More engine problems (Documentation of testing fuel system, failure of Hyd Head)

[Squirt-Truck]

I am with Gimp, sounds like a quill shaft issue, best I recall there is a tension pin that holds the gear to the shaft. Key here is that you said high EGT, the indicates late timing and that can be the slipped quill.
To add the part, if running straight WMO it adds load to the HH system and the quill, if it was weak the extra pumping load will make it move. You can confirm this by checking the "reference" location of the scribed tooth when the timing marks are aligned.
Only way otherwise to drop timing is for the 3 pump to driven gear fasteners have come loose, if the gear looses a tooth, you will have a broken from cover.

Keep us posted.

 

[rosco]

Bad dirty fuel can drive you nuts. Its not unheard of to have to change the filters several times, in close succession, due to dirty fuel. Change filters, check fuel pressure to verify, etc. Start over... that got it running again. I was last to believe I needed to change the filters several times, in a row, untill and "old time" mechanic rubbed my nose in them. It gets to be a mixed problem. Restricted fuel delivery, plus it being mixed with air.

 

[doghead]

I've killed a HH from plugged filters, using junk fuels.

 

[patracy]

Well I can get it to start. Only with starting fluid and holding it to WOT. It will clear up and finally start running right. I was able to get it to idle for about 5-10 mins on it's own. I stepped away again and it suddenly chugged a few times then cut off. Repeated the process again, got it started again. If I let it clear up and slowly back it down to 1000rpm or above it will run for a while. Then shut down after chugging a few times. If I restart it again, let it clear up, and keep it above 1500rpm I can rev it to around 2400 and back and forth no problem. If I hold it to WOT and try to get it to governed max RPM, it stalls out, starts popping then dies.

Sometimes playing around with it trying to get it cleared up, it will "kick" in and stop smoking. It clears up and runs well. Almost like it was flooding, then cleared up. Also noting EGT's everything is fine when running.

So IMO, the quill shaft is fine. The timing is correct as well. The lift pump provides 5-7psi at ON, not running. When I get the engine running and lower RPM down to 1K rpm, fuel pressure at the bleed port is 35psi. Revving high, 60+ psi. Also I pulled the plug on the HH and checked that the plunger moves freely and consistently while turning.

I pulled the check valve on the front of the HH, didn't see any gunk. Wasn't stuck either. Reinstalled it. Also did the same to the check valve on the secondary filter housing.

Also I noticed now when I was checking the return lines, I'm not pouring fuel out there now either. So perhaps the check valve was an issue earlier.

I did play around with the cut off valve with the cover off. I did notice there's a little play of the shaft in and out against the U shaped cover (with the two safety wired screws).

I'm wondering if Eric is right and I killed the HH due to the starvation. Perhaps the starvation allowed the plunger to wear (I know these are a very close fit) enough to not produce enough pressure for start up.

At this point, I believe the issue is certainly in the IP. As when I do get it to run, and run "right", the engine seems fine. I believe the lift pump is certainly ok since I see 5-7psi. I think the booster pump is ok as well, as I see 30psi at idle and 65-70psi at high RPM. I believe the check valves are ok as well, as I'm no longer seeing fuel trickling back through the nylon tubing on the injector returns. I have not checked the check valve on the booster pump. I need to study the TM's more to figure out exactly where that's at (I want to say it's mounted on the bottom of the pump). Perhaps this check valve is hung open. I could see it possibly causing the booster pump (since only 5-7psi is feeding in) to not allow the start as well. Only when I start it with fluid does it actually get enough RPM to allow the check return to cycle through the booster pump and create enough pressure to run.

Wait, now I'm thinking back to testing the HH plunger. I pulled the power to the lift pump to prevent it being a mess. Shouldn't there have still been fuel pumping through via the booster pump?

Sorry for the wall of text. I'm trying to talk my way through everything I've done.

 

[doghead]

Maybe the boost pump shaft seal has blown out?

 

[patracy]

Maybe the boost pump shaft seal has blown out?

Good point. I'll check the oil level next to see if I'm "making" oil.

I'm looking through the TM and I see where the check valve on the booster pump is as well. I will inspect that as well. I haven't found anything yet that says what pressure should be while cranking. (Assuming the booster pump is starting to pump) I'm starting to question my MacGyver fix to limp it home as well. I honestly have no idea what kind of pressure that automotive lift pump could have possibly been making. It stands to reason that it might have been too much and damaged the booster pump seal. Let me research that pump now to see if it could have been a factor.

 

[patracy]

Oh lord, I found out what that pump was. It was from a 7.3 powerstroke. Looking up the specs, that pump puts out at least 60psi. So it might have been introducing 60psi into the boost pump when I limped it home. I guess that could have killed the seal on the boost pump. I guess I need to check the oil level now and check the boost pump check valve.

 

[3dAngus]

Oops. Good read. Keep us informed of any further progress.

 

[gringeltaube]

................ I haven't found anything yet that says what pressure should be while cranking.

TM only says 7 psi (min) at 150 rpm...

(Assuming the booster pump is starting to pump)...

Even if not - as long as there is positive pressure at the HH inlet port it should be able to inject enough for the engine to start.

What if you pulled one or two injectors, hooked them up OUTSIDE and watch it work while cranking...? You should see mini-squirts, at least...! If not, the plunger is prob. worn too much for the relative low viscosity, straight diesel. (maybe that's why it still ran on WMO...)


G.

