1984 733 i idle problem

[jeffreyb4me]

hi Jim, sorry for the delay, hope you've fixxed it or haven't gotten too dirty trying yet. Read your latest posts, hummmm...the cold speed and warm idle speed ARE too high........I'm sure you've checked this by now with a tach besides the car's.
you may have been there but the ICU has a seperate 'cold' temp. switch that if open/bad connection will cause a 'cold' higher idle speed

Also, you said you've check the throttle switch, but have you check the 'throttle plate' as I suggested ??? something strange is going on......jb

[jimsbmw]

Jeff,

Thanks for the reply,

I have not used a tach other than the car tach. My meter is broken waiting for a new one. Even just listening to the engine without a tach I can tell it is too high of an idle. The sensor for cold start should go to both the idle control unit and the motronic unit. This is what it says in the bentley book.
Unless the wiring is no good.
And yes I set the throttle plate to where bentley wanted it, and adjusted the switch to click at the right time. Just for the hell of it I plugged
off the throttle throat with a plastic bag to see if it would change the idle any.....Nope!

I feel that the engine is running rich by using the sniff test. Little gassy for my liking. I adjusted the mixture screw to lean it out a bit. and it does help.
Most people say that adjusting the mixture out (lean) should start to make the engine stumble almost stall. Mine does not. So there again it must be running very rich. All I can think of is the injectors are either leaking or they are being told by the system to pulse more. Giving it more fuel.
I think I may try running some new wires from the sensors straight to the ICV unit to see if it helps.
The only sensor I have not replaced is the barimetric sensor. And there is also an outside air temp down by the heater blower which is also wired to the Motronics.
Dought they have anything to do with it though.
Keep racking your brain Jeff. Between the two of us we should figure this one out.....

Thanks,

Jim

[jeffreyb4me]

Jim, my last post seems to have vaporized, I'll be back 8/5 if you haven't executed the 733i yet. jeff.