Help needed. 2H sputtering getting worse (1 Viewer)

[Justcruzin]

Thanks for the suggestions guys. I will order a new Bosch pump today as the replacement I have is just a used OEM and, since my dual battery set-up is in my way to replace the primer pump and has to come out, I may as well do it only once if possible.

That's going to be the first step of my investigation. If it should prove unsuccesful, I'll try replacing the fuel filters.

What still bugs me is, if I have air leaking into the fuel supply system somewhere, why is it not acting up under load?

Thx.

M.

 

[lostmarbles]

Without having any return fuel line back to your tank (which is a feature of both your HJ47 and my BJ40 I believe), the key symptom of air leaking into the fuel supply would be "failure to start after a period of non-use" in my opinion. And you don't have that symptom to my knowledge, so, like yourself, I doubt a new primer will solve anything. (But if your primer leaks any diesel at any time ... ie. whether in use or not ... then you should be replacing it and doing so wouldn't be a waste of money. ...........And OEM-style primers are prone to leaking in use from my experience.)

Edit next day: I was thinking more about what I said above.. In fact what happens it that while your vehicle is just sitting unused, gravity very slowly drains the fuel from your fuel-pickup line and air replaces that fuel (entering through the pin-hole-type leak). So next morning (or whenever) when you try to restart, it actually does quite often start normally due to the uncontaminated fuel already in your IP. But after idling for a short time your engine then dies and won't restart at all unless you go through an air-bleeding operation. There is actually this delayed reaction because the slug of air in the fuel line stops your engine only once it reaches your IP..

So instead I think it is more likely to be a cylinder issue (ie. lack of compression on one or more cylinders) or an injector/injector-pump issue (assuming you haven't overlooked the obvious ....such as a leaking high-pressure line to an injector).

But I would replace the fuel filters before looking at those problems (and empty them out into a bowl to see if some fuel-outlet on your journey may have supplied you with fuel that's contaminated with water). I know you doubt water-contamination, but if just one fuel-outlet were to have supplied you with contaminated fuel, it may take a while for enough of that water (sloshing around in the bottom of your tank) to get picked up by your pickup tube and then fill your filters to the point where it gets into your injector pump.

It's unlikely to be a fuel-restriction (such as would be caused by debris blocking a strainer/filter) in my opinion because I believe that would first cause missing only when fuel demand is high (such as climbing a steep high with foot-to-the-floor).

 

[too tall]

try running a few feet of clear tube from filter directly to injector pump. leave a loop of hose poking out the side of the hood so you can watch for air bubbles as you drive. if air bubbles are visible, you have air in the system.
Then try running the hose from before the filter direct to the fuel pump to isolate whether the filter/primer assembly is the problem.

This is a good idea to eliminate air as a potential problem . I use a glass filter to watch for bubbles I do like the hose trick though .

 

[Justcruzin]

Hi.

My fuel filter system is not OEM. It uses 2 CAVCO type cartridge filters. The first one has a glass bowl and is fed from the water separator using the stock fule line. Fuel then goes thru the feed pump and then into the second filter (which has no glass bowl). Exiting the second filter, fuel then makes it way into the IP.

Looking at the first fuel filter when the problem occurs, I can see quite a lot of air bubbles in the glass bowl.

That pretty much rules out the primer pump as there's air in the fuel BEFORE it gets to the feed pump.

I'm now suspecting either a leak in the water separator (as you had, Tapage) or on the actual fuel line somewhere.

Problem is, we, as you know, are on the road (on our way to central/south america). We are currently staying at a campground in the San Diego area but the owners will not let me work on my truck here.

I have the tools and I can get the parts I need in the area, all I need really is a place where I can do the investigation and repairs. And the repairs really shouldn't be complicated as it will mostly be a question of replacing a fuel line/by-passing the water separator.

Anybody here in the San Diego - El Centro Ca corridor would have a place where I could park for a day or two and have a chance to address that problem?

Appreciate all the support. Thanks.

M.

 

[lostmarbles]

Do you find you're continually having to bleed air out (using the hand primer and bleed nipples) in order to restart your HJ47?

(Some people have had their fuel pickup tubes rust out enough to form pinhole leaks that suck in air ... but I'm still having trouble believing you have an air contamination problem when I've heard nothing from you about "engine-stalling and having to bleed out air before achieving a restart".)

 

[Justcruzin]

Do you find you're continually having to bleed air out (using the hand primer and bleed nipples) in order to restart your HJ47?

(Some people have had their fuel pickup tubes rust out enough to form pinhole leaks that suck in air ... but I'm still having trouble believing you have an air contamination problem when I've heard nothing from you about "engine-stalling and having to bleed out air before achieving a restart".)

Never had it stalled so far. Never had to bleed it either... Always fired right up after one turn of the engine. It was parked for one week last week and fired up after about 3 engine revolutions.

Only a bit after it has started will it begin sputtering...

