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Need some advice here.

Third year into ownership of my 115C, much of which has been spent undoing previous owner's nonsense and rebuilding stuff that should've been done decades ago.

Over the winter, I replaced the non-stock fuel tank with a correct original, and had a new tank sending unit /pickup tube fabricated. All fuel hoses were replaced. Non-stock tank was out of some 1980's car, with four lines coming out of what was probably an electric fuel pump setup for a 12v. One was used for fuel, two crimped off, one for a vent hose.

Recently the car stalled on the way home from a short trip. Restarted, but felt like it was starving for fuel. Seemed like the fuel pump had given up, so I rebuilt it. Diaphragms were worn but no obvious holes.

Today was a larger test drive. Made it to the destination and then it died again on the way home, same symptoms. Got it off the road with help from other drivers, installed a 6v pump that I'd prepared as a just-in-case.

Got it restarted, made it a few more miles and it died again.

I'm wondering if the fuel cap is sealing so tight that the pump is not able to overcome the vacuum in the tank, and if I should add a vent to the filler line.

Advice anyone?

Check your cap, you should be using a vented gas tank cap. It is possible for a good strong fuel pump to partially collapse a tank without a vent.

To repeat, for an original or of-the-era fuel delivery system your tank must be open to the atmosphere thru either a vented cap, or other means. Not saying your problem couldn't lie elsewhere, but that's where I'd start. If you determine you had a non-vented cap, check to see if the vacuum has collapsed the tank.

tsherry

I’m with OD, it’s axiomatic that for every gallon of fuel removed from the tank that a gallon of air must be allowed to enter. Even the modern cars, with a submerged fuel pump, will accomplish this, albeit via the carbon canister. Normally older cars have the vent the fuel cap, while the cap for a modern car does not have a vent . . . it’s sealed to allow the carbon canister to work. Assuming your car is now has an essentially unmodified fuel system the ‘filler’ cap should be vented.

Next subject: There are two types of electric fuel pumps that most of us use. One is a rotary vane pump (Carter for one), while the other is a solenoid ‘plunger’ type (Airtex for one). The ‘plunger’ type does NOT need to be powered all of the time. The rotary vane pump needs to be powered all of the time . . . or, every once and awhile the car will stall. Ask me, I’m the guy that owned a vane pump, and didn’t understand the ‘rules’! My ’48 would run normally for days and days, and then just decide to stall. After stalling just about every time at the same location I concluded that making a tight turn had something to do with it. And after I disassembled the pump it was clear that the fuel circuit can, and will be blocked by one of the vanes, but for a while the offending vane can allow fuel to pass. Taking a turn ‘pushed’ the vane into the offending position . . . every time
.
‘Junk’ in the tank or lines is also one of the usual suspects, but if you tripled checked that when you swapped the tank that is likely not the culprit
.
dp

Thanks, all. I'm probably going to add a vent to the filler tube. Car's on the the low-rise lift right now but I'm thrashed from dealing with it in the humidity and the heat (which is the hottest day of the year at around 80).

Right now, Jameson Cold Brew on the rocks.

Lines were all cleaned out from stem to stern, so not worried there.

I'll tackle this tomorrow.

Ernie, Duane, and I will raise you 31 degrees on the temperature. In the ‘Valley of the Sun’, right now it’s something like 111°F . . . not all that bad as long as you’re in the shade. A Packard makes a wonderful umbrella to lie under. We've got a few more days left of the latest high pressure weather pattern, and then the temperature should back-off 4-6 degrees (it makes a significant difference).

Good luck with the '37.

dp

Oh, I get it. My son's down in Tempe.

Up here in Spokane we've had about a month of rain; garden was three weeks late going in. Most days we've been struggling to hit 65.

I'm going to swap fuel caps with my '40 110 and hook up the mechanical pump tomorrow and try this again.

Hope it works--supposed to be part of a wedding photo shoot next weekend. If the Packard lets me down I'll take my Galaxie convertible, which is all well and good, but not near the fun.

I wouldn’t add a vent to the filler pipe! You’ll be asking for leaks. Just get a proper vented cap and not the type with the vent as a hole through the center that some sell as those will leak too.

I grabbed the vented cap from my project '40 110. Tomorrow I'll get after the project.

Jameson whisky for medicinal reasons at present.

Well, this got interesting today.

First off, removed the non vented cap. A vented one is available from my '40 110.

Second, removed the jury-rigged 6v fuel pump and reconnected the mechanical pump. Tried to start her.

Nothing. No fuel whatsoever. Since I had fuel with the 6v pump and the former cap, I knew I did not have a line issue, and with the cap off, it could not be a vacuum issue.

Off came the pump, unexpectedly much easier as the fuel pump lever was no longer part of the pump. The retaining pin was there, but had worked it's way 'out' far enough for the lever and spring to fall into the oil pan, where it's still sitting. The pin was replaced during the fuel pump rebuild as the original had some wear and scarring. The pin was shorter than the original but I did not see any difference in diameter.

So this week I'll drop the pan (for the very first time) and retrieve the parts. Hopefully no other damage has been done.

Concerned to hear you had a non-vented cap, if you avoided tank damage consider yourself lucky.

How was pin supposed to be secured?