Backfire??

[kioneo]

Originally Posted by gap

I had the V32.1.0 software installed two weeks ago to clear up compatibility issues with the alarm. Since then I have noticed a slight backfiring as stated in this thread, when cold and decelerating in 1st or 2nd gear. Not as bad as a pulpwood truck jake braking but louder than the pleasant gurgle that I normally get. After driving about 3-5 minutes the backfiring doesn't occur.
My car is a 4/08 build 135i with no engine mods. It must be something different with V32.1.0.

I noticed the exact same behavior on my 135i only after having my alarm installed (hence the software updated at around 10,000 miles, never heard it before that). It goes away after about a block and only happens when the engine is cold.

[busyguy8]

yep, so a number of us are having the exact same problem. First block or so, slight compression braking, then goes away..

[Evolved]

What some of you guys are talking about is afterfire.

Afterfire is when the unburned gas ignites inside the exhaust and that's why you see flames. Backfire is something totally different.

[Yearofthe1]

Cold engines do run slightly rich to help get the cat's to the proper temp, as an engine burns less efficiently, thus much dirtier, when cold. Unburned hydrocarbons are turned to heat in the cat. This is also why when you first start up any fuel injected car, the cold idle is higher, also to help warm the cats and engine up. More evidence is the exhaust smell of a cold engine - you can definitely smell unburned fuel. Thus, some of that richer fuel mixture that isn't burned when your cold engine is throttling down during engine braking is going to ignite in the exhaust. This isn't harmful, it's just a side effect of our emission requirements. Now, if your car is doing this ALL the time, this would present some worries that the A/F ratio is running too rich.

Besides, those pops sound wonderful coming out of my cp-e exhaust when leaving the parking garage at work.

[baseballbreath]

Originally Posted by Si-135i

Mine does it in 1st and second gear when slowing down. Much more when the car is cold. I like it though and wouldn't copmplain if it did it a bit more, I thinks it adds to the sporty sound. I didn;t realy nocitce it before I had the BMW performance exhaust fitted though.

Mine does too. If you let the car warm up for less than 5 mins before you go and drive it you should be fine. I only notice it when I drive it cold.

[Riss Racing]

This does happen from time to time. Nothing to be concerned with. You can bring it up too your tech when you go in for service. To double check everything....

[Sansnoetic]

Mine just started doing this everytime the car is fairly cold, and I'm pretty concerned. I wouldn't care so much if it was once in a great while, but this is practically everytime. I start the engine, get settled in the car, take off approx 10-15 sec later, drive away from my house or work, get the RPMs up to about 2500-3000, then push the clutch pedal into shift, and then BAM! Backfire, or afterfire, or whatever you want to call it.

Could the sound possibly be a faulty wastegate or blowoff valve? Also, could someone explain to me why the "gurgling" effect occurs after the throttle is let off (which I love!)? However, the sound I'm getting sounds like gurgling on steroids. And again, it doesn't do it once the car warms up.

[mtla4]

its normal my car backfires even in its stock form. I put the car to stock in order to get my HPFP swapped and it does backfire when you drive it hard.

[BlackjackMulligan]

Mine does this as well, I kinda like it.....I thought it had something to do with the golf tee mod that I did, but I guess not!

[pit1]

Exact same as described above. First block on cold start, I mean COLD. Nothing in the past few days with temps in the 70s in the AM.

At the shop now, I'll post explanation, if any.

[jchandler1]

I took the 1 to my dealer so they could investigate the sound, and now they want to keep it over the weekend and have a regional rep look at it next week... They seem concerned.

[Sansnoetic]

Hmmm....not good news. Mine is getting worse. The sound used to only occur once or twice, but now it does it many times as I drive down the road...but again, only when I shift and the engine decelerates, and only for 60-90 seconds after engine start. I'm concerned. Please let me know what they find out! Cheers, Matt

[Mega Man]

Hasn't happened to me yet, but then again, I haven't been driving it that hard. On the few occasions where I have, this hasn't happened.

[hbiscuit]

i get it now too on cold starts.

my e36 328 M52 used to do the same exact thing... i'm not too worried about it.

[Sansnoetic]

Originally Posted by jchandler1

I took the 1 to my dealer so they could investigate the sound, and now they want to keep it over the weekend and have a regional rep look at it next week... They seem concerned.

Any news jchandler1?

[scorcherjf]

I get a little barely perceptible burble after accelerating and then lifting off while leaving it in gear... no backfires though.

[jchandler1]

Been at the dealer for a week... When I pick it up, i'll detail everything to you guys. They assured me that this is by no means normal and everyone experiencing this issue should take it in pronto...

[rubadub]

Let me know the conclusion please, my car's having the same problem. Early 09 BMW 135i backfire within the first block or so after starting up the car...once it warms up it usually runs fine but i'm not taking any chances with a brand new car. Especially if I plan to mod it in the future. I don't need them telling me it was any of the mods I put on that caused the problem.

[Temple]

My car also just started doing this in the morning. Looks like I get to make a trip to the dealer...

and yes, please keep us updated...

[new2the3]

Originally Posted by Temple

My car also just started doing this in the morning. Looks like I get to make a trip to the dealer...

and yes, please keep us updated...

It's 100% normal, don't waste your time taking it to the dealer.

[Temple]

I would think this is not normal at all. The member above has had his car at the dealer for a week now so my guess is this is not normal. I work with 5 other people who have this car and none of them have this problem...

[rubadub]

Originally Posted by new2the3

It's 100% normal, don't waste your time taking it to the dealer.

Yeah, right...It's 100% normal...and I have a 12'' dick and can tap dance and sing too...

A brand new 135i with less than 3000 miles on it back firing sounds real normal...

To all you BMW drivers who's car DOESN'T backfire:
Since it's 100% NORMAL to HAVE back fire and your car DOES NOT--there's something wrong with your car and you need to take it to a dealership immediately. If your car is NOT back firing, it is NOT normal....I repeat, if your car IS NOT back firing, something is wrong.

...if you didn't catch the sarcasm...fail!

No stock car should backfire, period...especially a bone stock brand new 30,000$+ car from the dealership that is consistently doing it over and over.

EVERY TIME I get behind the wheel of the car with the motor still cold and drive a block, my car back fires when I press down the clutch. That to me tells me something is wrong and NOT in fact, 100% normal.