Hi, I have a 351W in a 1984 F250. runs great when it starts. When it starts, it will run for about 6 to 8 minutes then it shuts off and will not start until it cools down or overnight. It will not run longer than 8 min. I changed out ign.mod. on fender well. It has the Holley factor carb and works perfect. When it starts, it fires up at first hit of the key. Smooth as can be. Is there problem with distrib. ? I'm at a loss.
Please Help
Thanks
Jim

 

sounds like you have fuel pump issues, jim. i had a 91 explorer that had alot of the same symptoms as yours- i ended up rebuilding the fuel pump. I'm not 100% sure thats what your problem is, but maybe its something to check out. hope this helps, not hinders.
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1986 F250 XLT Lariat, 6.9L IDI, C6, 4:10, riding on 33's

 

Can you tell if you are getting fuel at the carb when it cuts off?

 

Thanks for the response. I put on a new fuel pump and replaced the few ruber fuel lines on trk. Could this be the electric valve, that switches from frt to rear fuel tanks? Maybe I should bypass the soliniod and try to run just the frt tank? Other thoughts?

 

Hi again, Well I just bypassed the dual tank valve under truck. Started truck and it ran for 6 minutes and shutoff. It has good fuel flow when it dies.. Like I said, it will start again after it cools for a time. Pulled carb apart and it is very clean and all parts fuction as it should. It shuts off as if it is a electrical issue. It has a factory distributor. I am lost,

Thanks for the help
Jim

 

As soon as it dies,

1) Check fuel output rate & pressure at the carb, and
2) See if you have spark.

 

Hi Folks, Me again on the 351 that dies after about 8 minutes of running. Pulled fuel lines apart and cleaned. Did get a little (junk) out of them. Have got 5#'s of fuel pressure when its running. Took the gauge and fitting off my drag car. There is spark. When it is cold it starts right up. Runs for 8 minutes and shuts off. Timing is 10 degrees. It does not stumble when it shuts off, it is like You turn the key off. Distributor when it warms up??? or how about the ignition switch on the lower part of the steering column??? 1984 F250, 351w, Auto trans. 2 wheel drive.
Thanks for the help.
Jim

 

sounds like a short to something.......have you tried a different coil? vacuum leak?....

 

It might be your ignition coil. If a coil is going out on you, they do get worse after they get hot.

http://www.PerformanceDistributors.com

 

yea......the oil filled canister style anyway.

 

Is there any way you can replace the coil and see what happens?

You could also hot wire directly from the battery to the coil bypassing the switch.

 

Thanks again for the help. I will swap coils in the morning with a new one. Checked tonight after it was running and then died for the spark and it was very weak to none.

Thanks again.
Jim

 

Well folks, I put in a new coil, dist.cap, rotor,fuel pump, fuel lines, filters, new fuel, ign.module, volt reg, battery, battery cables. Still shuts off after agout 10 mintes of running in the driveway. I am still open for suggestions please.

Thanks
Jim

 

You might want to use an ohm meter and test the resistance across the ignition switch when cold and after it gets hot and cuts out. It may be building resistance as it gets hotter so that it no longer has enough voltage to supply the ignition system with power to form a good spark.

 

I would like to try a different distributor. I need to purchase one for the 84 351 W -Dura sparkII. Any one with one for sale in good shape I'm interested in buyin it. I will check the ign. switch with ohm tonight. Need some more suggestions.

Thanks
Jim