90 ZR1 Randomly Dies - ZR-1 Net Registry Forums

fastpace · 02-11-2023

Did a bit of searching but wasn't seeing anything quite following my symptoms (many related to dieing at idle, cold or warm, or running rough).

Have a 1990, last drove it maybe 4 weeks ago and went to take it out today. Started right up like normal, pulled it out and left it idling while moving stuff around. Got back in the car and then it died at idle (hadn't fully warmed up yet), thought it was weird but it started right back up and ran smooth. Pulled out got a couple miles down the road and died again. Some cranking, then started again. Died about 6 times in a 2 miles loop getting it back home, each time happening after a shorter run time.

When running it runs very smooth, not noticeable issues. When it dies, the tach stays right around where it was, if you push gas it does/goes no where, and once you let off it dies and drops to 0. It doesn't fire right off, sometimes takes some cranking.

About 1500 miles ago I replaced to single fuel pump, new injectors, new spark plugs, and replaced some vacuum lines. Since then it's always run great. I will assume all other parts are original to the car.

Any common issues or quick things to check?
I'm thinking cam or crank sensor. Is there an ignition module? Any help is appreciated.

Andy · 02-11-2023

Maybe a new fuel filter?

WARP TEN · 02-12-2023

Or fuel pumps? --Bob

tiegsd · 02-12-2023

I suppose I'd start with pulling codes.

fastpace · 02-12-2023

Quote:

Originally Posted by Andy

Maybe a new fuel filter?

Installed a new wix filter at same time as fuel pump, so less than 2k miles. Also brand new pump sock and hanger assembly.

I'll still plan to add fuel pressure monitoring to my trouble shooting list.

Quote:

Originally Posted by WARP TEN

Or fuel pumps? --Bob

Has a new single Walboro.

Quote:

Originally Posted by tiegsd

I suppose I'd start with pulling codes.

After restarting the car there was no CEL present.

aafc · 02-12-2023

I had this same problem last year on way to National Corvette museum. On I-75 north in Georgia. Cruising along at 75 mph fuel pressure drops, pull over called AAA for tow. After setting for awhile at auto shop I was able to restart car. At this point I decided to go back home ( The Villages ). Car stalled 3 more times by the time I got home.
After checking I was able to isolate the cause of the failure. Fuel pump
relay# 1 would lose power at times.
Using the 8A section page 8A-22-6. That relay controls fuel pump relay #2
Replace fuel pump relay #1( 20 plus years old ) and car started right up.
No guarantee that this might be your problem, but it gives you something
to look at.
Hope this may help you.
John
1990 white/black # 2546
one of a few 4l8OE eq ZR-1's

secondchance · 02-12-2023

About 1500 miles ago I replaced to single fuel pump, new injectors, new spark plugs, and replaced some vacuum lines

When you say single fuel pump, you mean modified pump running on one pump?

fastpace · 02-13-2023

Quote:

Originally Posted by aafc

I had this same problem last year on way to National Corvette museum. On I-75 north in Georgia. Cruising along at 75 mph fuel pressure drops, pull over called AAA for tow. After setting for awhile at auto shop I was able to restart car. At this point I decided to go back home ( The Villages ). Car stalled 3 more times by the time I got home.
After checking I was able to isolate the cause of the failure. Fuel pump
relay# 1 would lose power at times.
Using the 8A section page 8A-22-6. That relay controls fuel pump relay #2
Replace fuel pump relay #1( 20 plus years old ) and car started right up.
No guarantee that this might be your problem, but it gives you something
to look at.
Hope this may help you.
John
1990 white/black # 2546
one of a few 4l8OE eq ZR-1's

This is a very interesting thought and would be a pretty easy check, thanks!

Quote:

Originally Posted by secondchance

About 1500 miles ago I replaced to single fuel pump, new injectors, new spark plugs, and replaced some vacuum lines

When you say single fuel pump, you mean modified pump running on one pump?

I used the Flyman pump assembly, you end up removing/isolating the 2nd pump wiring.

https://www.zr1.net/forum/showthread.php?t=33899

secondchance · 02-13-2023

I used the Flyman pump assembly, you end up removing/isolating the 2nd pump wiring.

Just wanted to make sure that you had a factory two pump set up and replaced one pump or had a new single pump set up. OEM dual pump set up will run fine until magic coolant temp and stall out if the primary pump has gone bad Sind secondary pump turns off. We can rule this one out.

mlipmd · 02-14-2023

Another suggestion - You didn't run out of gas did you?
Happened to me once when the gauge read about 1/8-1/4 full and the car died at a stop sign but started right up again and I drove home for about 5 miles with no problem. I was looking at the gauge but it turned out the tank was empty, and after filling it up with gas it never happened again. Added a bottle of Techron a couple of times with fill-ups to clean off the gauge and it seems more accurate now. Or you can remove the pump and clean off the gauge yourself. Being aware of your trip mileage in between fill-ups is another way to avoid this. May not be your problem, but just another thought.

