E23 Idling

[Nemesis]

Need a bit of sifu help here, as have a smallish problem which having trouble getting a handle on.On my '83 728i, when I switch on aircon the idle speed drops to the point where if I stop and reselect drive or reverse the engine will stall. Now I know this should be compensated for, but am a little unsure how.Here are my thoughts so far, on how:a) Aircon selection sends signal to ICV which compensates.b) Aircon sends signal to throttle bypass valve which compensates.c) No idead) No idea but know great place for nasi ayam.If anyone could prod me in the right direction would be appreciated.

 

[ICEMAN 68]

i would rather send it to a mechanic and then head to the nasiayam stall...

JK

 

[ez77]

e23

adjust the throttle cable to a optimum tune....if not call me for more answersss...0133698037

 

[Nemesis]

I am the mechanic hehe.

OK EZ I'll check the throttle cable for slack and let ye know. But without a/c the idle lovely.

 

[ez77]

check the vacuum pump as well...if u switch-on the aircond, the pointer of the pump must be inside and not touching the bodypart

 

[Nemesis]

Glad u mentioned the vacuum pump, the HVAC components on my E23 are in completely different locations to US/UK/South Africa models. Is this normal here as no heater core?

 

[M30]

What is this ICV? anyway mine does not have this thing which increases the engine power when the aircon is switched on so i set the RPM at 1k...but mine is set much higher now...somewhere around 1.25-1.5k rpm so that when the aic con is switched on the car will not vibrate especially in KL traffic. If you set at 1k it should drop to about 750 or the line just below the 1k line. There is a air by pass that u should be able to tune.

 

[Nemesis]

Haven't had time to follow this up as been been busy with more urgent repairs. Plan to adjust the valves this week so once that done will check the throttle closing correctly to the nominal gap and then work along from there.
ICV, idle control valve, not sure whether this is strictly an early motronic item but will have a ferret around this weekend as will have most of the intake apart, yay!

 

[M30]

Oh....maybe that is why mine does not have coz mine is a L-Jet...I was thinking of getting 1 for my car.

 

[Nemesis]

Yeah more I'm thinking on it the more I confused, but found this which is useful in parts b4 it gets too complex hehe.

http://bama.ua.edu/~darren/boschindex.html