Random Poor Running/Stalling

[Ratty_81]

Pardon my "canned" HEI answer but the pole piece (AKA "pick up coil" in the distributor) causes problems like that. While it may be fuel related, eliminate ignition first.

I was thinking of putting a pertronix module in it with rev limiter.

 

[1980RS]

Ride home wasn’t much better. Acted fine on the freeway, about 7-8 miles.
Jumped on it pretty hard and it pulled fine through 2nd gear and fell flat on it’s face going into third. Had to keep feathering the throttle to keep it running and it just didn’t want to pull the car along, even in 2nd gear. Let it die and coasted to a stop. Let it sit for 30 seconds with the fans running and it refired and ran fine. I didn’t test it again.
Fuel pressure is 6psi with a return style system. Is it possible my float level is so high that I’m flooding the engine through the vent tube under hard acceleration?
Doesn’t explain the episode this morning, though…

Take the carb apart again, blow out the needles and seats good, also here's a little tip I found, that little o-ring on the needle and seat can go bad and cause problems. Also make sure all the bleeds on the main body are free of crud. Seen that many a time, it's it's flooding or running bad from the fuel lever being too high you will see raw fuel coming out of the boosters.

 

[Ratty_81]

That’s the thing though, it runs and idles fine normally. I think I could cruise 2 lane roads for days and never have an issue. Gonna check float level. If that’s ok, I’ll put in my spare GM module and retest.

 

[Ratty_81]

Set float heights, rear a bit high, front a bit low. Same result.
Genuine GM HEI module. Same result.
I can absolutely hammer the car with no problem, then during a spirited freeway on ramp it falls on its face going into third gear.

Next I will replace the coil, but I’m thinking it might be the “smart” fuel pump controller I installed. When it runs like crap and dies, it starts running fine immediately after I refire it. This to me means it’s not heat or carb related. Something is getting re-booted, and that just leaves the fuel pump controller. Nothing else in the car has any brains.
I need to come up with remote fuel pressure gauge to confirm.

 

[Coadster32]

Is your car an automatic? Perhaps when it goes into third, the vacuum signal changes? (Just throwing darts here)

 

[Ratty_81]

No, manual.
When it starts running bad, it continues to run bad until I restart the engine. Then runs perfectly fine until it doesn’t. I’m thinking electrical. I still need to swap coils then if no change, I’m gonna hot wire the distributor, then go after the fuel pump controller.

 

[CorkyE]

Anyone nearby that you can try another carburetor?

 

[Ratty_81]

Anyone nearby that you can try another carburetor?

Nope, lone wolf.

 

[G72Zed]

Nope, lone wolf.

To bad you are not close to me....I have carbs for you try...many of them.

Question, what does your fuel pressure or AFR gauge do when you have this problem??

 

[Ratty_81]

To bad you are not close to me....I have carbs for you try...many of them.

Question, what does your fuel pressure or AFR gauge do when you have this problem??

Appreciate that. No AFR. I need to get a hose and fittings to temporarily mount my FP gage where I can see it.
Guy I bought the car from said he was having the same trouble, but when I got the car the fuel pressure was set to 4psi. Under hard acceleration it was draining the fuel bowls. I’m at 6psi now and it can run great for one WOT run, then stumble and die while steady state cruising or 3/4 WOT runs so I don’t think it’s a fuel pressure setting issue. Maybe the pump is cutting out due to the controller. Just restarting the engine ”clears the fault“ and it runs fine again.