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03-14-2009
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#1 |
 
Join Date: Mar 2007
Location: Crystal Lake, IL
Posts: 7,194
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High Idle...need ideas
Well, I pulled the plenum put it back together, had a vacuum leak.....vac would not hold on the line running from the D/S center of the plenum. Found a leak in the hard line, pin hole, fixed it....put it all back together and still have high idle.
Vacuumm holds on both the pass/driver side plenum inlets. Also vac is holding on the line running from the pump to under the plenum. Any other ideas, PCVs seem to be sealed. I did replacet the breather hoses, maybe I should check there first. I also swapped the new IAC form my 92 and no help.
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LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359 |
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03-14-2009
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#2 |
Join Date: Aug 2008
Location: Houston 90 Red ZR-1
Posts: 2,320
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Re: High Idle...need ideas
I wonder if your check valve is stuck. But if your check valve is stuck your vacumm pump would be running constantly so I'm not sure. Unpluging that drivers side hose from the plenum will definately cause high idle. And that line goes to the check valve.
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03-15-2009
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#3 |
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Join Date: Mar 2007
Location: Crystal Lake, IL
Posts: 7,194
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Re: High Idle...need ideas
My pump only kicks on for a few seconds every 5 minutes.
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LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359 |
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03-15-2009
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#4 |
 
Join Date: Jul 2005
Location: Mendota Heights, MN. 55120
Posts: 984
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Re: High Idle...need ideas
What rpm is the idle?
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Bob Anderson 1990 #2405 White/Gray Haibeck chip,4:09 gears,Power Effects Exhaust,5 spoke chrome,C5 brakes,49th Street rockers,K&N,Hurst,Headers,Upper & lower ported Minnesota State Director Founding Member #19 |
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03-15-2009
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#5 |
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Join Date: Mar 2007
Location: Crystal Lake, IL
Posts: 7,194
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Re: High Idle...need ideas
900-1000
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LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359 |
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03-15-2009
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#6 |
Join Date: Dec 2003
Location: Chicagoland,IL
Posts: 2,679
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Re: High Idle...need ideas
Lee did you connect the little vacuum hose under the TB it's 1990 specific.
Pete
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'91 #1635 PoloGreen 350 LT5 11.09 @ 129.27 11.04 @ 128.86 474RWHP 400RWTQ http://www.youtube.com/watch?v=SFNFOhGGlR4 http://www.youtube.com/watch?v=ZlRIOMwaDYY https://sites.google.com/site/peteszr1garage |
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03-15-2009
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#7 |
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Join Date: Mar 2007
Location: Crystal Lake, IL
Posts: 7,194
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Re: High Idle...need ideas
yup, got that one, everything is connected, car idled well before I tore into it....however gaskets had to go as they were leaking oil.
I will take a look tomorrow, and try a spray bottle to check leaks.
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LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359 |
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03-15-2009
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#8 |
Join Date: Jul 2007
Location: Bartlett, IL
Posts: 7,169
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Re: High Idle...need ideas
what PROM is in the car?
my 90 did the same thing, was fine when I bought it, but when I R&Red the plenum last year I had that problem.. I had an OEM variation in the car, I switch to the later version for better IAC steps and it seemed fine
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1990 Corvette ZR-1 #1051 Watson Headers (2" Primary) - Flowmaster Cats - Borla Catback Late Model IH - Plenum Coilovers - 4.10s Custom Interior NCM Lifetime Member #978 |
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03-15-2009
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#9 |
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Join Date: Mar 2007
Location: Crystal Lake, IL
Posts: 7,194
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Re: High Idle...need ideas
DRM chip, I think I am chasing a leak, just not in the usual vac lines.
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LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359 |
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03-15-2009
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#10 | |
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Join Date: Jul 2007
Location: Bartlett, IL
Posts: 7,169
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Re: High Idle...need ideas
Quote:
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1990 Corvette ZR-1 #1051 Watson Headers (2" Primary) - Flowmaster Cats - Borla Catback Late Model IH - Plenum Coilovers - 4.10s Custom Interior NCM Lifetime Member #978 |
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Linear Mode
