Stalling at quick stops - ZR-1 Net Registry Forums

rufcar · 6 Days Ago

My 90 zr1 started to stall when going from say, 40 to a stop. Turn the it fires right up. I spoke to Hibeck and he said just try and downshift to a stop. I have done that for the last 6 or more months and its been ok. A 2 weeks ago I came to a stop at a very crowed intersection, and someone cut me off and had no time to downshift and it stalled while moving like previously, so I caught it in gear like I have done before except this it stumbled and left me sit in heavy traffic. I pushed it to the side and it would start for 1 second and stop. I tried a few times and the same thing, so I called a tow service. About 45 minutes passed he showed up and the car started. I had him tow me to a friend's shop who has a zr1 and works on some. He had it a few days tested everything. No codes either. He changed out the fuel filter and tore it apart and it was ok so He installed a new one. The PO replaced everything as he was a GM wrench. Both pumps are new so is most every relay and hose including the starter. I had a spare NOS idle control valve so I removed the old one cleaned the area as there was some carbon installed a new one and I tried to make it stall and I couldn't. I thought I had it and the last stop coming home it did again. I could live with that as long as I never get the no start again. I also checked the throttle plate, and it was super clean. Any suggestions?

1991 Corvette ZR-1 · 6 Days Ago

The MAP sensor line or perhaps the sensor itself? It is happening when you get on the brakes, which are assisted by vacuum and to me it sounds like a hiccup in the engine management when vacuum changes suddenly. I had the same issue years back when the throttle blades were closed at low speed and attempting to make a turn. When off the gas and applying the brakes for the turn, the engine would stall.

In my case, it ended up being a poor choice by a previous owner for replacement MAP sensor line that was full of oil and softened to the point it collapsed under any vacuum. Once this was replaced with a proper hard line, there were no further issues.

rufcar · 6 Days Ago

did not check it as I know its been replaced by a proper GM unit about 3k mi ago.

-=Jeff=- · 2 Days Ago

Do you have a custom chip in the car?

rufcar · 1 Day Ago

yes Hibeck

-=Jeff=- · 1 Day Ago

ok. I had an issue with a chip before, but I am confident my issue wont be in Haibeck's chip

6 Days Ago	#1
rufcar Join Date: Mar 2023 Location: PA Posts: 54	Stalling at quick stops My 90 zr1 started to stall when going from say, 40 to a stop. Turn the it fires right up. I spoke to Hibeck and he said just try and downshift to a stop. I have done that for the last 6 or more months and its been ok. A 2 weeks ago I came to a stop at a very crowed intersection, and someone cut me off and had no time to downshift and it stalled while moving like previously, so I caught it in gear like I have done before except this it stumbled and left me sit in heavy traffic. I pushed it to the side and it would start for 1 second and stop. I tried a few times and the same thing, so I called a tow service. About 45 minutes passed he showed up and the car started. I had him tow me to a friend's shop who has a zr1 and works on some. He had it a few days tested everything. No codes either. He changed out the fuel filter and tore it apart and it was ok so He installed a new one. The PO replaced everything as he was a GM wrench. Both pumps are new so is most every relay and hose including the starter. I had a spare NOS idle control valve so I removed the old one cleaned the area as there was some carbon installed a new one and I tried to make it stall and I couldn't. I thought I had it and the last stop coming home it did again. I could live with that as long as I never get the no start again. I also checked the throttle plate, and it was super clean. Any suggestions?

6 Days Ago	#2
1991 Corvette ZR-1 Join Date: Sep 2018 Location: Florida Posts: 301	Re: Stalling at quick stops The MAP sensor line or perhaps the sensor itself? It is happening when you get on the brakes, which are assisted by vacuum and to me it sounds like a hiccup in the engine management when vacuum changes suddenly. I had the same issue years back when the throttle blades were closed at low speed and attempting to make a turn. When off the gas and applying the brakes for the turn, the engine would stall. In my case, it ended up being a poor choice by a previous owner for replacement MAP sensor line that was full of oil and softened to the point it collapsed under any vacuum. Once this was replaced with a proper hard line, there were no further issues.

6 Days Ago	#3
rufcar Join Date: Mar 2023 Location: PA Posts: 54	Re: Stalling at quick stops did not check it as I know its been replaced by a proper GM unit about 3k mi ago.

2 Days Ago	#4
-=Jeff=- Join Date: Jul 2007 Location: Bartlett, IL Posts: 7,144	Re: Stalling at quick stops Do you have a custom chip in the car? __________________ 1990 Corvette ZR-1 #1051 Watson Headers (2" Primary) - Borla Catback Late Model IH - Plenum Coilovers - 4.10s Custom Interior NCM Lifetime Member #978

1 Day Ago	#5
rufcar Join Date: Mar 2023 Location: PA Posts: 54	Re: Stalling at quick stops yes Hibeck

1 Day Ago	#6
-=Jeff=- Join Date: Jul 2007 Location: Bartlett, IL Posts: 7,144	Re: Stalling at quick stops ok. I had an issue with a chip before, but I am confident my issue wont be in Haibeck's chip __________________ 1990 Corvette ZR-1 #1051 Watson Headers (2" Primary) - Borla Catback Late Model IH - Plenum Coilovers - 4.10s Custom Interior NCM Lifetime Member #978