Miss After Heat Soaking - ZR-1 Net Registry Forums

vettn71 · 05-21-2009

Unless someone can come up with a better soultion, looks like it's injector and coil time. My 90 runs great when first started up and seems to run fine unitl I stop it and let it sit for a half hour or so. When I start it up again it has a miss; like one of the injectors is shut down. My guess is one of the coils is beginning to take a dump and when the car heat soaks it is putting out inadequate spark. Any other ideas on this?

Jim

tomtom72 · 05-21-2009

Jim, I've a 90 and the symptoms when my OEM injectors took a vacation were a miss after it was running long enough to come up to normal water temp. The miss was there almost from start up, but didn't get really bad until the temps came up. However if I stood behind the car I could smell a lean condition at one muffler. I had 4 bad primaries on the right bank, so it really smelled badly after warming up. It was enough to make your eyes water!

I would agree with your diagnosis. When I did the injectors in my car I did the coils at the same time just because it seemed to be the obvious thing to do while the plenum was off. I would caution against the use of after market coils. Use the GM D555 coils.

Jerry has all the gaskets that you will need and I just bought GM coils from one of the online places, partszoneonline.com....aka formerly P&G chevy in PA.

Tom

rkreigh · 05-22-2009

ohm out the injectors after they are hot. haibeck has the way to do this from the injector harness with the plenum on. my bet is that the injectors are failing when hot which is very typical when they go bad

05-21-2009	#1
vettn71 Join Date: Oct 2008 Location: Colleyville, TX Posts: 272	Miss After Heat Soaking Unless someone can come up with a better soultion, looks like it's injector and coil time. My 90 runs great when first started up and seems to run fine unitl I stop it and let it sit for a half hour or so. When I start it up again it has a miss; like one of the injectors is shut down. My guess is one of the coils is beginning to take a dump and when the car heat soaks it is putting out inadequate spark. Any other ideas on this? Jim

05-21-2009	#2
tomtom72 Join Date: Dec 2004 Location: Jacksonville, FL USA Posts: 4,645	Re: Miss After Heat Soaking Jim, I've a 90 and the symptoms when my OEM injectors took a vacation were a miss after it was running long enough to come up to normal water temp. The miss was there almost from start up, but didn't get really bad until the temps came up. However if I stood behind the car I could smell a lean condition at one muffler. I had 4 bad primaries on the right bank, so it really smelled badly after warming up. It was enough to make your eyes water! I would agree with your diagnosis. When I did the injectors in my car I did the coils at the same time just because it seemed to be the obvious thing to do while the plenum was off. I would caution against the use of after market coils. Use the GM D555 coils. Jerry has all the gaskets that you will need and I just bought GM coils from one of the online places, partszoneonline.com....aka formerly P&G chevy in PA. Tom __________________ 1990 ZR-1, Black/grey, #2233, stock. ZR-1 Net Reg Founding Member #316 & NCM member

05-22-2009	#3
rkreigh Join Date: Jan 2004 Location: Alex VA Posts: 1,087	Re: Miss After Heat Soaking ohm out the injectors after they are hot. haibeck has the way to do this from the injector harness with the plenum on. my bet is that the injectors are failing when hot which is very typical when they go bad __________________ 95 390 LPE ZR1 (505 rwhp) LSV = Lingenfelter Super Vette Twin Turbo 2003 Z06 (800 RWHP)