1/ trying to set 22RE idle to spec which says 750 rpm but I set it at 850 rpm in neutral for an automatic which in Drive gives me a reasonably rough 500 rpm. This normal? engine runs well but just seems to idle on the low side- set at 1000 in Park gives a smoother in gear Drive rpm.

2/ Talked to a good Toy tech and although they have cleaned the units- they have never replaced the wax pellet idle air valve under the TB. Anybody re/re these completely? Do they fail- or just need a good cleaning.

3/ found a 22R and wanted to take the double roller chain parts off it- other than it still running cast steel rockers and a slightly different sloped back valve cover I'm getting different stories about interchangeability with the 22RE- year unknown. Wikpedia gives different years of block/head design, my Toy tech says they are the same head/block except for carb vs efi.

 

1. Personally, I set mine so that the motor's sits at 750 in drive.

3. Your toy tech is wrong about the motor. I would know, I've owned several of each. Mid 84 they changed the motor around fairly significantly. The only parts that are really the same between the two are the crank and rods. The heads are different, the blocks are different, the pistons are different, timing chains are different, timing chain covers are different, etc. You can identify the model difference by the valve cover (they look different, early models have rounded corners. Take a look through google images.) There are carb and EFI versions of both early and late motors, however early EFI motors had a vacuum advance distributor. If your distributor doesn't have a vac advance, it's a late model EFI. There's a writeup online describing HOW to change the timing chain over, it's not as easy as you think. I don't know the link off the top of my head though.

 

it's Canada corner over here.
having your idle drop on an auto when you put it in drive is normal.
as for the high idle bypass, it's a bi-metal spring set up, not a wax pellet. I took mine apart because it did not open at all. I cleaned it and stretched the spring to open the door fully. I was luck and have a few of these kicking around so figured if it didn't work I could use another. it worked very well.
as for the double roller chain, it would be nice but I don't think you can swap it.

 

I'm learning these old horses little by little- I was surprised NOT to find a AIC stepper motor- which explains the idle not compensating.
So wikpedia was right after all...I'll have a look at the block serial and get a date.

I thought the bi-metal was a different animal, what is the difference to look at? Mine has 4 screws that attach it to the bottom of the TB with a type of o-ring gasket and coolant passing thru.

 

All 22RE motors use an IAC valve. Early style motors was a separate bolt on unit with an electical plug. The later style screwed into the bottom of the throttle body, and was controlled via water temp/pressure.

 

I guess I should have asked the year, mine are from early 22re's (86 &87). there are 2 coolant lines to heat the element and a blue 2 wire plug coming in from the back which is also a heater. the front is a plastic cover held to the housing with 4 screws. behind that cover is the bi-metal spring.
I hope this helps.

 

Mines a 1990- coolant lines only. Wanted to send my TB out for boring and was trying to get a 92 TB to work meantime but the idle wouldn't come down. So finally got serious about it and checked all clearances and changed the air valve to the 90 unit seems to work fine now- just wondering if it's worth cleaning the 92 unit or is it pooched.
BTW I have the timing at 9deg and was bringing idle down from that adjustment too.

 

it never hurts to clean it, while your at it clean the throttle and intake if you can, just remove the tps first. it doesn't like carb cleaner!
I got my truck this year with a fresh rebuilt motor, new head, RC injectors etc. but was never happy with the way it ran. disassembled the intake system, cleaned, replaced gaskets and injector seals, screwed around with the IAC valve, changed the "new" head gasket with a Toyota one, and did a valve adjustment. now she idles the way it should. I never really trust someone elses work.
Hopefully for you setting base timing and a little cleaner will do the trick.