Fuel pressure issue

[kennys@wi.rr.com]

Starting late last year my deuce has been acting up when when I'm driving. It will run 55+ all day long but anything slower it acts like it's out of fuel. At Iola we found a crushed copper line under the front cross member and thought that may be part of my problem. I finally got around to replacing the copper line with a rubber line and the secondary filters with a spin on filter. Still the same problem. I had another member take the truck for a ride and of course where we did there was no problem. Then half way home it started doing it again. I determined that when the truck is at operating temp, that's when I have my problem. I have noticed that some problems come in groups, what happens to my truck will soon happen to yours sort of thing. I just replaced the o rings under the HH on toddm's deuce and after that we discovered that his in tank pump was dead. The bottom cover fell off and got stuck frying the pump, not just the fuse. I thought to myself maybe my in tank pump is shot. So I pulled it. My pump is almost new, but so is the hose. Turns out when the motor pool replaced my pump the grabbed regular fuel hose and of course it was melting between the grooves of the hose clamps, and I could leave finger prints in the hose collapsing it real easy. I couldn't do that with Todds, his was far more rigid. Now I am experimenting with PEX. I heated it to slide over the fittings and then clamped the ends.
Now comes the real question. I put a pressure gauge on the fuel system after the pressure pump in the bottom of the IP. I always thought there was to be 15psi from the in tank pump and 60psi from the IP pump. So I bought a 60psi gauge, thougtht 160psi was a bit overkill. I am only getting 5psi from the intank and 40, at idle, from the IP. If I rev the motor I send the needle around so I am way over 60psi.
What is the correct pressures?

 

[Warthog]

Looking at the LDS Troubleshooting manual ( I just posted it today)

http://www.steelsoldiers.com/5-ton-up/88467-wtk-m54-engine-size.html

Looks like your pressure is in the right range.

 

[Vfflang]

At the 2nd Filters I get 5 psi when the master switch is on / 30 at idle and / 60 when rev.

Do you have the fuel turned up? <Mine was and not by me and I blew a head gasket because of the heat< just a thought don't freak

Maybe your getting air into the system....or maybe water in the primary ....Not an expert by no means just throwing it out there

 

[kennys@wi.rr.com]

All very good ideas. I have replaced all filters when trying to resolve the issue and it still keept doing the same. The best way to describe it would be as though the truck has a miss. Not all the time. Driving down the road just fine and it feels like you just took your foot off the throttle and put it right back on, real fast though. I fear my HH may be on it's last leg.

 

[gimpyrobb]

I think the last 10 words in your last post are the most important part of this thread. If the truck runs fine at 55, I seriouly doubt its a fuel delivery issue, sounds like an IP issue to me. Is this the one you did "head" work on?

 

[Wildchild467]

i think there is a pressure reliefe valve somewhere on the IP... has a spring and a ball or something. im not an expert, but what happens if that was sticking, maybe in the open position? just a thought if it was stuck open, it would cause pressures to be lower thus lower power... at higher RPM, the flow increases thus increases the pressure and make it run better? there are guys out there that have way more IP experience than me, but i know that pressure relief valve is something i checked on my deuce to make sure it was clean.... and it was. just a thought.

 

[Floridianson]

Look on the secondary filter and there you might see the return line from HH and the fuel tank return line in that tee there should be the pressure relieve.

 

[kennys@wi.rr.com]

Yes gimp it's the same HH. I was really hoping to get a lot more miles out of it to prove a point. But I guess considering I made it live one more year I should be happy.
I no longer have that bypass valve on my secondary filter set up. I will add a pic of my new set up.

 

[kennys@wi.rr.com]

Took the deuce for a ride today down to the Harley Museum. She made it there and back, so that's the important thing. I kept an eye on my new fuel pressure gauge and at idle it's about 39psi and while cruising at 30 to 40 mph it's at about 65psi. When I kick up the idle of the truck to 1500 to 2000 rpm I noticed the truck sounds like it has a miss. Not sure if it's a miss or not I have to clean my ears out and take a closer listen. What are the chances that I just have a bad injector or a plugged injector? Any sure fire way to know? Yes I am grasping at straws to prove my HH repair was a good fix. However, if my HH was bad wouldn't the truck either die or add lots of oil level in the pan? My oil level is holding steady and the truck does run.

 

[kennys@wi.rr.com]

I talked to Gimp and picked his brain for a while. He suggested that maybe it could be a governor issue. So I started looking at things a little closer today and read through the IP TM so I could learn more about the governor. I also did some searching on here and decided to remove my fuel shutoff cover and have another look in there. As always it had some oil in it, nothing much just enough to let you know it was there. I couldn't smell fuel but I did notice that it was real thin and runny, bad sign. So I started the truck with the cover off, I saw a few drops coming from what looked like the HH, but I thought it could have just been spray from the gear in there. I also watched the shutoff lever and it was floating a lot. I still find it odd that if I move that lever forward the truck revs up and if I move it back it shuts off. I have a few spare o rings for the shut off shaft so I thought I'd try to replace that and see if it helps hold the shaft a little more steady. As soon as I pulled it out the fuel just ran out and not just a few drops. I'm starting to think my HH could finally have died on me. Anyone have a spare HH or IP they are willing to part with? Looks like I will be in need of one now. Or I'll have to find a machine shop that can make a new plunger and rehone that bore for me. I think I'd rather just replace it and be done with it.

 

[kennys@wi.rr.com]

Interesting update. I replaced the o ring and put everything back together. I have had a few of these apart and back together now and never had such an issue puting the shaft back in as I did this time. Finally got it all together and started the truck. YIKES I have a run away and I can't move the sut off to kill it. Tried putting a board and a rubber pad over the intake and no luck that only slowed it down. I had to remove the fuel supply line to the HH to finally shut it off. Needless to say I hate the taste of diesel. I thought I somehow missed the shutoff block with the little clip at the end of the shaft. Took it all apart and put it back together again, same result. After doing this three times I was about ready to post a classified for a three color boat anchor. Upon closer inspection I discovered something very interesting. The bar that covers the shut off shaft was tight against the shaft not allowing it to move at all. I had to lossen up the screws a turn and a half each before the shaft would move freely. I have never seen that before where I couldn't tighten them all the way down, and I know I'm not strong enough to have bent that bar. Now the idle even sounds a lot better on the truck than it did earlier today before I took it apart. I highly doubt this will fix my problem but I am going to try it in the parade on Monday and see how she runs.
If anyone has had a problem like this with that bar being too tight please let me know how or why you think it happened.