I have a 99 F-550 7.3 that misses out. My local dealership told me I need to replace the fuel pump, but I wanted to ask others before I do it. With my napa scan tool I'm getting code P1211. At idle my fuel pressure is 47 psi, ICP absolute pressure 480 psi, IPR 9%. while driving WOT fuel pressure will drop to around 30 psi, ICP absolute pressure 2,600 psi, IPR 32%. The truck has 240,000 miles. I replaced all the injectors within the last year. The truck has a dump bed, so i've already checked my fuel tank and pickup screen for any blockage. everything looks good inside the tank. I appreciate any help

 

Sounds like a dumb question but what about your fuel filter? where are you checking the pressure before or after the filter. There are two ports on the back of the filter bowl one is before the filter and one is after. If you have checked this and the in tank screens I would assume a pump is in order.

 

Take the quick connect off of the suction of the fuel pump and blow compressed air into that line with the fuel filler cap off. Then look at the pressures again. If the pressure comes back up to about 47-48 psi at WOT then the screens need to be modified with the hutch mod(in tank fuel modification). If this does not change anything then change the fuel filter and look at the pressures again. Just like Jason is telling you above. Filter and in tank screens. If you blow out the screens and change the filter and you still have low pressure then you will need to look at the fuel pressure regulator on the drivers side of the fuel bowl and then finally look at replacing with a new fuel pump. Go OEM if you have to replace it.
Dwayne

 

Here's one more vote for nothing but OEM on the fuel pump if you need to replace it. Anything else will not last you very long if your truck is a daily driver according to those who have tried the aftermarket pumps.

Drake

 

Good job on checking the screens, but if those quick-disconnects are still in there... you're likely getting a lot of air. I put a temporary clear-housing filter on my fuel line during the in-tank mods, and that's when I learned I has sucking a lot of air into my fuel line from the quick-disconnects (250K on truck then). I replaced my fuel pickup line (from the tank to the pump intake) with diesel-rated fuel injector hose and fuel injector hose clamps. The engine quieted down and I no longer see air on the permanent fuel strainer I put on the line (no strainer in the tank after Hutch mod). I dropped my tank four times while experimenting with this, so this is not a guess on my part.

If you still have a problem after the new fuel line is in there (but I bet the pressure improves), the mod is still a good preventative action and will quiet some of the cackle... so it won't be a waste of money or time. If it fixes the problem completely... well there you go.


OEM (Bosch) is absolutely the only pump that should go in there, even if your sticks are AC 160s. I did exhaustive homework when it came time to look at fuel pumps that would reliably feed my new injectors. Nothing else on the market was engineered specifically for diesel fuel at these flows and pressures... except the OEM. Ford approached Bosch with some specs for the Powerstroke HEUI system, and Bosch designed our fuel pump with the fuel bathing the brushes (a weak point on DC motors). This lubricates the brushes and extends their lifespan significantly (but can blow up with gasoline). Careful scrutiny of the documentation on aftermarket direct-replacement pumps shows 2 caveats:

• Not rated for diesel
• Not rated for extended use (racing component)

 

I have been running a Bosch pump I got from Napa for years. I chased the same problem on my F450 shortly after I bought it with 165k miles on it. I replaced the FPR and pump on the truck but it still had issues at 1500rpms and above, it would not hold pressure. I found the in tank screens plugged. Sadly I didn't know about the in tank mods back then or I would have done them then. I am at 215K miles now and it has started sucking air at just under 1/4 tank now.... Looks like I am going to have to drop the tank again or keep filling it up every 2 days...

 

It's more likely the quick disconnects again. O-ring seals... well... suck at sealing suction. As the fuel level in the tank drops, there is less "head of pressure" on the feed line to the pump. More and more vacuum is created in the fuel line as the level drops and this makes the o-ring seals leak more and more. This gives the impression the problem is at the 1/4 tank mark in the tank itself. If the whole fuel system was made out of clear material, you would see some air get into the line at the tank QD, and some more enter the system at the pump inlet QD. Pumps cavitate with air and are less efficient. Once on the pressure side, air compresses... so it contracts (using up pump volume) and it bleeds quickly out the fuel return line at the fuel bowl. Cavitated fuel/air makes foam and it doesn't always separate in the fuel bowl, so foam reaches the injector system... which is hard on the nozzles and makes more cackle.

 

You will love this then, I have been noticing that my truck has been getting worse mileage lately, these past 3 tanks or so. I chalked it up to the trailer I have been dragging the entire time.... Well I was running down the freeway this morning cussing that truck that was in front of me that was burning oil and smelled of diesel. Well once I was past the truck that was burning oil I could still smell diesel. I noticed half way through the day that my truck was leaking more then usual in the front. ( it has a slow oil leak off the LPOP, it is on the list) Well I started up the truck and backed up, jumped out and holy crap! I found the larger hard line that feeds the fuel filter housing was spraying fuel on the crossmember and dripping down pretty fast.... It was getting worse as the day went on too.
I called Ford and they had it, I got it for $105 out the door using my buddies account. It is both tubes as they are welded together at a bracket that I guess mounts to the side of the engine. I have not put it on yet, it is on the list for this weekend.
I got HORRIBLE mileage coming home from work today. It took a 1/4 tank to go 30 miles.. If you wanted to you could follow my trail and know every where I went today. I am glad that I don't pay for fuel for my work truck, or that would suck.

 

To the OP,
How much fuel do you keep in your tank? Did you replace the pickup foot in your tank?

 

Fancy font. You demonstrate the benefit of the forum here. Each brings their own experienc and there is far less likelyhood of something being overlooked.