JoeKnowsBaseball

iTrader: (5)

I have a 99 Z/28 A4 with almost 150k original mines on the motor. For probably the past 15k miles I've been getting backfires after medium excelleration at highway speeds (65+) or heavy excelleration at slower speeds (40-65). It always back fires after letting off the gas, but never while I'm still acellerating.

My mods include, air lid, long tube headers, no cats, custom ORY, and dumped Flo-Pro Twister. Not a whole lot of power adders... Also I have removed secondary air, PCV and EGR.

There have been a few times when I've bumped it off the rev limiter. I know usually that bent pushrods come from over reving, but I also know the stock pushrods are "fuses" in the motor, in that they are weak. It's starting to bug me and I want to figure this out.

Any help of why I'm back firing would be helpful.

beedo

iTrader: (28)

150k and have you do done a tune up yet? do you have a ses light on?

nemss1

^^^could be a tuneup if u havent had one in awhile. bad plugs/wires will do this. happened right before i had my tuneup and a tuneup solved my problem

Joshiedoom

iTrader: (4)

Define backfire.

Mine does it with the free flowing exhaust pop of a cutout.

Just did a tuneup about 20k ago.

JoeKnowsBaseball

iTrader: (5)

It's had a tune up. Just never gotten any internal or major work done to it. It got NGK TR6 plugs probably 30k ago (according to the seller).

And yes I do have an SES light on and all of them are emissions items. I check the codes every couple weeks.

And a backfire is a loud pop after I let off the gas after excelleration. It comes from my exhaust tip.

Larzzzz

i'm new here and don't know how to post...any help please?

Bullet95z28

iTrader: (3)

May just be because of a very free flowing exhaust, my camaro does it as well, i have long tubes to 3" y pipe, no cats, to 3" piping all the way back to a mac muffler with a turndown at the bumper. Its more of a poping sound for me than a backfire. It doesnt do it while accelerating, but after i let off. I dont hink its a problem, im not worried about it.

Joshiedoom

iTrader: (4)

Exactly as mine does. If I tap the gas while braking the engine(letting off the gas) it does it loud as ****, my guess is its just needs a tune. I need to get a video of it while the weather is nice

Relapse

iTrader: (4)

It could be a loose spark plug wire, or an exhaust leak too, check your wires and make sure they're secure

foreverzero

iTrader: (5)

ok why does it have tr6's? was it a nitrous car? tr6's are usually in boosted cars or nitrous cars because its a colder plug. If there isnt nitrous on it now you might want to put in nkg tr55's. that very well could be your problem. Or it could still have a nitrous tune on it... or it could be a grounded plug wire...mine did that 2 weeks ago then i found a plug grounded against the header causing it not to fire and a bad backfire

1 FMF

iTrader: (1)

why would you remove the PCV ?
if you have removed the EGR have you repogrammed the PCM to account for that? Do you know what your A/F ratio is?
give this a read for starters: http://tpiparts.net/emissions

Disregarding your mods for the moment, I would say shitcan the TR6 plugs, they're too cold and only worth using in a boosted or nitrous motor. Run TR55 plugs. If the plugs are dry-fouled that can cause backfiring under load. But I would guess the plugs are in combination with the rest of the mods causing the problem along with an incorrect tune for what is on, or not on, the engine.





sorry but i have to make fun of this, I hope you didn't buy this.
what a ******* scam.
-less restrictive than glass-packed design, yeah ok.
-dual flow path creates vacuum effect that accelerates exhaust, there really is no limit they'll go to marketing a product with lies and bullshit info.
-continuous spiral design minimizes turbulence, yeah but increases restriction.
- welded construction for strength & durability, as opposed to what glueing? Guess they had to throw something in to fill the top left corner of the pic.
this is great, and as we are laughing at this in the office someone mentioned we have a patent on a similar design which is used as a suppressor!
no wonder this country's economy is in the *******, nothing but lies and bullshit in the market.