Zr1 fuel pump 1 not working - ZR-1 Net Registry Forums

Crazytruk · 01-17-2021

I have a 1990 zr1 that sat for a few years. I changed injectors and fuel pumps. The car starts and gets up to a certain temperature and loses fuel pressure and stalls. When I start the car cold and I pull the fuse from the block under the passenger side dash it loses fuel pressure and stalls. I do not think this should happen because the fuel pump one should keep pressure and keep it running. I connected the Lead coming out of the firewall to the positive on the battery and still no change car still stalled when it got warm.
Any Ideas?
Mike

Ccmano · 01-17-2021

Pull the FP2 fuse and see if it starts in the same manner. If it doesn't start you have a bad FP1 pump. The other possibility to check are the hose clamps on the pump assembly or a cracked Y block on the pump assembly. I'm betting it's a bad FP1 pump.
H

Corvette95 · 01-17-2021

Quote:

Originally Posted by Ccmano

Pull the FP2 fuse and see if it starts in the same manner. If it doesn't start you have a bad FP1 pump. The other possibility to check are the hose clamps on the pump assembly or a cracked Y block on the pump assembly. I'm betting it's a bad FP1 pump.
H

agreed, you can also check initial fuel pressure with fuel pressure gauge, it will pressure up to 55psi then drop about 5 psi if both pumps are working, no drop equals one pump bad. (this was part of this morning project for me BTW)

rkreigh · 01-24-2021

if anyone needs pumps, I gotz em cheap. I upgraded on the LSV and my fresh stockers are no longer needed.

Young1 · 01-25-2021

Mike,
We can help but we need to know the fuel rail pressures. Get a gauge set from harbor freight. Read the stickies on fuel pumps here on the forum. I think you have a cracked hose or fitting in the tank. We need more info sir.

jss06c6 · 01-26-2021

As others have said, very likely pump 1. The LT-5 runs on both pumps until temp comes up and engine switches to closed loop, then it turns off #2 and only runs on #1 unless demanded at WOT by ECM. Make sure you check the bulkhead connector as well (for corrosion) when you have the assembly out.

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01-24-2021	#4
rkreigh Join Date: Jan 2004 Location: Alex VA Posts: 1,087	Re: Zr1 fuel pump 1 not working if anyone needs pumps, I gotz em cheap. I upgraded on the LSV and my fresh stockers are no longer needed. __________________ 95 390 LPE ZR1 (505 rwhp) LSV = Lingenfelter Super Vette Twin Turbo 2003 Z06 (800 RWHP)

01-25-2021	#5
Young1 Join Date: Sep 2016 Location: Ocala, FL Posts: 890	Re: Zr1 fuel pump 1 not working Mike, We can help but we need to know the fuel rail pressures. Get a gauge set from harbor freight. Read the stickies on fuel pumps here on the forum. I think you have a cracked hose or fitting in the tank. We need more info sir. __________________ 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.

01-26-2021	#6
jss06c6 Join Date: Aug 2015 Location: Magnolia, Texas Posts: 884	Re: Zr1 fuel pump 1 not working As others have said, very likely pump 1. The LT-5 runs on both pumps until temp comes up and engine switches to closed loop, then it turns off #2 and only runs on #1 unless demanded at WOT by ECM. Make sure you check the bulkhead connector as well (for corrosion) when you have the assembly out. Sent from my SM-G950U using ZR-1 Net Registry mobile app Last edited by jss06c6; 01-26-2021 at 06:16 AM.

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01-17-2021	#1
Crazytruk Join Date: Jan 2021 Location: New york Posts: 1	Zr1 fuel pump 1 not working I have a 1990 zr1 that sat for a few years. I changed injectors and fuel pumps. The car starts and gets up to a certain temperature and loses fuel pressure and stalls. When I start the car cold and I pull the fuse from the block under the passenger side dash it loses fuel pressure and stalls. I do not think this should happen because the fuel pump one should keep pressure and keep it running. I connected the Lead coming out of the firewall to the positive on the battery and still no change car still stalled when it got warm. Any Ideas? Mike

01-17-2021	#2
Ccmano Join Date: Jun 2006 Location: Sparks, NV Posts: 2,852	Re: Zr1 fuel pump 1 not working Pull the FP2 fuse and see if it starts in the same manner. If it doesn't start you have a bad FP1 pump. The other possibility to check are the hose clamps on the pump assembly or a cracked Y block on the pump assembly. I'm betting it's a bad FP1 pump. 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.