Runnung Issue

Post Mon Mar 10, 2014 9:09 pm

I have a 325i m20b25 and recently its been playing up. runs fine for a while then starts to splutter and wont take any throttle. i have to pull over for a bit, it idles ok then after a bit it goes back to normal and drives fine. then after a bit it goes again, so far ive changed the fuel filter as i thought it was a blockage but it still happens. any suggestions would be appreciated.

Post Mon Mar 10, 2014 9:36 pm

Possible crank position sensor.
How long is a while and a bit?

Post Mon Mar 10, 2014 9:53 pm

well it started doing this last month, it lasts for maybe a minute or 2 at the most. but yesterday it took me ages to get home. 5mins fine then 2mins no throttle then 10 mins fine and 2mins crap. i havent bothered with it today as i cant be assed breaking down again

Post Mon Mar 10, 2014 9:58 pm

Do you have to turn the engine off or will it recover just idling?

Post Mon Mar 10, 2014 11:02 pm

no it seems to idle fine but soon as you touch throttle it dies and goes back to idle when you lift off. then it just goes back to normal for a few miles till it happens again.

Post Mon Mar 10, 2014 11:10 pm

If you have access to a multi meter check the throttle position switch under the throttle body and the afm through its range of travel. It's been ages since I worked on a m20 I'm sure the search will show what values to look for.
It shouldn't take too long to get this sorted.

Post Mon Mar 10, 2014 11:10 pm

Throttle position switch at a guess but I'm not a time served E30 trouble shooter.
If you do a search you will find the test values.

Post Mon Mar 10, 2014 11:10 pm

If you have access to a multi meter check the throttle position switch under the throttle body and the afm through its range of travel. It's been ages since I worked on a m20 I'm sure the search will show what values to look for.
It shouldn't take too long to get this sorted.

Post Mon Mar 10, 2014 11:15 pm

Lol beat me to it Supafly
You may need to do the test when it plays up.

Post Fri Mar 21, 2014 4:28 pm

Either way they're both easy fixes. TPS needs a hole drilling in it and contact cleaner sprayed in til its clean or replace and the AFM needs the arm bending slightly to move on a clear piece of track.