02-05-09, 09:39 PM
The last couple of days, during cold start, I am seeing very high engine speeds for about 5 seconds, then it settles down and idles normally. I did clean the EGR and TB about 2 weeks ago. starts and idle were good then. Outside temps. have been 10-20 degrees the last few days. Thanks
02-06-09, 09:24 AM
.........Hmmmmmm......Your car, cold, should start and idle at 1200 rpm for 20 - 30 seconds, drop to 900 or so for another minute, then down to normal idle - 650 or so.
I have seen engines that do this have a vacuum leak and it is just hard to control for the PCM till it warms up even a little bit.
As Ranger said, how high is high? 1000 rpm in 32F weather is expected, 1100-1200 in -10F is probably ballpark.
A bat IAT or CTS will cause them to be unusually high. A vacuum leak will also.
My 3800 L67 V6 idle table:
02-09-09, 12:38 PM
RPM's at initial cold start about 2,500! for about 5-7 sec.
My 80 Turbo T/A 301 V8 was spec'd at 3000 rpm cold start on the high step of the high idle cam, 2500 on next step down (I didn't allow it that high, I fixed it to my tastes...).... Love carbies!
Yours is unusually high, things I would think to look for:
1. IAC sticking in park position (open I think)
2. Vacuum leak somewhere, intake ports on the plastic intake are easy to have problems with. Our resident N* mechs can advise there, either way, not hard at all to remove and replace gasket.
Yikes! That is high. Just for the hell of it, I'd pull the IAC valve and see if anything looks amiss. Then clean it up a bit. Nothing to loose.
02-15-09, 04:35 PM
on my 02 dts was at 1800 at start up and 1400 when warm, untill i replaced that iac ($200) now its at 1200 at start and 700 when warm or so. i dunno how to test the iac but mine was stuck open all the time.