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Why is my idle so low? round 800rpm

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Old Dec 11, 2011 | 11:38 PM
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NZJacksonNZ's Avatar
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Question Why is my idle so low? round 800rpm

So i get my car back from speedtech, plugs have been cleaned and its finally going. But its only idling at around 600-800rpm, before it was at around 12-1300rpm. warming it up changes nothing. it still boosts very hard (50-180km/h in about 4 secs). Vacuum reads normal, oil pressure normal and battery fine. So whats wrong?

NOTES:
Its recently been run out of gas by a retard mechanic and badly flooded
Starts up fine
possible spark lead failure? or could they have been put on the wrong way round?
Recently been rebuilt (1000ks on the new motor) so apex seals should be mint
accelerator cable never been tampered with

Any help would be greatly appreciated!!!!!!
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Old Dec 12, 2011 | 12:21 AM
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Ol-Skool's Avatar
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Just wind the idle up higher... they probably set it to around 800 as that is stock idle. Actually i think stock idle is 700 or 750?

I set mine to 1000rpm for idle.
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Old Dec 12, 2011 | 12:29 AM
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Just adjust your idle screw and bring it up to your liking. It is located on he throttle body.. Kinda like a circleish screw.. Grey in color..
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Old Dec 12, 2011 | 03:22 AM
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I could do that, but it hasnt been touched in the first place. wouldnt that just be like putting a band-aid over it and pretending that nothings wrong?
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Old Dec 12, 2011 | 08:15 AM
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stock idle is 750-800rpm.

if its rock solid and no issues are apparent. let it alone.
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Old Dec 12, 2011 | 12:23 PM
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They could have adjusted the idle screw that you can't see where the throttle body elbow bolts on
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Old Dec 12, 2011 | 01:02 PM
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Per page F-17 of the 1994 factory manual, stock FD should idle at 720 (+30, -20 ) rpm.
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Old Dec 12, 2011 | 01:11 PM
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Ok, thanks for all the reply's. I'll wind up the idle today and see what happends. still a bit confused on why it would drop all of a sudden.
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Old Dec 12, 2011 | 01:26 PM
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What mods do you have?
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Old Dec 12, 2011 | 01:28 PM
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Did yet call and ask them?
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Old Dec 12, 2011 | 05:17 PM
  #11  
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what kind of port does your engine have?
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Old Dec 12, 2011 | 06:15 PM
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May have had a Vac leak prior to the work causing a higher idle. Leak fixed and the idle returns to normal.
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Old Dec 13, 2011 | 12:16 AM
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Ok so today i unplugged the black cylinder thing on the back of the intake plenum (has a white plug) and the idle didnt change. Im thinking that maybe its faulty and the butterflys staying shut. I'll clean it out tomorrow and see if it fixes the problem. Also driving it today, the idle seems steady at 600rpm, and its about to stall. smells VERY rich aswell
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Old Dec 13, 2011 | 12:34 PM
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Ok so today i unplugged the black cylinder thing on the back of the intake plenum (has a white plug) and the idle didnt change. Im thinking that maybe its faulty and the butterflys staying shut.
Are you sure you disconnected the IAC valve connecor and not the Accelerated Warmup System (AWS) valve connector?

Both the primary and secondary butterflies should be closed completely at idle. The Idle Air Control (IAC) valve opening is what sets idle speed, in conjunction with the Air Bypass Screw, which allows air to bypass the IAC. If you disconnect the IAC electrical connector, its internal valve will close completely, and you will have an idle speed set solely by the Air Bypass Screw, unless your butterflies have been opened with the external set screws.
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Old Dec 13, 2011 | 11:22 PM
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Originally Posted by wstrohm
Are you sure you disconnected the IAC valve connecor and not the Accelerated Warmup System (AWS) valve connector?

Both the primary and secondary butterflies should be closed completely at idle. The Idle Air Control (IAC) valve opening is what sets idle speed, in conjunction with the Air Bypass Screw, which allows air to bypass the IAC. If you disconnect the IAC electrical connector, its internal valve will close completely, and you will have an idle speed set solely by the Air Bypass Screw, unless your butterflies have been opened with the external set screws.
Yeah thats the one. i unplugged it and idle did not change. took it out today and put 12v thru it, nothing happened. It must be stuck closed. I'll get a new one and hopefully it'll be good as new. cheers for the help
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