 

[patracy]

Ok, checked the oil. It was last running about 18:30. I checked it at 20:00. Was showing about a quart above the highest point. I'm going to just say the 1.5 hrs it had to drain allowed the oil filters to drain down enough for that. I dropped some dipstick oil on a newspaper, didn't see a halo effect around the oil drop. (Something I picked up in the past to see if there's diesel fuel in crankcase oil)

Good point I suppose about the positive pressure G. The plunger is what really does the heavy lifting to pop off the injector. I know I'm getting fuel pressure to the HH when I have the in tank pump running. However I did not get fuel to the HH with only the engine cranking and hoping the booster pump would push some fuel. Course I didn't run it for very long like this. So that might not be a valid test.

I looked at the TM's a little more and see the check valve on the booster pump and how the booster pump mounts. I will try pulling the check valve to double check that. But to pull the booster pump with the IP still mounted will require the steering column to come out. I'm going to hold off on that for now. As I should see a lot of fuel in the crankcase oil if that seal failed. (But of course the check valve could be open)

I know while tinkering I did have a injector outside the engine and did get fuel squirting from it. But honestly I don't recall if I was WOT'ing it while checking that. I've got the other set of injectors. I'll just pull one line loose from a injector and plumb the other injector outside and test it at normal idle throttle position to see if it pops off. I think that will give me a determination if the HH is the culprit at this point or not. Especially now that I know that 7psi at 150rpm is all that's needed to start the engine. That can, and does, come from the lift pump from my testing.

 

[gimpyrobb]

Just to throw it out there, I have replaced a HH on a pump that only had 3 good ports of 6. What we did was take the injection lines off the head and crank the motor. There was only 3 ports that fuel popped up on, the others had nothing. It looked like a "L-D" water fountain.

 

[Heavysteven]

Just going to throw this out there...all your fuel lines good and the rubber hose on the fuel pump in the tank solid.

 

[patracy]

Just going to throw this out there...all your fuel lines good and the rubber hose on the fuel pump in the tank solid.

The in tank hose was a little loose when I swapped lift pumps. I clamped it down a little harder when I reinstalled it. I guess it wouldn't hurt to go back and replace it. The rest of the supply fuel lines haven't been touched. None of them were leaking. Just the injector return lines. I suppose the lift pump could be an indirect culprit now as well. As previously it was doing nothing more than working as a draw straw in the past with the external lift pumps. The hose could possibly leak in those two places.

 

[patracy]

I think before I mess with the in tank hose (since I see 5-7psi from the lift pump), I'm going to test the HH with an external injector at idle throttle to see if it injects.

 

[Heath_h49008]

I'm sorry you're having trouble, but thanks for the details and the thread. This is a good one for diagnostics and the dangers of WMO operation.

 

[gimpyrobb]

Well, until he finds out what the issue is, it might not be fuel related. It could be that the lack of fuel is what caused the problem. So many folks bad mouth "alternate fuels". Sure it could be hard on the system, but I have run a few thousand miles on it and have done fine. Besides, at the cost of fuel today, I have saved enough to purchase new IPs and have them sitting on the shelves. Heck, Kenny even is putting together group buys of cheap hydraulic heads. I filter the crap out of my fuel, maybe it helps, maybe not. Good luck getting her going again Drew.

 

[patracy]

Well, until he finds out what the issue is, it might not be fuel related. It could be that the lack of fuel is what caused the problem. So many folks bad mouth "alternate fuels". Sure it could be hard on the system, but I have run a few thousand miles on it and have done fine. Besides, at the cost of fuel today, I have saved enough to purchase new IPs and have them sitting on the shelves. Heck, Kenny even is putting together group buys of cheap hydraulic heads. I filter the crap out of my fuel, maybe it helps, maybe not. Good luck getting her going again Drew.

Honestly my reply to the first reply was a "screw you" to the WMO haters. I'll still run WMO. I'm not blaming WMO on my issues here. I'm blaming my issues on:

1. I ran the tank dry.
2. I tried to drive it home 6 miles on 100% WMO in below 40F temps.
3. I used a bad choice for a lift pump to get me home. (60psi or more)
4. I totally forgot to change my secondary filter housing last year when I swapped engines.

I certainly did a number of things that weren't beneficial to the fuel system, even if I WASN'T running WMO (1,3, and 4).

Before the Family and I take off for the day, I'm going to sneak out and install one injector externally to check if it pops at idle.

 

[patracy]

Well the external injector test was successful at idle throttle. It started injecting in short order of me turning over the engine.

But I must admit, I've been having helpers with me operating the starter while I was testing various fuel system issues. I noted today that the oil pressure (fuel) is showing 5psi at ON not running. It will drop below that cranking. So I'm guessing I still have a supply issue causing the problems.

My next plan of action is the following:
Remove the in tank pump and replace the questionable hose.
Pull the primary filter, replace again.
Replace secondary filters as well again.
I will also probably dump the fuel if I see reason to from the filters.

 

[M920]

I'm really sorry to hear about all your trouble, I know how frustrating this can be! I'm not real familiar with your particular engine, but for whatever it's worth, here are a couple of probems that I have run in to in the past. All the things that you mentioned in your thread, (only runs at WOT, runs only for a few minutes when idled back down, and I know this sounds really weird, but despite starving for fuel, the engine can still smoke black!) are obviously pointing to starvation for fuel. Of course this can have all kinds of diffrent causes, but in most of my cases were I took half the engine apart and replaced a bunch of parts, chasing an "elusive mechanical problem" it ended up being the FUEL FILTERS or even worse: a secondary issue that I had caused, trying to find the original problem!
Maybe you can try to drain the tank and use straight diesel fuel or, if you don't want to do that, rig up a jerry can or a clean bucket with fresh diesel fuel, change all the filters again and see if you can't get it to run like that, before doing any "major surgery"......You can always add the WMO back later, when you got the engine running good again.

Whatever it turns out to be....I hope you get it fixed soon!

Soni

 

[Warthog]

I wonder if the intank fuel hose is collapsing. Just a thought.