C3 Corvette headlight causes rough idle, 75 C3 Corvette, Volume 44

I explain the troubleshooting & repair I did on this 75 Corvette C3 when I discovered the headlight vacuum relay(s) were causing rough idle on the L48 350 engine.

[@DesertRatFabrication]

Great video Dave, nice way to start the day, my buddy Dave and a coffee, good trouble shooting, back when I was a young man I did a valve job for my girlfriend’s brother, when I got done the the car which was a 70 Chevelle ran rough kinda like it did before we tore it apart the valves where definitely burnt so it should have ran smooth, I drove it over to this old time mechanic, he took some starting fluid and sprayed it down along the intake manifold and yes you got it right she smoothed right out so I went back and redid the intake and she purred like a kitten, yes Dave I will find out this morning around 10 if the boat checks out ok , if it does we will sail Sunday morning, good Lord willing, I will stay in touch my friend, have a nice spring☀️😀

[@dougtaylor-xl9kg]

Luv it Dave!

[@Volfandt]

Thanks Doug.

[@DesertRatFabrication]

Hi Dave saw this one late tonight, can’t wait to jump into the video in the morning, we got delayed a couple of days due to an engine issue,hopefully will sail on Sunday morning, catch you in the morning 😀

[@Volfandt]

Hey Mike. Gotta have the powerplant right. Take care my friend.

[@davidkrull]

Thanks for the video, Dave! I think maybe you've given me a clue as to why the wiper door on my '71 opens and closes on 1st startup. I suspect it is sharing it's vacuum source with the HVAC or headlights and is being starved. Once the engine is going the wiper door works fine, and usually doesn't do it again on warm restart.

[@Volfandt]

Hey David. The vacuum system(s) on our Vettes can be daunting to troubleshoot but when broken down individually they become much less complicated. It does sound like your wiper control is bridged with another system thats got a vacuum leak. You might try it on one of the unused vac ports on your carb. Once I moved the HVAC vac line from the headlight control vac line to a spare Vac port on the carb my headlight winking problem went away and the engine hasn't idle this smooth since I got it. Good luck.

[@gvxclassics]

Nice Dave. Great technical video, and your engine compartment looks great! A friend told me years ago that my cars always got better when I owned them, as my maintenance fixed things faster than they broke. You are doing the same kind of work. Making your cars better and better. Some mechanics never get to their cars, but others have the time to take care of at least one special vehicles. How many do you have there?

[@Volfandt]

Hey Lee, I've got 2 classics and 2 daily drivers. Funny my daily driver 98 F150 just turned 25 so I might have to reclassify it, LOL... You know what they say, a tidy engine is a happy engine, LOL. Have a good 'un. Hope the weather is better in your parts...

[@rustedjunkgarage3316]

Great video Dave , thanks for sharing Brother. 🫵🏼💯🆒, You need a RJG Sticker on your shop door, I think they add 25 HP to any of your projects.😂😂🤣

[@Volfandt]

Hey Steve, sounds like a plan. email me your addy and I'll email you mine and we'll trade stickers. I definitely can use Mo' power LOL

[@JulioDiaz-eq4nz]

What if you don't have a leak what next???