I’ve fought this problem since it started in bowling green. Back then, it seemed like the heat was the culprit, and it may still be temperature related. It was frustrating enough down there that I stopped driving it till the car show Friday. Car runs phenomenal until I get in stop and go traffic or I shut it off and restart after a few minutes. Original carb was rebuilt by me. Throttle response is near perfect. Choke works just as it should. It really wasn’t even that bad to begin with, but I figured I’d get the old gas out, change gaskets, and install a new accelerator pump. Gas tank was clean. Second new fuel filter after the rebuild also. Timing is currently at 8* at idle. Ignition is fired with Todd’s lectric limited conversion kit. Still stalls out at stop lights. Also tried unhooking and plugging the vacuum advance. Does it either way. I dug a new stage 1 fuel pump out of my stash, but I’m honestly sick of just throwing parts at it, so I haven’t changed that yet. Any help would be appreciated
Tim try setting the initial timing at 10° And adjust the idle with the vacuum advance disconnected and plugged
It's definitely a fuel issue? If it's a fuel issue and only when hot, when it's hot out, I'd look at a vapor lock issue. Had it with the aquamist car. The alcohol in the fuel would just boil and the car would just crank . It was a bitch to start. A quick and dirty fix is to just pit a tank of VP 110 and see if the issue resolves itself
I thought of vapor lock. If you give this a little gas after the stall, it starts up. I have to rev it some for it to clear out though. How did you fix the vapor lock problem in the aqua car?
It didn't like pump gas in the summer. I'd run as much vp110 as I could. It was a different car with race fuel.
Still doesn’t, I try to avoid the heat altogether. Big block, 4spd, black vinyl, no ac, no thanks. I’m fortunate to have a bunch of small airports in my area 100LL non ethanol is readily available.
I’ve been driving my GS a lot lately and noticed similar behavior. Doesn’t stall but is tough to start and idles rough when heat soaked. Thanks!! Patrick
I just dumped 2 gallons of 114 on top of the 4 gallons pump 93 that’s in it. We’ll see how that goes.
Vapor lock is certainly a real solid explanation but I'm wondering if its pig rich at an idle. Revving it to clear it out makes me think it's way rich.
I'm sure the exhaust crossover is open and functional to use the choke. That means the intake is getting super heated. Combine that with the cat-piss fuel and vapor lock is all but assured. Ethanol free fuel, or Race Gas should help a lot. Is it an A/C car with a vapor return line?
Took it for a 25 mile drive. It’s definitely better. Still stalled a little just now after restarting it from sitting a few minutes. It even runs way better. Gonna find a gas station that sells non ethanol and maybe add a gallon or 2 of 110 vp on my next fill up. I didn’t realize how much I miss driving it till now.
Dude, I drive mine at least 3 or 4 times a week. Last week, the GSX went to autozone with 5 gallons of used motor oil on the passenger floor, picked up lunch with it and then went to CVS for some bathroom supplies. One of these days I'm gonna take a pick of the trunk filled with bags of mulch from HD.
If I hadn’t had this problem, I’d have been driving it all summer. But they tar and chipped our road a month ago, so none of the Buicks have really been out. It did have a nice layer of barn dust on it, though.
