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04-05-2023
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#1 |
 
Join Date: Sep 2018
Location: Groton, CT
Posts: 382
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Secondary fuel pump dead?
Car runs fine, except when at full throttle going through the gears. Then acts like fuel shutoff. For short bursts of full throttle, everything is ok. I'm thinking the secondary pump isn't keeping up, or only the primary is working.
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1992 ZR1 #442, 2 tops, White, White, Haibeck 415, 3.90 gear, Coilovers 2018 Audi RS5, 2.9 V6 Twin Turbo, Auto, Black, Black 2021 Audi Q3, 2.0T, 8 spd Tiptronic, Navarro Blue metallic, Pearl Beige |
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04-05-2023
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#2 |
Join Date: Sep 2016
Location: Ocala, FL
Posts: 899
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Re: Secondary fuel pump dead?
Most likely yes. To confirm perform the fuel pumps amperage test on the red pigtail at the wiper motor. Your meter will read 7-9 amps if both are running. 3-4 amps if one is running. Details in the Stickies.
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Steve Young 1991 ZR-1 Quasar Blue Metallic/Black #729 Second Owner 1991 ZR-1 Dark Red Metallic/Black #2040 SOLD 1990 ZR-1 Dark Red Metallic/Saddle #1670 SOLD Double your happiness.....complain half as much. |
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04-08-2023
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#3 |
 
Join Date: Dec 2003
Location: Arcadia,OK
Posts: 3,394
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Re: Secondary fuel pump dead?
Do you still have the Secondary Port Throttle (SPT) system still in place?
If so, test the vacuum pump and each of the vacuum actuators. A failure of any 1 of those 3 items can cause the same symptom.
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Jerry Downey JERRYS LT5 GASKETS & PARTS http://www.jerrysgaskets.com 1994 ZR-1, Black/Black, Lingenfelter Aerobody, 416cu in, 3.91 gears, coil-over susp, Brembo brakes, etc. 2016 Black-Red, 3LT-Z51 Auto 8-speed. |
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04-08-2023
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#4 |
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Join Date: Sep 2018
Location: Groton, CT
Posts: 382
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Re: Secondary fuel pump dead?
Secondary Port Throttle (SPT) system is still in place. Entire system was checked by Marc when my 415 was built less than a year ago. Vacuum pump doesn't cycle at all. Pretty sure its a pump. Will be replacing both today.
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1992 ZR1 #442, 2 tops, White, White, Haibeck 415, 3.90 gear, Coilovers 2018 Audi RS5, 2.9 V6 Twin Turbo, Auto, Black, Black 2021 Audi Q3, 2.0T, 8 spd Tiptronic, Navarro Blue metallic, Pearl Beige |
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04-08-2023
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#5 | |
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Join Date: Dec 2003
Location: Arcadia,OK
Posts: 3,394
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Re: Secondary fuel pump dead?
Quote:
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Jerry Downey JERRYS LT5 GASKETS & PARTS http://www.jerrysgaskets.com 1994 ZR-1, Black/Black, Lingenfelter Aerobody, 416cu in, 3.91 gears, coil-over susp, Brembo brakes, etc. 2016 Black-Red, 3LT-Z51 Auto 8-speed. |
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04-08-2023
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#6 |
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Join Date: Sep 2018
Location: Groton, CT
Posts: 382
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Re: Secondary fuel pump dead?
My first check was the current draw. Current reads 9.3 Amps, so it seems both pumps are running.
Next check will be fuel pressure.
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1992 ZR1 #442, 2 tops, White, White, Haibeck 415, 3.90 gear, Coilovers 2018 Audi RS5, 2.9 V6 Twin Turbo, Auto, Black, Black 2021 Audi Q3, 2.0T, 8 spd Tiptronic, Navarro Blue metallic, Pearl Beige Last edited by Subfixer; 04-08-2023 at 06:22 PM. |
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04-08-2023
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#7 |
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Join Date: Sep 2018
Location: Groton, CT
Posts: 382
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Re: Secondary fuel pump dead?
Fuel pressure check.... not good.
Only 42psi at cold idle.
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1992 ZR1 #442, 2 tops, White, White, Haibeck 415, 3.90 gear, Coilovers 2018 Audi RS5, 2.9 V6 Twin Turbo, Auto, Black, Black 2021 Audi Q3, 2.0T, 8 spd Tiptronic, Navarro Blue metallic, Pearl Beige |
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04-08-2023
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#8 |
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Join Date: Sep 2018
Location: Groton, CT
Posts: 382
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Re: Secondary fuel pump dead?
I really am disappointed in aftermarket Chinese parts.
After replacing both pumps with Delphi FE0039 units, I now have a combined fuel pressure of 20psi.....
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1992 ZR1 #442, 2 tops, White, White, Haibeck 415, 3.90 gear, Coilovers 2018 Audi RS5, 2.9 V6 Twin Turbo, Auto, Black, Black 2021 Audi Q3, 2.0T, 8 spd Tiptronic, Navarro Blue metallic, Pearl Beige |
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04-08-2023
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#9 |
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Join Date: Sep 2018
Location: Groton, CT
Posts: 382
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Re: Secondary fuel pump dead?
Vacuum pump does cycle, just not excessively. About once every 45 seconds after initial pump up.
Put old (original) fuel pumps back in for now. After removing and replacing the assembly 3 times, I'm now an "expert".
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1992 ZR1 #442, 2 tops, White, White, Haibeck 415, 3.90 gear, Coilovers 2018 Audi RS5, 2.9 V6 Twin Turbo, Auto, Black, Black 2021 Audi Q3, 2.0T, 8 spd Tiptronic, Navarro Blue metallic, Pearl Beige |
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04-08-2023
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#10 |
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Join Date: Sep 2018
Location: Groton, CT
Posts: 382
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Re: Secondary fuel pump dead?
Any recommendations for "good" fuel pumps?
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1992 ZR1 #442, 2 tops, White, White, Haibeck 415, 3.90 gear, Coilovers 2018 Audi RS5, 2.9 V6 Twin Turbo, Auto, Black, Black 2021 Audi Q3, 2.0T, 8 spd Tiptronic, Navarro Blue metallic, Pearl Beige |
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