Idle question/survey

[BTERRY1]

I wanted to take a quick survey regarding idle. My car seems to idle really low when I first start it in the morning. I have a new DME temp sensor and a brand new TPS. My first thought was maybe my new sensor is no good. Today I unplugged it right after cold start, and it works just fine as the car really ran crappy till I plugged it back in. Maybe I don’t have an issue and just have a motor mount on the way out causing the lower idle at start to seem more violent than normal. At cold start I idle at 700 RPMs. When warm 900. What is everyone else seeing…….

[John_AZ]

'88 cold start ~950rpm. No difference cold, first morning start or hot start during the day.

'87 cold start ~1050rpm. Same as above, cold or hot. Got the car at this rpm and never adjusted-just works well.

J_AZ

[cdc]

Originally Posted by BTERRY1

I wanted to take a quick survey regarding idle. My car seems to idle really low when I first start it in the morning. I have a new DME temp sensor and a brand new TPS. My first thought was maybe my new sensor is no good. Today I unplugged it right after cold start, and it works just fine as the car really ran crappy till I plugged it back in. Maybe I don’t have an issue and just have a motor mount on the way out causing the lower idle at start to seem more violent than normal. At cold start I idle at 700 RPMs. When warm 900. What is everyone else seeing…….

Mine does the same thing as yours idle's about 700 on first start then goes about 825-850 when warm.

[Gawernator]

~950 almost always

[Aussie944S]

950.... all day every day

[BTERRY1]

Hmmm. I wonder what causes mine to be 200 RPMs less till warm. Electric air valve right behind air filter? Auxiliary air valve? I cleaned that with carb cleaner and WD-40. How can I test functionality of these two items?

[mattdavis11]

I have never checked the actual idle rpm myself, but the last time it had to undergo the required state stuff, it was 895 rpm. That was in 2006, but I don't know how accurate their stuff is. The tach has read the same since 1991, hot or cold, there is no difference. It does, and always has had the infamous dip or "shutter" the early cars have after getting off the gas. When that happens, it drops to around 600rpm and bounces back to normal.

The idle speed doesn't increase when the ac is turned on either. It draws it down some, maybe to 850rpm.

One thing that concerned me years ago was a hissing sound at idle. It sounds like a vacuum leak or a PCV valve. However, it has always done so, still remains the same, and I intend to leave it be as long as it runs great.

[mueller944s2]

my S2 is 950, does dip a little when you hit the AC.

[ditch68]

Cold, 800 for just a few seconds, then 950 very consistently for mine.

Jeff

[VirginiaF1]

'88 n/a 944 8-valve..
Idled poorly at 850 when I bought it..
Adjusted idle screw to 1100 hot or cold, ac on or off..
Purrs like a dozing lion..

[shadetree944]

For my '83 on a cold start, I get 850 or so for a couple minutes until it warms up, then 950 or thereabout.

[honerboys]

on the 84 it's lower on startup if it's below about 60 degrees - around 825 - after 2-3 minutes up to just below a grand

[Gawernator]

'88 n/a 944 8-valve..

Idled poorly at 850 when I bought it..

Adjusted idle screw to 1100 hot or cold, ac on or off..

Purrs like a dozing lion..

Mine purrs like Aussie's kangaroo

[BTERRY1]

thanks everyone, i guess mine is not to terribly different. i will stop worrying about it