screw or no screw?

[jcr2fast4u]

okay so i have been having bad idlel problems with my car not wanting to start and when it did it had a very low idle, and was runnig rich i have done almost everything(changed, spark plugs change all vacume lines,full tune up everything) but i think i might have finally found the problem. i Finally got my car started an when i did i kept hearing a hissing sound. i was like this is impossible i have changed every vacume line there is, so iam checking around by the throttle body and i notice a hole so i put my finger on it and it stoped i am woundering if this is what causing my car to idle so bad and should it just be pluged with any screw? or do i need to get the stock screw back? and will this make my car idel better? i have a pic of what iam talking about coudn't get a pic of my car so i borrowed one. let me know if you can help i need all the help i can get. :aigo: :1zhelp: :cry: thanks

-josh

 

[gaboonviper85]

if im not mistaken.....that should make your idle faster haveing a vac leak in the intake....maybe turbo cars are different.....i knew when you undo the brake booster line it makes rpms jump and the engine will kinda rev up and down.

 

[thechori]

if im not mistaken.....that should make your idle faster haveing a vac leak in the intake....maybe turbo cars are different.....i knew when you undo the brake booster line it makes rpms jump and the engine will kinda rev up and down.

of course turbo cars are different, instead of negative pressure like N/A cars there is positive pressure (FORCED induction)

fix that leak, it might be the reason you're running rich (that is a boost leak)

 

[Who]

Here is a photo of my intake on a 1989 turbo supra. I do not have a screw but you can see that there is no hole. Its stamped metal shut by the factory. My wild guess is that you had some kind of back pressure and it blew it out. Maybe a bad turbo blow off valve would cause a massive boost in pressure when you let your foot off the gas under boost. Don't take my word on this. I am new to this but I do remember reading something about blow off valves controlling pressures in the intake.

 

[jcr2fast4u]

oh okay so it's just stampeded there.so would i need a new throttle body or could it be replaced some how?

 

[jcr2fast4u]

so wheres the idle adjusting screw?

 

[Dan_Gyoba]

There is no idle adjustment screw. The idle is controlled by the ISC (Idle Speed Controller) which is that fitting that gets air from the accordian hose, and is located on the intake manifold, in front of the throttle body. The ECU uses that to adjust the idle. The fitting that you have open there is supposed to be just sealed.

@thechori: Turbo cars have negative pressure in the intake at idle, too. They have to. If they were under boost at idle, that'd be a BIG problem. At WOT is another matter, but it's idle that's being asked about.

 

[thechori]

@thechori: Turbo cars have negative pressure in the intake at idle, too. They have to. If they were under boost at idle, that'd be a BIG problem. At WOT is another matter, but it's idle that's being asked about.

oooooo0o true true, forgot about that. just when he said that there was hissing i assumed there was air coming out of the hole, and by that he was in boost, ANDDD by that i based my statement. my apologies for anything misleading

i could've swore the 7Ms did have idle adjustment screws, is that only on the GE's? or none at all

 

[HommerSimpson]

I think thats just a acces port when they machined/drilled the holes.. for the pvc breather.. Id guess you can get a plug from parts store and peen the housing around it..

 

[Quin]

Misinformation explosion!

Early 7Ms do have idle adjustment screws! My 88 has one. I don't think it's there, and I don't know how the fuck you managed to blow that out, but I don't see why you wouldn't be able to grab another TB and replace it.

 

[brs86supra]

theres supposed to be a screw in there, but i dont know how you managed to get it out b/c i tried to take mine out and it stops at a certain point and just keeps spinning (wont come out) Your really not supposed to mess with this screw b/c ive read that some say it will mess things up, but some say it does nothing. but it really adjusts your idle, it makes your rpms go up when u bring the screw out and makes the rpms go down when u tighten it. When i bring the screw out i hear a hissing noise coming from my air filter and when i tighten it, it doesnt hiss anymore. Hope that helps and sorry for the long post

 

[Poodles]

Messing with the factory adjustments on the TB is asking for tuning issues.

The idle is NOT controlled by the TB on our cars, and should not be tuned as such.

 

[sneakypete]

Misinformation explosion!

Early 7Ms do have idle adjustment screws! My 88 has one. I don't think it's there, and I don't know how the fuck you managed to blow that out, but I don't see why you wouldn't be able to grab another TB and replace it.

Wow... how did that go on for so long. turbo cars do have the screw. the previous owner of my car messed with it before i bought it. the idle was off. i adjusted it a little bit to even out the idle and its been fine since.

 

[Who]

1989 supra turbo see the pics. Wheres the screw?

 

[cuel]

PRE-89 have a bypass screw on the throttle body(It might even be only to 87, but not sure). Although it will effect idle, by letting air bypass the throttle plate, it is NOT an idle adjustment screw. If everything is working correctly, that screw should be fully closed.

 

[Quin]

My 88 has one, as previously stated. I didn't have an ISC, and that screw kept my idle at a pretty steady 800

 

[Who]

1989 supra turbo see the pics. Wheres the screw?

My bad. Should of know it could change over the years.

 

[jcr2fast4u]

okay so i got the hole pluged again and the car idle is like a brand new car thanks guyz for the help! :biglaugh: :icon_razz