11-10-2017 | #11 |
Join Date: Aug 2014
Location: Trois-Rivieres (QC)
Posts: 473
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Re: Hunting idle issue
I like the idea of resetting that IAC. Thanks a lot for your detailed answer, will continue my homework ASAP!
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11-11-2017 | #12 |
Join Date: May 2007
Location: Chicagoland, IL
Posts: 9,699
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Re: Hunting idle issue
Disconnecting the throttle cables necessitates re-doing the Min Air Adjustment.
That’s why I remove my plenum w throttle cables attached unless absolutely necessary otherwise. The idle oscillation can also be a result of the throttle plate being open beyond the idle setting. Check ur TPS v and adjust if needed.
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[SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX |
11-11-2017 | #13 | |
Join Date: Jun 2006
Location: Sparks, NV
Posts: 2,852
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Re: Hunting idle issue
Quote:
With regard to a vacuum leak, while there are many possibilities, how much is your vacuum pump running with the ignition on but engine not running? H
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90'ZR-1 #1461 Red/Black Ported Intake, Degreed Cams, OBX Headers & Exhaust, Fidanza FW, Secondary Delete, Custom tune, C6 GS Wheels. Sold 08 C6 Z51 Crystal Red Metallic Sold Vararam Intake, Tune, Sold 05 C6 Z51 Red/Black Sold 90'ZR-1 #1723 Black/Gray Sold but not forgotten 91' Z51 L98 White Vert. My First, you always remember your first. Sold. Last edited by Ccmano; 11-11-2017 at 11:07 AM. |
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11-11-2017 | #14 | |
Join Date: Aug 2006
Location: McLean, VA
Posts: 3,721
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Re: Hunting idle issue
Quote:
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11-11-2017 | #15 |
Join Date: Aug 2014
Location: Trois-Rivieres (QC)
Posts: 473
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Re: Hunting idle issue
Tonight I checked some stuff.
-No obvious leak. -Vaccuum pump stays quiet for 13 seconds. -TPS checked: 0.55V. -Throttle cable isn't too tight, there's a slight slack in it when at rest. -Tried to reset IAC, procedures don't seem to do anything. Still no success... When I let the car coast in 2nd gear I'm at 18 mph! Last edited by MuRCieLaGo; 11-12-2017 at 12:06 AM. |
11-12-2017 | #16 | |
Join Date: Jun 2006
Location: Sparks, NV
Posts: 2,852
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Re: Hunting idle issue
Quote:
I would start here with Haibecks write up. http://www.zr1specialist.com/HAT%20W...5%20Engine.pdf H
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90'ZR-1 #1461 Red/Black Ported Intake, Degreed Cams, OBX Headers & Exhaust, Fidanza FW, Secondary Delete, Custom tune, C6 GS Wheels. Sold 08 C6 Z51 Crystal Red Metallic Sold Vararam Intake, Tune, Sold 05 C6 Z51 Red/Black Sold 90'ZR-1 #1723 Black/Gray Sold but not forgotten 91' Z51 L98 White Vert. My First, you always remember your first. Sold. |
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11-12-2017 | #17 |
Join Date: Jun 2005
Location: CenCoast California
Posts: 899
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Re: Hunting idle issue
If your secondary vacuum pump runs every 13 seconds you likely have a small leak somwhere in the SPT vacuum system.
However, as others have suggested if you have a vacuum leak which is causing the idle speed problem, it's not a leak in the SPT system causing the trouble. If you can't find a leak, then maybe the TB is worn out and leaking. In any event, fooling with minimum air to solve your problem is not a wise idea. Marc's discussion of vac. leaks is outstanding. Like others suggest, start by reading that.
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Hib Halverson Technical Writer former owner 95 VIN 0140 current owner 19 VIN 1878 |
11-12-2017 | #18 |
Join Date: May 2007
Location: Chicagoland, IL
Posts: 9,699
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Re: Hunting idle issue
Just to set the record straight, nobody is suggesting that Murcielago’s issue would be remedied by resetting the Min Air. Whenever addressing issues like this my approach is to first confirm that the basic settings and parameters are within spec. And that’s ALL I was recommending.
However, I would suggest getting a scantool (don’t need a Tech 1), to look at IAC COUNTS. You should have one anyway. It pays for itself many times over IMO.
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[SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX |
11-12-2017 | #19 |
Join Date: May 2007
Location: Chicagoland, IL
Posts: 9,699
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Re: Hunting idle issue
What was the coolant temp that video was shot at? Just after startup?
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[SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX |
11-13-2017 | #20 |
Join Date: Aug 2014
Location: Trois-Rivieres (QC)
Posts: 473
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Re: Hunting idle issue
So I guess I'll go through that pdf, seems to be fairly simple! I bought a Bluetooth adapter but it doesn't work in real time, I get a reading every 3 seconds when I'm lucky (frustrating). I might remove that Secondary Vaccuum System (and sending my chip to Marc Haibeck)...
Video was taken at the startup after disconnecting the battery. Temperature was just starting to rise on the needle (10 minutes after I started the car). PS: When I removed the plenum, there was still some pressure in the coolant system. I know it basically filled the hole that goes to #6 cylinder. The car had a lot of white smoke for maybe 15 minutes at idle. Not sure if it could have affected something. I can't thank you enough for your help guys. I love the ZR-1 community, so friendly. |
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