"The great 1HZ Smoke show": (losing fuel pressure overnight?) (1 Viewer)

[JDM Journeys]

I've been chasing down cold start/white smoke for quite a while, which some of you may be tired of hearing about. I recently had my injection pump rebuilt, but the problem persists. I am in the process of fitting a clear hose on the line right before the injection pump to look for air but I happened to pump up my primer and thought I heard a very high pitched sound coming from the area of the pump. This is of course before I started it up and it pressured up. Is this normal, or is this a possible source of leak?

If one of you fine folks is near your 1hz, would you mind pumping up your primer and seeing if you get the same high-pitched sound from the area of your injection pump? This is obviously not while running, and I'm surprised my ears can still hear such a high-pitched sound, but that's kind of what you're looking for. It only lasts for about 5 seconds or so.

If someone can do this and report back then I owe you a future beer.

EDIT: Title change as this moves forward, and thanks to @Rigster for pumping his primer and reporting back to me that his wasn't hissing...

 

[coldtaco]

Don’t have a HZ but that sounds rather suspect

 

[bj70bc]

seal on the primer?
air bleed valve on the pump not tight?
copper crush washers on banjos?

 

[JDM Journeys]

seal on the primer?
air bleed valve on the pump not tight?
copper crush washers on banjos?

Primer is new. And the sound is from the injection pump (opposite) side. All new copper washers on the banjos.

Just had my wife listen while I pumped the primer again (younger ears ). We may have it narrowed down to that short little length of hose that goes from the pump manfold to the injector rail return... Swapped clamps but no change and I don't have any new hose that small on hand.

But yeah @coldtaco it does seem suspect eh? I just wonder if it's enough to affect a cold start...if it is in fact a leak and not some factory pressure relief valve thingy...?

 

[coldtaco]

Primer is new. And the sound is from the injection pump (opposite) side. All new copper washers on the banjos.

Just had my wife listen while I pumped the primer again (younger ears ). We may have it narrowed down to that short little length of hose that goes from the pump manfold to the injector rail return... Swapped clamps but no change and I don't have any new hose that small on hand.

But yeah @coldtaco it does seem suspect eh? I just wonder if it's enough to affect a cold start...if it is in fact a leak and not some factory pressure relief valve thingy...?

Hadn't thought of there being some kind of a factory pressure relief valve. Might need to look through a manual if you have one

 

[Squash]

If she runs purty when warm then most likely you are overthinking the cold start.
Now if your cold start is in the -double digits then you can expect smoke because the combustion chambers are cold and therefore things will shake, clang and sputter before smoothing out as the engine warms up.
We run a fleet of 1hz powered HZJ79's and during -30C everyone of those engines will complain and smoke until warmed up.
The primer should only require a couple pumps before it gets quite stiff.
Again: If it fires up beautifully when warm then don't worry to much. Now just be certain all six glowplugs are working.

 

[janyyc]

@Squash it's not a "cold" start as in AB cold but engine cold (i.e. not at operating temperature).

 

[Rigster]

Gosh Phil... I am at a bit of a loss here as well. I have not seen this before after all the work you have done.

Just a thought, but have you reached out to the experts that rebuilt your pump to see what they have to say? They may want you to bring ol'betsy to the shop to troubleshoot, but maybe there will be some goodwill you can leverage since they just rebuilt the pump for you. In hindsight thankfully you sent the pump to an hour away as opposed to sending it to the shuswap (about an hour from me).

I will continue to think on this and message you if I have an epiphany (hey, I realize it is rare, but it does happen, in fact I take a day off work on the anniversary when it happened once before)

In all seriousness though, keep your stick-to-itiveness and it will pay off. Sorry you are having such frustration with this.

 

[JDM Journeys]

I THINK the high pitched sound is my fuel pressure bleeding off? Here's what I've done today:

-put a clear line on the last line from the filter before the injection pump.
-replaced the short line to the injector rail, and the hissing sound under pressure went away.

But I couldn't pump enough fuel to fill the clear line I guess, since the pump would need to be rotating? So of course when I started it up, it smoked horribly, and had a slight miss, until I added a few more pumps with the primer, then the line filled with fuel, the smoke cleared and everything smoothed out. A few more large bubbles went through and then it was all fuel, and no more smoke.

