RAY63CUTLASS

Car is a 63 Cutlass Convertible. Just had the gas tank drained and cleaned and the fuel lines cleaned or replaced. Car had been sitting for about 4 years and I didn't want to take a chance with old questionable fuel. Just had the gas tank drained and cleaned and the fuel lines cleaned or replaced. I discovered a fuel delivery problem when getting stuck on the road after about a 7 mile run. New fuel pump installed and gas cap venting checked. The Mechanic drove the car for a few days around town after installing the new pump, let it sit and idle for varying times and thought it was OK. Picked it up yesterday and started easily, ran smoothly but after driving about 10 miles the car backfired and coasted to a stop and would not restart. A quick check confirmed that there was gas delivery to the fuel pump but apparently no gas in the line between the fuel pump and the carburetor. Disconnected the gas line at the carburetor, cranked the engine and gas was flowing. Reconnected the gas line and the car started and ran fine the rest of the way home. There is a filter in the gas line between the fuel pump and the carburetor which I'm thinking is the problem. Two questions -- Would the filter plug randomly and then be OK, and is there something else that would cause a back pressure or blockage in the gas line that we are missing. Thanks

Grace Stinespring-Welch

could be the filter, or even carb issues.

jaunty75

I doesn't take much crud to clog a fuel filter enough to cause problems, and a fuel filter dirty enough to cause problems might not appear all that dirty to look at. I know this from experience with my '67 Delta 88.

Your gas tank and fuel system has been significantly disturbed with your redoing of it, so it seems reasonable that stuff could be churned up and get into the line. I would certainly replace the fuel filter, even though the one in there might be only a week old, and see if that help.

RAY63CUTLASS

Thanks -- we'll change the filter and hopefully that will do it.

RAY63CUTLASS

Thanks -- filter will be replaced and hopefully that will do it.

droldsmorland

Would the filter plug randomly and then be OK, and is there something else that would cause a back pressure or blockage in the gas line that we are missing. Thanks[/QUOTE]

Doubtful. Generally once a filters plugged its plugged. Tee a fuel pressure gauge in line before the carb and run it. 4.5-5.5 psi your pumps ok. As stated many things were disturbed. You may need to replace the filter again. Cut it open and look for debris. Its cheap so just replace it. Check for leaks everywhere including the new stuff. Sometimes a slight weep will pull air in but not necessarily drip on the ground.
Next Id be suspicious of the carb. Something could have been pushed into the carb or ahead of the filter causing a blockage? Pull the air-horn and inspect for debris float condition and level settings. Whens the last time it was rebuilt?
Are you sure your not losing spark once things heat up? Get one of those in-line testers that you put between the plug & wire or cap & wire to verify you have a solid ignition when it quits on you. I like the in-line tester that flashes the little light inside verses the one which jumps a gap. Either will work.

oldcutlass

It almost sounds like old fashioned vapor lock.

jaunty75

You're assuming a fuel filter is either totally clogged or totally not. A partially clogged filter could lead to the symptoms he's describing.

When I had trouble with my '67 Delta, it was never at idle in Park or sitting at a traffic light. It would be when I would get the car up to speed, often after a few miles of driving as the OP describes, when it would suddenly start to sputter and lose power.

I didn't suspect the fuel filter at first, either, because of the reasons people here are describing--why does the car run at all? But a fuel filter is a 2-minute, $2.00 fix on this car, so I figured why not.

As I said above, the old filter did not look much different from the new one, but it made all the difference in the world putting in the new one. This was three years ago, and the problem was cured instantly and has never returned.

I'm not saying with 100% certainty that this is the OP's problem. What I'm saying is that it's possibility that shouldn't be overlooked as I had symptoms just like his, and the fuel filter was the cure.

starfire

I've been told that the bowl style fuel filters between the fuel pump and the carb are very prone to causing vapor lock. Take the whole assembly out and run a non-filtered fuel line and see if the problem goes away.

MDchanic

What, exactly, does this mean?

Did you watch whoever did this do this?

Your symptom is classic for a piece of crud in the gas tank getting randomly stuck against the fuel pickup.

- Eric

joe_padavano

Did you replace all the rubber lines between the tank and the engine? The 61-63 cars have relatively long runs of rubber between the tank and the hardlines on the body, and again from the hardlines to the pump. A crack in any of these let's air into the system, causing the pump to loose prime.

RAY63CUTLASS

Thank to all the folks who gave us ideas on the fuel problem. Just replaced the old filter with a new glass-bodied filter housing. With the gas line disconnected from the carburetor and cranking the engine, the flow seemed much stronger than with the old filter in place. Car started and ran fine after the new filter installed. Cut open the old filter housing and found a great deal of particulate. You can see from the pictures that this amount of particulate could easily disrupt or stop the flow. We asked a person who is an expert on carburetors why the mechanic had no problem when testing the car on short trips and letting it idle for varying times while I made it just about 10 miles. He thought that the change in gas flow through the filter during the short trips kept the filter relatively "clean" and when I drove it home at highway speeds with no "stop and go" the constant flow loaded the particulate onto the filter element until there was no gas flow and the car stopped.

jaunty75

That is quite a bit of crud. Glad to hear you tracked down the problem.

The question is, where did it all come from on a car which has just had its gas tank drained and cleaned and its fuel lines cleaned and/or replaced? This what I asked myself when I had the same problem.

The answer, I think, is that this major a disturbance of the fuel system will inevitably churn up stuff that would otherwise stay stuck somewhere, and even the "cleanest" fuel systems have some crud in them. We mostly don't notice it because it accumulates and just sits on bottom of the tank.