Stumped with high idle need help?

super7mgtepower

super7mgtepower

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Okay im pretty sure ive replace every vacum hose on my 7mgte and i replaced the idle air control valve, as soon as i replaced that my idle was normal later that day it was high again its always different the highest idle is 1500 and then it sometimes 1000. The way its always different makes me believe their is a vac leak somewhere. Any suggestions?:1zhelp:
 
ForcedTorque

ForcedTorque

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I have this problem as well, and the sad thing is, I know what it is and won't just go fix it.

When things weren't close to right with my car, a buddy adjusted the idle through loosening the screw and changing the positioning of my throttle. I have read this is a bad idea, and need to move it back. I have just worked on other things when I work on my car. It's getting a lot closer, and this should be fixed very soon.
 
jdub

jdub

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The thing is, opening the screw on the TB doesn't work...the ISCV simply closes down more. What's happening is you are taking idle control away from the ECU...it still tries to regain control and you end up with all kind of weirdness. What's what the idle adjustment screw was removed on later year TBs...on a TB with the screw, it should be screwed all the way in.
 
jdub

jdub

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There is no idle adjustment screw on the late '89+ TBs.
It's not needed...the ECU controls idle.
 
super7mgtepower

super7mgtepower

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I thought i had it fixed till i drove it. Im not sure whats going on but i think its my bov, its a turboxs recerculating valve and my idle is like 1500 at times but first start up is 1000 but ive checked all vacs and replace isc. Any reason for bov causing this?
 
super7mgtepower

super7mgtepower

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When i first put the bov on the idle was a little higher and shifting was terrible but i adjusted it and the shifting is good but the idle hasnt changed. When i first start the car it idles about 900 then ill drive and stop at a light and it will be like 1500 to 1300, sounds like a vac leak.
 
Supra87T

Supra87T

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Feb 23, 2006
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I would check IAC for proper operation. Make sure you do not have a code 51. Make sure the throttle plate closes all the way too. I don't think the BOV would be causing a high idle.
 
jdub

jdub

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Supra87T;1131359 said:
I would check IAC for proper operation. Make sure you do not have a code 51. Make sure the throttle plate closes all the way too. I don't think the BOV would be causing a high idle.
Click to expand...



He swapped the ISCV (post #8)...he has no codes (post #10).

"I don't think" doesn't cut it in the Tech Section...if you don't know, don't post. The only way a BOV can cause this is if the vac line routed to it leaks.
 
super7mgtepower

super7mgtepower

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Well currently im at work but at lunch im going to try jdub's info, my iscv is new i tested it by unpluging it while running which if their's no leaks the idle would drop but as i unpluged it idle had no change. I should hook it up to our smoke tester here at the shop, were just to busy though. Although with the whole dashpot deal my vtv is broke off.
 
jdub

jdub

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The dashpot does not have a VSV...there are two. One for the hot start ilde up function (leads to the FPR) and one for the EGR. The EGR VSV has no effect at idle...the other does though. If it's busted, just splice the vac lines together till you can get another.
 
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