Technical POSSIBLE IGNITION ISSUE - 235 I6, 6 Volt Pertronix

The hose is new. I replace it with every fuel filter, otherwise its factory routed hardline. The fuel pressure gauge to windshield is a good idea.

 

By testing, I actuated the arm against some flat stock and could here the pump working. The OLD pump arm would actuate pretty easily, virtually no resistance, and would be able to build pressure. Making me think while it is a weak arm, it probably is fine. This weekend I am going to start back at the tank, verify its venting properly and go from there. I replaced plugs and fuel filter just as a maintenance point and all the plugs look great and even front to back, so to me there is no worry of any internal issue at this time.

 

"Assume nothing" is correct School teachers station wagon would idle all day, run great. Take it on the road a while, would have to tow back in. Fuel pump bad,fuel filter clear. Take on road again after pump replacement. Tow back in. Finally remove fuel tank,look in tank, sugar covered the bottom.

 

A “little fuel dribbled out” and ….

So get a helper or a remote starter switch.

take the fuel line off the carburetor, have the helper try to start the engine (coil wire disconnected) and see what’s coming out of the fuel line.

Just a thought, as I didn’t read every reply, but pumping the pump by hand is something I’ve not heard of before to check volume and flow.

 

Most of the time now it’s rust chunks or the black varnish goo from the black lagoon. That stuff is worse than the Blob.
You’ll spend 3x the cost of a new tank on home remedies to clean a rotten tank. Then...you’ll buy a new tank anyway.
A tank is either good or it’s not. You can’t make a good one from one that’s not.

 

Been having this problem with a few customers, cars and mine also. For whatever reason, all of a sudden, these gas tanks that were nasty inside started coming apart and clogging up fuel lines and filters. Replaced
The fuel tanks on about 5 cars this year and also the few lines just because. I've got a 40 Ford Sedan in the shop right now. That has the original tank I believe and has been having Drivability problems. I put a fuel filter right after the fuel tank and it immediately filled up with rust chunks. I took The sending unit out from the trunk and looked into the tank and it looks like the bottom of the ocean in there. Here is the carburetor bowl and the fuel sending unit float.

 

There is the inside of the carb bowl. Not a ton of garbage, just some.

I did put a fuel pressure gauge and ran it up to the windshield, drove and watched fuel pressure bleed off at acceleration, and slowly dip to 0psi, and then the car began to buck and die. Looks like possible fuel pump. New one on the way, single action, to determine. Then the hunt for a dual one begins.

 

Okay there are three checks you need to do on the fuel pump, pressure, vacuum, and volume. The pump must be able to make pressure as you saw it on the gauge. It must also be able to pull a vacuum and hold it. You can test this with it on or off the car. Connect a vacuum gauge to the inlet, actuate the pump and see it it will pull and hold a vacuum. If it will do these two, the proplem most likely isn't the pump, but the supply to the pump. A bad fuel line, or crap floating around in the tank.

I didn't mention the volume test as it requires some plumbing like was supplied in the old Sun fuel pump test kit. You run the engine and have a "T" in the line going to the carb. The open end of the "T" has a shut off. With the engine idling, you open the "T" and the pump should be able to pump a half pint in 30 seconds.

 

My next step would be to see if there is a sock, filter etc on the inside the tank on the end of the pick up tube.

For fun one thing I would do for sure is pull the gas cap off, pull the main feed line into the fuel pump FROM gas tank and using a air blower blow threw the line back wards to see if you get any resistance. Then go drive it and see if it changes.

Ran into this before on a couple cars, it'd drive fine for a couple hours to a day or so after then start again, it was a filter on the inside the tank....

....

 

Further update... installed a single action fuel pump (local, easy to get) to see how my issue fares. Same issue.
I will say, when priming it, I did see some fuel color that was not favorable. A dark yellow almost, but was cleared away after a little running.
I did notice with the new pump it seemed to stay in its 'limp mode' shorter (didnt buck as much, just died) and would take longer to get started and rolling. Maybe a sign? Maybe just me grabbing for nothing.
Fuel filter never 'fills', more it just barely gets under 1/2 full. At least thats how I see it at idle, and after it shuts off.
Both ideas are great. The fuel gauge never has worked, so I may end up removing the sender anyways and see how it looks, and possibly replace. While there I will either flush the fuel line with compressed air or just replace depending on shape/condition. I didnt note the fuel line being cruddy when I had it on the lift at work.

 

My son went thru 4 fuel pumps on a buddy’s bomb. This after complete tank and line refresh. So what I’m saying is, the new pumps are junk.

 

On old cars with suspect tanks, I always ran a Holley canister just after the tank. They picked up an astounding amount of crap. A simple clear one is a good diagnostic tool and isolates the tank from the lines going forward.

 

Those are the inside of the tank, and the fuel sender (WOW! no wonder I never had fuel readings). There are some chunks and gross looking buildup 'floaters'. Im going to do a cleaning job in this tank, new sender, new primary fuel line. Once I finish this job, if it continues to do this, I will be out of guesses. I will also install a fuel filter right after the pickup to catch and garbage I didnt earlier.

And to add - there is no fuel 'sock' on this pickup. I assume it never had one, as it is separate from the sender.

 

For everyones knowledge - the junk in the tank was the issue. It is now solved!

 

Sweet