of high-end power.
- The car only has 96,000 miles, but is it possible that the timing chain has developed enough slack to advance timing for a few seconds when you stomp the gas, and then return to normal when it takes off?
- Is there anything on these engines that electronically advances and retards timing?
- MAF sensor?
- Any other ideas?
Any help is greatly appreciated!
Teching In
Joined: Jul 2009
Posts: 12
Likes: 0
I know this sounds stupid but, I know this by experience. Have you changed the plug wires? After my cc306 install I had the 3 and 5 cylinders crossed and the car ran fine except the occasional backfire thru the intake. I mean it really ran fine besides that. The backfire thru the intake at the first of WOT and it killed me so I started looking at things and found 3 and 5 crossed up.
Thread Starter
Teching In
Joined: Mar 2010
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After changing the plugs, plug wires, cleaning the MAF sensor and several other things... I found the problem.
The rubber intake elbow with the "donkey dong" that connects the MAF sensor to the engines intake had a huge split in the bottom of it. It was allowing the engine to suck in air that was bypassing the sensor. Since the MAF sensor was only reading a portion of the air that was being sucked into the intake, it wasn't adjusting for more fuel and it was causing a lean condition at wide open throttle.
I'm pretty relieved
The rubber intake elbow with the "donkey dong" that connects the MAF sensor to the engines intake had a huge split in the bottom of it. It was allowing the engine to suck in air that was bypassing the sensor. Since the MAF sensor was only reading a portion of the air that was being sucked into the intake, it wasn't adjusting for more fuel and it was causing a lean condition at wide open throttle.
I'm pretty relieved
