mattyboi

90' 4runner 22re

Im pretty sure mine is bad because it starts strong when its cold but if I let it cool down for atleast 10 mins or so it sputters upon startup and the idle slowly climbs up to where it should be.

Anyway I'll confirm its bad soon enougj but Im wondering if this could also be giving me a high cold start idle? Doesnt matter if its 30*C or 0*C. It always idles at 1000 then slowly climbs to 1700-1800. Its fine during the winter months but I hate it when it idles that high on a warm summer day! Could it be the cold start injector going off or related to a bad thermal time switch?

wallytoo

iTrader: (1)

you describe two different problems, which cannot both be the result of a defective csts. if the csts is not working, the csi won't work, either. the csi only fires for a very brief period WHILE THE KEY IS IN THE "START" POSITION. it does not pulse/fire during warmup, or at any other time.

mattyboi

^ Ok I see, any other ides what may be causing the high idle?

And just confirmed my cold start switch is indeed working. Anything else worth looking at for the warm start issue?

RAD4Runner

Like Wallytoo says^^^.
AND If temp-dependent problem, one simple and important step is to eliminate doubts on temp-sensors and their connection to the ECU.. All temp sensors AND THEIR MOUNTING THREADS should be cleaned down to bare, shiny metal at least once every 27 years
Do not use insulating sealant on threads.

wallytoo

iTrader: (1)

this may or may not have anything to do with your high idle. simple enough to check, and free. http://www.toyota-4runner.org/3rd-ge...ml#post1159391

wally

mattyboi

What do the mounting threads have to do with the sensor?

Thanks for posting that. That's another slight issue I'm having. I see my idle going from 500-750 randomly.

millball

The sensors require strong grounding in order to send correct values to the ECU.

old87yota

Just to add, the sensors ground through the threads into the engine block. The block is then grounded to the battery.

mattyboi

Ok that makes sense. I thought it would have grounded through one of the connectors.

wallytoo

iTrader: (1)

on questions electrical, i defer to ray (rad4r); unless you know different, what he states is the word.

seems like you would benefit from having a FSM.

Terrys87

iTrader: (1)

Erratic Idle can be caused by having air in the cooling system. I raise the front end really high and let it idle and cycle the Thermostat 3-4 times to get the air out of the cooling system. You will need to leave the radiator cap off while this is happening.

mattyboi

I removed my radiator to get at the front main not too long ago. Had to hit it with air. Of course I completely forgot to bleed it afterwards so hopefully that's it!

RAD4Runner

Re Idle: I once had hunting idle when I stopped from freeway speed with my AC on. It went away when I checked timing and restored idle RPM to spec.

I have not taken a very close look at other sensors but yes, the CSI timer Switch requires good electrical contact between sensor and block.
CSI is only powered while cranking. However, if it leaks it could cause issue even when not powered. Here's how it works. (https://www.yotatech.com/forums/f199...l#post52339700)