Injection pump screen

[Waterhouse]

I’m working on a proto type military vehicle that has a humvee motor (6.2L) After much searching I found that the injection pump has a inlet screen. I think maybe mine is clogged. Has anybody changed/cleaned theirs with out removing the pump from the motor? It looks like the screen cover just un threads after you remove the fuel line, but it is kind of tight in there. Is that all there is to it?

Also, could you guys look at this pic and tell me if this looks like Hummer brakes/rotor/hubs? (Hummer wheels mount to it)

 

[87cr250r]

Inlet screen on the injection pump? Are there no other filters before it? A screen on the IP should NEVER clog.

 

[Coug]

There is nothing in that picture that even remotely reminds me of anything HMMWV.

The wheels/tires are just because that's what the Army has lots of, so using that in a prototype would simplify supply chain if ever adopted.

What does the equipment look like overall? It's usually pretty cool to see what some of the prototypes look like, as most end up getting destroyed/recycled/sold overseas.

 

[Waterhouse]

Inlet screen on the injection pump? Are there no other filters before it? A screen on the IP should NEVER clog.

This thing was sitting for 30 years and I rigged a temporary fuel system up with no filter to see if I could start it. To my amazement, it started and ran for 10 minutes. I shut it off because I had some leaks in other systems. (Hydraulic and coolant) I cleaned out the fuel system and installed a new pump and filter. The lines were full of (EDIT) and I realize I should have cleaned them first. Now, it starts and immediately shuts off.

 

[Waterhouse]

There is nothing in that picture that even remotely reminds me of anything HMMWV.

The wheels/tires are just because that's what the Army has lots of, so using that in a prototype would simplify supply chain if ever adopted.

What does the equipment look like overall? It's usually pretty cool to see what some of the prototypes look like, as most end up getting destroyed/recycled/sold overseas.

Ive had it on here before. It’s a “Vulcan Wheeled Carrier”. I’m trying to get it running.

 

[Mullaney]

Ive had it on here before. It’s a “Vulcan Wheeled Carrier”. I’m trying to get it running.

View attachment 895871

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Neat!!

 

[Mogman]

The screen should come out with the inlet fitting, sanitary conditions are a must, good luck!

 

[87cr250r]

I looks like the end cap has to come off the pump.

 

[Waterhouse]

I looks like the end cap has to come off the pump.


View attachment 895896

Ive seen a pic of the cap off, but I couldn’t see any threads in the pic. It couldn’t be pressed on, could it?

 

[Mogman]

That is a great question, let me go out to my shop and chuck up one of my scrap IPs in a vice and find out!

 

[87cr250r]

There is a serrated edge where the cap meets the pump body. It has a small Allen screw with a plate that engages the serrations lock the cap in place. Remove this screw before trying to turn the cap. There are wrench flats on the cap near the inlet fitting. You can see them in the image I posted.

There may be parts that fall out if the pump isn't oriented vertically, a spring and valve. Again, see the diagram above.

 

[Mogman]

Yes it is threaded pictures to follow

 

[Mogman]

But before you go any farther you MUST make sure the return is not plugged, there is a check valve screwed into to top of the IP (return fitting) and if it gets trash in it or the return line is plugged it will give you the exact symptoms you have it will start and immediately shut down and then will re start in a couple minuets.

 

[Mogman]

Here are some pictures.
there is a "keeper" threaded in at 12:00 to keep the cap from turning.


Then three pieces will come out with the cap.


the end of the IP will look like this, showing the small charge pump.

And it should look like this when it goes back together.

I have no idea if there is a "calibration" involved with re-installing the cap, it was not very tight but it may have been removed before, If I felt I had to go in there I would mark that cap so I could get it back in the exact spot.
Hopefully someone else will chime in with some actual experience..

 

[Waterhouse]

Thankyou so much for all of that. I’m going to attempt it after I check the return.

 

[Mogman]

You understand this is a last ditch effort before pulling the IP for rebuild, you want to make DANG sure you have a good fuel supply to the IP, a good voltage source to the IP and as before a clear return line before going into the end of the IP, I have no idea if that cap has some sort of calibration but I would mark the caps "timing" so it was put back in exactly as it was removed.

 

[Waterhouse]

So I just pulled the IP top half case off and removed the fitting with the check valve. It would allow compressed air through it going out, but not in. It seemed to require a bit of pressure to pop. I guess that’s correct. Anyways, I put it back together and it ran the same. Would start right up and then quit.

So I removed the check valve completely and hit the starter. Same thing, start and quit. When I did this, no fuel came out of the hole where the check valve went. Is that correct? Doesn’t seem right.

 

[Mogman]

You should have fuel flow out of the return port especially when running, not allot but flow, this flow cools the IP, but you have to have fuel going to the IP also.
If you crack the inlet line is there good flow there?
And yes the return check valve sounds normal. should take 2-4psi to open and be closed the other way.

 

[Waterhouse]

Yes, there’s lots of flow at the inlet line. (If it’s not hooked up to the IP) I guess I’m back to the screen. It was starting to get dark and I didn’t want to try it. I should get to it tomorrow. I will mark its location although I don’t really see why it’s necessary. Judging by what came out of the old pump and lines, I’m sure its got lots of junk in it. I just hope it’s not ridiculous working under the manifold. I had a hard enough time hooking up the fuel line.

I want to thank you again. Your pictures give me some confidence that I can do it. I was looking at it and found the Allen lock you spoke of. I’m really hoping the only things “falling out” are the ring and screen.

 

[Mogman]

Yes, there’s lots of flow at the inlet line. (If it’s not hooked up to the IP) I guess I’m back to the screen. It was starting to get dark and I didn’t want to try it. I should get to it tomorrow. I will mark its location although I don’t really see why it’s necessary. Judging by what came out of the old pump and lines, I’m sure its got lots of junk in it. I just hope it’s not ridiculous working under the manifold. I had a hard enough time hooking up the fuel line.

I want to thank you again. Your pictures give me some confidence that I can do it. I was looking at it and found the Allen lock you spoke of. I’m really hoping the only things “falling out” are the ring and screen.

When I took it apart it was horizontal like being installed, all that came out is what you see in the pictures, it might be a challenge to get back together in that position. Also the regulator ass, shown in post #8 has the regulator piston, spring and plug in it, you do not want to dissemble those components.