460 dual fuel problems, doesn't want to run on gas

krol · #1 (**permalink**) 02-05-2008, 02:50 PM

I have a 1992 F250 with the 460 running on either gas or propane. I have run into a problem, the truck sometimes does not want to start or run on gas, but will then start on propane and run just fine. Also, if it starts on gas, it will run for a half a minute and then die, but I'll be able to start it up on propane. Sometimes it runs just fine on gas and I won't have any problems. I don't know what the main problem is. I used to always start on gas and then switch to propane to run on.
Could it be some wiring or maybe a fuel pump?
Thanks for the input.

Turbokid15 · #2 (**permalink**) 02-05-2008, 08:35 PM

Sounds like your fuel pump is not kicking on to deliver fuel to the engine.

NewGuy_99 · #3 (**permalink**) 02-05-2008, 10:23 PM

Could also be fuel shut off acting up. It shuts off the gas when running on LPG

krol · #4 (**permalink**) 02-06-2008, 01:13 AM

NewGuy, any idea how I could check if it is the fuel shut off?

NewGuy_99 · #5 (**permalink**) 02-06-2008, 09:01 PM

I don't remember if you have EFI or not. If not, follow the fuel line away from the carb, until you get to something with wires on it. bypass the fuel line around it, leaving the fuel switch on "gas", and test drive it. In hind sight, you probably have EFI. This would mean the switch on the dash probably controls a relay,in series with the fuel pump relay, to shut down the fuel pump on propane. If you can find the relay, and remove it from the circut, you will be able to test as above. Of course, this will not check any other wiring in the pump cct. or the pump itself

dutchlincoln79 · #6 (**permalink**) 03-20-2008, 04:54 PM

How is the propane fed to the engine? What kind of system do yoou have on it?