I hope some of you can help me, I have a 99 superduty, with the V10. Yesterday my truck lost power, I checked all the fuses, relays, and checked the fuel rails to see if there was pressure and there was, I went and started it up this morning and everything ran great, it broke down far away from my house. I went back later to retrieve it, it started and made it about a mile before it did the same thing. I can hear the puel pump working. I just replaced the fuel filter, air filter, and pvc valve a couple of months ago. The elbow that goes from the pvc valve to the throttle body was shot, and I replaced that, and I still get the same results, it is stuck in the mountains and I need help getting it home, I love this truck, it is the best, and I have maintained it very well. I am lost because it started up this morning just fine and ran like a champ, but then this afternoon, it dogged really bad and then just died!! Please help!!!

 

You will want to check the fuel pressure both at idle as well as in the upper rpm range to make sure your within spec.

 

I am having a hard time finding the proper specifications for the fuel pressure.

 

28-30 psi at idle and 38-40 psi at WOT.

 

Wouldn't you expect to get an "check engine" code if the fuel pressure wasn't within spec? ...if no code maybe it isn't a fuel problem and is a problem with the computer itself?? don't know just throwing out ideas.

 

When drinving did it cut in and out at all. Very well could be the fuel pump. As soon as you check pressure you will know for sure. Once they heat up they like to shut down completely.

 

It does cut in and out, and then straight dies, I am getting a code scanner to read the codes, if it is totaly cold, it will run then it will die out. I ran starter fluid in it and it will run off that, and the rails still have pressure, I don't have a gas pressure gauge, but I am thinking of buying one today, thanks for letting me know the pressures. I will let you know what the codes are, hopefully it is just the fuel pump. It is stuck up in the mountains, could I buy a inline fuel pump, and put it in just to get the truck somewhere where I can either tow it or drive it home?

 

Engine working cold, but dying hot is also typical for CPS going bad. Still starting with measuring fuel pressure is the best idea. Fuel rail always suppose to have few psi of static pressure but needs over 30 for the engine to run, so testing for pressure without the gauge is useless.
I wouldn't risk driving it in the mountains unless you can really fix it. The feeling of engine dying and loosing power brakes and power steering while going down on curvy road is not a good memory.

 

I highly doubt the CEL will come on, misfires do not even light the CEL or throw codes a lot of the time. The system is the basically the old OBDI system with an OBDII port.

 

I gotta agree with you about the misfires. Mine had an intermittent misfire and no code was generated. Thought that was odd, but I guess that's one of the quirks with this computer.

 

there are no codes coming from the scanner, so I am guessing it is the fuel pump, I will find out tomorrow! Thanks, I will post what the problem is, and what I did to figure it out!

 

I just bought an AirTex fuel pump for my truck, Nobody in colorado had the motorcraft pump, and I need my truck running badly, Does anyone know how good this pump is? And I am trying to find the fuel pump relay, and is there any way I can test the original fuel pump? I have no pressure at the rails, just a spurt of gas at times, but no solid psi. I just want to do this right the first time, and everyone on here know's what to do, better then some of the mechanics at the dealership!

 

I never had to look for the relay. Here is thread with some info.(Last post) https://www.ford-trucks.com/forums/9...250-5-4-a.html

As for the Airtex pump I'm not real familier with them but they are a major manufacturer of aftermarket and OEM fuel pumps. For all I know the Motorcraft pumps are made by them, Ford doesn't make their own fuel pumps, they source them to outside vendors.. If your not getting steady fuel pressure to the rail a bad fuel pump is my best educated guess. If th efuel pump wasn't getting any power your truck would not have ran for a little and then died, it just would not have started at all. If you stop and think about it the fuel pump in your truck is over 11 years old so having it go bad at that age is no shocker.

 

Ive tested a pump by touching the leed wires right to the battery termrinals. However Im not sure that is safe, its what I did. Unfortunately after I had installed the new one and found the culprit, broken supply wires up the frame rail.

 

I replaced the fuel pump, if you can get a motorcycle jack, it makes life so easy. I tested the pump after I replaced it with a new one, and it worked, so I am thinking that the pillow filters on it may be to blame, but I know I have a back up in the future. My truck has over 234k on it, and still runs like a beast. The only is I am now having is that my idle sticsk about 1.5 to 2 rpm when I put it into park, what would cause that? I didn't notice until after I put it all in that the instructions said to remove the fuel pump relay before you disconnect the battery cables, can this cause any problems? And I wan to say I thank you all very much for the help you have given me, it makes a big difference!!!