jonm1a1

I have a 84 f150 351W H.O Carb over 100K miles(stop working)


The truck is hard to start and once I get it started I have to let it run for 4-8 minutes. If I don't it will die as soon as I put it in gear. Once I get it warmed up it will drive for about 20 minutes and then start to die. It slowly dies and doesn't seem like its choking itself out. It has an electric fuel pump. Fuel filters look good there is one between the carb and fuel pump and between tank and fuel pump.
Once it dies I have to let it set for almost an hour to get it to drive again. The engine as far as I can tell is all original. Compression test all good. not really sure where to go from here.


When it is warmed up I can start it with little issues and when I turn it off there is no sputter, just turns off.


I have a new timing chain to install I am sure it needs it.
Heard it could be distributor getting hot or going bad how do I check that.
Could be vapor lock doesn't seem like it but never had the issue.
would a carb do all that but run so good then just die out?




Thanks a lot for your help

jonm1a1

any ideas? lol

Manuellabour247

I know one of my old ford's had a butterfly valve in the exhaust manifold. I was told to take it out as it was a 70's truck and they were known to go bad after a while. Not sure if your 351 will have that or not. I believe it was a type of EGR to help warm up the motor when it's cold. Might check into that.

Also what type of carb do you have? Has it been rebuilt recently? Check the choke to make sure it doesn't stick open or shut. Carbs are cheap to rebuild and if done right, work like new.

Aaoxen

Ugh mine does the same thing! I have a 1977 f150 2wd with a 400. Just driving along today and it was like someone just turned the key off. It has done this a half a dozen times of the last 2 years in the hot summer. But It has always started back up after a few hours. I had to walk over four miles home in extreme heat.

I am going to check the choke and the exhaust valve as mentioned above.
However I am thinking is there a possibility of bad wire or something on the ignition?

Manuellabour247

Has the distributor been upgraded? What I mean is, does it have points like the old 292's? Also check for a fuseable link in your wiring. Or the coil.

1967 Tempest

Pontiacs have that too. They are designed to fail in the open position. That said it could have rusted in the closed position..

I like the coil idea as it is an easy thing to replace and is cheap insurance anyway. You can get an HEI for this for less than $75.00 and solve ANY ignition problems.

http://www.ebay.com/itm/FORD-351W-351-WINDSOR-HEI-DISTRIBUTOR-ACCEL-WIRES-6510-BLUE-KIT-/371037144117?pt=Motors_Car_Truck_Parts_Accessories&vxp=mtr&hash=item5663898435

I am leaning towards the carb though. Ignition errors are usually a stumble and a fall. Not a starts and then stops etc.. Especially a coil failure. DIW when that happens.

If your carb is a Holley, the first spot I would go to is the power valve. If it is ruptured, the car will get flooded.

Next I would go to the floats. If they are shot they will fill with gas and the engine will be flooded again.

Both issues can cause your symptom.

Aaoxen

I was able to fix my dying issues today that sounded like a similar issue you are having. I wasn't getting spark. I got the ignition coil wires replaced ( coil was already replace months ago) along with a few other wires around it. Man, now is starts right up with the first crank. It usually took 2 or three. It has not died since. However It has only been a few days but I think that was the issue.