Backfire in a 3.2

[SRISER]

Have a backfire in a 3.2. Car has 65k, FS pre-muff, Dansk dual out and Steve Wong chip. This is a new thing. Didn't do this before R/R of CAT. Do you guys think the chip is putting too much fuel in the system? Doesn't backfire 100% of the time and only when you blip the throttle...it's not very loud either.

Is this bad for the car?

Will this day ever end? (Dead battery, missed class, parking ticket and now this new backfire issue)

[BGCarrera32]

The chip could do it, but odds are something is out of spec causing it do this if you've been running the chip for a while without problems...worn injectors maybe, sticking throttle linkage...check your fuel pressure...

[SRISER]

Chip has been in only two or three weeks.

[Victor]

Mines stock, backfires worse than Roseanne Arnold the morning after an all night chilli and bean fest.

[SRISER]

That is not a pretty mental image...no, not at all.

[Tim Stevens]

I had a backfiring issue this past weekend at the Road Atlanta DE. I went through tech with no problems and I was driving back to the hotel and the car backfired and then quite. It would not start and I had to tow in back to the racetrack. The outcome of this problem was a bad rotor and distributor cap. After a kind soul (Steve) helped me out, I went for a test ride and it did the same thing. Come to find out the Distributor went bad. Steve said he does not see it that often – but it is something to check out – Good Luck –
Tim

[masraum]

Depends on the kind of backfiring. Is it just a light popping? If you run up through the revs and then slow down under part throttle, is that the same sound that you hear? Most cars will "pop" not really "backfire" (most people associate backfiring with something nearly as loud as a gunshot) during deceleration because of the unused fuel. This is (usually) completely normal. If you just went from having a cat to having a cat-bypass/pre-muffler then you are just now hearing something that's always been there, but was silenced by the exhaust.

I believe that's what you are hearing.

[don911]

what steve said.

[cab83_750]

Same thing here. I gutted the CAT and I started to hear popping. I ignored it for a while until finally the distributor had too much play. When I replaced it, woooh hoooh!

Search the archives and look for my post about a month ago!

Good luck.

[geof33]

Ditto with Steve... I get a little pop when running through gears guickly from 1st to second. If it's a TRUE backfire, that's a problem, but like most cars with a free flow exhaust (read race cars) they make all kinds of pops etc on fast deceleration. The removal of the cat opens things up and can allow this "pop" to occur...

[Wayne 962]

Swap the chip with the original one and see if it still happens...

-Wayne

[SRISER]

That was what I was thinking Wayne...maybe just too much fuel...not popping during decelaration...this is idle, blip throttle, definite light backfire...not loud, but not a crackle either.

[Rick Lee]

Sam, it's probably a broken head stud and a piston is slamming into a valve. I'm afraid you're in for a 3.6 swap.

[BGCarrera32]

Throw a spark plug in the exhaust tips to ignite the extra fuel and throw flames out the tailpipe at night...yeah...that's it...

[Never Lift]

The little pops in between shifts is totally normal. I have the same set up as you and thought the same thing too. I noticed the little pops sometimes when I shifted after I put in the Dansk sport muffler and premuffler. It was doing the pops before I put the chip in. My mechanic stated its the free flow exhaust that does it. I got used to it, it reminds me of the Race 911s at the track. I just had my car tuned up and it still has tiny pops sometimes between ****s. I love when you first drive your car after tune ups! She just rips! Man I love these older Carrera's.

[rob911]

Me too - began to get worried about my 175,000 miler when I mentioned this to mechanic last service. He suspected all manner of alarming problems (don't want to repeat them for ffear of angering the gods of air-cooled rebuilds)
Gues this is just "character" - more noticable after fitting new Stainless crossover and CAT bypass pipe :-))

[bigrubberjeep]

Same problem here, Im going to try and re-install my stock exhaust this weekend to see if trouble go's away

[stlrj]

I would put things back to stock one item at a time until the back fire disappeared.

86 Carrera

[toolman]

I don't think it "dissapears", you just will not be able to hear it. Mine never did it until I adjusted the valves, some of which were pretty lose.