325e surging

[gregcullie]

i have a 1984 325e it has starting surging when you excellerate. if you floor it it picks up good . but under normal conditions it surges. the car has 166000 miles and this is the first problem we have had . replaced the timing belt and adjusted the valves 10000 miles back but that didnt help. the car is still very drivable but it gets annoying. was wondering if this problem is in the fuel or electrical system? any advise would be much appreciated

[KC Ron Carter]

The WOT, wide open throttle, bypasses the AFM, air flow meter, and allows the fuel injector pulse to go to the maximum.

That would explain the issue you are seeing so the answer is the AFM, requires adjustment.

You can test by manually moving the flapper door to see if it makes the engine run better.

You can test this by measuring the output of the o2 sensor at the diagnostic plug on pin 15.

o2 sensor readings.

You can check it on your diagnostic plug though.

Use a VOM on pin 15.

.6 volts is dang rich .3 volts is dang lean.

http://www.kemparts.com/TechTalk/tt07.asp




http://www.unofficialbmw.com/images/reset1.gif


1. Ground
4. Temperature sensor
7. Reset
8. TDC sensor yellow
9. TDC sensor shield
10.TDC sensor black
11.Start signal
12.Alternator charging excitation voltage
13.Ignition coil
14.Alternator charging supply current
15.Oxygen sensor output to test with.


Later,

[325iMbeema]

At idle my beema makes a rotary wha wha wha sound.
it lurches/surges up to about 1500rpm. from there it runs ok but i think this sounds simalar to the above problem. what do you reckon?

ta.

[KC Ron Carter]

Sam is the idle on BMW guy.

Pay particular attention to the drilling a coin with a 5mm bit and installing upstream from the idle air valve. It limits the maximum the valve can go to.

http://www.mesaperformance.com/faqs/idle.html

Later,