How to: Set Idle Speed???

**ra23celica** · 04-03-2006, 11:24 AM

I should know this but my memory is rubbish these days:

Engine is a 1988 1G-GZE with ISCV and TPS

Warm engine up to operating temp.
Short E1 to T1 (TE1) in the diagnostic port.
Disconnect ISCV electrical plug.
Adjust screw on side of throttle body and check numbers on tacho.

Does this sound about right?

I have stuffed around with the screw previously and now when driving and lifting off the throttle the revs drop to almost nil and occasionally it stalls before the ISCV can catch it.
Is the ISCV stuffed or at least in need of a good clean ? Refer Lambolica's recent post?

Thanks.

**JustCallMeOrlando** · 05-03-2006, 03:26 PM

That sounds somewhat right, after my findings of the last week, this problem was mostly solved by cleaning the ISCV, and restoring my AFM idle screw. I'd played around with the AFM, and as such, the setting was no longer incorrect. It still drops below 500rpm, and if I turn into a driveway at the same time as it doing this, it has stalled previously, but generally it comes right back up to 700rpm.

**wilbo666** · 05-03-2006, 03:42 PM

Originally Posted by JustCallMeFrank

and if I turn into a driveway at the same time as it doing this, it has stalled previously, but generally it comes right back up to 700rpm.

Do you have a PS idle up valve?

Cheers
Wilbo

**ra23celica** · 05-03-2006, 04:10 PM

Thanks JCMF, I am cleaning the ISCV just as I type this and am about to test it as per the Supra TSRM for its resistance and stepping in and out. Them I will check the AFM bypass screw again.

Wilbo, I took the PS off my 1G-GZE, but would I still have a PS idle up valve?

Cheers,
Mitch.

**JustCallMeOrlando** · 05-03-2006, 04:13 PM

Originally Posted by ra23celica

Wilbo, I took the PS off my 1G-GZE, but would I still have a PS idle up valve?

Nope, it's in the pump itself, and is for letting more air into the engine when the pump starts putting load on the engine.

**ViPeR_NiPPleX** · 05-03-2006, 04:27 PM

the idle speed screw on the throttle body should be left screwed in fully afaik. The ISCV does all the idle air management.

**JustCallMeOrlando** · 05-03-2006, 04:27 PM

The idle speed screw is like the AFM idle screw, the ISCV and ECU *should* handle everything, but everything still needs to be tweaked

**ra23celica** · 05-03-2006, 05:39 PM

Thanks guys.
The ISCV is all squeaky clean (was not very dirty in the first place) and back in.
I took the TPS sensor off for a look, found the buttery nut underneath and then put it back on.
Now I start the car and it continuously revs from 1250rpm to 1860rpm and repeats, and is throwing code 41 - Throttle position sensor.
Have I put it back on the wrong way?

**JustCallMeOrlando** · 05-03-2006, 05:52 PM

Make sure you haven't jammed the throttle body open slightly when you put it back on. I did this quite bad (really borked it up) and the car would rev from 1000-3000 over and over. Take it off and put it back on.

**ra23celica** · 05-03-2006, 07:23 PM

Dammit dammit dammit, I have done exactly this and it does the exact same thing, revs from 1000 to 3000 over and over. Now, I have taken it off and put it back on and can adjust it by hand so this does not happen, but as soon as I rev it, this starts again. Car is undriveable, I have stuffed up big time.
Time for a new thread!!!

**terra** · 05-03-2006, 09:15 PM

Could i get some details on the AFM adjustment? ive taken apart my IAC and cleaned it but i find that my Idle is still 500RPM on my car... my AFM has had the spring tension changed so this is throwing it off.

**ra23celica** · 05-03-2006, 09:31 PM

Is there a number stamped on the body of the AFM at the base of the adjustment screw column?

**JustCallMeOrlando** · 05-03-2006, 11:28 PM

In what way has your AFM spring tension been adjusted? If you tightened it, you need to close the screw some more. If you loosened it, the screw will need to be open.

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