Posting this inquiry for a friend. He has an f-250 PSD that started out getting about 18 on the highway. It is now getting 13 on the highway. The dealer had the truck for a week and couldn't find any problems! Any ideas out there? I do know the truck sat for a while and that the mileage hasn't been the same since that time. What problems could the sitting have caused (that ford wouldn't find)??

Thanks

 

What year truck, how many miles, how long did it sit, auto or manual trans, how many miles has he drove it since it was sitting? Has this friend changed the oil & air filter since this sitting time? I know when I had my PSD, the mileage would always drop when the air filter was filthy, or anything over 70 mph.

 

Actually this is pretty common and the dealerships are clueless as to how to fix it.

THe problems starts back in his fuel tank. The fuel pick-up has two screens and then a valve above them. The idea is that if the screens plug, then fuel will by-pass the screens and flow through the valve. The problem is that when he gets below half a tank, then the system picks up air.

Next problem. There are quick connects on the top of the tank with o-ring seals. When the o-rings start to leak, the system picks up more air. And yes, they can be sucking air even though fuel is not leaking out.

Third problem, these quick connects are also present at the fuel pump. The fix is to drop the tank, remove the in tank screens and just pipe directly down to the bottom of the tank. He can use his exsisting "foot" or what ever it's called. Then remove all the quick connects and just clamp the hoses. And finally, install an inline fuel filter to replace the intank screens.

Here's the deal, injectors aren't meant to pump air. The engine gets louder while performance and mileage suffer. Plus it will eventually damage the injectors.

I did this to my truck plus what is called a regulator mod. I picked up about 2.5 mpg, way better performance and my truck is quiter than it's ever been. Bear in mind, the worst the o-rings the more this mod will help. So I would say that if he's down to 13 mpg he may actually pick up 5 mpg or better.

Go over to Ford-Diesel.com. There are countless pictures and articals on how to do this.

Hope this helped

 

hey con, where did you get your kit from???

I saw you have a v10 in the x...

Which do you prefer????

 

Mach 1,

I got my kit from David Lott at Diesel Innovations in Houston Texas. Couldn't be happier. His website has detailed pictures showing how to install the kit.
Ph. 713-984-9441
www.Dieselinnovations.com

It's probably the best thing I've done for the truck. Really quite and smooth now. Plus my mileage came up by 2 1/2 mpg. One of the nicer things is the quicker throttle response. Big difference there.

Good question on the V-10 vs PSD and kind of hard to answer since I'm doing two totally different things with the two trucks. We bought the X first and went to buy one with the diesel. In fact, drove one with the diesel all day but decided for the hell of it to try the V-10. Changed our mind on the spot. Better throttle response, quieter and smoother. I mean, it is the smoothest engine I've ever owned. And we're getting 12 in town and about 14.5 on the hwy. We love it. And one reason is that my wife makes a lot of short trips taking my daughter to school and a diesel would never get warmed up. Plus the heavest thing we pull is a 4,000 lb boat and it handles that effortlessly. So for what that truck does, I think the V-10 is a good choice.

Now for my truck, I must admit it took me awhile to be won over to the diesel. Slow throttle response, loud, idle knock, smell, etc. Since I've had it I've done the fuel mods which gave it the throttle response of the V-10. I've installed a 4" exhaust and a Superchips Micro Tuner. Now the truck is WAY quiter and way faster. I'm getting 18 to 20 on the hwy and probably around 16 in town. I'm getting 12 to 13 pulling a 9,000 lb 5er and she never breaks a sweat.

So to answer your question, if I could only have one, make mine the PSD. You can just do so much more with it and while the V-10 will pull, it has to do it at such a high rpm while the PSD just lopes along effortlessly.

Only downside, I shouldn't be having to do fuel mods on a +$40,000 truck. Ford should sell it right in the first place.

Little long winded I know, so sorry!

 

I have never been under the impression that diesel has never offered good gas mileage. I think your previous mileage was god-like for a diesel engine. It could be as simple as a fuel injector problem.

Anti-Honda