292 Trouble

[Ryanz]

Hey guys - I'm at a loss and looking for your expertise.

292 is cutting out, almost like fuel lock, at around 50mph. It regains itself when you let off the gas. It seems to be a lack of fuel issue because when you pull the choke all the way it keeps going until you run out of air (of course). However, we've tried everything.

So far we have, swapped out single barrel carb (no change), put new fuel pump, changed fuel filter. We even hooked up a camera to see if the fuel was draining out of the fuel filter at that speed (installed clear one) which it wasn't.

I will say, after changing all of the above it did get some better. Before it wouldn't go over 40mph, and had less power than it does now, but it's still cutting out. We put petronix and new coil in last year but was running fine up until a few weeks ago.

We're at a loss and curious if any of you have ever experienced the same. FYI it runs absolutely perfectly until you get up to speed under load.

[Steeveedee]

Did you inspect or replace the fuel pump suction hose(s)? One on the tank, one on the pump. Also, the one at the pump can kink when fuel demand is high, if it is old.

[Ryanz]

Originally Posted by Steeveedee

Did you inspect or replace the fuel pump suction hose(s)? One on the tank, one on the pump. Also, the one at the pump can kink when fuel demand is high, if it is old.

Yes, I believe all hoses are new but will reinspect one on tank. I also took my air compressor and blew back the line behind the fuel pump in case anything was stuck in there, or on end of sending unit sock, but it didn't help. Thank you for your help.

Ryan

[tim_mc]

New coil last year and stumbles under load? That sounds like when my ACDelco HEI coil failed after about a year. Here are the symptoms from then:
Occasional backfire or load up when driving. Progressively got worse to where it would start OK, but would die when put into gear.
It would idle and rev OK, but ran badly under a load, or when stopping. Had to put it in neutral a few times to keep it from dying at intersections.
Later it would lean out and backfire after it warmed up and eventually would not restart when warm.
Luckily the coil completely gave out when testing, making it obvious. Trip to a local parts store for a new coil did the trick.

If fuel delivery checks out, maybe confirm good blue spark. Also, if you're using vacuum advance, it's quick and easy to eliminate it by pulling its hose and blocking the port, along with any other vacuum hoses that might be causing or contributing to the issue.

[HO455]

I agree ^. Try swapping the old coil back in if you still have it. Also try disconnecting the vacuum advance and take it for a drive.

Put a timing light on it and slowly raise the RPM and see if the spark stays consistent. You can do this on all 6 cylinders.

['68OrangeSunshine]

I hate Pertronix. I had an Ignitor II/ Flamethrower II set up on my 292 L6. Ran fine for about 7 years, then -- once I got above 3000 RPM it would shut down. Leaving me deadmilling at 65 on the Freeway. Key Off then ON and a popstart in 4th and it ran again, but the mishaps caused valve spring damage later on.
Ignitor II is supposed to amplify ignition above 3 grand, not dead stop.
Talking with Pertronix' customer service didn't help. They said send in the module and they'd check it out. That was in 2016. Still waiting.
I went back to points for a year, then lined up parts for an L6 GM HEI w/Remote Coil.

Gonna ask the obvious-- did you run a fresh 12 VDC wire from IGN/UNFUSED to the Positive terminal of the Coil? Because using the stock points Resistor Wire [Yellow 20] at the coil causes failure. That Iconel line out of the Bulkhead Connector drops voltage to ~9 volts when it heats up.Good for Points -- Bad for any electronic ignition.
My switching to an L6 GM HEI cured my gripe.