The “free” F-250 saga continues. This first part is history/lead-up to the current problem, just trying to provide the whole picture. My ’99 F-250 (CC, LB, V10, auto, 4x4, ~128k miles, sat for roughly 5 years without being used much) was leaking coolant from somewhere on the backside of the engine, near the top and on the left side (when looking at the engine bay from the front). Through various research and inspection, I came to believe that the leak was from a crack in the coolant tube that sits in the valley of the engine and attaches to the back of the left head, where it transitions to a soft line that runs to the heater core. So, I got all the new parts needed, and 2 months ago we pulled the intake manifold out (followed Haynes/All-Data walk-through), only to find that the leak was actually the coolant tube that’s pressed into the rear left corner of the intake manifold. The tube completely broke at the flange that seats against the top of the manifold. No biggie, got that tube replaced, still replaced the coolant tube down in the valley, put in new Motorcraft plugs because we had easy access, put everything back together with new gaskets, installed all new Delphi COPs (again, because we had easy access), new thermostat, & new DPFE sensor (the truck had been throwing the DTC for a bad DPFE). Everything went back together very smoothly, we followed all torque specs, double checked all connections, and we had no missing or left-over pieces.

With everything buttoned up, I cycled the fuel pump a few times to prime the system, turned the key over, and the V10 fired to life as easily and smoothly as it always had…then immediately died. Cranked it again, same thing. Cranked it again, wouldn’t start. We ultimately got it to start and run, with significant influence from the gas pedal, but it would not maintain idle for more than a few seconds. It would idle, then sputter, then rev up, sputter, hunt for idle, then die. We got to a point where it was holding 2000 RPM and seemed to be humming right along, but as soon as throttle input was removed, it was fall, sputter, and hunt for idle. If it DID idle for a bit, throttle response was incredibly bad. After screwing with it for a couple hours, it was late and we gave up. A few days later, I went to tinker with it again and it wouldn’t start at all. I was so frustrated that I just locked it up, and since then I’ve been busy with other projects, work, and more fun activities.

Fast forward 2 months, I’m trying to figure out what’s going on. I got a KD Tools spark plug tester for HEI systems, and we’ve verified that each new coil is in fact functioning and firing. When the key is cycled to the ‘ON’ position, I can hear the fuel pump running inside the tank. Now, the fuel pressure issue: I attached a fuel pressure gauge to the shrader valve on the fuel rail, we primed the system and pressure only showed ~8 psi. My buddy cranked the engine and the pressure maxed out @ ~14 psi. This is way low, nowhere near the 30-45 psi that the Haynes manual specifies, but I’m trying to figure out what the problem is. The likely culprits I see are: fuel pressure regulator, fuel pump, OR a blockage in the fuel line.

The biggest confusion to me is that the truck ran quite well before I had to stop driving it because of the coolant leak (stopped driving it in mid-January). The last time it ran well was probably mid-March, when I was still hunting for the leak, then it was disassembled and reassembled over the course of 2 weekends in mid-April. The only things we did related to the fuel system were: unplugged the inertia switch so the fuel pump wouldn’t run and cranked the engine to relieve system pressure (this was recommended by the Haynes manual, and the switch is definitely reconnected and is not tripped), disconnected & reconnected the fuel feed & return lines via the quick-connect couplers behind the intake manifold, and disconnected/reconnected each fuel injector (the damn brittle retainer clips on each plug broke, but the connections still seem to be pretty snug).

Is there a way to independently check the FPR or fuel pump? I’m hoping to avoid just randomly throwing more parts at this, as the FPR is around 50 bucks and the fuel pump could cost a couple hundred depending on the route I go. Any thoughts on what I should look at? Anything I’m missing? I don’t know how I could have a blockage issue, as the 4 exposed coupler ends were covered by plastic wrap & rubber bands while disassembled. I guess I should change the fuel filter just to be sure, but I don't think it could suddenly become clogged, lol.

As always, any help is MUCH appreciated! Thanks!

 

I was thinking to myself that you should probably change the cheapest part first, the fuel filter, but then you finally mentioned that in the last sentence. I agree with it not suddenly being clogged, but it could have been borderline before without realizing it. I've had friends and family have similar problems on vehicles that are not driven enough, and it can take a while to track down these problems. My uncle even had an '88 Mercedes diesel that he bought with around 40k miles on it in '97 and while driving it from Oregon to Alaska it broke down after slowly losing power while in Montana (long story, but had to drive to Nebraska first). The fuel system and first filter had broken down from being parked for so long and clogged the primary filter. Once we towed it the rest of the way to alaska on a dolly, he changed the filters a few times and replaced a few lines it was fine. I don't think anything like this would happen on our trucks, but it's very easy to change, and is cheap so I would change it and re-check your pressure before you move onto the FPR or the pump. It sure would be nice if there was a test port before the FPR so you could rule that out.