As I mentionned, I can see air bubbles in the glass bowl of my first fuel filter which is before the feed pump...

My guess is that's not normal and probably the culprit. What i need to find now is where its coming from...

thx

 

[lostmarbles]

Never had it stalled so far. Never had to bleed it either... Always fired right up after one turn of the engine. It was parked for one week last week and fired up after about 3 engine revolutions.

Only a bit after it has started will it begin sputtering...

As I mentionned, I can see air bubbles in the glass bowl of my first fuel filter which is before the feed pump...

My guess is that's not normal and probably the culprit. What i need to find now is where its coming from...

thx

I suspect it is common for a little air to remain trapped in various high points in our fuel supply systems .... and that that air will only causes a problem if it moves on into the IP ... and even then, it will only cause problems if it moves there in significantly greater volume than "just a few tiny bubbles at a time"...

I guess the position of the glass bowl you're referring to (in your fuel supply system) will determine if it could just be showing you "trapped air that's undergoing some turbulence" or "continual entry of air contamination"..

 

[Justcruzin]

I suspect it is common for a little air to remain trapped in various high points in our fuel supply systems .... and that that air will only causes a problem if it moves on into the IP ... and even then, it will only cause problems if it moves there in significantly greater volume than "just a few tiny bubbles at a time"...

I guess the position of the glass bowl you're referring to (in your fuel supply system) will determine if it could just be showing you "trapped air that's undergoing some turbulence" or "continual entry of air contamination"..

That filter (with the glass bowl) is pretty much in the same location the OEM filter would be, up above the IP, so yes, i suppose the air in there could have been there for a while.

On the other hand, there is quite a bit in there so maybe a good idea to try to bleed it anyway.

This is getting confusing...

M.

 

[roscoFJ73]

Without having any return fuel line back to your tank (which is a feature of both your HJ47 and my BJ40 I believe), the key symptom of air leaking into the fuel supply would be "failure to start after a period of non-use" in my opinion. And you don't have that symptom to my knowledge, so, like yourself, I doubt a new primer will solve anything. (But if your primer leaks any diesel at any time ... ie. whether in use or not ... then you should be replacing it and doing so wouldn't be a waste of money. ...........And OEM-style primers are prone to leaking in use from my experience.)

Edit next day: I was thinking more about what I said above.. In fact what happens it that while your vehicle is just sitting unused, gravity very slowly drains the fuel from your fuel-pickup line and air replaces that fuel (entering through the pin-hole-type leak). So next morning (or whenever) when you try to restart, it actually does quite often start normally due to the uncontaminated fuel already in your IP. But after idling for a short time your engine then dies and won't restart at all unless you go through an air-bleeding operation. There is actually this delayed reaction because the slug of air in the fuel line stops your engine only once it reaches your IP..

So instead I think it is more likely to be a cylinder issue (ie. lack of compression on one or more cylinders) or an injector/injector-pump issue (assuming you haven't overlooked the obvious ....such as a leaking high-pressure line to an injector).

I 100% agree. Although my 1HZ in my 75 series ute would somehow drain the pump overnight until I found a bad fitting in the fuel line.
It would take a huge air leak to cause spluttering while you are driving.
Mis fires from bad compression usually go away once the engine has warmed up and the piston and ring have expanded.
I think the problem is most likely between pump and injectors

 

[Justcruzin]

I 100% agree. Although my 1HZ in my 75 series ute would somehow drain the pump overnight until I found a bad fitting in the fuel line.
It would take a huge air leak to cause spluttering while you are driving.
Mis fires from bad compression usually go away once the engine has warmed up and the piston and ring have expanded.
I think the problem is most likely between pump and injectors

I think and hope you are right. A good friend supplied a place for me to work on the truck at a friend of his places'. I have found a semi-loose fitting at the injector #1 fuel return to the IP. Also, the rubber hose that carries the fuel from that return point to the IP was not as tight as I thought should be normal so I replaced the OEM hose clips (spring type) with hose clamps. It's been 4 days since and no re-occurence so far, although it mostly only did it in the mornings.

Chances are we nailed it.

I'll let you guys know.

Muchas gracias to all who pitched in!

M.

 

[lowenbrau]

A crack on the scavenger line would cause similar symptoms. It could be diagnosed but removing the rubber line where it returns to the pump and diverting it to a catch can while plugging the inlet to the pump.

 

[Justcruzin]

A crack on the scavenger line would cause similar symptoms. It could be diagnosed but removing the rubber line where it returns to the pump and diverting it to a catch can while plugging the inlet to the pump.

That's the rubber hose I'm referring to. Thx.

M.

 

[roscoFJ73]

I replaced the OEM hose clips (spring type) with hose clamps. It's been 4 days since and no re-occurence so far, although it mostly only did it in the mornings.

Chances are we nailed it.

I'll let you guys know.

Muchas gracias to all who pitched in!

