2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

Idle variance... think its clutch related.

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Old Aug 31, 2005 | 01:58 PM
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Idle variance... think its clutch related.

If I start my car and don't touch the gas nor clutch, it will idle just fine... like a dream. If I engage the clutch... it will rev from about 1.5k to 2k but if I turn on the a/c fan (more load on engine) it will smooth out. If i then disengage the clutch I will now do the rev thing until I turn off the a/c. Thats only sometimes though... most the time it just does the rev thing no matter what I do... but if i slowly let off the clutch it will correct itself then when fully disenange it will be tempremental on what its going to do (sometimes its smooth, sometimes it will do the rev thing). Already set my TPS and there is no dead spots, and adjusted the idle on the trottle body (no emissions) and timing the best i could... so anyone have any ideas?
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Old Aug 31, 2005 | 02:02 PM
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ummm....thats weird as hell....
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Old Aug 31, 2005 | 02:05 PM
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Check for vac leaks?
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Old Aug 31, 2005 | 02:11 PM
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Originally Posted by Sideways7
Check for vac leaks?
Checked for them as good as I could as well, went through with starter fluid, and traced all the lines and still couldn't find anything...

Could this be something like the clutch not being aligned? or the bearings giving out?
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Old Aug 31, 2005 | 02:25 PM
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Hey, is the spoiler on your car off a stock rx-7? I have the same one and I thought it was an aftermarket piece. Anyways, there could be a bad wire or a short somewhere because there is a switch that tells the computer if the clutch is depressed or not. There could be a short somewhere along those wires.
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Old Aug 31, 2005 | 02:37 PM
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Afaik its part of the finishline or whatever (the dealer-installed body kit), but I could be wrong, I never *really* figured out where its from.
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Old Sep 2, 2005 | 04:11 PM
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Okay... i just checked my vaccuum lines... and now I have a huge question...
according to this http://208.62.166.66:82/guest/shop_m...20simplify.jpg I should have a few vaccuum lines... but now when i go out to actually check those... I only have 2 of those..
1 is going from the turbo to the wastegate (like where it says boost controller here) and the other is going from the pressure sensor, to the back of the UIM, and then to the pressure regulator (on the fuel rail)... everything else is capped off. (well except for the oil fill line thats just venting until i get a catch-can for it)
also i visually checked the clutch switch wires looks fine, and the switch (tested with multimeter) is fine.

Last edited by Kouta; Sep 2, 2005 at 04:19 PM. Reason: follow up on the clutch switch
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Old Sep 7, 2005 | 02:47 PM
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Alright, now that I know I was jumpering the right thing before (for the initial set connector) I have some more information.

This is what happens when the LEADING timing is right on the mark (thereby making the trailing off... 1/2 between the marks on the pulley)
--When warmed up it will idle perfectly, no variance, right at 800rpm.
--With clutch OUT (not pressed) if I give it gas it will rev to whatever, then drop to 1.5k rpm then surge from 1.5k to 1.8k rpm.
--With clutch IN (pressed) if I give it gas it will rev to whatever, then drop to 1.5k rpm then surge from 1.5k to 1.8k rpm.
--Also the car has a nice amount of acceleration.

This is what happens when the TRAILING timing is right on the mark (making the leading off)
--When warmed up it will idle perfectly, no variance, right at 800 rpm.
--With clutch OUT (not pressed) if I give it gas it will rev to whatever, then drop back down to 800rpm
--With clutch IN (pressed) if I give it gas it will rev to whatever, then drop to 1.5k rpm then surge from 1.5k to 1.8k rpm.
--Also the car is extremely sluggish on the acceleration.

EDIT: also for reference my vac lines are like in the attached picture
Attached Thumbnails Idle variance... think its clutch related.-myvaclines.jpg  

Last edited by Kouta; Sep 7, 2005 at 03:11 PM.
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Old Sep 8, 2005 | 07:23 PM
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From: Olympia, WA
Ok... I took some lil vids of whats going on....

http://home.comcast.net/~kouta/clutchout.AVI
-- After starting car and hitting the gas just a hair it will do this....

http://home.comcast.net/~kouta/clutchin.AVI
--When I press in the clutch it raises it up to that rpm

http://home.comcast.net/~kouta/leadingon.AVI
--This is what the timing looks like with the leading being on... notice it jumping around... (but I have good acceleration)

http://home.comcast.net/~kouta/leadingontrailingbad.AVI
--This is with the leading set to the position above... notice how its off, and how this again is jumping around

http://home.comcast.net/~kouta/trailingok.AVI
--This time the timing is set via the trailing... completely smooth

http://home.comcast.net/~kouta/trailingokleading.AVI
--Look how far off the leading is (i also have horrible acceleration)
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