Is an M44 suppose to fast idle?

[b*saint]

Mine NEVER has.

[KenC]

No. About 750-800rpms.

[b*saint]

Ok. Because even when its 5 degrees out the car still has the same idle as when its warmed up.

[KenC]

It doesn't adjust the idle to warm up faster.

My buddy's X5M will idle at like 1300 when cold. Unless you're going to leave it idling for a while, I don't see the point.

[b*saint]

So why doesn't the little 4 banger fast idle?

[KenC]

That X5 is really the only car I've seen that does... maybe something to do with the TT V8? I've never seen M20s do it, and the M54 in my e39 doesn't. I don't see the point of it.

[b*saint]

S14 does. I was standing next to m-technik-3's car and after a few minutes dropped in idle.

[nando]

uhm, ken, you're wrong.. sorry. :(

it's not a "fast idle" either. it's a PWM solenoid that regulates idle air. It does increase idle while the coolant temp is cold, but not a lot - not 1300rpm or anything. It might bump it 100rpm or so depending on temp. You probably wouldn't even notice if you didn't know how it worked. It always regulates idle speed depending on load, temps, AFR, A/C, etc.

"fast idle valves" were usually used on lower end cars and were basically just an on/off solenoid. so you'd have a ~1300rpm idle with a cold engine, and suddenly it would drop to normal idle speed. there wasn't any real idle regulation at any other temps either.

[Click]

Hmm my m20 idles pretty fast when its cold out, probable around 1000 rpm IIRC.

[TobyB]

...not in an E30, it doesn't...

M42 doesn't, either, altho the idle will stay up (900) when the car's
idling and rolling to keep vacuum and ps pressure up...

t

[b*saint]

Yea it does that. I honestly think its time for a head job or pony up the money and get it smoke tested. I get FANTASTIC mileage but always a rough idle that sometimes will hunt and very temperature dependent.

[KenC]

uhm, ken, you're wrong.. sorry. :(

it's not a "fast idle" either. it's a PWM solenoid that regulates idle air. It does increase idle while the coolant temp is cold, but not a lot - not 1300rpm or anything. It might bump it 100rpm or so depending on temp. You probably wouldn't even notice if you didn't know how it worked. It always regulates idle speed depending on load, temps, AFR, A/C, etc.

"fast idle valves" were usually used on lower end cars and were basically just an on/off solenoid. so you'd have a ~1300rpm idle with a cold engine, and suddenly it would drop to normal idle speed. there wasn't any real idle regulation at any other temps either.

Noted. :)

I never noticed it at all with my M42. I can't say I've noticed it at all in the M54. I'll take a look this evening; it's supposed to be around freezing.

That 4.4TT is the only one I've noticed with a real pronounced higher idle speed.