taco_man96

Can anyone explain how the idle air control valve works on a 90 toyota pickup. I understand the concept behind the valve but i do not understand why it has coolent flowing throw the valve and what acually causes this valve to move

toyota4x4907

It has a wax valve much like a thermostat, it expands and contracts according to the temperature of the fluid running over it. The valve has coolant running over it to allow more air in when its colder (colder coolant temperature) so the idle increases to warm the engine up quicker.

taco_man96

Ok well that isnt the cause of my idle problem im stumped

toyota4x4907

...okay... What is it doing?

taco_man96

Well after the truck warms up you can turn the headlights on and the blower motor on and the engines starts running like crap. runs fine driving it and while driving when u let off the gas and start to slow down the truck will cut off like half of the time. I figured the alternator was bad maybe not putting out enough amps out Put a new one on the same thing checked plugs, wires rotor, cap, injectors are good, egr is clear all intake gaskets new no vaccum leak found I changed out the maf or what ever the name is and problem didnt change the iac valve works as it should I cleaned all my known grounds. and I made sure the throttle body wasnt clogged
can the tps cause that kinda problem

i hint a wall hear never ran into this kinda problem on a toyota before

bbrideau

well its no secret the alt doesn't pump out a lot of power. think its only 60amps peak. and at idle it drops right low. i know the odd occasion my truck will cut for a split second when i flip my high beams on. but the plug on my alternator is screwy and falls out on its own sometimes. You definitely have an odd problem there tho. check your contacts on the 80 amp fuse in the engine bay fuse block. any rust or corrosion in that block especially there can cause some nasty electrical issues.

taco_man96

i am goin out there now Oh i did put the alt kit on it from lc thats uses the gm alt and nothing got better I already had the kit on my other truck so stuck it on there no fix

bbrideau

on top of your pump there is a round spot with 2 vac lines that come out of it. well it should. mine has it and its an 88. try removing them from the pump and bridging the lines. see if that keeps giving you the noise.

taco_man96

if u mean the power steering i have it off of the truck right no and both lines blocked off but not bridged together

bbrideau

not the pump lines. the vac lines that go to your power steering idle up. with those vac lines removed it wont demand your engine to idle up at low speed. i'm just shooting in the dark here but it might help troubleshooting. My buddy has an 86 and he had to remove those lines because it pulled to much vacuum and would stall the truck out.

bbrideau

you can take the one line off the idle up valve and put it in the manifold to were the other one would hook up. that will keep your intake from pulling in un metered air. i will go take a picture of what im talking about might make it a little easier.

bbrideau

just realised i got 2 threads mixed up. my bad. but this could still help with your funny idle issue! haha

bbrideau

okay so the wife has the camera so i cant take a picture. but right behind the dizzy you will see a round black thing with 2 vac lines coming out. that is your idle up for when you turn your wheels at a stop or in low rpm. if you remove the line from there and take on and bridge it to where the other one come out of the intake it will stop it from pulling vacuum when turning your wheels. the idle up could be faulty and pulling vacuum all the time. a lot of people remove those lines completely when they do their egr and vac line removal. Its a shot in the dark but it could help you idle. Apart from that it has to be something electrical. How old is your battery? have you had the alt tested? Could have shorted something in the alternator when swapping it in. Check the wires from your alt to the 80 amp fuse and to the battery. any breaks in the wires could be grounding it out to the truck. google search for the ground wire locations for the 22re. i was missing the one from the back of the engine to the fire wall and it gave me a world of troubles with my idle and voltages. it could be something as stupid as a small little wire came lose in a plug somewhere haha.