Faulty AFM?

Wed Apr 18, 2012 10:46 am

Hi, there.

I have an M50 conversion, and when I started the car today, it was ok, but the more it was running, the more the idle changed. The revs stayed the same, but it sounded very rough to the point where the car actually shook. I checked all air pipes for leaks, all seemed ok.
I had a quick look on here and found info on the AFM, I disconnected that and it settled down, and soon as I put it back, it went bad again.

Inside the connector to the AFM, there are only 5 metal connectors in the holes, should there be a 6th? and if not, is the AFM itself faulty and is there a way of making it drivable until I can get a new one as I cant be stuck without my car.

Thanks

Wed Apr 18, 2012 11:44 am

it could be an MAF, not 100% sure what it's got actually

Wed Apr 18, 2012 7:09 pm

Just had another look, and the protection grids either side of the MAF are damaged, the one nearest the front of the car is very damaged while the other only has a small hole. could this be the cause of the problem?

Fri Jun 15, 2012 5:37 pm

I've changed the split pipe after the maf, got new grids, checked everything else and there is no apparent air leaks. It was still running very rough so I took it to a garage for a diagnostic test and they say that its showing a temperature of -40.

I've had to borrow a car until I can figure out what is wrong. Due to the conversion, many garages are wary of looking at it, so I was hoping you levelly people on here would be able to assist me in at least finding something to test/change

Fri Jun 15, 2012 6:18 pm

where was is showing a temp of -40 ?

Air temp or Engine coolant temp

Fri Jun 15, 2012 8:03 pm

Air temp I think they said

Fri Jun 15, 2012 8:08 pm

sounds like the temp sensor in the MAF might be giving the wrong reading. or its got one of those +20bhp chip resitors in the wiring somewhere !!!

Fri Jun 15, 2012 8:23 pm

would the wrong temp reading cause it to use much more fuel than normal?
it sounds like its flooding sometimes, like its choking, and really struggles to keep running. It is odd though, sometimes the revs sit really low and sound like its going to cut out and other times it revs high (this is on idle)

Fri Jun 15, 2012 8:28 pm

LilJen wrote:would the wrong temp reading cause it to use much more fuel than normal?

Yes, Colder air is more dense, therfore you can add more fuel.

but if the air is not actually cold, then the mixture will become rich.

Fri Jun 15, 2012 9:23 pm

So best bet is to replace the MAF then and see if that solves it.

Thanks for your help