Bill Graham

Is it possible, or worth trying, to remove and clean the cold start valve, similar to how you can clean the ISV? I've got a low idle when cold, and this is one thing I need to check.

The MFTS has been replaced, throttle control switch has been replaced, and the ISV has been cleaned out. Not sure what else to check. Basically I'm getting about 750 rpm during idle until it's warm.

Thanks.

Bill Graham

mint875000cstq

Check your ISV temp sensor. It will cause what you are describing if the connection is bad or the switch has gone bad. Mine did on my 5000CSTQ, not sure if your 200QT 20 v has one though...
-Aaron

Bill Graham

Thanks. I know where the multi-function temp sensor because I've replaced that. I know where the ISV is, but I'm not familiar with the the ISV temp sensor. Can you point me in direction of where it would be or a part number?

Thanks for your help.

4Driver4

The cold start valve just helps the car start when it is cold (as you might guess from its name). Once the car starts and you release the key, the cold start valve's job is done. It is not related to your idle issue.

Bill Graham

Thanks. I'm learning that.

Wondered if it's not a temp sensor issue, but I'm not sure which. I may be wrong, but doesn't it have 3 temp related sensors? Sorry I don't know more. I'm still trying to learn this car.

Bill Graham

One time this winter:

It was really cold, and it idled at 750+/-. This was the morning after an ice storm and I let it run longer than usual to thaw out and avoid scraping. Well, I didn't tap the pedal, it never raised it's rpm's, and evidently didn't recharge the battery after cranking. When I got back to the car, it was not running, and the battery was dead.

I usually monitor the car more closely when it's warming up, so it's never had a chance to do this before.

I should also state that I can not find any vacuum leaks. I don't have access to a "smoke" machine however.

Thanks.

86_5K

This picture is from SJM site.Idle temp sensor is the one you are looking for.Click on the picture and see how to test it.
<a href="http://www.sjmautotechnik.com/10vcoolt.html">
<img src="http://astro.uchicago.edu/~mzm/personal/hobby/gif/tempsw2.jpg"></a>

Zhaoming

Bill Graham

When I said I'd changed the MFTS in an earlier post, I was wrong. From this picture, I changed the after-run sensor.

I'll check the link.

Thanks.