Hi guys wondering if i could get some input on a small problem.
3rd gen pickup with a 22re motor (MY 1994) and has a high idle on cold starts.

when i say cold start i mean any outside temp but the engine is cold, the idle will run up to around 2000-2200rpm for approx 3-4 mins before dropping down to the proper 750. the truck didnt used to do this

-ive replaced the green top coolant temp sensor in the intake manifold, and tested the cold start injector time switch beside it (79Ω resistance above 30°C when checking across both terminals and the same resistance when checking STA-Ground, which if i read the FSM correctly that is within spec - http://personal.utulsa.edu/~nathan-b...ne/39colds.pdf). I would like to replace this sensor to be certain but iam having a hard time locating one at the parts stores
-cleaned the throttle body
-check for vacuum leaks and cant find any
-unplug the 5th injector and idle drops to normal

is there anything else that controls the length of time the 5th injector stays on?

 

Well for some reason your start injector time switch is not shutting off.

If you remove that plug does it idle down.

Have you measured the real temperature at the sensors.

It could be your engine takes that long to get up to temperature or for the sensors to think it does.

You must have coolant flow or they will give false readings

Just when did this issue start??

Were you doing some engine work then it started ??

 

I removed the connection the the time switch. No difference

It's been doing this for a while now I just finally got sick of it and have started to investigate. No work was done when it started acting funny

I have a feeling that sensor is to blame I just need to track down a replacement
I will also try a coolant flush not that I think it's related but it needs to be done and sometimes things like that are in fact related....

 

Haven't measured real temp at the sensors other than the "is it hot to the touch" test

 

I have the same issue with my truck except it seams to go on longer than 3min I but it's super high and I don't like it I have a 2 core radiator, I don't know if that's stock or not wold like to find out wats wrong

 

Well have you checked that the coolant temperature sensor is working ?

Sometimes just cleaning them on a wire wheel allows them to work like they should if your coolant has not been changed in quite a while things do happen like this.

The only other thing in the circuit is the ECM

 

There is a device mounted to the bottom of the throttle body, it allows more air into the intake when the engine is cold to raise the idle. It has a metal spring in it that as it heats up it closes off the air passage inside it. It has two coolant lines going to it. Maybe something is wrong with it?

 

Did anyone ever figure this one out?
I e been having this problem for a year or two and aside from replacing literally everything I can’t figure this one out.

1991 2wd single cab 22RE base model 160,000mi and still going strong

 

You really should give more details about your problem and specific situation.

 

kinda figured the title of the thread spelled it out. When my truck is cold starting. It idles up to roughly 2300rpm for roughly 20-30 minutes till everything is hot then it idles normally at a happy 750 rpm. I’m just wondering why and how I can fix this issue. I’m in the process of cleaning my TB right now but sadly I now need an easy out for the screws holding the IACV on, as mine are stripped out.

 

The IACV could be sticking. I had to replace mine on my 92 22RE. It was causing random high idle when engine was warm.

Standard Motor Products AC141 is the same as Toyota part, and it's made in Japan too.

 

This is a perfect example of why you need to give details and might want to wait for a response also.

A: the original poster had an issue where the cold start injector was leaking, sticking open, received a long command, or was shorting out.

B: You need an impact driver to get those IAC screws out.

You can test this theory of the iacv being the issue. On 1st gen vehicles with aux air valves you pull the air hoses and cap off the ports. On 2nd gen vehicles with iacv a foam ear plug fits the port or you can tape over it. This disables the idle up.

The 1st gen aav is easy to inspect visually for adjustment where the 2nd gen's iacv requires good technic to readjust and is error prone because to get a baseline you have to run the adjuster in all the way and count turns of the screw and if there is a physical obstruction your count will be wrong. If you poke around you'll find some details on setting the depth/tension on the iacv valve, from memory it's something like 1/4-3/4" but that's still a wide range.

 

thank you and I do apologize for being “snippy” I was up for over 48 hours (insomnia is a bi&$h)