Help...

 

My bmw is driving really rough to a degree where i couldnt drive it this morning. Over last few days it's been getting worse and worse.

 

When you accelerate the car doesn't go, it shakes like it's peaking. The revs take ages to build up and hardly move.

 

I'm going to take a look shortly, what can I try?

 

I'm going to check the plugs, leads, blockages in the air intake, fuses. Any loose pips in engine bay. Anything else?

 

Any ideas??

crank angle sensor or flywheel sensor, locate the cable connector and disconnect and reconnect, you may need to get a diagnostic done though as with high level OB2 it like looking for a needle in a haystack job.

 

Having said that you never know, sometimes going too technical can lead to missing the very obvious like plugs air filter etc.

 

Jeff TT

I called the Rac out in the end.

 

Unplugging the air flow meter fixed it. He said ok to drive short distance e.g. to a garage.

 

Am i correct to assume that replacing the AFM will cure it? if so i can do that myself instead of taking it to a garage as its easy peasy.

 

I found one on ebay for £30. Will this be any good? or are non genuine parts asking for problems?

 

http://cgi.ebay.co.uk/Air-Flow-Meter-BMW-316i-318i-316Ci-318Ci-740-0280217124_W0QQitemZ190304896188QQcmdZViewItemQQptZUK_CarsParts_Vehicles_CarParts_SM?hash=item2c4f0e44bc&_trksid=p3286.c0.m14&_trkparms=66%3A2|65%3A2|39%3A1|240%3A1318|301%3A1|293%3A1|294%3A50

 

 

Also found this, its a chip and takes the afm out of the scenario and cheaper. Apparently gives more bhp, but how do i know it is actually working?

 

http://cgi.ebay.co.uk/AIR-FLOW-METER-CHIPPED-BMW-3-4-5-6-7-SERIES-M3-X3-X5-Z4_W0QQitemZ260417656832QQcmdZViewItemQQptZUK_CarsParts_Vehicles_CarParts_SM?hash=item3ca21a1800&_trksid=p3286.c0.m14&_trkparms=66%3A2|65%3A2|39%3A1|240%3A1318|301%3A1|293%3A1|294%3A50

 

Which option is the better one?

 

I thought my car was getting heavier on fuel. that explains it.

 

Thanks for your reply Jeff.

Ok by disconnecting the afm the ecu then see`s a disconnected sensor the ecu then runs in limp home mode which is much sweeter than run crap mode!! but still not perfect

 

Now it is very likely the afm has fails so a quick replacement will sort it and you can do that yourself, however the afm works by measureing the air been drawn through it and fuels accordingly, if however the sensor fails incorrect signals are fed to the ecu and hence run like poo as you have experienced BUT any air leaks in the system will have the same effect due to additional air been drawn through these leaks points, this air is unmetered and so no calculation is done by the ecu for this and hence fueling errors and poo running.

 

So BEFORE replaceing the afm check all the air ducting connections and any breather hoses and only when you sure no leaks exist then purchase an afm, and by the way do not buy the airflow meter trickery box, BMW spent a few million developing that afm and I think if a little box did a better job they would be well peed off.

 

Ok good luck matey and let us know how you get on.

 

Jeff TT

Ok by disconnecting the afm the ecu then see`s a disconnected sensor the ecu then runs in limp home mode which is much sweeter than run crap mode!! but still not perfect

 

Now it is very likely the afm has fails so a quick replacement will sort it and you can do that yourself, however the afm works by measureing the air been drawn through it and fuels accordingly, if however the sensor fails incorrect signals are fed to the ecu and hence run like poo as you have experienced BUT any air leaks in the system will have the same effect due to additional air been drawn through these leaks points, this air is unmetered and so no calculation is done by the ecu for this and hence fueling errors and poo running.

 

So BEFORE replaceing the afm check all the air ducting connections and any breather hoses and only when you sure no leaks exist then purchase an afm, and by the way do not buy the airflow meter trickery box, BMW spent a few million developing that afm and I think if a little box did a better job they would be well peed off.

 

Ok good luck matey and let us know how you get on.

 

Jeff TT

 

Cool Thanks Jeff.

 

Will do, it is easy to check as it set at the top of the engine and very little pipe between the AFM and the throttle body.

 

Would it be ok to go with a cheaper copy rather than a genuine BMW part?

Cool Thanks Jeff.

Would it be ok to go with a cheaper copy rather than a genuine BMW part?

 

Mmm....well its one of them things where saving some £££ss now could bite you later in the long term or it could work out just fine. For me I would go with a genuine part by that I do not mean a BMW part but an original manufacture part such as Bosch rather than an unbranded one.

 

Jeff TT

That worked thanks.

 

Engine light still on though, just need to reset it.