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late motor in early car, teething problems...

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    late motor in early car, teething problems...

    hi everybody, just finished my swap from the tired old 2.7 to a freshly built 2.5.
    everything went fairly smooth, got the whole 1.3 motronic in and almost all underhood wiring connectors accounted for. i still have a female 2 prong conn. that i think is for the evap can. also a 3 prong that comes out of the harness near the CPS, CID, and diagnostic wiring. i can't find that on any wiring diagrams? neither of those are plugged into anything.
    there are a few obvious intake leaks (bad ICV to intake boot, maybe throttle body gasket) but the car idles and revs in the driveway nicely.

    here's where things get weird. we fired it up, let it warm up, checked for leaks, shut it down, let it cool down, adjusted valves to clear up some chattering. fired it up again, let it warm up again for a minute and took it out for a drive. it backed out of the driveway fine, but as soon as i put it in 1st and tried to let off the clutch it starts jerking and bucking like it wants to stall or maybe the timing is way off.
    almost totally undrivable. i managed to put it in reverse and slip the clutch while feathering the throttle and limped it home. we checked that the CPS and CID weren't swapped into the wrong plugs, they weren't. unplugged the ICV. took it out again and it drove fine!! had a little fun for a few minutes then took it home and shut it down for the night.
    next day i try to drive it with the ICV unplugged and it tries to idle at 2000+ rpms (tach not hooked up yet, but it's high)
    plug the ICV back in and the idle hunts like mad. intake leaks. also, it doesn't hum like the old one from the ETA.
    also, we had taken it out and cleaned it with brake cleaner and a little air. looks good inside.
    please don't tell me i need a new ICV!! those basterds are almost $400!

    also, i couldn't find any good answers anywhere about swapping in a later dash with higher revs. i'll save that for later...

    any advice is greatly appreciated!

    #2
    There are a few tip out there of ICV problem diagnosis but what finally worked for me. Drill a 1/4 hole in a penny and place that before the ICV. If it idles smooth after that, odds are you have an ICV problem.

    I was chasing multiple bugs, temp sensor, TPS and finally a bad ICV.
    2004 525i Manual - 1985 325E Coupe Manual

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