3cRider

At around 240k I recently rebuilt the top end on my Yota and completely cleaned everything. After putting the truck back together it runs flawlessly but does not like to idle when its cold. I checked for vacuum leaks and even replaced the cold start injector but the truck refuses to idle when cold above 4-500rpms. But when warm it either idles fine or sometimes way too high.
I checked the MAF with my OHM and have noticed some dead spots as well. Also, throttle transition can be quite on/off and the truck will sometimes cut out power and then pick it back up at light throttle positions in an on/off manner.
After some reading I decided to check and replace the TPS before the MAF. But no where can I find info about the late 83 3-prong non rheostat type TPS's. Do you have any info about the TPS adjustment on the early 84 TPS's or have any idea why the truck wont cold idle right, idle inconsistent sometimes and throttle tip-in is now really abrupt?
I've follwed what the factory manual says as far as feeler gauges and a an OHM but that manual contradicts itself. Seems there is a lot of info about the newer 4-prong TPS's but not the more mechanical late 83's.


Thanks

84sr5yoty

I've got an 84 22re as well. When I get home, I'll post up the info from the factory service manual. However, I can go off the top of my head about a few things.

Your cold idle issue is most likely the auxiliary air valve. This valve has a bi-metallic spring that has coolant moving through it which increases the idle. Most of the time, the port in the throttle body gets clogged and the air can't pass through the air valve to increase idle. If you're an idiot like me, and try to clean the passage and don't remove the large vacuum hose that's leads from the air valve to the throttle body, then you fry the heater unit in the air valve and the air valve is permanently damaged. So remove the vacuum line first before cleaning any of the passages.

I can't remember the exact ohms for the air valve, but it's somewhere around 30-60 ohms with a cold motor.. Anyway, if there's a problem with it, then the ohms will be infinite.

If you still have the original TPS, then the springs in it are probably weak which makes it become impossible to adjust it properly. I think that's your problem, at least it was mine. I have the original microfiche slides that Toyota uses and can give you the part# to order a new one. It cost me something like $42.00 at 1sttoyotaparts.com, much cheaper than 150.00 like the ones used from 85-94.

3cRider

Update:

So I replaced the TPS even though it still met the factory manual settings and it got rid of the on/off throttle response. But the truck still idles way too low when it's cold.
Can anyone elaborate on the above post or have any idea why the truck doesn't like to idle when cold but then idles fine when it's warm.