1950s 1959 Cadillac fuel starvation issue.

[Eric DeVirgilis CLC# 8621]

Clean original 1959 Cadillac I've owned four years. Car has been in regular (fair weather use) all along without any issues all along.

How it all began:

Took the car out two months ago for the first time this year. Temps were in the mid 70s. After about half an hour, the engine behaved as if it ran out of gas. Briefly fired up when starting was attempted but would not remain running. After a few more attempts, it would not fire up at all. Opened hood, fuel bowl was full. Removed fuel cap to see if vacuum in tank (from blocked vent tube) was created but no air noise was apparent. Still would not start.

Had the car towed back home and had a new fuel pump installed. Engine now runs.

Several weeks later after driving about half hour, the engine died again just as it did before. Opened hood, fuel bowl was filled just as before.  Didn't bother removing remove fuel cap. Towed home again and didn't touch it.

A couple weeks later I was explaining the issue to a CLC member who thought the problem was due to a restricted vent tube and the car was likely to start.

After the call ended, I went out to the garage and managed to start the engine. Left it idling for a while and seemed fine. I did not take it out for fear it might leave me stranded again.

My mechanic seems to be convinced the problem is due to debris in tank clogging the "sock" strainer in the tank. He also said that vacuum in the tank would be unmistakable when the cap was removed and that the car should've started once vacuum was relieved. I've had clogged tank socks where the gasoline had so much rust that the fuel was red. This would significantly reduce power under acceleration but never did it prevent the engine from starting or idling. The fuel in the filter bowl of the '59 is clear as a bell.

Thoughts?

[Jeff Rosansky CLC #28373]

It wouldn't be a vent if you didn't get a hisssssss when you opened the gas cap-- good thinking on that. The full fuel bowl had me puzzled but I don't know if it is up or down so it could still be full, but without anything else going thru it, the carb runs dry.

From personal experience,  I'm thinking holes in your fuel line.
Remove the fuel line at the rubber connection at the tank and plug it. Then remove the other end at the pump. Then fill it with mineral spirits or something similar-- you basically want the metal line full of some liquid, but something that won't evaporate too quickly but also won't explode. Then, use shop air and blow into the fuel pump end of the line which pressurizes the metal fuel line. Use a reasonable pressure but leave it there a few minutes. Then look at the metal line. It should be 100% dry. Any moisture, any at all, indicates a leak. I had several, all under the hold- down clips. Several small holes = 1 big hole (think Titanic).
Fuel doesn't escape and show during normal use because it is under constant suction. But pressurizing the line as described does the opposite and exposes any weakness in the hard line itself.
The fuel pump cant overcome sucking air, and you are stuck on the side of the road.

Let us know what you find, and good luck

[Eric DeVirgilis CLC# 8621]

Wouldn't that be accompanied by the smell of gas?

Second question: Wouldn't moisture on the fuel line be visible without the need to pressurize the line? After all the engine does run now.

[TJ Hopland]

What is jumping out at me is that its not running with the full bowl?  I'm assuming we are taking about the float bowl in the carb?   If so then why are we talking about getting fuel to the carb?  If the carb has fuel it seems like the focus should be carb and ignition.

Some dribbles of fuel down the throat or some starting fluid when it dies will tell you real quick if its a fuel issue.  If it fires that way and the bowl is full you got something clogged up in the carb.

[David Greenburg]

I'm assuming you know when the filter was changed. Is the new pump actually brand new, or rebuilt by some unknown entity in some unknown country, or was it rebuilt by a reputable rebuilder? Not unheard of to have the "new" ones or rebuild by unknown rebuilder go bad quickly.

[Clewisiii]

Your tank should have a vent in the rear. So I would not think you have vacuum pressure



You can see the vent at the back here.

[Roger Zimmermann]

If you take the air cleaner away and, with the engine not running, open the throttle. You should see two jet of fuel if the carburetor has some gas.

[Big Fins]

I'm going to go in another direction. Ignition. You have fuel at the carb and in the glass bowl, so it is getting there. I would get an ohm meter and read the resistance wire from the ignition switch to the coil and see what your getting. Also look close at the coil itself. Does it look bloated. It could be shorting internally and once it gets hot, ceases to deliver proper voltage to the plugs. When it cools, the engine starts again.

If you have a coil on the shelf, a quick change out may answer you questions. You need 3 things to run. Spark, air and fuel. You have air and according to the initial post, you have fuel. Next on the list is...

[Eric DeVirgilis CLC# 8621]

The fuel filter bowl is what I was referring to- which was visibly full on both occasions after the engine quit.

The replacement fuel pump is a brand new Carter.

