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

[m-35tom]

I would be somewhat surprised if one load of bad fuel would take out the HH that fast. Did you check the screen on the lift pump?

running out of fuel is EXTREMLY hard on the HH and can take one from working ok to dead in just a few seconds. at 2000 rpm the plunger is stroking 6000 times a minute and no fuel = no lube.

 

[glcaines]

When I have confusing difficulties like you are having, I always start at the beginning. I would drain and clean the fuel tank and discard the fuel or save it for later filterning. Add Fresh diesel, no WMO. I would then replace the in-tank hose. I would remove the primary and secondaryfilters and let the fresh diesel flush out the short line to the primary. Replace the primary filter with a new filter and then flush out the next section of lines. Put in new secondary filters. Bleed air out of the system and see if it runs ok. You will have elimated everything except the IP. Even if this wasn't the cause, it is still good PM to clean and flush out the system periodically. Good luck, I know you are frustrated.

 

[patracy]

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

I doubt that hose could be collapsing now since it's under pressure. Previously I had an external pump drawing fuel through the hose under suction. Now the same hose (that I noted was a little swollen/loose during install) is under pressure and has two, not one points to leak at.

running out of fuel is EXTREMLY hard on the HH and can take one from working ok to dead in just a few seconds. at 2000 rpm the plunger is stroking 6000 times a minute and no fuel = no lube.

I would cut out when I drove it home at high throttle. However I thought that was more attributed to the fact the hose I used was collapsed on the fuel pump inlet side. I don't believe I got over 35-40mph on the drive home. I know I kept it under 2300rpm at least.

When I have confusing difficulties like you are having, I always start at the beginning. I would drain and clean the fuel tank and discard the fuel or save it for later filterning. Add Fresh diesel, no WMO. I would then replace the in-tank hose. I would remove the primary and secondaryfilters and let the fresh diesel flush out the short line to the primary. Replace the primary filter with a new filter and then flush out the next section of lines. Put in new secondary filters. Bleed air out of the system and see if it runs ok. You will have elimated everything except the IP. Even if this wasn't the cause, it is still good PM to clean and flush out the system periodically. Good luck, I know you are frustrated.

I've already dumped the WMO that was in the tank and filled it with 18 gallons of diesel fuel. I should get a better understanding of the primary fuel system tomorrow when I pull the pump to replace the hose. (Picked up some hose tonight that won't swell like the old stock hose). I'm not frustrated. Sad, yes. But far from frustrated.

 

[m-35tom]

if you have good fuel pressure at the final filter that is all ok. you can flush the HH plunger by removing the center plug, turning engine so plunger is at lowest point, remove fuel supply line to HH, set throttle to max, and use clean air and fuel to push fuel and air down the plunger. this will dislodge any debris that may have blocked the plunger inlet. it may also show if any 'stuff' comes out the in port of the HH.

 

[patracy]

Just another update.

Pulled the in tank pump. I noticed not only were both ends of the in tank hose swollen. (The end closer to the pump was loose, the end near the tank plate was snug) Also I noticed the barb on the pump itself wobbled and was loose. It's not optimal, but I'm trying to epoxy it back into place so it can't move/leak.

I also used the air gun to loosely blow air into the supply line. I was able to see pressure on the test gauge as well. Fuel also flowed back to the tank via the return line. So I don't believe there's restriction in the fuel system. But given the lack of constant pressure when cranking, I'm wondering if the hose/fitting on the liftpump is an issue.

The lift pump I've installed is also a little different from the original one. There are two check balls on it. One is spring loaded, this one appears to be a bypass if the screen gets clogged. (Wasn't clogged BTW) The other is on the output side of the pump. It is not spring loaded. It appears that if the feed is blocked, it will allow the check ball to "float" enough to allow the fuel to bypass.

 

[patracy]

Reinstalled the lift pump. Replaced the hoses. Added 10 more gallons of diesel fuel. Fuel pressure is over 5psi now cranking. Stays up there as well. Pulled the center HH plug, great fuel flow there.

Couldn't get it to start at all. No smoke from the exhaust. A whiff of starting fluid and WOT it fired right up. Idled great. Fuel pressure was at 30-35psi. Revved ok as well. Gave it WOT, stumbled, shut off. Would not restart. 5-7psi cranking.

