Quite a while ago I read a knowledgeable opinion on 2 pump fuel system failures. I've an 89 F250 bought new w/2 high pressure pumps. Yes, 2 pumps, no transfer pumps in tank and high pressure on rail. Phord has yet to acknowledge this system. At any rate, I have, again, fuel pump issues. The front tank is overflowing when the rear runs, the rear is noisy anyway, so I'd like to replace both pumps. Ford gave me check valves for fuel feed lines years ago, never anything in the return, which is where my issues have been for years and many pumps. The last 2 pumps from Ford, have not lasted a year, and we're overflowing again. I read where this was due to a shuttle valve failure, which was caused by high pressure spikes from the pressure regulator. I've spent quite a bit of time searching the archives and cannot retrieve that thread. What do you guys think? I'm pretty disgusted with Ford pumps not lasting a year and am hesitant to purchase them. The engine has recieved exetensive mods over time, line honed, bored on crank center, lifter bores sleeved and bored on cam center line, roller rockers, lifters, balanced etc. With a Gale Banks exhaust system, and 4:10 gears, 5 speed (I didn't buy it for the women) I get 15 mpg pulling a loaded goose trailer (around 1500#) Very happy with the truck, it's the work horse of my farm. Why change? Any help out there with the fuel pump issues? Many thanks;

 

So you have 2 tanks with a high pressure pump in each one correct? If so that's how all the trucks are setup after 1990. There are check valves built into the pump resovoir inside the tank, if you have a problem where 1 tank is overflowing the other then these check valves are the problem, and fixing it should be as simple are changing the resovoir in the tank that is overflowing.

 

Yes, this 460 has the same system as the later trucks, just a bit earlier with a couple of difference, worked out in the 90s. Are you saying the shuttle valve that is failing, is IN THE RESOVOIR and not internal in the pump? What about why the system has been giving so much grieve over the years? What's your take on the fuel pressure regulator? Not just my truck, but lots of trucks. I guess my basic question is: Is Ford still selling the same prone to fail parts, ala 460 ex manifolds, 3.8 engines etc etc or have they been updated, improved or whatever? Buying 2 systems and having them blow out again in 6 months is my concern. I've gotten tremendous service out of this truck and am more then willing to replace parts, it just seems no one at the dealerships knows or cares. Thanks

 

Here's an exploded view of the in-tank fuel sending unit...



There are check valves integrated into the yellow plastic resovoir cover that should prevent backfilling of a tank when it's not in use. When these fail for whatever reason Ford offers external check valves to put in the fuel lines as a bandaid fix. I'm not sure what your question is regarding the FPR, it won't have any affect on the pumps or your overflow problem.

 

The check valves, available from Ford, as described in their TSB of the 90s, was only for the Larger of the fittings on the tank, which is the fuel feed lines. There has never been, to my knowledge, an external check valve for the return lines, which is the side the fuel is entering the tank from. The fuel pressure regulater deal is again, a TSB, from Ford that alludes to pressure spikes in the system, allowing fuel pressures to rise to as high as 70 psi for a second or so, enough to blow the shuttle valve. What I was reading, years ago, (I taught automotive mechanics for 35 years so had access to tons of info) was that Ford replaced the fuel pressure regulator with one that did not spike pressures, and revised specs for the shuttle valve that allowed it to take the higher pressures, if it saw them. My issue is that of a personnel brain phart in that I cannot locate the info, that contained part numbers etc. I bought, from Ford, 2 new assemblies a couple of years ago, and now with less than 20,000 miles on them I need 2 pumps again. I'm not sure that I didn't just buy old stock pumps, not the newer technology, I just don't know and before laying out that kind of money again I'd just like what's going on. I'm sure someone is aware of the problem. I remember Ford recalling trucks in the 90s because of this issue, tanks were overflowing and there were fires. Now they can't remember, and it's to old to concern them. Hence the question to you guys. Thanks again