[MuTang Clan]

Hi, I have a 1966 mustang with a straight six motor. The car starts fine. It will run for 1/4 of a mile and then it stalls out and dies. At this point the fuel filter is completely dry. I can wait for 10 minutes and restart and get fuel to run through the line, but it will stall out again quickly. The mechanical fuel pump has recently been switched out with a new one, and this has not helped. My friends are stumped as to whether it is a vacuum leak, the fuel pump piston is bent, or the cam is not pushing fuel. I have repeated this starting and stalling process 6 times and it happens at the same point in the same way everytime. This leads me to think it is some kind of overheating issue. My friend thinks that switching to an electrical fuel pump might fix the problem. I need some expert advice about what is happening and how I can fix it. Thanks for your time.

[mustanghelper]

get another fuel pump. after the fuel pump heats up it dies thats why you can start after 10 to 20 minutes later. are you using a ford pump? in tank pump?

[MuTang Clan]

The guys at one shop now think that it could be vaporlock. They recommend moving to an electric fuel pump. Will this fix my problem and is it tricky plugging hole and switching pumps?

[Veronica]

Hello.If the new fuel pump didn't fix the problem then it probably isn't a fuel pump issue.Ford built hundreds of thousands of cars with that motor/fuel pump set-up and they ran just fine for years and years without needing an electric fuel pump.What it sounds like is the filter in the gas tank is clogged up with a bunch of crud from the tank.I think that the first thing that I would do is is drain the gas tank and see what comes out.If your tank has the drain plug, take a 3/8 drive socket extension and put it on the drain plug as if it was the wrench and take a 12 point 11 mm socket and use that turn the extension.The extension fits the drain plug perfect and the socket fits the male end of the extension perfect.That way you don't just tear up the plug without ever getting out, as per the vise-grip method that many seem to enjoy.Once the tank is drained remove the sending unit and clean or replace the filter sleeve on the end of it, then, with both ends of the fuel line disconnected, blow the line out.That should get you back on track.Hope that helps.

[mystic2004]

If the filter is dry it may be a problem with fuel line being plugged from tank to pump. You may also have something in tank going over fuel line hole. When we where kids we put ping pong balls in gas tanks. It would float over the hole and stop flow but after a while would desolve and problem would go away.

[MuTang Clan]

I have blown air through the fuel line to unclog the line. I took the gas tank out and am in the process of cleaning it of rust and grime. I got a new fuel sending unit to put on there also. Hopefully this does the trick. I should know by tomorrow. Thanks for all your help so far.

[dougp]

Make sure the gas tank vent is not plugged. To do this next time it stops open the gas cap if there is a significant vacum you know your problem. Remember the manual fuel pump will pump up to about 20 psi before it stops moving gas. I had this happen on an early car years ago. good luck

[cobraPC]

If all else fails, and you have the pump off again check the lobe that drives the pump arm.

Jim

[JimC07]

Vaper lock possible, ran into this problem long time age. person sold me the car after they put new pump on changed out all the fuel lines, clean out then replaced the tank. turns out the fuel system was not air tight, would run dry (out of fuel) they after it sat for 10 to 15 mins it would start again run for awhile the die again. I found the fuel fiter was not air tight and would suck in air, displacing the fule. Replaced it and never had that problem again. bought the car for (are you ready) $1.oo thats right one dollar. sever people tried to reslove the problem, the owner gave up. I sold the car for $3,000.00 which I used to help buy my current home. Not saying anything here other then before you start replacing/ rebuilding your car. take some time to give it a good - complete fuel system inspection...

[cobra350]

its your fuel pump,get a new one

[Mexstang]

If you know what you're doing.........Run a new hose line from the fuel pump to a Gas container & test. This eliminates/points to the tank & feed line.
If it still stalls & the filter is dry......
Then make sure NEW fuel pump PSI is sufficient.
Then test issue w/an electric pump.
Wrecking yard $5(1984+ Fords).....

Vapor lock only happens when the metal fuel line is too close to the exhaust parts...I don't think a 1/4 mile is enough time for Vapor lock to occur...It sounds like the PSI is incorrect or the plunger in the fuel pump is defective. Make sure the line & fuel filter are the right size & new. Don't bother troubleshooting old parts...New ones are cheap.
There's a small %age that it's the Centric. Unless it's the wrong one.

Will it do it while idling...or do you have to drive it? Was it ever working before?

[gmont]

I had a car like that when I was young. Its sounds like an easy fix. First take off your pump supply hose. Have someone spin the engine over with your finger over the hole on the pump. It wont hurt your finger. You should feel slight suction. If You dont its either a bad pump or a worn lobe on the cam. A worn cam is extremely rare. You can check the pump if you take it off and work the arm manually. If everything is ok with the pump it sounds like its either a small leak in your fuel supply line or the sock(screen on the sending unit) is clogged. It could also be the vent on the tank but it would take a while for this to affect the engine. Leave the gas cap off to test this. I had this happen to me once and it was a pinhole in the rusted supply line. I put a lenght of rubber hose over that section with two clamps and it fixed it until I replaced the whole line. I hope this helps. Any questions email me. gmonte11111@aol.com

[BredN65]

Hi,

Newbie to the forum and this Mustang hobby, so all of this info is awesome, but;

I had the same problem, it was gunk in the tank clogging up the fuel line etc. (the guy I bought it from let the car sit for....(who knows). Drain the fuel, blow out the line and pull off the sending unit and replace. Worked for me! (I struggled with this for a long time).

[gmont]

I forgot to mention 1 thing last night. If a car sits for a long time the gas goes bad and gets all googy. Some guys call it shilack.I t smells really bad.
If you have this in your gas line you can clean it with carb. cleaner and blow it out. Watch out for splash in your eyes. If this doesnt work just replace the whole line(steel and rubber).Sometimes the rubber gets little splits in it and you will suck air instead of fuel.

[sixtsixstang]

I agree with Veronica. Check you sending unit in the tank. Also make sure the tank doesn't have a bunch a trash in it. I had a similar problem. Screen on the sending unit was all blocked up. Electric pump won't make any difference.