Update...

Wednesday evening we did the bucket trick suggested by Chris, and it pointed to a weak pump. The new pump from Clay arrived, but USPS is not being fast about getting the new pickup foot here from Bob in Colorado... should be here tomorrow.

Tank is out and spotless. We did get some trash out of the tank as we siphoned it down into buckets.

The filter element has been replaced.

New tubing is run between the filter and pump, and will also be replaced between the tank and the filter when the new foot arrives (Saturday morning completion plan).

Out of curiosity, we tore the original stock pump apart to see how it is put together, and also to see if we could find anything obviously wrong inside. Benjamin snapped a lot of pictures as we tore it down, but he has not sent them to me yet. When he does, I'll post a new and separate thread showing the pump construction (or, rather, destruction). It was very interesting.

Inside the pump, we did find some very small trash caught on the internal screen in the suction. There was some vertical shaft movement, but no side-to-side movement. I am suspecting that it was giving as a problem only after being heated up and run for a while, and that it was more than likely an internal clearance problem which was only realized once it got warm and everything expanded inside. Still just a theory, though.

At this point, once the new pickup foot arrives and we get it all put back into the truck, I am expecting the truck to run great again with the new pump, new filter, new lines, and verified clean tank. The only thing which we have not checked is the discharge line between the pump and the fuel filter housing in the engine valley... if anything actually broke apart in the pump suction, which we cannot verify because we can't get it apart, then there might be a slim chance that it is still caught in the discharge line, but that is highly unlikely due to the fact that it would have had to make its way through the check valve at the pump discharge and that is a very small opening... not large enough to create line pluggage issues.

We'll keep you posted.

 

Looking forward to see how the pump was built, thanks for your hard work and sharing with fte.

 

I am very curious about the pump as well. I heard a rumor about the construction and want to see this confirmed. Great job! You'll get this nailed for sure.

 

One thing I can say about the inlet screen on the pump suction, it is flat, circular, and full pump diameter, and the screen mesh size appears to be very similar to the screens inside the OEM mixing chamber in the tank (the ones we get rid of when we do the in-tank mods). The black stuff which was on the screens appeared to be more sludge-like as opposed to being "crumbled intake foot".

It was interesting to see that the entire motor armature is completely engulfed in the diesel fuel inside the aluminum pump housing. Perhaps some of you might have already known that, but it was a surprise for me since I've never even really thought about the potential fuel pump construction before now.

We actually threw away the parts last night after we took the pictures, but I just called the house and one of my sons is taking the parts back out. I could not get the pump impeller section taken apart last night, but I really want to get that open and see the inside impeller workings. I was thinking that it is a type of "positive displacement" style pump, but reading this morning suggests that it has a turbine style impeller... I just cannot tell which type without taking it apart completely. (The engineer in me is really kicking in on this point).

 

subscribing

 

I forgot to ask earlier... what rumor?

 

I heard that the fuel passes over the brushes - thereby lubing them and extending the life of the pump.

 

It is absolutely true, Rich. Like I said, the entire armature, including the brushes at the top of the shaft... they are all immersed in fuel. Then the fuel makes it's way through a plastic cap of sorts where the electrical connector studs also pass completely through with one end of each stud inside the internal cavity which is fuel-filled.

 

That's what I thought. I wouldn't run that pump on a gasser. I researched the heck out of pumps before I replaced mine, and I stuck with OEM in part because of this. I called it a rumor because I forgot where I saw that, and I couldn't back it up until I found the reference again - or somebody (else?) took one apart. I think woodnthings may have been the other source... and his word is solid in my world.

 

Pump replaced, everything hooked up, clean tank, new filter element, new fuel hoses, new pickup foot inside the tank... everything is golden again. Now Benjamin just has to run all the air out.

With the new pump, we see the fuel pressure start out at 60 psi, but it ends up right at 70 psi after it runs for a while and purges some air out. At WOT, the pressure dips down to about 56-58 psi, but it starts recovering even before the throttle is released. I think that Benjamin is in love all over again!

Well, I've been busy with helping Benjamin and prepping for more tile work at the house, so I have not yet gotten the pictures together of the pump tear down, but I will do that this week... once I have the tile installed and grouted... hopefully by Wednesday night.

Thanks again for all you guys' input.

 

That sounds great Pete, but it's supposed to be Benjamin updating the thread.

Just sayin.

 

I know, Chris. Right now, he's in love and getting ready to get married in mid-January, and his mind is only on his truck when it's giving him trouble. I, on the other hand, know that the feedback to you guys is helpful and appreciated, and am glad to fill in that gap for him.

Shoot, even though the problem is resolved (or so it still seems), I think we might still have a few things we can learn about our pumps to develop a more complete understanding of our fuel supply system. It may prove to be a simply academic exercise in the end, but how often do we get a chance to tear down one of these things and see how it's built and operates? Might just find a surprise or two.

 

Hey guys...sorry I haven't been updating the thread myself lately. I think my dad said it best...I'm less than 8 weeks away from my wedding, and I've been just a tad bit overwhelmed with work, wedding, and my truck issues.

However, here's where I am right now...
Truck has started really rough the past 2 mornings, much better this morning. I have just had to crank/prime/crank/prime etc. Until it finally started running. Ran rough for a couple of minutes then smoothed out. This morning it started on the second crank, so I think the remaining air bubbles are starting to work themselves out. Besides the first start of the day, trucks been running perfectly. Smooth power, very consistent, and smooth idle.

I'm seeing a solid 60-62 psi at idle and coasting, acceleration will drop it down to 55ish (maybe a bit lower for half a sec under WOT) but it recovers consistently every time. If I drive at highway speeds for more than 20 or 30 minutes, pressure seems to creep up to 65 or 68 psi when I'm cruising and not accelerating.

All in all, I think we've got the issues resolved. New pump, new aux filter, new lines, new pickup foot, and twice cleaned tank.

I really appreciate everybodys suggestions and input. I'm sorry I haven't been posting more through it! I'm just really glad Were through this issue so I can get these other things taken care of lol. Thanks guys!

 

OK... just to follow-up on my earlier promise for pictures and put closure on that issue in this thread.

So, for all of you who wanted the nitty gritty details on how the stock OEM pump is put together, I just finished the complete tear down yesterday afternoon. I took lots of pictures and compiled everything in a PDF which is attached to the first post in the thread below.

https://www.ford-trucks.com/forums/1...-and-pics.html