Throttle's mechanical stop screw setting

[arjunior45]

Trying to adjust my idle, with ICV disconnected, idle does not go under 900 rpm.
So, I need to adjust the 'throttle valve stop screw' {number '4' in the attached photo} and I need your help.

Do I need to remove the hole throttle body or is there another - easier way?

Nick

[wrinx]

Is 900rpm the gauge reading or actual rpm measured some other way?

wrinx

[arjunior45]

it's the gauge reading. Do not know how acurate is or if it is actual.

Nick

[wrinx]

Idle is often quoted as being +/- 50rpm, so you'll have to find a more accurate way to measure....not I'd bother for such a small amount :/

....in fact, thinking about it, mine might be the same!

wrinx

[Evodelta]

What are you trying to do? Your post implies you want to get your car to idle under 900rpm?
If the throttle plate is shut when you release the throttle then all is well. The throttle bypass is used to fine tune.

[arjunior45]

Dear wrinx,

to tell you the trough I'm not that sure if it worth all the trouble to register idle so fine. But I believe that it is my character. If things can be done properly {or should be done} I prefer to do it, even my self.
On the other hand, having troubles with air-con in a day with 40- 42 C is very ...unpleasant. And that’s how all these ‘thinks’ started.

Looking with a mirror this screw, from beneath, seams that there is a metal cover – but I’m not that sure – and need to be removed in order to unscrew it.
Tomorrow, I’ll try to remove the throttle body and see how this ‘so Alfa’ screw can be adjusted.

Nick

[axaQ42]

Have you tried to adjust the TPS sensor maybe? I had the same problem and the TPS wasnt in the right position so it read wrong the position of the throttle.

[arjunior45]

Have you tried to adjust the TPS sensor maybe? I had the same problem and the TPS wasnt in the right position so it read wrong the position of the throttle.

yes, I've already adjusted the TPS at 0.27 volt but nothing changed, as for the rpm.

What I'd like to do is to have approx 750 rpm, with :
a} engine hot
b} ICV disconnected
c} by-pass screw {idle speed regulation screw} completely screwed
and
d} TPS at 0.27 volt {for completely close throttle}.
Then, adjusting the by-pass screw I'd like to bring the idle at approx 800 rpm.
Connecting the ICV, idle should rise by + 50rpm {according to the manual} giving me the approx 850 rpm idle.

With 'a', 'b' and 'c' the only way to have approx 750 pm is to 'adjust' the throttle's mechanical stop screw

I've heard that this is the 'state of the art' idle adjusting and I'd like to test it.

Nick

[arjunior45]

well, the throttle body I believe is ok.
It's the bl***dy ICV that even disconected I believe it let too much air to pass through - even the second one I've tested.
If I block the incoming air hose to this valve, rpm drops down to 700prm or lower. Leaving it open rpm goes up to 900 - 950 rpm and sometimes even more, up to 1050 rpm.

Do I need to search for another ICV or it is normal to leave some air to pass through even if disconected?

Nick