Lacking power, check engine light on sometimes....

[bmw318ti95]

Hey everyone,

So im trying to figure out whats going on with my car without spending a bunch of money for someone else to diagnose the problem. My car seems to be lacking alot of power when i get on the gas. Also, when i try and push it hard, as in full throttle to about 5200 rpm, the check engine light comes on after every shift. Driving normally the check engine light does not come on. Also, sometimes upon startup the check engine light comes on, but goes away if i rev it to about 3500 rpm. Finally, my car seems to be idling somewhat rough and at low rpms. Any insight would be greatly appreciated. Thanks in advance.

[ATF]

For starters, find out why the CEL is coming on. That should lead you to the correct path to fixing your problem.

I *think* because you have a 95 (judging by your username ) that you can do the pedal trick. Search for something on the forums with the likes of "pedal error code"

[bmw318ti95]

Hey thanks for the info. I did the test and it is giving me the code 1215 which from the list is a Mass air flow sensor fault. So should i just replace the sensor or could it be other things? Thanks.

[ATF]

The MAF controls the fuel/air mixture which would explain your CEL coming on at certain RPMs. Not having this problem before, how I would go about it is.. 1. Check your Air Filter to see how dirty it is (and related parts, tubing, airbox). 2. I'd get some MAF cleaner (make sure it's MAF cleaner, the MAF is very delicate), and spray the MAF down and let that dry out. Make sure everything is clean and back together correctly afterwards. If that doesn't work, I'd say your MAF has seen better days and needs replacing. That's my take on the situation, if anyone else has suggestions, please feel free to jump in.

[bmw318ti95]

Sooooo, i just went out to check the filter etc. and i found something interesting. The rubber intake boot is ripped about half way around. Im guessing this is the main cause of my problems. Its sunday so i probably can't get one till tomorrow so im gonna have to try and tape it up until then. Do you guys think that this will clear up the mass air flow sensor code?

[ATF]

That will probably not throw your error code, but that shows that the maintenance is needed. You should definitely replace the filter. Your MAF could be fouled from a variety of things and it could be that it's finally seen its days. I'd try cleaning it first.

[Mallard]

dont forget the cam position sensor and the flywheel / crank position sensor

if failed, both will give you poor performanse and read as a fault on the ecu.

get a code reading done on the car to see if any info is currently stored.

it will work out cheaper than a new MAF atleast

[bullmand]

If the tear is after the MAF sensor it could be causing the check engine light. The engine is getting a different amount of air than the computer thinks it's getting and it's having difficulty reconciling the readings between the MAF and the o2 sensor. I'd replace that boot and see what it does. Of course it wouldn't hurt to clean the sensor as ATF recommended.

[ATF]

Ahhh I misread what he found, I was thinking the rubber/foam seal around his air filter, not the rubber boot. Bullmand is right, the rubber boot (since on the 95-96 models is after the AFM) tear will confuse your computer. Try replacing that

[pnosker]

I suggest checking the vacuum lines... mine were dryrotted and gave me the same problem (I even got the MAF sensor failure CEL) just not as frequently. remove the upper intake manifold and check the lines. It takes around 10 minutes to remove the upper intake manifold including removing the cabin air filters.