So... am I safe to assume that that line should stay full of fuel all the time, even when shut off?

If that's true, then my theory is that the leaky overflow line (that short little one to the rail) slowly bleeds off pressure when shut down, and then the main feed half fills with air. The next cold start then needs to clear all the air out (and thus a smoke show) before it can run properly again.

Shoot this full of holes please. Or don't. I can neither confirm nor deny until later in the day, or tomorrow, once everything has cooled...

 

[JDM Journeys]

If she runs purty when warm then most likely you are overthinking the cold start.
Now if your cold start is in the -double digits then you can expect smoke because the combustion chambers are cold and therefore things will shake, clang and sputter before smoothing out as the engine warms up.
We run a fleet of 1hz powered HZJ79's and during -30C everyone of those engines will complain and smoke until warmed up.
The primer should only require a couple pumps before it gets quite stiff.
Again: If it fires up beautifully when warm then don't worry to much. Now just be certain all six glowplugs are working.

I don't think there's ANY doubt that I'm overthinking it.

But I'm not talking about a -30c start. This is a 10*c start. And there's more than normal smoke. Possibly I'm getting to the bottom of it, RE: my post above this one.

 

[Felde]

I THINK the high pitched sound is my fuel pressure bleeding off? Here's what I've done today:

-put a clear line on the last line from the filter before the injection pump.
-replaced the short line to the injector rail, and the hissing sound stopped after 5 pumping the primer stopped hissing.

But I couldn't pump enough fuel to fill the clear line I guess, since the pump would need to be rotating? So of course when I started it up, it smoked horribly, and had a slight miss, until I added a few more pumps with the primer, then the line filled with fuel, the smoke cleared and everything smoothed out. A few more large bubbles went through and then it was all fuel, and no more smoke.

So... am I safe to assume that that line should stay full of fuel all the time, even when shut off?

If that's true, then my theory is that the leaky overflow line (that short little one to the rail) slowly bleeds off pressure when shut down, and then the main feed half fills with air. The next cold start then needs to clear all the air out (and thus a smoke show) before it can run properly again.

Shoot this full of holes please. Or don't. I can neither confirm nor deny until later in the day, or tomorrow, once everything has cooled...

Hi
After all your rebuilds done, I doubt it is any of those rebuild pieces.
Yes, the hose should stay full of fuel. And yes, if the overflow line is somewhat leaking, your theory may come true and this might be the culprit.
Other than that I can only think of a) stupid little things, like a leaky bleeding plug on the fuel filter, priming pump, a cracked hose or something, or b) pure fine tuning (came to my mind when you said tweeking the amount of fuel a bit made a difference).
Keep up the spirit! You do a good job and improvement is visible!
Good luck Ralf

 

[Rigster]

I THINK the high pitched sound is my fuel pressure bleeding off? Here's what I've done today:

-put a clear line on the last line from the filter before the injection pump.
-replaced the short line to the injector rail, and the hissing sound under pressure went away.

But I couldn't pump enough fuel to fill the clear line I guess, since the pump would need to be rotating? So of course when I started it up, it smoked horribly, and had a slight miss, until I added a few more pumps with the primer, then the line filled with fuel, the smoke cleared and everything smoothed out. A few more large bubbles went through and then it was all fuel, and no more smoke.
View attachment 3289124
So... am I safe to assume that that line should stay full of fuel all the time, even when shut off?

If that's true, then my theory is that the leaky overflow line (that short little one to the rail) slowly bleeds off pressure when shut down, and then the main feed half fills with air. The next cold start then needs to clear all the air out (and thus a smoke show) before it can run properly again.

Shoot this full of holes please. Or don't. I can neither confirm nor deny until later in the day, or tomorrow, once everything has cooled...

Your stepping through it logically, and that is the best you can do. Rule out the little things one by one... and definitely check that clear hose again after it sits overnight. If it is still full of fuel, before AND after you start it up, then that is one more thing ruled out. IF it is full of fuel on check prior to start, but has air after the startup, then I would move that clear hose to the supply line before the filter and do the same test to make sure no air is getting into the system betwixt the filter and the tank.

Hang in there bud, you will succeed!

 

[Squash]

I THINK the high pitched sound is my fuel pressure bleeding off? Here's what I've done today:

-put a clear line on the last line from the filter before the injection pump.
-replaced the short line to the injector rail, and the hissing sound under pressure went away.

