Weird backfire issue

[atufo1475]

Hello everyone

Ever since I cut my muffler off (came with the car when I bought it, flowmaster 40 series) my car has of course sounded awesome and had the occasional backfire.

Well ever since I cut it off, at WOT once it hits the 4800rpm to redline area the thing has like rapid backfire. I'm not sure if it is holding the car back but it sure makes me think so.

Now if you gradually get the car up to redline without slamming on the gas, it doesn't backfire at all.

I'm honestly thinking its because I took the heavily restrictive flowmaster 40 off, but I'm not totally sure.

I put a brand new opti and plugs and wires all within the last 2 months.

Anyone experience this issue?

Literally my car sounds like its going to explode when I get into the high rpm range with wide open throttle

Any info would be greatly appreciated,

and as always,

Thanks!

T

[popo8]

is that "rapid back fire" really a backfire...or is it misfiring?

MEMBER @ LTXtech.com

[atufo1475]

Thanks popo!

I guess it could be misfiring

But it really sounds and feels more like a backfire.

Cause when you're misfiring there is like an obvious performance flaw.

Thats not necessarily happening in my case so I'm not to sure.

And I'm also beginning to think my car has always done this it was just being covered up by the restrictive muffler.

Any ideas on what could be causing this?

Never changed the knock sensor..

Heard that could be it?

Thanks!

[popo8]

Thanks popo!

I guess it could be misfiring

But it really sounds and feels more like a backfire.

Cause when you're misfiring there is like an obvious performance flaw.

Thats not necessarily happening in my case so I'm not to sure.

And I'm also beginning to think my car has always done this it was just being covered up by the restrictive muffler.

Any ideas on what could be causing this?

Never changed the knock sensor..

Heard that could be it?

Thanks!

Do you have any way of data logging it so see what kind of knock it is "seeing?"

[atufo1475]

Unfortunately I do not. I've been trying to purchase one of those cables to run to my laptop since I already got the free software.
However money is to tight right now..

Think I should just put in a new knock sensor?

Think I can get one for like $30

[popo8]

Unfortunately I do not. I've been trying to purchase one of those cables to run to my laptop since I already got the free software.
However money is to tight right now..

Think I should just put in a new knock sensor?

Think I can get one for like $30

I would hate to see you spending money, or throwing parts at it blindly.

Hopefully someone else will chime in with some input

[atufo1475]

Okay I greatly appreciate it,

Thanks for your help, maybe someone knows another way to test

[atufo1475]

Anyone?

Please?

[firebird_1995]

Did you cut the muffler off before changing the opti, plugs and wires?
I would check all plug wires for burns/abrasions fires. Also, what plugs did you put in and at what gap?

[atufo1475]

The muffler was cut off about 3 weeks after the new opti.

Before I cut it off the car ran great and would redline just fine.

I put in ngk iridiums and gapped them at what it says under the hood.

I think .050

But tonight coming home from work I was able to get a better feel.

It definitely is holding the car back, you can almost feel it start to shake when this happens.

Car has stock manifolds running into a magna flow high flow cat (previous owner decision) and I cut the single pipe right after it goes over the rear axle.

Do you think it's possible that the car isn't getting enough back pressure?

Tomorrow if I get some time I'm going to check plug wires.

But when I put them in I zip tied them very far away from anything heat related.

Only issue I had was the steering bumping one of the wires but I fixed that the same night I did the plugs and wires.


And thank you for responding