M.

The spring clamps are what I replaced to resolve the hard starting.

 

[markthemenace]

I have heard of a number of people suspecting their fuel-tank vacuum is causing them fuel delivery problems but I don't recall anyone ever fixing their problem by swapping to an "open-vented cap" (or by using other solutions for eliminating tank-vacuum).

(I suspect my fuel pump could maybe suck my tank so hard that atmospheric pressure would begin to crush it before fuel delivery would become an issue for me.)

Your tank should have some degree of vacuum inside for emission-control AFAIK.

Hi there, actually I was one of those having that problem and after I changed my fuel cap, the problem disappeared. Mine was intermittent too, and once in awhile, it could give sphincter-puckering moments when an "intermittent" happened as one was merging into a freeway!

I picked up a cheap cap at O'Reillys after that freeway incident and the "intermittency" never happened again!

 

[markthemenace]

I think and hope you are right. A good friend supplied a place for me to work on the truck at a friend of his places'. I have found a semi-loose fitting at the injector #1 fuel return to the IP. Also, the rubber hose that carries the fuel from that return point to the IP was not as tight as I thought should be normal so I replaced the OEM hose clips (spring type) with hose clamps. It's been 4 days since and no re-occurence so far, although it mostly only did it in the mornings.

Chances are we nailed it.

I'll let you guys know.

Muchas gracias to all who pitched in!

M.

Hope you nailed it. Anything semi-loose at the injector would probably cause your symptoms too. However, I'm curious about the bubbles at your water separator. In my other daily driver (Merc 300D) there're always bubbles in the little plastic prefilter that leads to the primer pump and IP. Never seemed to ever affect it.

 

[lostmarbles]

Hi there, actually I was one of those having that problem and after I changed my fuel cap, the problem disappeared. Mine was intermittent too, and once in awhile, it could give sphincter-puckering moments when an "intermittent" happened as one was merging into a freeway!

I picked up a cheap cap at O'Reillys after that freeway incident and the "intermittency" never happened again!

Is the O'Reilly cap a "free-venting" one?

If it is, I can't help wondering if the elimination of tank vaccuum is now hiding a weak joint somewhere in your fuel line.

I guess it is possible for the vacuum control mechanism in a valve cap to stick or otherwise maintain too much vacuum though.

 

[markthemenace]

Is the O'Reilly cap a "free-venting" one?

If it is, I can't help wondering if the elimination of tank vaccuum is now hiding a weak joint somewhere in your fuel line.

I guess it is possible for the vacuum control mechanism in a valve cap to stick or otherwise maintain too much vacuum though.

View attachment 999518

That is possible too. I have no idea if the new cap is a "free-venting" one. It is possible as they gave me one based on what a Landcruiser needs. But if there's a weak point,I would think it would've showed up by now. So far, touch wood, nothing odd has happened.

 

[Justcruzin]

Well, my problem hasn't re-appeared since I tightened up that fitting and hose. So I guess we can say it is solved. Thanks for all the suggestions and support. Much appreciated.

M.

 

[MoeGasim]

good to hear you got it nailed...remember to clean out the in tank filter...sock thing....caused major issues for me over here.

 

[Paraglider]

Do you find you're continually having to bleed air out (using the hand primer and bleed nipples) in order to restart your HJ47?

(Some people have had their fuel pickup tubes rust out enough to form pinhole leaks that suck in air ... but I'm still having trouble believing you have an air contamination problem when I've heard nothing from you about "engine-stalling and having to bleed out air before achieving a restart".)

Lost Marbles, I recently got an HJ47 and drove it to Southern California from Northern Cal. I had to stop about 5 times to bleed the air out of the line at the fuel filter. It varied in times it would last from 1.5 hrs. to almost 5 hours. I then had to be out of the country for almost 3 months (It had been sitting before I got it for about 7 months.). When I returned, it would start up and idle for a couple of minutes and then stop. After doing that for a few times, it stopped starting at all but would act as if it wanted to. I also checked the primary filter to see if water came out and it didn't, but I didn't bleed a lot of fuel. I assumed water would come out first because I think it's heavier than the fuel. I did the usual bleed the air and then also opened up the injector nuts and only fuel came out. I was not pumping the fuel, though, when I did that and so maybe didn't really test whether there was air in the injector pump. When fuel started to come out (kind of leaking around the nut area, I closed it. Maybe I should have left them open longer? The edic seems to be working when the engine's turning over. So I guess my questions are:
1. Should I be pumping the lift/fuel pump when opening up the nuts on the injectors (seems like you kind of need 3 hands)?
2. Should I leave open or open more the nuts to see if anything else escapes besides fuel? (I assumed that if there were air, it would come out right away, but maybe that's a bad assumption).
3. Do I need to bleed more fuel out of the primary filter (like up to a cup of fuel or something) to see if there's water in it?
4. Any other ideas on what's going on?
Thanks!