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LV2NR #1
02-27-08, 02:14 PM
I have no idea if anyone else has this problem or if it has been posted before here, I have looked and I didn't find it. I just installed a custom cai about a month and a half ago, the I got tired of seeing my service engine soon light on for not having a cat. After I got the codes cleared by a friend at the local parts store, every now and then about once or twice a week, if I barely tap the gas while slowing down the engine will sound like it is backfiring (sp?) out of the throttle body. Please let me know if there is anything i can do im a lil :confused: on this.

Mikz86TA
02-27-08, 04:07 PM
That would be like mis-installed distributor causing that.
The CAI wouldne cause that issue. Maybe you have a CAI boot loose or the PCV vent tube unhooked and not plugged at the intake.
What year and engine?

exodus
02-27-08, 04:25 PM
Hmmm interesting. I have a similar issue, but i am pretty sure mine is due to just putting on new headers and exhaust, and the new muffler just isn't deadening the sound. I know the noise I'm hearing is definately coming from behind (from the muffler) so I don't think we have the same problem. But mine does make that backfiring sound type thing right after i let up on the gas. It didn't do that on my truck until i put the new headers and exhaust, so maybe it has something to do with your exhaust? You said you have no cat, so you must have done something to it. Maybe we do have the same thing after all?

I get this noise all the time though, which is why i was pretty sure it's just cuz i have a High Flow Flowmaster 40 series muffler that really isn't much of a "muffler" at all, lol. :) Either that or it's the fact I have a muffler with no pipes coming out the backside lol. Just Headers>Cat>muffler>(pipes out not installed) :)

ace2fine
02-27-08, 05:47 PM
mine gurgles and pops all the time on decel. are you sure its coming from the throttle body? thats what you connected the cold air intake to. sorry for the obvious but i'm not sure of your auto knowledge:o. we've had some crazies on here lately:D

What?
02-27-08, 09:26 PM
do you have a 2.2L or 2.5L?

LV2NR, remove the o2 sensor after cat, put nut plug on that sensor location, ziptie or whichever to hold sensor away, so it'll have fresh reading 24/7

if ses light still appear for o2 sensor, if it reads bank 1, replace it with delco, and same for after cat

12sws27
02-27-08, 11:00 PM
isnt backfiring threw to tb/carb usually a timing issue?

LV2NR #1
02-28-08, 05:04 PM
I know it isn't from a distributor because its is the 99 2.2 it doesn't have one. I know it isn't the exhaust bc when it backfires it sounds like a 12 gauge shotgun, i guess that's what happens when you have a 4" tip with no restrictions in the exhaust lol. I'm thinkin it could be the timing chain or belt, not sure what this motor has I havent torn one of these down yet, yet. Oh and Ace no offense but I do know it is a backfire form the throttle body I've heard that noise a thousand times workin on race cars. I have been under the hood of cars since I could walk lol. Like I said no offense man I understand the crazies and the people that don't exactly know what they are talkin about especially the young guys.

LV2NR #1
03-07-08, 04:23 PM
BUMP

Does anyone have any ideas? It is getting worse and more often.

Nickelin'Dimer
03-23-08, 06:56 AM
How many miles are on your truck? Reason is the factory "Quiet" chain (Yes, it's a chain that drives the cam that's located in the block) tend to be due for replacement around 80,000-100,000mi. And when it does let go, look out! The frags could find their way into the oiling system & procede to contaminate & take-out the lifters & cam bearings, and the mains & rods (In that order). Changing the chain is now prob. Just be sure to use a GM approved replacement, otherwise you'll be lookin' at going through replacing it again sooner than expected.

LV2NR #1
03-25-08, 07:40 PM
It just rolled over to 150,000 and I know where the cam is. I know when the chain goes it tears up just about everything. We had a double roller let go at 8,000rpm on the grand national last year. It broke the water pump, flattened the cam, and of coarse exploded the timing cover.

Nickelin'Dimer
03-26-08, 10:34 AM
I wasn't writing that to insult you, I've actually seen what results from a fragged chain on a LN2 (That's this engine's RPO) that gets into the oiling system. Looks like you're right on the edge of failure with it, and that I know from having driven a few vehicles that needed chain replacement as they showed the same signs as you're experiencing. Best change that chain ASAP, unless you want to change the entire long block (Yeah, it gets that bad).

LV2NR #1
04-02-08, 06:38 PM
I also think it is the timing chain that is making the motor backfire and it is getting worse, it is coming out both ends now. It is almost deaffening (sp?) when it comes out the exhaust. But a friend of mine has a 98 Cavi with the same motor, and he had the same problem. He was told it was the coil packs, he changed them and the motor stopped acting up. Is there anyone else that thinks it could be the coil packs, I really don't wanna tear the engine down to change the timing chain. Well atleast the front of the engine.

Nickelin'Dimer
04-02-08, 10:18 PM
You have 150,000mi on your engine now, right? Well electrical parts do build up resistance with use, and I'd say with that many miles they're due. Give 'em a try & if it don't change, well... at least you eliminated something.

Jay-Sliver
04-02-08, 10:23 PM
I know in the small engines worls, a coil going bad will cause a single cylinder, or twin cylinder (briggs especially) to backfire out the intake.

What?
04-08-08, 01:19 AM
you said there was code what are the codes?

What?
04-08-08, 01:38 AM
I have no idea if anyone else has this problem or if it has been posted before here, I have looked and I didn't find it. I just installed a custom cai about a month and a half ago, the I got tired of seeing my service engine soon light on for not having a cat. After I got the codes cleared by a friend at the local parts store, every now and then about once or twice a week, if I barely tap the gas while slowing down the engine will sound like it is backfiring (sp?) out of the throttle body. Please let me know if there is anything i can do im a lil :confused: on this.

has anything occur BEFORE doing this?

LV2NR #1
04-08-08, 03:25 PM
The code was for cat converter deffincency. My cat got plugged a couple months after I bought the truck, so i took it off gutted it and put it back on. I changed my timeing chain, tensioner and gears last weekend. Even though it didn't seem to be stretched and the gears were perfect but I already tore the motor apart so I changed it to be on the safe side. I also changed the fuel filter because it had about 40,xxx on it. It hasn't backfired yet again but it has only had 250 miles on it so far. Just driving around and taking it easy. If it keeps doing it I'm gonna change the coil packs. I'm going to swap for the accel's I think the voltage it 45,000. They aren't much more than stock ones anyway.

Nickelin'Dimer
04-08-08, 06:32 PM
Accel's are considered junk... Go with MSD's 8224's, they're considered much better.

Jay-Sliver
04-08-08, 06:42 PM
x2 Accel is Junk. Coils melt down, wires arc...

LV2NR #1
04-08-08, 06:46 PM
I was gonna do the accels with msd 8.5s, I'm not sure what plugs yet. But I trust y'all, so the msd 8224's are better. I'll have to look them up and do a little research.