White smoke 1HZ - solved (1 Viewer)

[janyyc]

Good evening all

I’m completely stumped here.

On my HZJ76, which I’ve had basically since “new” (full story here: Ali, the 2008 HZJ76 - https://forum.ih8mud.com/threads/ali-the-2008-hzj76.1272844/), quite suddenly I’m experiencing severe smoking and hesitation. The engine has 16,000km on the odo.

No major maintenance was performed, no major “event” (eg overheating) occurred beforehand. Oil change a few weeks and approx 1K km ago.

What may be pertinent info:
1) refueled almost empty tank with 60L diesel a few days ago (but basically immediately before noticing the smoke today, hasn’t been driven in the interim)
2) replaced air filter and fuel filter after smoking started.

Tomorrow I’m planning on getting Liqui Moly and running it through but I have a hard time believing bad diesel could be SO bad.



The smell is not coolant-sweet, but diesel or oil - stinky and unpleasant for sure.

Any brilliant ideas to help me ease my pain in the meantime?

 

[4Ruster]

I'd say you have some air in your diesel.

 

[4Ruster]

It looks like she sat for a long time just quickly going through your write up. Rubber hoses and seals degrade quicker when they just sit, I'd say go through your entire fuel system and check for cracks.

 

[mudgudgeon]

The smell is not coolant-sweet, but diesel or oil - stinky and unpleasant for sure.

Almost a guaranteed sign you have air getting sucked into the fuel system.

Easily verified by running a piece of clear pvc hose from fuel filter assembly and the injection pump

Strong stink of diesel in the smoke is due to incomplete combustion of the fuel, which indicates its being inje¹qcted at the wrong timing, caused by air compressing in the injector lines which delays injection.

 

[janyyc]

Almost a guaranteed sign you have air getting sucked into the fuel system.

Easily verified by running a piece of clear pvc hose from fuel filter assembly and the injection pump

Strong stink of diesel in the smoke is due to incomplete combustion of the fuel, which indicates its being inje¹qcted at the wrong timing, caused by air compressing in the injector lines which delays injection.

Still at work, but starting off troubleshooting today by clear hose after fuel filter housing and then before - I have a sneaking suspicion the fuel filter housing may have failed. But in any case I will find the problem or rule out one possibility - hopefully the former. Thank you all for your help.

 

[mudgudgeon]

The rubber diaphragm in the fuel filter housing primer pump is a common failure point.

Poorly seated o-ring at the fuel filter is another common cause.

Can also be a leak around the end of a hard rubber hose that's no longer clamped tightly. Or a minor crack in a hose.
Fuel lines are under suction, they can leak air in without showing any visible fuel leak

 

[janyyc]

OK, clear fuel hose test done.

Clear hose between fuel filter and IP:



Then I installed a clear hose also leading into the fuel filter to clarify whether it was actually the fuel filter diaphragm causing the issue:

 

[janyyc]

So then I decided to bypass the fuel filter. Indeed, no air bubbles, but still a lot of smoke. Likely as a result of the air now in the injectors, probably have to bleed them after I get a new fuel filter primer. Am I thinking right?

 

[janyyc]

Also, here's a still of the fuel lines. Frothy!

 

[4Ruster]

I'd say it's a good time to replace that filter housing!

 

[janyyc]

I'd say it's a good time to replace that filter housing!

Oh it's in the cart at the moment

 

[mudgudgeon]

Air in the injector lines will clear itself while driving. Should only take a few minutes of driving.
If you buy fuel from a big metropolitan fuel station, I'd probably just bypass the filter while you wait for new one to arrive

 

[JDM Journeys]

Yeah agreed Jan. It takes almost no time. All those hours I wasted cracking injector lines last year were for nothing. Once there's no air getting in - the system purges itself in minutes.

I had all my injectors and lines off the other day and once there was enough to start and run it just basically hiccoughed once and then went down the road like no air had been in there...

Let me know when the parts come in, and you're back in in town and I'll make the trek south if you want, and give you a hand.

 

[veiloctane]

with that clear hose connected and if you manually prime when the engine is running are you getting more air showing in the line or is the air bubbles disappearing and going away?

 

[janyyc]

Arrived back home late last night. Today, after fulfilling some basic obligations, rushed out to change out the primer. Other than now having a shiny primer (yay) unfortunately there's no change. Back to diagnostics.

But at least it looks good...

 

[JDM Journeys]

Darned. Did you give it a good drive to try to purge the air? Filter is good and sealed? I hate doing stuff *thrice*. Although I usually do...

 

[janyyc]

Darned. Did you give it a good drive to try to purge the air? Filter is good and sealed? I hate doing stuff *thrice*. Although I usually do...

With today's snow and yucky conditions I didn't drive it but ran it long enough to get to operating temperature, including revving up many, many times. I can still smell the unburnt diesel, as can all my neighbours. Seems to be holding prime well now. But of course one can't directly compare old with new.

 

[janyyc]

Well, TL;DR version is - the problem is fixed, thanks to @gnarlynick2072 and his friend. Thank you, guys!

Together @JDM Journeys and @gnarlynick2072 we were already seeing the end of this 1HZ... what could it be? It must be a catastrophic failure...

All the while, Nick's calm and controlled friend simply diagnosed a misfiring injector and suggested we start by buying diesel injector cleaner and running it through, first 50/50 from a jar, and then about half the container into the fuel tank. And a smart decision this was, since it fixed all the problems. We went for a nice drive afterwards and there was no smoke, no stumble, no hesitation. Can I say - problem solved?

 

[mudgudgeon]

And a smart decision this was, since it fixed all the problems. We went for a nice drive afterwards and there was no smoke, no stumble, no hesitation. Can I say - problem solved?

Maybe? Or did all the air finally get out of the lines?

Either way, sounds like a result was had

 

[janyyc]

Maybe? Or did all the air finally get out of the lines?

Either way, sounds like a result was had

Nah, it stopped smoking despite us running it from a jar. I also tried yesterday with the fuel filter/primer from the HZJ78 (benefits of having two rigs side-by-side) and it was smoking like hell. I was going to go and start replacing fuel lines… glad I didn’t have to do that as emergency maintenance, and can relegate it back to the preventative pile for warmer temperatures.