Got my son to jump back in and hit the start button while I whiffed it again. It stumbled for a bit, finally cleared up with a lot of whiffing. I didn't touch it. Idled at 800rpm. No wandering or stumbling. 30-35psi of fuel pressure. It idled no problem for 5 minutes. I stayed around it this time. I heard a ever so slight stumble. Then 2-3 seconds later it shut completely off like as though someone pulled the engine stop.

I've given up for the day.

I'm baffled at this point. I've chased so many things, I'm not sure what to try next. The fact that it will idle and rev great at times makes me think the HH functions correctly. As well as the booster pump. But the fact that it acts at start up like there's no fuel, and if I WOT it, it will stumble and die, makes me think it's the governer. The cutoff linkage moves completely free. It's at the 7 O'clock position. I haven't pulled it out of the pump yet though. But I know the cutoff is just like the ambac IP I dealt with on my generator. If it moves, it should function. Unless that little wedge is broken maybe? But that still wouldn't account for the perfect idle/running at times.

I could try swapping fuel filters again, but seeing the flow and pressures I'm getting I don't think that's the issue. I could try replacing all the nylon tubing as well. But after that, the only thing I could try is replacing the HH?

 

[bill2444]

Does the fuel return to tank with just the in tank pump running? I have had problems with 100% wvo in cold temps not fully purging the system and causing the fuel not to freely return to the tank. Causing a "like over fuel for low rpm condition" which would run only at higher rpm freely and would stall when I would release the accelerator. It has happened to me twice and both times after getting fuel flowing freeley it cleared up. Why this happens I don't know. But when on straight diesel mine will push fuel thru the system back into the tank with the in tank pump. And once I have had this happen but for a totally different reason, Exact same symptoms and running condition. The problem was air, the fitting for the fuel line at the HH. The brass piece that slides over the hose had started to cut into the hose causing a suction leak that did not leak under pressure. It was a few days of pulling my hair out untill I found that.

 

[doghead]

It idled no problem for 5 minutes. I stayed around it this time. I heard a ever so slight stumble. Then 2-3 seconds later it shut completely off like as though someone pulled the engine stop.

This sounds like one of mine. I changed the HH and it solved my problem. This was after I used a couple gallons of WVO and that broke loose a fine black(soot like) in my fuel system. This caused filter plugging and fuel starvation. I went through 5 sets of filters( before giving up and doing a complete fuel system flush and HH replacement.

Never had a problem since.

 

[patracy]

I'm also starting to lean more towards HH issues. I'm also speculating that while I did see the injector fire externally of the engine. It's much easier to pop off without having to also overcome the cyl pressures. I also think it feeds back into what you mentioned earlier Eric. The 100% WMO was a much thicker viscosity, that's why it sorta ran the way back home. But thinking it though. I couldn't go WOT. It would also cut out and die then as well. I had attributed that to the makeshift lift pump I used having a kinked hose on the inlet side. But what are the odds of the same result (when I get it running) happening as well at WOT?

I'm just going to stop tinkering at this point and try to source a HH to swap onto it. The HH that is on the pump is certainly timed correctly and I'm sure the quill shaft is good with it running intermittently. Prior to me bandaiding it back home, I did end up with a "dead peddle" going downhill to my friends shop for at least a quarter of a mile. I probably should have dropped it into neutral and tried to coast in, but I was afraid I wouldn't make the turn into his shop if I didn't keep my foot in it.

I'm still going to say that I doubt the WMO was the sole factor in this failure. It might have played a part. But I'm more inclined to blame my stupidity.

 

[gringeltaube]

This sure is getting interesting - a good learning experience, at least! ... and probably having many of us scratch our bald spots at this point, too...!
Swapping HH's may solve your problem, but then we will never know what exactly caused that intermittent failure...

100%, its NOT the external fuel supply to the HH; so I'm trying to think of what does- or can- shift/disengage/change by itself inside the HH, to suddenly stop injecting, after the engine perfectly idled for 5 minutes. ... and then not allowing it to re-start normally...?

