Packard Forum Index » V-8 (1955-56)

Hi Everyone,

As you may recall, last week I took my '55 back to my mechanic for some fine tuning (hard starting) and while on the way, the fuel pump pivot pin worked it's way out to stop the pump from pumping.

Got her back yesterday but something new has been added. On the way home she started bucking and lurching. When I pressed down on the gas or let up completely she'd even out. Didn't matter how fast I was going; 50, 60, 70 - as soon as I was just at constant speed it was rodeo time. I'd also experience something like that when stopped at a light, just not as severe and in both cases, it was after the automatic choke had gone off.

Since the only part that experienced any "trauma" was the fuel pump, I'm wondering if when the pivot pin was no longer doing it's job the internals of the pump got messed up a bit. Maybe a small rip in the internals or something along those line. When she's doing acting that way it almost seems like she's running out of gas.

Do my symptoms suggest anything along those lines or am I just grasping at straws.

She was running so fine before the pin went on vacation.

Any and all ideas are welcome and appreciated

Consideration of who else is available as a mechanic would seem to be in order.....

Look into your ignition. As in, the coil wire is loose or the point gap is wrong.

Where to start? When's the last time the car had a good, thorough and comprehensive tune-up?

A vacuum leak perhaps?

Good luck!

Mark

My thanks to Pat, Blackbeard, O_D and D-train. Your help is much appreciated. The tip about the coil wire struck a chord as I had been mucking about with the Oil Pressure sender recently and could be messed some of the wiring up.

The car had a good sorting about as per the FSM maintenance guide including a by the book tune-up. She ran great until the Fuel Pump Pivot Pin tried to leave.

I am wondering about a vacuum leak but so far, all the lines seem tight cutting them off one by one doesn't change anything. I will take a closer look at the fittings and hose from the base of the carb to the vacuum tank on the Power Brake circuit.

I'm helping out my 89 year old neighbor at the Bar-B-Que cafe she's run since my '55 was new tomorrow so I won't be able to do too much until Sunday.

But, keep the ideas coming, please

It appears you have two threads running on the same problem? So I'll essentially double-post.

I did have symptoms somewhat like yours some years back with my 34. Actually they were more severe than yours, the car would run fine for a few miles and stop completely. After sitting for 5 minutes it would go another couple of miles and stop, always having a bit of surging just before it quit.

There was a piece of "tiger snot" in the gas tank, not from the liner but from some idiot who used silicone gasket cement on the bolted filler neck mounting flange. This piece of snot would ultimately find it's way to the uptake tube, enter it and begin to and finally plug it; the car would stop, the pump suction would stop as the engine stopped, thus releasing the piece of crap to fall back into the fuel tank. And the cycle kept repeating itself.

So the circumstances are somewhat similar and perhaps worth your further investigation.

One other thought - is the vent in your gas tank cap clogged?

Quote:

Thank you O_D, yes it seems I do. At the time I was updating the blog, my previous question got a response as well. Thank you for BOTH responses.

It would be as well if the two were merged.

For finding a vacuum leak, use carb cleaner, ether or brake cleaner. With engine running, squirt a little in the carb to see what it does, speed up or stumble. Then spray it on all the joints one at a time to find the leak.

"Bucking and lurching when you let off the gas, but evens out when you give it some gas."

I just saw your project thread, and it looks like you said it sat for many years without running.

I once had a Mazda RX-4 many years ago, and it exhibited the exact same problem. We tried and tried everything, and could find nothing. Then, one day it went "poof!," and then it would run, but burn oil. It wouldn't burn as much when I'd get up some speed, though.

Ultimately, it was concluded by the Mazda dealer that some engine seals had failed. The car was not worth the quote to repair it, and so that was the end of that.

That little car would sputter and sputter until I'd give it some gas. Reminded me of the cartoon I grew up with.... "Speed Buggy." If you are familiar with the cartoon, watch here at 40 seconds in:youtube.com/watch?v=MpQd8R1nqZs Yep! That was my Mazda!