L78 idling issues

[ss427copo]

I have a NOS of the Holley Heat Shield. Soulds like a perculation problem if it only happens after running....?

Jeff x 3

[JRSully]

addressing the opinions, Rob, I currently have the choke wired wide open, so that one is probably out. Will have to check the floats if the 160 stat and heat shield install don't solve it. Is anybody running one of those ugly Holley shields currently and do they have any noticable effect.? I guess Chevy installed these for a reason. The 569 intake sucks and lays the Holley right on top of the intake runners, I should just throw a 163 on it and shelf the 569. Thx all for the tips, keep them coming

[SuperNovaSS]

Or put the blocking gasket back in.

[Chevy454]

Have you looked for a vacuum leak, around the carb and/or intake...?

[azcamaros]

Two things come to mind. Have you adjusted the valves recently? If you have you may want to recheck them. I recently helped a friend with the same symtoms and discovered he had recently set his valves and got them a little too tight. As soon as our summer heat set in the car started giving him similar problems to yours. His coolant temp said 190 but the ambient temp. did make a differance.. Another thought is the rear power-valve. I have chased idle issues for days and overlooked the rear powervalve on my LT-1 vette. I don't no why it went bad but after a day of troubleshooting fun I replaced the re powervalve and I was back in action. I run my cars in 110 degree heat and my idle issues have never been related to boiling fuel, just other weird stuff.. Good luck

[Mr. Chevy]

Sully, I had a problem with my 70 L78 Nova when driving it. When it would get hot it would stall/shut off. I put the heat shield, GM one pictured above, on and never had a problem again.. I figured it was because the intake and carb. were soo close together it was boiling the fuel in the primary bowl. That shield really does work!!

It does not look that bad either under the carb... Rich

[Jeff H]

My 70 L78 Camaro never had that problem but the motor wasn't stock spec L78 either. It had the stock 569 intake and a generic Holley 750 with no choke setup and double gaskets, no heat shield. Maybe try the double gaskets or heat shield to reduce the temp at the carb itself.

[WILMASBOYL78]

I think it's the bad air on Long Island

[Salvatore]

Maybe a vacuum leak. When cold it runs a little richer. When hot it vaporizes. I would go over and retrace all your steps and make sure the set-up is the same as it was before you took the intake and distributor out. Recheck idle circuits, dwell,timing and any lean condition around the carb and intake you may think you have. It didn't do it before so trace your steps.

[ss427copo]

I had taken the heat shield off a few years ago and ran around for a few weeks and began to have "silly" carb issues. SO.....I put it back on and they went away Haven't had any since. AND....the plate has been there since 1972 when BWAG owned the car as a SS/EA. He even painted the underside of it gloss white. Ugly? maybe...Works? Way to go Bob! YUP! (smart man!)




Jeff x 3