04-15-2012 | #1 |
Join Date: May 2007
Location: Chicagoland, IL
Posts: 9,708
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Riddle me this Batman
Got the motor put together and am battling what appears to be a vacuum leak. I first addressed what appeared to be an issue with a sticking throttle. Took primary throttle apart and cleaned off shaft of any "paint" and re-installed throttle blade. Took car out for drive and it actually didn't behave badly but idle speed was a bit high. However the "cruise control" sticking throttle seemed to be fixed. However, I still have what feels like a vacuum leak. Pulled the PCV and the 2 side ports of the plenum. In each case, idle would INCREASE when I exposed them to atmosphere.
My concern is a leak at the throttle body somewhere. It tends to raise idle from 825 commanded to a 975-1000 actual. Here's what is interesting. when I first start the motor it will "flare" to 1500-1700rpm then idle will drop to 1000 w coolant temps at 50C. As coolant temp increase I can see the IAC counts drop and so does the idle rpm. OK, so now the motor is idling at about 850 or so with IAC counts of ~ 10. GREAT except then I blip the throttle. IaC counts drop to 0 and now idle has a bit if a surge at about 900-1000. Otherwise the car drives well with no surging at PT cruise. So why does blipping the throttle upset the apple cart?? Any suggestions before I pull the plenum are appreciated.
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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 |
04-15-2012 | #2 |
Join Date: Jul 2005
Location: Las Vegas, Nevada
Posts: 777
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Re: Riddle me this Batman
Just a guess, but did you check your TPS?
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JB 1990 #148 Red/Saddle Haibeck AYBKG5 Chip/RC Engineering/Flowmasters/K&N/Samco/Fuzzy Dice :cheers: |
04-15-2012 | #3 |
Join Date: May 2007
Location: Chicagoland, IL
Posts: 9,708
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Re: Riddle me this Batman
.55v. I put a scantool on it, yes.
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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 |
04-15-2012 | #4 |
Join Date: Aug 2008
Location: Houston 90 Red ZR-1
Posts: 2,320
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Re: Riddle me this Batman
Dom after I had my top end powdercoated and put it back together I had a high idle problem. And when id blip the gas peddle the idle would drop back down to normal 900. This is a vid I made of the problem and how I fixed it.
http://static.photobucket.com/player...-04-26_724.mp4 Im not saying this is the cause of your problem but its worth taking a look at. |
04-15-2012 | #5 | |
Join Date: May 2007
Location: Chicagoland, IL
Posts: 9,708
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Re: Riddle me this Batman
Quote:
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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 |
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04-15-2012 | #6 |
Join Date: Aug 2005
Location: Iuka, Mississippi 38852
Posts: 756
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Re: Riddle me this Batman
try again. i just watched it.
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04-15-2012 | #7 |
Join Date: Jan 2009
Location: Portland Oregon metro area (Washington side)
Posts: 3,207
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Re: Riddle me this Batman
Video worked for me. Well done.
I have not seen sticking there before but will keep it in mind. What I have seen on two TBs is the big two sticking.
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Scott Vett owner since 1979._It's about the car and the people |
04-16-2012 | #8 |
Join Date: Aug 2008
Location: Houston 90 Red ZR-1
Posts: 2,320
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Re: Riddle me this Batman
Were you able to veiw the vid Dom? I don't know how else to get it to where you can veiw it. But in a nutshell the little lever outside the TB housing on the drivers side that opens the primary throttle plate was sticking open from lack of lubrication. Hitting it with brake clean and then white lithium made it operate smoothly.
