Ford 460 in an RV

I thought I would ask this question here as you all seem to have an endless supply of experience in the bizarre and interesting. I have a 1996 Jayco camper on a E350 chassis and the 460 engine. Recently on a long trip, 11 hours of driving, I had some problems. I had stopped several times and got gas on the trip and everything was fine. At the end of the trip when I slowed down to below 20mph the engine sputtered and died. I could restart it but it ran very rough and died quickly. After sitting overnight everything was fine again. Then after 4 days of camping on the return home it did it again. One thing I noticed is that it seemed to happen after I ran the AC for a while and the engine got hotter. The temperature gauge stays within the acceptable range but did get higher. Some google searching shows that the fuel pump on these were known to be a weak link when things got hot. Does this sound reasonable? I looked and ford wants ~$600 for them but they can be found on ebay for ~100. What would you all suggest?

Thanks Jon

Sounds like overheating to me. When the engine is running at speed there's enough air flowing over/through the cooling system to keep everything happy. Once you slow down, things get unhappy. It still might be the fuel pump, but this is a EFI engine, right? Pretty sure the pump is in the tank.

If the RV sits (and it seems most do), the fuel filter(s?) may be clogged a bit. It might flow enough fuel to run the engine under normal conditions, but not enough to keep the fuel flowing through the system fast enough to keep it from vapor-locking when the engine bay gets hot.

Hook up a fuel pressure gauge and try to replicate the issue. Report back with your findings. Things like ignition coils can act up when hot also.

I'd also look into the fan clutch. If it heats up when you slow down it may not be pulling enough air through the radiator to cool things off. And check radiator condition, fluid,debris, etc.

Beat me too it.

Vapor lock in the fuel line?

Unlikely vapor lock but possible. They use a return-style pressure regulator so there is always a fresh supply of fuel from the tank.

Failing coils like to die when they get hot

Check your IAT and coolant temp sensor with a data logger/scanner. It gets really hot in those small engine bays and if its not properly reporting intake air temps or engine temps it will get all kinds of confused.

Could be a failing fuel pump crapping out after extended use. Any fuel pump will be fine. It doesn't have to come from Ford. Ebay or parts store is 90% as good. You also don't need to replace the whole sending/pump unit. You can buy just the pump. Walbro makes a 255lph pump that is darn near universal.

You may also have a CEL or pending code that could be scanned.

My question is do you have two fuel tanks or only one. The dual tank Fords did have an external pressure pump so they didn't have to have one in each tank. IT could overheat since it's not in a tank.

jimbbski wrote: My question is do you have two fuel tanks or only one. The dual tank Fords did have an external pressure pump so they didn't have to have one in each tank. IT could overheat since it's not in a tank.

Are you sure of that? My 95 had a pump in each tank, but it was a diesel.

In reply to curtis73:

Ditto my '90 E150 w/ a 5.0 EFI. Two tanks. Two pumps. From what I remember, the switch for the tanks did nothing more than switch the power and sending unit feed from one pump to the other.

I remember when the sending unit on one failed. "No big deal. They're cheap..." until I found out the sending unit is part of the pump. And is not cheap (or at least didn't seem cheap at the time). So I'd run that tank first until it ran dry and started bucking and then switched to the other tank with a working sending unit.

Thanks for the input guys. It only has one tank. How hard and cheap is it to install a fuel pressure gauge? Any recommendations on what kind to get? I did think about the coils and radiator fan also. May end up doing these as preventative maintenance.

Thanks