The carburetor had been rebuilt last winter and new fuel filter installed at the time.

Driving it around without the gas cap on would eliminate the vent theory but I don't want to risk another $175 tow bill.

A CLC technical expert is all but certain the '59 doesn't have a sock filter in the tank.

@Big Fins - it doesn't seem to be flooding. The way the engine cut out doesn't seem to be a "hard" off as if ignition was suddenly lost. It would sputter a bit as if it was running out of fuel. This happened both times before it shut down.

[David Greenburg]

$175 tow bill? You need to get AAA Plus or equivalent. 100 miles free towing; just used it this weekend when a fitting on badly installed electric pump broke off 50 miles from home on the way to a Region event.

[Eric DeVirgilis CLC# 8621]

$175 tow bill? You need to get AAA Plus or equivalent. 100 miles free towing; just used it this weekend when a fitting on badly installed electric pump broke off 50 miles from home on the way to a Region event.

I'm not sure if it's available for car dealers.

[Jeff Rosansky CLC #28373]

Wouldn't that be accompanied by the smell of gas?

Second question: Wouldn't moisture on the fuel line be visible without the need to pressurize the line? After all the engine does run now.

The line clips do a pretty good job of masking things.
Don't forget that when sitting, it is just under static pressure. The tank isn't that much higher so I don't think the static pressure is too high.
However when running, the line is subject to 7 or so pounds of negative pressure (more if the pump has some type of internal regulator).

I understand your questions here, but this is what happened on our 55 so I know it's a valid issue, especially under the clips.

Now I'm assuming you have narrowed it down to fuel and not a condenser or coil.

[Big Fins]

Well, you could always rebuild the engine, transmission and rear end. Then the fuel system, the electrical system and then finally, install seat belts for good measure.

That's the CLC forum way!!

[dn010]

I had this with my 57. Ran fine getting into town but then quit on me on the way back. Sometimes I could get it restarted again and get another mile or so before it quit and would not restart to the point the battery would die trying. Mine was ultimately the accumulation of fine rust particles that would clog my filters and lines.

Removing, cleaning and sealing the tank, along with running new aluminum fuel lines solved this issue once and for all. I probably did not need the fuel lines but I didn't want any more possibilities of rust coming up in the future and the tank looks nearly as great as it did inside and out, as the day I put the seal coating on/in it.

Today you can get stainless fuel tanks, I did not have that option back when this was happening and probably wouldn't have had the funds for something like that back then even if they did, but those are quite nice to have.

[Eric DeVirgilis CLC# 8621]

Mine was ultimately the accumulation of fine rust particles that would clog my filters and lines.

Was there any visible discoloration of the fuel through the glass filter bowl or indication of sediment?

[Cadillac Jack 82]

Fuel pump or vapor lock or both.  Had the same issues and it ended up being the pump with the help of some hot temps (vapor lock).

[dn010]

Was there any visible discoloration of the fuel through the glass filter bowl or indication of sediment?

I had two filters back then, one of those little aftermarket glass cylindrical ones with a fine mesh filter, and then the glass bowl. The aftermarket was installed down from the original and it had particles all over it with some patches of particles that looked like sludge. I can't remember how bad the glass bowl was, maybe some sludge on the bottom but I can't remember for sure. The only way I got fuel discoloration is if I took the filter out and shook it to disturb the particles, otherwise it looked normal. This was in addition to larger particles collecting upon each other to block up the lines. The theory was I'd shut the car off and once things would settle the lines would open back up but I can say it was amazing how much crap shot out of the lines with compressed air.

If fine particles are your problem I'm sure you'd see some sort of evidence on the filter rock, or in the inlet screen of the carburetor especially after two months of dealing with this.

Admittedly, I also did eventually dump the mechanical fuel pump for electric to further prevent any issues that may arise. I was driving this car daily for a long time so I wanted to be absolutely confident in my fuel system.

[TJ Hopland]

Well, you could always rebuild the engine, transmission and rear end. Then the fuel system, the electrical system and then finally, install seat belts for good measure.   That's the CLC forum way!!

Could be the wrong white wall width and placement? 

[Big Fins]

Could be the wrong white wall width and placement? 

It could be, but I think he has enough suggestions to keep him busy for a little while. We all can't be wrong.

[Jon S]

Hi Eric - I'm a little late to the party, but have some suggestions. If you have a Carter carburetor, there is a second "bronze" gas filter where the gas line attaches to the carburetor. It's spring loaded. While you have that fuel inlet line detached, have someone crank the engine and see if the glass bowl fuel pumps out of the line. If so, then the tank end is fine and I would check for a sticking needle/seat after checking the second filter.