How to adjust RPMs

I have a 1995 BMW 518. The engine runs at about 1100 when idling. I do
a lot of slow city driving and feel that this rpm are a bit high for
optimum fuel consumption.
Two questions
1. What is the recommended rpm when idling?
2. How can I adjust rpm - the accelerator cable is adjusted to
maximum?

Thanks People....

"Louis Carroll" > wrote in message
om...
> I have a 1995 BMW 518. The engine runs at about 1100 when idling. I do
> a lot of slow city driving and feel that this rpm are a bit high for
> optimum fuel consumption.
> Two questions
> 1. What is the recommended rpm when idling?
> 2. How can I adjust rpm - the accelerator cable is adjusted to
> maximum?
>
> Thanks People....

Sounds like a problem with the idle control valve, or perhaps a vacuum leak.

What happens when you are idling and you go from nothing to engaging all
power accessories you can and your A/C, does the idle drop, race, or stay at
1100? Any difference from cold to warm?

-Russ.

> I have a 1995 BMW 518. The engine runs at about 1100 when idling. I do
> a lot of slow city driving and feel that this rpm are a bit high for
> optimum fuel consumption.
> Two questions
> 1. What is the recommended rpm when idling?

I think it's 650 for the M43 1.8.

> 2. How can I adjust rpm - the accelerator cable is adjusted to
> maximum?

First, make sure your floor mat's not touching the accelerator. Happened
on a mate's 520i :-)

You can't adjust the rpm as it's computer controlled.

If it's high you have:

a badly adjusted throttle position switch

a vacuum leak

the car still think it's in cold start mode due to a bad temp sensor
(I'm not certain that affects the idle rpm).

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Thanks Russ..when engine is started revs hover just below 1000. As the
engine warms up they climb to 1100. When warm (at 1100) it drops maybe
back to 1000 if I put on lights, fan and radio.

Rgds

Louis