Backfiring

[BMW Blues]

Hey can someone please help me...I just change my water pump on my 91, 525i and put everything back exactly how I took it off......Now when I went to start it, it starts but wont Idol and then it starts backfiring, if I Gas it. What could I have done wrong ...please help any solutions welcome ...thankyou

[sp0rky]

Do you have the m50 or m20 engine?
If you have the m20, did you mess with the timing belt at all? Check the timing and reset it if it's off.

And as for the crank position sensor, did that get tweeked at all?

[BMW Blues]

Originally posted by sp0rky@Jul 6 2005, 06:14 AM
Do you have the m50 or m20 engine?
If you have the m20, did you mess with the timing belt at all? Check the timing and reset it if it's off.

And as for the crank position sensor, did that get tweeked at all?

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How can I tell if it is a m50 or m20 engine? And also where is the crank position sensor situated? I dont think I messed with the timing belt unless it is the bigger belt of the 2..... Thanks for youe help

[sp0rky]

Bigger belt of the two tells me you most likely have the m50 engine in which case you don't even have a timing belt. Thats chain driven.

Here is the m20 engine:


and below is the m50 engine:


http://www.bmwe34.net/e34main/Maintenance/...e/M20Timing.asp
That link has some info on the crank position sensor.