Runs 30 minutes

[jhj747]

69 roadrunner changed gas line by carburetor to fule pump cause I thought maybe vapor lock. No car runs about 30 minutes then acts like running out of gas and dies. Try to restart starts for a second then dies. Let sit 20 minutes fires right up. Just to get home..× I have a regular coil and a red msd distributor. I'm thinking it might be the magnetic pickup. He is the strange thing, this time when i tried to restart i had nothing. No power at all. I tightened the ammeter wires under the dash and then I had power but still had to wait 20 minutes for car to start and stay running. 2 weeks ago I wrote into the forum that I lost power and they said check ammeter connection and sure enough I tightened them and it was fine. Anyhelp would've appreciated

 

[R413]

Is the fuel tank vented? Take the gas cap off when it quits, do you have a vacuum inside the gas tank at that point?

 

[jhj747]

The gas cap fits very loosely on but yes I removed the gas cap first time when it did it no air sound when I removed cap even tried starting with gas cap off no.

 

[coloradodave]

Before throwing parts at it, you need to diagnose whether the problem is fuel or spark. The next time it quits running, with the engine off, work the throttle while looking down the carburetor. Is there a good stream of gas shooting down toward the butterflies?
If so, then the problem probably isn't fuel, although it could be....SO check spark at this point.
Pull the main coil wire from the distributor cap and set the end near metal on the engine. You may have to stick a nail between the boot and terminal and set the nail near metal. You are trying to see if turning the engine over produces a good, strong spark between the nail/wire and the metal.
Try the above and let us know what you find. We'll go from there...

 

[jhj747]

Ok also I have a mallory distributor part days 2757801H .I see A at the end when I look it up i don't know if it has a magnetic pickup or electronic points? Any ideas

 

[pnora]

Ok also I have a mallory distributor part days 2757801H .I see A at the end when I look it up i don't know if it has a magnetic pickup or electronic points? Any ideas

You need to properly diagnose whether its spark or fuel. Otherwise you are just wasting time and money. Get a squirt bottle with gas in it. Drive it till it quits and wont start. Give it a shot of fuel and if it fires you know its starving for fuel. If it wont fire its spark or electrical. My bets the fuel tank has junk in it and its plugging the suction screen.

 

[jhj747]

It will fire up for 2 seconds and then dies out. Then if i try again maybe but I ha e to wait for like 20 minutes. Now it did it by my home I towed it back home to 10 minutes I got to the drive it started and ran just enough to get in garage.

 

[pnora]

It will fire up for 2 seconds and then dies out. Then if i try again maybe but I ha e to wait for like 20 minutes. Now it did it by my home I towed it back home to 10 minutes I got to the drive it started and ran just enough to get in garage.

Which tells you nothing unless you diagnose the problem.

 

[copper67sat]

Check the fuel filter sock on the pickup in the tank. I had this problem before when the tank was full of rust and crud. The filter was full of junk, would suck shut and engine would die. Wait 10 min or so for filter to re-expand and engine would start and run for 10-15 min or so before cutting off again.

Disconnect fuel line at the pump inlet and route it to a gas can of clean fuel. If engine continues to run. You know there's a clog between the tank and the pump.

 

[toolmanmike]

69 roadrunner changed gas line by carburetor to fule pump cause I thought maybe vapor lock. No car runs about 30 minutes then acts like running out of gas and dies. Try to restart starts for a second then dies. Let sit 20 minutes fires right up. Just to get home..× I have a regular coil and a red msd distributor. I'm thinking it might be the magnetic pickup. He is the strange thing, this time when i tried to restart i had nothing. No power at all. I tightened the ammeter wires under the dash and then I had power but still had to wait 20 minutes for car to start and stay running. 2 weeks ago I wrote into the forum that I lost power and they said check ammeter connection and sure enough I tightened

Is it fuel or spark? What are you losing that makes it not run?

 

[Geoff 2]

Keep the trips down to 29 min.......

This sounds like fuel. If your dist uses a mag trigger, the symptoms listed do not tally with the p/up being the problem.

What is a 'regular coil'? If you mean stock, it requires the 0.5ohm bal res even when used with the MSD dist [ is it the Ready to run MSD dist? ].

 

[Demonic]

Sounds like heat building in the ignition maybe? As others said, have to pinpoint whether it's fuel or air.

 

[dadsbee]

Does it instantly die or sputter out?

 

[gdrill]

I had a coil that would fail once the engine got hot enough. But it would not start again for at least the 20 minutes. No 2 minute run at all.

 

[Davefinan]

Post #6 sounds a strong possibility. Easy enough to check too.

 

[coloradodave]

I'm sorry but I still don't see where you have tried to diagnose the problem. If you simply ask what the problem could be without proper diagnosis, you are no further along than you were before you asked the question...

 

[jhj747]

Well everyone was right i needed to diagnosis it. I ran the car at idle sure enough died out took air cleaner off and getting plenty gas. Went by the box on the fire wall withe the 4 plugs with all the wires started wiggle them car fired up. The box and the wires really look good so I double checked all connections re plugged in ran fir a long time no problem. So it's electrical. I know the two post on the ammeter the one post is loose. I retightened the bolts but one post is loose . Some people say join the two wires together. My question is if I do will the dash still work. Tach and gas gauge.

 

[gdrill]

Yes, you can join them and bypass the ammeter. Use a bolt. Seal, tape them up really well. I then also run another wire outside direct from the alternator to the battery lead to remove the majority of power running through those wires inside. It will take the easiest / shortest path.

The loose post is an issue.....possible fire from heat.

 

[Sinitro]

Suggest that U check closely the (3) bulkhead connectors...
Over time they can get a buildup of oxidation,
that causes high resistance, poor unreliable connections.
Disconnect the battery, pop out each one,
wire brush and burnish each tab connectors.
Next coat with dialectric grease and reassemble.
Over the years we have done this many times
with our 50/60 year mopars and it has fixed many, many intermittant
electrical issues..

Just my $0.02....

 

[jhj747]

Yes, you can join them and bypass the ammeter. Use a bolt. Seal, tape them up really well. I then also run another wire outside direct from the alternator to the battery lead to remove the majority of power running through those wires inside. It will take the easiest / shortest path.

The loose post is an issue.....possible fire from heat.

Ok but by doing this does it affect the dash gauges