A few ideas, none conclusive or guaranteed...

The FITV is supposed to close itself as the engine warms up. If it needs a little encouragement (from bumping the gas) then maybe it's sticking just a little. I don't know whether it's possible to tighten the plunger too much?? Or maybe it'sjust -um- about 17 years old...

You mention a couple adjustment screws& 'tuning it'. What's the one 'underneath the throttle'? I believe it might be the mechanical stop for the throttle. When you let go of the throttle, the spring closes it against this little screw. You need to FIRST adjust this so it's holding the throttle open BARELY AT ALL. Just barely open enough so the butterfly plate doesn't wedge & stick closed. Then you never touch this one again.

Finally, you've cleaned up everything - EXCEPT that other air valve at the end of the manifold. Maybe that's doing something??

 

horrible weather all day. i got it so close, but it still has a slight delay when i tap the gas. the problem still seems to be when i put her in gear, than tap the gas. car in gear, never letting the clutch up. just putting her in gear and tapping the gas is when the idle goes crazy. only when i attempt to drive. the rpm's dont stay up when i'm driving. if i'm driving and let off the gas, the rpm's stay at like 2k for a second or 2 than drop, where as before, it would just stay at 2k till i put the breaks on. going to take a stab at it in a few days once this snow and storm passes. figures my exhaust will be here in a couple days and now snow. ttyl

 

Is the CEL coming on? If yes, what codes are presented?

regards

 

whats up. i'm not sure what the CEL is. and codes, if your talking about the lights on the dash, none light up. only time i can recall them comming on is when i took off my FITV 12v. i was looking on ebay at idle and vaccume parts for my car to get ideas, and this guy bought a FITV and IACV cause of and idle problem, now is selling, and he quotes,""These whole units were replaced in the summer of 2005 to find a problem with the engine, it turned out to be moisture in the distributor.". so i guess thats another thing to do when the weather gets better huh.

i was also doing other research and found in a picthat i'm missing a vaccume thats supposed to be in the front(behind headlight) on the drivers side. it looked like a "spaceship". as well, the cruise control vaccume was removed, but car is supposed to have it. so the hoses that went to it came with screws in them. does that effect the problem.??

the people before put this engine in the car, and did the least they could do to get it running, i beleive. owell. thanks.

 

tested the FITV todayi assume its bad. at cold, the bottom hold did draw air like its supposed to.when warm, it still had strong vaccume when i covered it. opposite of what it was supposed to do, and car didnt turn off.

when engine warmed up, i covered top hole like supposed to, and car did NOT shut off like it was supposed to. i just sputered down and than sat idle.

it wasnt part of the test, but when it was warm, and covering the top hole didnt work, i covered the bottom one for the fun of it, and car didnt turn off again, just sputtered than idle'd low.

i was messing with the butterfly adjusting it tryin to make it perfect, and thought maybe it was open to much and pulling air through when i plugged the top hole, but i lowered it all the way to be srue and the car still didnt shut off when i covered the top hole. thanks, eric

 

also, i let her run again today at cold start up, when yesterday i got her running the best ever(so far) still not like it should be. anyway, i let her run at start up and the rpms sat at 1500 (were 2000 always before)for 7 minutes. and never went down, again till i tapped it. from what i've learned and read so far, i would say bad fitv. but you guys are the experts. so let me know what your thinking. thanks again, Eric

 

I'm thinking that I've never owned a '90. I said that the FITV should never need a kick to get it to drop the rpms back, but now I'm beginning to wonder.

I also wish I knew what that other air valve is - out on the opposite end of the manifold (#9 in post #17)... It's clearly a valve that can let air into the manifold so if it's messed up it can raise the idle.

 

That is called the ( air boost valve ) and you are correct if it has a leak it will make the idle surge or too high ,, there is a rubber diaphram under the cover, remove the 3 philip screws, remove the cover and chk that diaphram i have seen a few of those crack and leak, thus causing an idle surge

 

I'm curious about the purpose of that. Is it only supposed to open on over-run (deceleration with closed throttle)? So it only opens when the vacuum it really high? Or is it controlled by the ECU?

 

ok,i took the valve off andapart today, and cleaned her up. the valve #9 i'm talking about. she was pretty darn dirty. i just dunked her in a thing full of gasoline, let her sit a minute, swished her around, and cleaned her with a toothbrush where i could. put her back together. unfourchantly i also got my exhaust today and put it on today earlier, but my catalytic coverter is so rusted to the old system, i just ordered and offroad one offline today. So its going to be a few days before i can start her up. I did take pics tho so you all can see what that valve is all about


http://i10.tinypic.com/2j32uch.jpg"

next pic is of the underside before cleaning
http://i12.tinypic.com/482t1rp.jpg

and after, what its supposed to look like.
http://i10.tinypic.com/2rh319x.jpg

my new exhaust next to stock
http://i14.tinypic.com/2w2m2b5.jpg