Hi everyone,

Here is my problem.
After cold start my '91 4Runner manual trans. (3.slow) idles around 1500~1700 rpm, but the problem is that it idles like it for a quite long time. I suppose that there is something wrong with cold start injector system or engine temperature sensor. How to check it? Maybe problem is caused by something else?

 

how long is quite long time? the engine does run a lot higher at initial startup as designed.... in colder climates, it will take longer to get to operating temp than warmer climates... also city stop and go traffic takes longer to warm the engine up as well

 

It idles much higher than it should for about 10 - 15 mins even in summer.
It is also hard to start after I turn it off before it warms up well. Cranks very well. Starter and battery are perfect.

 

There's a coolant passage that runs through the throttle body. Make sure it's not clogged.

 

check what steve said, also the cold start injector may be sticking

 

I've found that when the temp sensor for the computer (not the temp gauge) goes bad, it doesn't high idle for a long time - it runs like crap all the time. Still, it may be worth checking.

 

my 91 idles around 450-550RPM

 

That's too low even when it's warmed up! Should idle at 800 rpm.
Fast idle spec is really high, like 3000 rpm. Mine only high idles for a 30 seconds or so, even in winter. And I don't think it hits 3k!

 

Yeah the 3.0 generates a lot of heat. My truck engine's cooling system is in top condition (fairly new water pump, new rad, new coolant, hoses, etc.) and even my truck warms a lot faster than I remember other vehicles I've owned and/or driven in the past.

 

Thanks. I'll check cold start injector and this water passage, and let you guys know.

 

whats wrong with a low idle?

 

Nothing really, long as it runs fine. Can have a problem with fouling the catalytic converter in some cars, can foul plugs in some cars, can have stumbling issues off-idle when hitting the gas, making it harder to pull out smoothly, that sort of thing.

BTW - I checked and mine fast idles when cold at 1800. Books says 3000 but MAN that's high!

 

problem with a low idle? My truck is 10 years old and i set my idle perfectly to 800 when it's warm. It idles perfectly smooth, you cant hear it at all. I would want the correct idle just so it runs smoothly. I think those toyota engineers know a little something more than you do

as for the original question: if you drive it right when you start it and as soon as it's warm, does the idle go down to normal? sounds like it might just be acting normal. i know that if i start cold in the morning, even if i let it sit for 10 minutes to warm up, it'll stay at a higher idle until i touch the gas, then it'll go down

 

no. it idles high even when it's warm and after driving it. It has to be almost hot to idle at 800.
It idles smooth though.

 

On the TB, is the coolant passenger inlet located on the side facing the firewall; underneath the TB's electrical connection? I have a high idle problem as well.

And uh, sorry for reviving a dead thread.