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04-10-2019
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#21 |
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Join Date: Dec 2018
Location: Long Beach, CA
Posts: 68
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Re: 1990 ZR-1 Hesitation when full Power
TPS set to 0.56V, working a little better but now it still has the hesitation, I'll look into vacuum leaks some more.
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04-10-2019
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#22 | |
 
Join Date: Jun 2006
Location: Sparks, NV
Posts: 2,852
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Re: 1990 ZR-1 Hesitation when full Power
Quote:
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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04-10-2019
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#23 |
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Join Date: Dec 2018
Location: Long Beach, CA
Posts: 68
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Re: 1990 ZR-1 Hesitation when full Power
IAC count still goes down to zero when warm and idles a little high, I'm just not sure where a leak could be.
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04-10-2019
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#24 |
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Join Date: Jun 2006
Location: Sparks, NV
Posts: 2,852
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Re: 1990 ZR-1 Hesitation when full Power
Is it still hunting at idle?
H
__________________
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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04-10-2019
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#25 |
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Join Date: Dec 2018
Location: Long Beach, CA
Posts: 68
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Re: 1990 ZR-1 Hesitation when full Power
Yes it still hunts at idle. It also has moments of a rougher idle, and jumps to smooth but I don't see anything in the data about it.
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04-10-2019
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#26 |
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Join Date: Jun 2006
Location: Sparks, NV
Posts: 2,852
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Re: 1990 ZR-1 Hesitation when full Power
Sounds like you went through everything on Haibecks list. I’ve seen them leak at the injector o-rings, a little carb spray at each injector and see if the idle speed changes would show that. We have also see air leaks at the throttle plates. Was the throttle body around the plates cleaned with carb cleaner recently? If so the DAG sealant may have been removed causing more air to bleed by. If you haven’t already read through what member “Roadster” discovered on that subject. http://www.zr1.net/forum/showthread....=Throttle+body
In any case you have an air leak somewhere and if it’s hunting rather than just a high idle it’s fairly significant. Along with the hunting the zero IAC count is the telling factor of an air leak. Will you be at the Socal meet in Fontana at the end of the month? I wouldn’t mind looking at it while I’m down there. H
__________________
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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04-10-2019
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#27 |
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Join Date: Dec 2018
Location: Long Beach, CA
Posts: 68
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Re: 1990 ZR-1 Hesitation when full Power
I'm hoping to have it fixed by then, here's another symptom. When I floor it in full power mode, the car shakes quite a bit, and its MUCH less noticeable in valet mode. I figure if the issues is a vacuum leak at the throttle plate, it wouldn't cause an issue once not at idle.
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04-10-2019
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#28 | |
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Join Date: Jun 2006
Location: Sparks, NV
Posts: 2,852
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Re: 1990 ZR-1 Hesitation when full Power
Quote:
H
__________________
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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04-10-2019
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#29 |
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Join Date: Dec 2018
Location: Long Beach, CA
Posts: 68
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Re: 1990 ZR-1 Hesitation when full Power
Injectors have been replaced, fuel pumps are new and are functioning properly according to the scanner, secondaries are opening, and the coils were ohm tested to be okay. Does it when cold or warm so I didn't think it was a break down issue with the coils.
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04-10-2019
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#30 |
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Join Date: Jun 2006
Location: Sparks, NV
Posts: 2,852
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Re: 1990 ZR-1 Hesitation when full Power
You really have done quite a bit. Ohming the coils is not the best coil test, they can ohm good and still be going bad. Drive the car at low speed in a high gear and accelerate slowly. If it misses likely a coil is bad. I assume wires have been ohmed and plugs replaced too. Have you checked to see if the system has thrown any codes. Also what is the fuel pressure static and at full throttle. We’ve seen the Y and connectors at the fuel pumps go bad and loose pressure. Fuel filters get plugged and fuel pressure regulators go bad.
At the risk of stating the obvious are the vacuum hoses hooked up to both the MAP sensors? Something is going on and likely all related. 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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