325I M20 ENGINE SURGING PLEASE HELP!!!

[naif]

hi im new to this ,but really need your help!!
i have converted a 318 cab (92) to a 2.5 m20. using a 325 sport (89f) as a donor car. since fitting the engine /box and diff. the engine will start and idle. ticks over slightly higher than before.(the engine was running perfect before swap), but when revimg the engine it just revs and drops off again continuously. also misfiring occasionally. anybody come across this???

[leeparkes]

Need to post in tech help buddy

Check for an air leak in the intake system first.

[E30BeemerLad]

moved to tech section

[E30BeemerLad]

Are you saying that the revs fluctuate up and down when holding it on the gas or when just trying to tick over?

[DmcL]

first port of call is check for intake leaks, second thing id do is check ALL electrical connections around the engine for sensors, etc, maybe give them a blast with WD-40 and insert/remove each connector a few times for good measure.

if u want to take a shot in the dark.. to me it kind of sounds like it could be a chafed wire on the crank position sensor thats grounding on the engine or the metal water pipe behind the radiator.. seen that happen before first hand.

if the engine is actually bogging when u try to rev it and u have to let off for the engine to idle properly again then that sounds like an airflow meter issue, possibly bad/loose connection.

[naif]

Hi sorry for very late reply...... But it was the idle control valve!! Doh!!

[Grrrmachine]

That's a hell of a time to wait for an update!