Miss at low RPM - United Bimmer Community

**Jimmie34** · 05-27-2007, 12:22 PM

I have a miss at low rpm. When taking off in 1st gear it misses until 2500 rpm. It almost sounds as if the enginie is loading up and seems to fire every other rotation causing a noticeable poping from the exhaust. I have pulled the plugs to check for a possible rich cylinder but all 6 are consistantly light brown and look to be burning clean.
It seems to only happen in low gear when the most torque is applied. I took the car on a 800 mile trip thinking I had repaired all of the bugs and this showed up a week later.

The car has new plugs and one new coil.

**xsperf** · 05-27-2007, 07:02 PM

are you sure ALL your coil packs are good?

**stevo** · 05-27-2007, 07:08 PM

coil packs, generally speaking, are all fitted new together so therefore it would follow that they will all start to break down together, only way to tell is to have them tested or replace them all. Also have the timing checked.

**xsperf** · 05-27-2007, 10:00 PM

Quote:

Originally Posted by stevo

coil packs, generally speaking, are all fitted new together so therefore it would follow that they will all start to break down together, only way to tell is to have them tested or replace them all. Also have the timing checked.

thats true, but often not the case, usually they never all go at the same time, although they start, so if one or two went, that only means its time for the other 6 to start going, and as i said, usually a few at a time, and it really depends on other things too....

**Jimmie34** · 05-31-2007, 05:59 PM

I am not possitive that it is not a coil pack and have noticed it a lot more lately. The previous owner did not take care of this car and allowed simple mantenance taske to multiply until he thought it was blown up and I stole it off of him for $700.00. He is 19 and drove the crap out of it so it makes anything a ppossibility.
How and where do you get the coil packs tested?
If it would miss during idle it would make it a lot easier.
Thanks, I was about to start checking on a throtle position sensor and mass air flow sensor.

**stevo** · 05-31-2007, 11:34 PM

could be a number of things causing your problem, i've noticed a lot of the guys your side of the pond swear by using seafoam have you considered using that or maybe get a diagnostic test done on the car could save you a lot of time and money.

**Jimmie34** · 06-01-2007, 08:05 AM

I use Lucas fuel treatment injector clean and have cleaned this one especially due to the lack of maintenance on the rest of the car. I have also changed my fuel filter after runing the cleaner through a couple of tanks of fuel. I am concerned due to this being on the low end of the rpm range and only when high torque is needed.
Has anyone ohm'ed out a coil pack and does anyone have the values?
I am currently in school and have limited cash for a trip to a BMW dealership.

**stevo** · 06-01-2007, 10:57 AM

take a look here see if any of it relates or helps your problem
http://www.unitedbimmer.com/forums/e...ignition+coils

**215BIMMER535** · 06-01-2007, 01:02 PM

+1 for the seafoam! it may not solve this problem but that sh*t works wonders!! the trick is dont leave it sit for 5 minutes or whatever the can says, leave it for like a few hours. the results will be much better that way. i treated my car a couple times recently through the brake booster line in the intake manifold and then i poured it in the gas tank as well. it now idles better, starts smoother, and my gas mileage seems a bit better too! its good stuff and only 6 bucks a can

**xsperf** · 06-01-2007, 01:28 PM

there is a way to test your ignition coils actually, its a simple tool that you can buy at autozone or anything of the like, its basically a spark plug and you see how far a gap the spark can jump, and if it is a certain distance, they are good, if not, they are bad

**Jimmie34** · 06-04-2007, 07:02 PM

Thanks for the link stevo. I left stroker a message to find out what terminals he tested with the ohm meter. It will help ruloe out the obvious.

**Jimmie34** · 06-07-2007, 08:12 AM

My coils ohm out to the correct values. They all ohm out to .8 including the new one that has 1000 miles on it. Anyone have an idea. Thinking I may have to spend tuition money on this to get it checked out. No shop in this town has a scan tool for my BMW.

**smokeewon** · 03-11-2008, 10:27 PM

There comes a time when fuel injector cleaner just won't get the job done. If your injectors are old then you might want to by a new set and upgrade them while you are at it. When they don't atomize the fuel enough during high load you'll get incomplete combustion. Hey.., you can always try taking one of those small bullet vibrators, set on high, and place it at the top of the injector, (against the fuel rail) for a few minutes while the car is idling. It might dislodge what is blocking your injectors.
It ain't ultrasonic cleaning but it might be close enough. You'd have to do it at idle though to keep the pressure in the rail high. Or disconnect the vacuum line from the regulator, plug it and then idle up slowly to near 2500 and see if it clears up.