(I need to play a bit more with an old HH, tomorrow......)


G.

 

[patracy]

That's why I'm documenting all the steps I've taken and the events.

Furthermore I failed to mention, the truck has never started without starting fluid and WOT since I ran it out of fuel. I'm kinda inclined to think that the starvation of me rolling it for 1/4 mile at 2500rpm probably did the HH in. The fact it would bog at WOT on the limp home corresponds with the dying at WOT now.

The drive home, it cut out on me a few times, but I kept on pushing it. If I kept it under WOT it would limp along. I'm thinking perhaps the plunger wore enough that it's no longer fuel tight (especially on straight diesel now), but maintained idle on 100% WMO.

 

[Flyingvan911]

Thanks for the details on the HH when the fuel runs dry. I had a clogged primary a while back and limped along quite a ways. I had better watch out for mine.

 

[Warthog]

Just another update.

Pulled the in tank pump. I noticed not only were both ends of the in tank hose swollen. (The end closer to the pump was loose, the end near the tank plate was snug) Also I noticed the barb on the pump itself wobbled and was loose. It's not optimal, but I'm trying to epoxy it back into place so it can't move/leak.

Did you replace the intank hose? Did you remove it an look thru it?

I have seen hoses that will delaminate inside and part of the hose will block the passage.

Do you have a spare intake pump you can test with?

 

[patracy]

Did you replace the intank hose? Did you remove it an look thru it?

I have seen hoses that will delaminate inside and part of the hose will block the passage.

Do you have a spare intake pump you can test with?

Post 46.

Hose replaced, inside was fine, just the ends had swollen. This is a new lift pump, provides 5-7psi as it should.

 

[Warthog]

Missed that. Thanks.

 

[m-35tom]

my money is on the HH plunger sticking. this would account for almost 100% of your problems. the fuel system is so simple that many people over think it. if you have fuel pressure in the final filter relative to the rpm and it still stalls, it has to be the HH. also remember a worn HH will not start at cranking speed but will start on starting fluid and MAY run as low as 800 rpm but usually only run over 1000.

 

[patracy]

I'm also of the same mindset now Tom. I really feel as though my HH is dead from the starvation. The fact it will not start without fluid directs me towards that. Noting that there's no smoke when cranking means I'm not getting fuel during start up. I know I will get injectors to pop off outside the engine at idle. But honestly it's a lot easier for the HH to pop off an injector that's not subject to 300-350psi cyl compression pressure on the nozzle side. Honestly once I got it to run, and it settled down, I didn't try to idle it above 1K rpm. Perhaps the engine dying at WOT is due to the HH starving again due to wear/clearances.

Regardless, I think all the testing I've done certainly points to a failed HH. Now to find a replacement.

 

[rrrr]

Keep us posted. Good lesson in trouble shooting a fueling issue. I know I won't let my deuce get low or run out of fuel again. Because of this thread I've thought about using the best additive for the low sulphur fuels we now have. Jatonka's web page has a great article on this I will be using an additive to help prevent IP wear.

 

[patracy]

Well I used half my lunch break to pull the HH. (Thankfully my kids are off today, I enlisted the help of my oldest to watch the gear on the HH while I turned the engine over) Got everything apart pretty easily. (FWIW, just lining up the pump is 50% of the work!) I'm really starting to question the HH now. While the plunger isn't stuck and doesn't stick, it's very very easy to cycle up and down. I didn't tear apart the HH yet (I probably will for a postmortem after I replace the HH). I'm pretty certain that it's clearanced itself too much from starvation. There also was some gunk in the outlet ports of the HH as well, but I'm honestly not certain if it's from the fuel or the fact that the lines had two years worth of rally mud on them . I recall them feeling a little gritty when I unscrewed them. The fuel feeds up through the base, there wasn't anything crummy lodged in any of the corners down there.

 

[m-35tom]

testing the HH is very easy, remove the two keepers so you can pull the plunger out. hold the plunger in your fist for 5 to 10 seconds. if it will go back in it is bad. yes it fits that closely. also if the surface of the plunger has elongated swirl marks that indicates excessive wear, it should be bright with no visable blemishes.