1994 Coachman Santara Ford F53 engine stalls after about 45 minutes of driving

[ReneTampaBay]

I have a 1994 Ford Coachman Santara on F53 chassis 460 engine with 33K original miles, I just bought it 2 months ago, the people I bought it from said that it was sitting for a long time. I got it running pretty well but it does a very strange thing I can't figure out, the engine stalls after about 45 minutes to an hour of driving, it just loses the ability to accelerate, and it shuts down. Then I can start it again and it will go for a little bit but then does the same thing again. Does anyone have an idea what could be causing the stall. It runs pretty good once it gets going engine sounds smooth and shifting is good, but occasionally something happens and it stalls, it loses its ability to accelerate, when that happens, I am pressing on the accelerator, but it doesn't move and then it shuts down. Does anyone know what might be happening. It has new plugs, rotor and cables, I am thinking about changing the coil.

 

[John&Andrea]

Could be a fuel pump issue?

 

[rjwilliams11741]

Could also be a computer issue. I had a 1997 Jeep Grand Cherokee that acted like that.

 

[GypsyR]

Sounds like the fuel filter might be clogging up in the pump. I've been through the exact same thing. The pumps draws the ick left in the tank from year sold gas into the filter as you go. Worse as you keep going until it chokes off the fuel supply completely. I'm guessing that after resting a bit the particles drift back out of the filter a bit allowing you to go on a bit. What I do know it that eventually cleaning the ick out of my tank and installing fresh fuel filters fixed it up for me. While I was in there I put in a new high quality fuel pump too.

But what you really need to do is throw some actual diagnostics at it instead of parts. I purchased a fuel pressure gauge but I'm told they also have them on the list of "loaner" tools at many chain auto parts stores. Put one on and see what your actual fuel pressure is and what it is when the RV falls on it's face and then you'll KNOW whether or not you have a fuel feed problem.

I documented my personal 1993 F53 460 fuel feed issues and adventures in great detail on another RV forum.

 

[ReneTampaBay]

thanks for the feedback , that would be a good possibility except in this case the gas tank was dropped all the old fuel pumped out and the bottom thoroughly cleaned , then a brand new original motorcraft fuel pump was installed, the pump cost me $475 but the other one was the original and I didn't want to go through lowering that fuel tank again that's a 75 gallon tank and its a bear to to, so I shot gunned it, at the same time I replaced the fuel filter so there is a brand new fuel pump and fuel filter, I think the only thing left on the electronic side is the ignition coil or the computer, I was also thinking about some kind of vacuum lock, any other ideas , thanks

 

[ReneTampaBay]

Could also be a computer issue. I had a 1997 Jeep Grand Cherokee that acted like that.

thanks for your suggestion , yes I thought about that . I have the ignition coil possibility I'm thinking it might be failing intermittently, for the computer possibility I would have to hunt down a used computer at a junkyard because a lot of the parts for this motorhome show as unavailable at the dealer

 

[ReneTampaBay]

Could be a fuel pump issue?

thanks for the feedback , that would be a good possibility except in this case the gas tank was dropped all the old fuel pumped out and the bottom thoroughly cleaned , then a brand new original motorcraft fuel pump was installed, the pump cost me $475 but the other one was the original and I didn't want to go through lowering that fuel tank again that's a 75 gallon tank and its a bear to to, so I shot gunned it, at the same time I replaced the fuel filter so there is a brand new fuel pump and fuel filter, I think the only thing left on the electronic side is the ignition coil or the computer, I was also thinking about some kind of vacuum lock, any other ideas , thanks

 

[GypsyR]

I lowered my 80 gallon tank multiple times and changed multiple filters and pumps before I, my engine, and my fuel pressure gauge were happy. Until you put a gauge on it and PROVE what you do or do not have for fuel pressure you can't say it's not a fuel problem no matter how many new parts you've thrown at it. It certainly can be something else but I wouldn't take a single step forward until the fuel pressure was rechecked.
At one point on mine I discovered corroded wire connections on the back of my fuel pump relay which I'm sure wasn't helpful. To assure me that my fuel pump was getting proper power I installed a dedicated ammeter to see what current it was being fed. After I was through testing I just installed the ammeter on my dash permanently. Just because I rebuilt my entire fuel system doesn't mean it's perfect and will last forever. I like that I can keep an eye on it. The ammeter helped me prove one of the pumps I bought was lacking in performance.

 

[ReneTampaBay]

I lowered my 80 gallon tank multiple times and changed multiple filters and pumps before I, my engine, and my fuel pressure gauge were happy. Until you put a gauge on it and PROVE what you do or do not have for fuel pressure you can't say it's not a fuel problem no matter how many new parts you've thrown at it. It certainly can be something else but I wouldn't take a single step forward until the fuel pressure was rechecked.
At one point on mine I discovered corroded wire connections on the back of my fuel pump relay which I'm sure wasn't helpful. To assure me that my fuel pump was getting proper power I installed a dedicated ammeter to see what current it was being fed. After I was through testing I just installed the ammeter on my dash permanently. Just because I rebuilt my entire fuel system doesn't mean it's perfect and will last forever. I like that I can keep an eye on it. The ammeter helped me prove one of the pumps I bought was lacking in performance.

 

[ReneTampaBay]

Thanks , the only issue is that to prove that the fuel pump is not the issue I would have to place the gauge permanently on the line so I can look at it at the moment it happens , it would be great if there was an inline fuel pressure gauge , I don't think they make one so I guess I will need to use a standard one and leave the doghouse open and then when it happens I will have to connect it at that time , I'm going to do that, ,thanks