500 rpm idle, to low?

[mikesride]

Just tuned up the old girl ( 82 mostly stock 3.0l sc) . Thought I had hit the sweet spot on idle and mixture settings, car sounded deadly purring through the ssi's and m&k stainless!!! Looked at the tach and the needle hoovers just at 500rpm ( from 900 before) . Car starts runs responds great....any reason to turn the idle up more?

Mike

[RSTarga]

did you check your timing?

[James Brown]

You messed with the mixture? used a AFR meter? adjusted the timing? Checked control pressure? There is a lot more involved (only if you mess with it) in a tune-up. I'm sure you did all that, just checking. If everything is set, than just bump up the idle, with the big screw.

[mppickett]

I like the idle up a bit because I like the oil pressure at idle up. Probably doesn't make a lot of difference, but it's something that I don't have to worry about.

[aigel]

It isn't this easy. If you up the idle, the mixture and idle timing will change again. It all has to come together as a unit. I always looked through the back window at the tach when setting up my car. The spec for idle is 950 IIRC.

George

[euro911sc]

Idle is 950 +- 50 IRRC. Time to go back to the garage and redo it

-Michael

[Joe Bob]

too low....

[mikesride]

Thanks guys, Looks like its back in to the garage next weekend! I was wondering about the oil pressure at idle. To bad cause she sure sounded mean.

[Pazuzu]

Don't trust your gauge.

If the engine was really at 500rpm, you'd know it, it would not sound healthy. It's very possible that your gauge is incorrect, and that you're sitting at closer to 900rpm.

I have a timing light that shows RPMs, and it's consistently about 10% lower than my gauge is reading. One is reading directly from the distributor with a nice computer circuit calculating on the fly, and the other is reading through 30 year old wires and using a 30 year old gauge. I know which one I trust