E30 Zone

hi eventually got my m40 1.8i engine to start but it wont idle under about 2000rpm had a look through haynes but to no avail please help me

have you checked to see if all the vac hoses are on and also check the afm

whats an afm

Air Flow Meter

Id guess at an air leak?
Or maybe,this may sound daft,but if youve been revving the engine from the throttle body then the outer cable may have moving and not reseated itself,happened to me this week

oh so how do i check the afm

gotabmw wrote:oh so how do i check the afm

Have you checked for air leaks first?
Could be split elbow from TB to AFM?

this is prob wrong but i just unplug it and if it runs worse then the afm is working if there is no change then try swaping afm`s

i must sound realy thick but whats a tb

is the tb the throttle body chears

Yes.

ok will check after work tomorrow to dark now and got to go to bed as go to get up at 4am

well checked for air leaks couldnt find any i disconected the round plug from the afm and the revs dropped to about 1500 revs but it ran rough conect it back and it revs its nuts of does this mean the afm is naff or is it somthing else

Have you checked the accelerator cable hasn't become dislodged from the throttle body housing. Ensure there is some slight slack in the cable when the car is at idle.

acelerator cable is fine but checked for air leaks again and i believe there may be a few as can here a kind of hissing nois probably from inlet manifold so am going to wip it of tommorow after work and fit new gaskets and do up to correct torque you never no it might work

If there's a gasket failed on the engine side of the throttle butterfly, you've found the problem!