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04-16-2012 | #9 |
Join Date: May 2007
Location: Peoria, AZ
Posts: 9,155
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Re: Riddle me this Batman
Dom I could send you back your old TB you sold me a year ago to test out your TB theory. Its just sitting in the parts crib. LMK Daryll
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GOLDCYLON - 91 ZR-1 #2014 GOLDCYLON - 90 ZR-1 #2794, 4L60e (Formerly Schrade's) GOLDCYLON - 11 CTS-V Arizona State Director 91 WHITE/BLACK #2014. 380 P&P&PCed,Ported Heads, Jeal Long tubes, Corsa Exhaust/FIKSE FM-5s /LED TLs, LED Headlights, Front Wilwood 6 piston narrowlite calipers and rear Wilwood caliper street shop mod,CNCed Coolant Pipes,TPI Cvr,Filter cover,Stainless Bolts, DRM/DOM PROM /ZFDOC mod build #102,DRLs,BMAD with stainless Debris Screen,Coplan Air Blaster, Pioneer APP Radio 4,Brey-Krause HB,Sub Bar,Fire extinguisher seat mount,DRM Coilovers,LEDs everywhere,Compass mirror (orange),V1 DIC hidden display, Homelink sun visor, Carbon Fiber top x3 and APSIS Carbon Fiber interior, APSIS CF Steering Wheel/NAPA Leather, Banski trailing arms, Guldstrand front suspension,urethane bushings from Prothane (total suspension) ZFDoc drive shaft safety loop, raptor shift light (orange),AO engineering louver front plate, Console seat cushion, 96CE seats with black custom Sheepskins, ss billet catch can,Viper remote entry/alarm,Cragar Rear Louvers,LED side louver lights, Dewitts Radiator with SPAL fans and a Woods 160 T-Stat 90 RED/BLACK #2794. 4L60e Automatic Stage V by RPM Transmission, TCI Dedicated TCM, OBX Stainless Headers, Corsa Exhaust, SAN Secondaries and Haibeck PROM, Exotic Muscle Coil overs, LED Interior Lights, LED Tail Lights, LED Headlights, 94 Sport seats with black custom Sheepskins , Cragar rear louvers, GS Front calipers, Banski Trailing arms, APSIS Carbon Fiber steering wheel, Front and Rear Baer Eradispeeds, DRLs, Guldstrand front suspension,urethane bushings from Prothane (total suspension), Dewitt's Raditor with Dual SPAL fans and a Haibeck 170 T-Stat 11 RED/GREY CTS-V |
04-16-2012 | #10 | |
Join Date: May 2007
Location: Peoria, AZ
Posts: 9,155
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Re: Riddle me this Batman
Quote:
Good video. Last time I had a simular problem the IAC valve on the oposite side had seperated inside the side of the AH. The spring and the check valve had seperated from the valve body and were sucked into the side of the AH. Just another possibility.
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GOLDCYLON - 91 ZR-1 #2014 GOLDCYLON - 90 ZR-1 #2794, 4L60e (Formerly Schrade's) GOLDCYLON - 11 CTS-V Arizona State Director 91 WHITE/BLACK #2014. 380 P&P&PCed,Ported Heads, Jeal Long tubes, Corsa Exhaust/FIKSE FM-5s /LED TLs, LED Headlights, Front Wilwood 6 piston narrowlite calipers and rear Wilwood caliper street shop mod,CNCed Coolant Pipes,TPI Cvr,Filter cover,Stainless Bolts, DRM/DOM PROM /ZFDOC mod build #102,DRLs,BMAD with stainless Debris Screen,Coplan Air Blaster, Pioneer APP Radio 4,Brey-Krause HB,Sub Bar,Fire extinguisher seat mount,DRM Coilovers,LEDs everywhere,Compass mirror (orange),V1 DIC hidden display, Homelink sun visor, Carbon Fiber top x3 and APSIS Carbon Fiber interior, APSIS CF Steering Wheel/NAPA Leather, Banski trailing arms, Guldstrand front suspension,urethane bushings from Prothane (total suspension) ZFDoc drive shaft safety loop, raptor shift light (orange),AO engineering louver front plate, Console seat cushion, 96CE seats with black custom Sheepskins, ss billet catch can,Viper remote entry/alarm,Cragar Rear Louvers,LED side louver lights, Dewitts Radiator with SPAL fans and a Woods 160 T-Stat 90 RED/BLACK #2794. 4L60e Automatic Stage V by RPM Transmission, TCI Dedicated TCM, OBX Stainless Headers, Corsa Exhaust, SAN Secondaries and Haibeck PROM, Exotic Muscle Coil overs, LED Interior Lights, LED Tail Lights, LED Headlights, 94 Sport seats with black custom Sheepskins , Cragar rear louvers, GS Front calipers, Banski Trailing arms, APSIS Carbon Fiber steering wheel, Front and Rear Baer Eradispeeds, DRLs, Guldstrand front suspension,urethane bushings from Prothane (total suspension), Dewitt's Raditor with Dual SPAL fans and a Haibeck 170 T-Stat 11 RED/GREY CTS-V |
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