02-12-2023	#3
WARP TEN Join Date: Apr 2007 Location: Lake Bluff, IL Posts: 2,035	Re: 90 ZR1 Randomly Dies Or fuel pumps? --Bob __________________ 2016 Long Beach Red Z06 #10281 "POPS Z" 1995 Polo Green #409 "WARP TEN"--Haibeck 350/510 package, 4.10s, Hurst, Stock Exhaust with QTP Cutouts --Sold but still running strong 1993 Quasar Blue #161 "HIL KING" --Sold but still running strong, now with more than 120,000 miles 1967 Marlboro Maroon/Saddle Corvette Coupe 300 hp/4-spd --Sold a long time ago ZR-1 Net Registry Founding Member #95 NCM Lifetime Member Favorite Quote--Attributed to Mickey Thompson: "Too Much Horsepower is Almost Enough"

02-12-2023	#4
tiegsd Join Date: Jul 2017 Location: West Chester, PA Posts: 367	Re: 90 ZR1 Randomly Dies I suppose I'd start with pulling codes. __________________ 1990 Black/Black ZR-1 #1155 1993 White/Red coupe (Regrettably sold)

02-12-2023	#6
aafc Join Date: Feb 2010 Location: Ochlocknee, GA Posts: 424	Re: 90 ZR1 Randomly Dies I had this same problem last year on way to National Corvette museum. On I-75 north in Georgia. Cruising along at 75 mph fuel pressure drops, pull over called AAA for tow. After setting for awhile at auto shop I was able to restart car. At this point I decided to go back home ( The Villages ). Car stalled 3 more times by the time I got home. After checking I was able to isolate the cause of the failure. Fuel pump relay# 1 would lose power at times. Using the 8A section page 8A-22-6. That relay controls fuel pump relay #2 Replace fuel pump relay #1( 20 plus years old ) and car started right up. No guarantee that this might be your problem, but it gives you something to look at. Hope this may help you. John 1990 white/black # 2546 one of a few 4l8OE eq ZR-1's

02-12-2023	#7
secondchance Join Date: Aug 2006 Location: McLean, VA Posts: 3,703	Re: 90 ZR1 Randomly Dies About 1500 miles ago I replaced to single fuel pump, new injectors, new spark plugs, and replaced some vacuum lines When you say single fuel pump, you mean modified pump running on one pump?

02-13-2023	#9
secondchance Join Date: Aug 2006 Location: McLean, VA Posts: 3,703	Re: 90 ZR1 Randomly Dies I used the Flyman pump assembly, you end up removing/isolating the 2nd pump wiring. Just wanted to make sure that you had a factory two pump set up and replaced one pump or had a new single pump set up. OEM dual pump set up will run fine until magic coolant temp and stall out if the primary pump has gone bad Sind secondary pump turns off. We can rule this one out.

02-11-2023	#1
fastpace Join Date: Mar 2022 Location: Houston, TX Posts: 39	90 ZR1 Randomly Dies Did a bit of searching but wasn't seeing anything quite following my symptoms (many related to dieing at idle, cold or warm, or running rough). Have a 1990, last drove it maybe 4 weeks ago and went to take it out today. Started right up like normal, pulled it out and left it idling while moving stuff around. Got back in the car and then it died at idle (hadn't fully warmed up yet), thought it was weird but it started right back up and ran smooth. Pulled out got a couple miles down the road and died again. Some cranking, then started again. Died about 6 times in a 2 miles loop getting it back home, each time happening after a shorter run time. When running it runs very smooth, not noticeable issues. When it dies, the tach stays right around where it was, if you push gas it does/goes no where, and once you let off it dies and drops to 0. It doesn't fire right off, sometimes takes some cranking. About 1500 miles ago I replaced to single fuel pump, new injectors, new spark plugs, and replaced some vacuum lines. Since then it's always run great. I will assume all other parts are original to the car. Any common issues or quick things to check? I'm thinking cam or crank sensor. Is there an ignition module? Any help is appreciated.

02-11-2023	#2
Andy Join Date: Aug 2014 Location: Chantilly, VA Posts: 35	Re: 90 ZR1 Randomly Dies Maybe a new fuel filter? __________________ 1990 black on black #1042 - sadly - sold 1993 Ruby #140 - stock 1991 QB #1608 - heads and top end ported, Watson headers, B&B 3"exhaust, Haibeck chip, 4.10 gears

02-14-2023	#10
mlipmd Join Date: Mar 2021 Location: Crawfordville, FL Posts: 200	Re: 90 ZR1 Randomly Dies Another suggestion - You didn't run out of gas did you? Happened to me once when the gauge read about 1/8-1/4 full and the car died at a stop sign but started right up again and I drove home for about 5 miles with no problem. I was looking at the gauge but it turned out the tank was empty, and after filling it up with gas it never happened again. Added a bottle of Techron a couple of times with fill-ups to clean off the gauge and it seems more accurate now. Or you can remove the pump and clean off the gauge yourself. Being aware of your trip mileage in between fill-ups is another way to avoid this. May not be your problem, but just another thought.