Good luck, hopefully you'll get more input on this.

 

One way to check would be to pull the fuel line **going into** the fuel filter. And see how much pressure there is.
If there's good pressure, hook it back up and try the output of the fuel filter.

My brother ran my F-250 out of gas once, and we started having problem from that.
The fuel filter had dark brown gas coming out when we replaced it!

 

Good suggestions about fuel filter were already been made . The second item should be to verify the functionality of "pressure regulator " to see if it is working to build/ maintain the fuel pressure .

Good luck,

 

My suggestion was to make sure 1: fuel pump works, it's pretty obvious if its making 14psi instead of 40psi. 2: doing the same on the output would see if it was a fuel filter problem if #1 was followed.

For $15 at O'reilly's just replace the filter anyway imo.

 

Thanks guys. Went ahead and picked up a fuel filter, it's so cheap it just makes sense. Hopefully I'll change that out this evening. While I'm putting in the new one, I think it should be a good opportunity to test the fuel pressure as close to the pump as I can realistically get:

My plan is to remove the old fuel filter, hook up the inlet line to the new filter, then put the fuel pressure gauge on the outlet side of the fuel filter using a piece of hose and clamps. Turn the key to 'ON' for a second or 2 so the pump runs very briefly, and this should tell me what pressure the fuel pump is supplying in a "closed" system. If it's relatively high, I think anywhere over 50 psi, then the fuel pump is probably not the issue, so that should point toward the fuel pressure regulator. If the pump is only providing low pressure, then it's time to pull the bed off and get into the fuel tank.

 

That sounds like a good plan.
One thing, when you turn the ignition "ON" the fuel pump cycles for 1-2 seconds then turns off. To prime everything I guess.

 

True, the pump doesn't run indefinitely, but the pressure could potentially spike very quickly and the jerry-rigged connections for the gauge might not be 100% tight, so I'm gonna have someone else turn the key in case it needs to be turned back off immediately.

 

Yep, when my dad and I tested ours I was the unlucky guy under the truck.
To release the fuel filter from the connector requires a special tool. Didn't see anyone mention it.
You can buy/rent at any auto parts store I think.

 

Yup, and the tool needed is a spring-lock disconnect tool, correct? The kind that's typically plastic, clips around the male end of the line, then slides into the spring-lock coupling to release it? I've got those, and that's what I believe the fittings @ the fuel filter require, but haven't actually tried them yet.

 

Yep, I've got a nice aluminum set.
I think they're 3/8 or something close to it.

It's a pain in the butt to unlock it, at least it was for my truck.

Good luck!

 

Same with my truck, I just did mine a few weeks ago and it was the original filter on my '99. I'll just say it involved a lot of swearing, once I got the first one off though the second one was a little easier, probably because I got a feel for the tool and the connector. I also had to clean a layer of mud and dirt off of mine before I started.

 

Mines a '99 also. It sucked!! Lol
My brothers volvo has a button that you press and it unlocks. Takes 2 seconds.

Take note ford!!!

 

Ugh...tried to remove the fuel filter this evening, it did not go well. I found some sort of plastic retainers in the coupler on each end of the filter:

Inlet side:


Outlet side:





These damn things are preventing the release tool from sliding into the spring lock coupling and releasing it. When I first started on this, the plastic pieces had 2 small ears on them, but they snapped off as soon as I pulled on them with some force. Before they snapped, the pieces didn't budge at all. I tried to fish the remaining pieces out with pliers and a very small flathead screwdriver, but no progress, any piece I'm able to grab hold of just breaks off.

This is ridiculous...has anyone else encountered these? Any idea how to get these pieces out? I can't get the spring locks to release with the plastic in the way.

After the tabs broke off, I thought maybe these stupid things aren't meant to come out, but exact same style of coupler on the return line does NOT have a plastic retainer. I'm really hoping someone has a trick, I'm stumped and frustrated Thanks.

 

I don't know what those plastic pieces are, there was nothing like that on my '99. I always hate it when a simple job is made difficult by something like what you encountered. I don't like those fittings anyway though, what was wrong with a regular old fuel hose and good quality stainless hose clamps?

Good luck, hopefully someone else will have seen those before and offer some advice.