toyota4x4907

Before you rag on me, I know the idle is supposed to be high when its cold. Trust me, I know. I live in Alaska

Problem: The cold idle is too high for the ambient temperature. When I first bought the truck, it was 75*F+ everyday. As the summer passed and it got colder, the idle started to increase depending on the temperature, like vehicles should. As soon as it got below 70, the idle would shoot up to 2K rpm. I only got that high of idle with my other two 22res when it was below freezing, usually around 0F and colder. At 71F the cold idle would be at like 1200 rpm for a minute or so, but once below 70, it would shoot up to 1800-2K rpm. Now its around mid 30s at night and mid- to high 40s during the day, the idle goes to 2K rpm at cold start-up. It just seems too high for the temperature. There is no in between. It was/is either idle at 1200 or less, or shoot up to 2K rpm.

Problem areas: Cold start timing switch? AFAIK, the timing is advanced some, so could that be a problem? I have the idle set at about 900 rpm with TE1 and E1 jumpered and it idles at around 1K without. ( I wanted it to be that high). The coolant is in good looking condition, I dont know what the mix is, Im going to test that today. What else?

I mean its not TOO big of deal right now, but when it gets down to -50F this winter, I dont want my fast idle to be like 3500 rpm....

pruney81

I'm having the same problem on a 1990 I just acquired, it doesn't have a tach though but I can tell when it's around 50 here in Mass it seems to be idling way too high on a cold start.
I don't really know where to start though and it doesn't have a tach so I'm just going by noise and looking at it, I would guess mine shoots up to around 2k also...

putneysmachine

It's possible the intake air temp sensor in your MAF is going south. It's inside of your MAF sensor, but you can check resistance at the pins (resistance changes depending on temp)

There are links floating around here to factory service manuals that will give you the proper resistances to check for at certain temps. (Sorry, I'm not smart enough to have the links, d'oh)

If that checks ok, then check the coolant temp sensor (for the ecu, not the gauge) for the same issue.

BC-Luc

I'm dealing with the same thing. My cold idle was 1900 and now it's at a 1000.

It should be your aux air valve, cold air bypass air valve, forget the actual name.

Under your throttle body there is a little air valve that is open when the engine is cold and allows air to bypass the throttle plate. Easy to find, it has two coolant lines going to it. Sometimes the coolant area gets plugged up or the valve needs to be cleaned up. You'll need to remove the throttle to clean it out. At the back of the valve is a small covering plate, that gives you access to the preset cold idle speed.

Double check my info, good luck.

Luc

toyota4x4907

MAF. Could be....I have some weird starting problem and it was similar to the '88 I had for a while with a faulty MAF. It wasnt bad all the way, just failing and hte plug wouldnt connect all the way.

The IACV is possible as well. Forgot about that little bugger

spanish-road

hey i have a meter and a heated shop, i gotta get my winter bugs out of my truck too.

Junkers88

Is it a set screw that can be adjusted or is it preset from the factory and non-adjustable?

toyota4x4907

I have a heated garage and meter too, so But I'm closer to town than you are, AFAIK.

BC-Luc

The Toy originals are adjustable, I haven't been able to fully remove the valve body, but have managed to turn down the setting to a much better level. The "set screw" is sort of an outer ring with two slots that has part of the valve body/springs protrude from. Hard to explain.

I now have a second valve so I can adjust it and just swap out my tempermental one = less down time. I have not been able to get the rubber gasket that is required, but, RTV seams to be doing a good job.

I've read that at some point you could get replacements (non Toy) that were fixed.

Hope this helps, Luc

Firebb15

I know what your talking about being that I live in Michigan. The colder it gets, the higher the cold idle. I hate it when it's below freezing, better yet below zero and I turn the key, fires right up and slowly climbs right up to about 1,900. When I push in the clutch it hits 2,100. That oil must be so thick in there. Motor still runs like new, all original at 220K and it's been through almost 15 winters like that. I figured it's a normal Toyota thing. The only thing I thought about doing is buying one of those heated patches you can buy on ebay. You stick it on the bottom of the oil pan, and just plug your truck in at night. I thought that would help me sleep a little better at night.

toyota4x4907

I'm used to it being high when its cold, not when its not below freezing yet or when it was almost 70*....