No More High Idle on Cold Start (1 Viewer)

[roncruiser]

Ordered up some new links from my local Mr. T. Will install tomorrow. RPM's kick up when I crank the A/C on like it should. Pulled the EFI fuse and it seems to be starting "differently" now. Cranks up fine and hits the high idle point, but instead of falling on it's face for a second, it drops down to 650 RPMS, the same RPM it would be sitting at when warm. Runs great as mentioned. I'm just looking to get my high idle back which is hilarious because most people on here are trying to get rid of their ridiculously high cold start idle! Does this point to the IAC valve regardless of the fact that it tested out just fine?

I would say yes.

For me, I lost my cold high idle start. It's been gone for months and months dating back to last winter. I went nuts looking for the issue. Readjusted everything I could adjust. Cleaned everything I could clean. Measured to make sure all components were in working order.

Get this, before I replaced it, the IAC tested out just fine by the book. I cleaned and reinstalled it. Never gave it a second thought. I was at my wits end. On a whim, I ordered a used IAC. Cleaned and tested it. It tested out fine out just like the current one.

Replaced the old one with the new (used) one. Guess what? My high cold high idle start is back! Go figure. Weird.

Highly frustrating but I'll take it.

I missed my cold high idle. My 80 sounds tough again. Low idle is consistent @650 too. Before the replacement, the low idle would be so low I had to step on the gas to keep idling at stops.

 

[harrydunn]

That is awesome. Yah, I swapped in another IAC. No change. That 80 has been sold and I now have a '97 LX with high idle. Ha.

 

[Flank]

I would say yes.

For me, I lost my cold high idle start. It's been gone for months and months dating back to last winter. I went nuts looking for the issue. Readjusted everything I could adjust. Cleaned everything I could clean. Measured to make sure all components were in working order.

Get this, before I replaced it, the IAC tested out just fine by the book. I cleaned and reinstalled it. Never gave it a second thought. I was at my wits end. On a whim, I ordered a used IAC. Cleaned and tested it. It tested out fine out just like the current one.

Replaced the old one with the new (used) one. Guess what? My high cold high idle start is back! Go figure. Weird.

Highly frustrating but I'll take it.

I missed my cold high idle. My 80 sounds tough again. Low idle is consistent @650 too. Before the replacement, the low idle would be so low I had to step on the gas to keep idling at stops.

Well, before I just blew my head gasket last month, I was having the same issue... So, after I fix that crap, I'll swap the IAC.

 

[Inukshuk]

Thanks for this thread. I spent a chunk of yesterday troubleshooting. Today I read this entire thread and found my solution: Wait for warmer weather!

 

[roncruiser]

Thanks for this thread. I spent a chunk of yesterday troubleshooting. Today I rad this entire thread and found my solution: Wait for warmer weather!

No, not necessarily. The IAC could be bad, even if it tested out good per the manual. I tested the bad IAC with an ohm meter as outlined in the owners manual. It tested out good. Even though it was really bad.

There's another way to determine if the IAC is bad. It requires hooking up to a 12V source. That test is also outlined in the owners manual. I neglected to do that test. Oops.

 

[Inukshuk]

No, not necessarily. The IAC could be bad, even if it tested out good per the manual. I tested the bad IAC with an ohm meter as outlined in the owners manual. It tested out good. Even though it was really bad.
There's another way to determine if the IAC is bad. It requires hooking up to a 12V source. That test is also outlined in the owners manual. I neglected to do that test. Oops.

I did the FSM diagnostic test to the IAC a few months ago. It tested fine. Seemed to make an improvement to smoothness of idle but high idle at start did not return.

Its 11 degrees here now so I went to start both 80's. No high idle the 93. High idle on the 96. But, with some throttle the 93 idles fine.

Great thread. I'm sure it has helped many. If I learn any more I'll post

 

[petegangies]

adding to this historical thread. I've also lost a proper cold idle. I get an extra 150-200RPM over the warm idle, but nothing close to or over 1000rpm. I did everything the op did. Replaced the following:

- new genuine ECT sensor
- 3 different VAFs
- 2 different IACVs
- adjusted TPS
- adjusted throttle cables
- cleaned throttle body
- adjusted valve clearances
- checked earths
- new plugs, leads
- checked for vacuum leaks
- 2 different ECU's
- fixed exhaust leak
- o2 sensor was replaced 20,000kms ago with genuine

Haven't had higher cold idle RPMs for years now. 94 Model in Australia. Drove myself mad trying to solve this, and was hoping your thread had a fix.

The only thing I haven't replaced is the IACV o-ring, but the one on the car looks fine (my vehicle only has 150,000kms).

I keep thinking it's something electrical, so will start tracing wires, as the car is dual fuel with LPG which splices into some of the same sensors. No cold idle on petrol or LPG.

It bugs the hell out of me, because something that should be working a particular way, isn't.. and that just doesnt sit right with me. There HAS to be a reason and fix for this, but it seems nobody knows what it is. I wonder how many others have had this problem?

Cheers,
Pete