High revs on start

[Tom S.]

OK,heres one I couldn't find with a search; on starting my 318i it fires instantly but revs to 3 to 3.5k as if I was flooring it. After a second it settles back down to a normal 1000 rpm. This is more pronounced when cold but does it to a lesser degree when warm.

New plugs, wires, dist. cap, rotor, and vacuum lines (except for pcv hose), including the L hose to ICV.

Ideas?

[EtaSport]

Dont know about the m10, but the eta revs to about 2k. That is because of the cold start injector. When the car is cold, it gets a shot of fuel to get the rpms up so the oil pump can send oil up to the cam and such. Just gives it a little boost. Someone with an m10 jump in here. If it does turn out to be not normal, you may need to replace the injector, or at least test it and clean it. If you have access to a hanyes or bentley manual the procedure is in there.

[diegom6]

1000 RPM is NOT normal for idle, it should be arround 750 or so ;)

[bimmerlover]

My 318 does the same thing. Always has.. and never bothered me. Sorry, no advice for ya.

[KenC]

It's supposed to rev up like that when you first start the car. And I have my M10 idling at 1000rpms too; it's fine. Mine won't idle steady below.

[Tom S.]

What worries me is that it's only been doing this for about 5 months, not the prior 16 years that I've owned it. I think I will test the cold start valve, and if it's toast, I'll live with it because I don't want to part with 80 bucks. If you all say it is normal, then that's good too, just somewhat embarassing to have it do this in a parking lot full of onlookers.

Tom

[///M Powered]

My 318 does the same thing. Always has.. and never bothered me. Sorry, no advice for ya.

[BavarianBimmer]

When my M10 starts it goes to 2k rpm after a second it goes down to 1k rpm,
when the engine warms up it goes slowly to ~850 rpm

It thinks that's normal
the injection system is engineered in the late '70s
it has restrictions too

[arnoldgtr]

Revving up to 2K RPM is normal for cold starts. It's not the cold start valve, though. The ICV is held open for a second or two to help burn the excess fuel produced by the cold start valve.
To prove that the CSV has nothing to do with the revving, do the penny trick. The engine won't rev at all when starting. It also will be very hard to start cold unless you hold the accelerator pedal down.
If it revs past 2K, or revs for more than a couple of seconds, it's probably your ICV starting to give out. Eventually, the idle speed will start to creep up, until you won't be able to bring the idle speed below 1500.

[Tom S.]

Penny trick??