But I couldn't pump enough fuel to fill the clear line I guess, since the pump would need to be rotating? So of course when I started it up, it smoked horribly, and had a slight miss, until I added a few more pumps with the primer, then the line filled with fuel, the smoke cleared and everything smoothed out. A few more large bubbles went through and then it was all fuel, and no more smoke.
View attachment 3289124
So... am I safe to assume that that line should stay full of fuel all the time, even when shut off?

If that's true, then my theory is that the leaky overflow line (that short little one to the rail) slowly bleeds off pressure when shut down, and then the main feed half fills with air. The next cold start then needs to clear all the air out (and thus a smoke show) before it can run properly again.

Shoot this full of holes please. Or don't. I can neither confirm nor deny until later in the day, or tomorrow, once everything has cooled...

You are correct in thinking that the primer should stay firm and/or get firm with a couple of pumps at most.
We run tons of Toyota's in our underground mines as well as other diesel engines. If ever I go to a suspect unit the first thing I do is prime the fuel before attempting a start.
On a side note I've disconnected the glowplug temperature sensor on my BJ74 just because I find it doesn't glow during mediocre temperates. My HDJ81 and 1hz have no glow plug issues.

 

[JDM Journeys]

Appreciate all the input. I believe I'm getting closer, and as with all difficult to solve problems, there's usually more than one cause.

-I replaced the short line to the fuel rail with a proper sized 4mm line, and good clamps.
-still got a smoky start, but it only lasted about 10 seconds, and then dissipated.
-Bench tested the glowplugs directly off the battery (above 24 volts )and noticed they didn't reach max glow until about 8 seconds, whereas in normal use my glow light goes off after about 4 seconds.
-yet.... only saw 22v off the busbar when testing the system in place!?!

After what @Squash said above, I got to wondering if my system was a little cooler after 32 years, despite the new plugs, and resistor? So for the last two cold starts, I tried a double glow and then waited 4 seconds more after the the light turned off before cranking. Lo and behold: This afternoon, after sitting all day at work and reaching a high of -1*C, I saw almost ZERO smoke, no stumbling, no hesitation!

So lower fuel pressure, air in the line, and a cooler glow seem to have conspired to turn the 1hz into a smoke machine. I did notice another bubble in the clear line this evening before I started it up. Not sure if this is an artifact of cooling temperatures over the day, or if I should be looking for more air leaks, but it didn't have an effect on my start, and there were no "bubbles" as such, once it was running... I think I'm going to keep the clear line in place for a while longer. Its food grade, so at least she'll be drinking through her straw safely.

If you look closely you can see the bubble...

I'm also going to give all the grounds and connections in the glow system a good hard look, as well as the water temp connection. Might have to consider disconnecting the water temp sensor, at least until temps come up to a consistent "fit for human habitation" level. Maybe I'll put a switch inline and label it "winter mode"? I assume with the temp sensor disco'ed, that the glow system will light for the maximum time every time?

Thanks again fellas. Troubleshooting is a lot easier when there are folks looking over your virtual shoulder. Cheers!

 

[African]

frustrating

Cold temps and condensation I feel we would have come across if what your seeing was the norm

Do you have a video of the amount of smoke ?

I live in gunnison Colorado and most of the winter it’s well below zero.
(I cringe to start an old diesel in those temps)
On my 1HZ if really I will glow x2 as you mentioned above, turn the key let the the glow light run, once the light goes off wait 5 seconds. Repeat and on the second cycle fire it up …Very little white smoke.

I’d leave the clear line in for a while until you feel you have it figured out.
Your prob not far from having clear lines everywhere if you don’t get it narrowed down.

As to what is normal on the good sized air bubble your seeing in there honestly we don’t know as there is no way to ever see it. So it’s hard to say if that air bubble should be there or not.

How would you check if air was getting in between the pump and injectors?

I’m assuming like here humidity is low.
Is there a way water could be causing it from something other then condensation?

 

[Rigster]

Nice work bud!

Just a note, so you do not feel your 1HZ glow system needs anything. I also wait 3-4 seconds after the glow light goes out before I start. Same thing, I don't get any white smoke that way.

This is pretty common for the individual glow plug style preheat. Hopefully this is the end of your woes, and from here on it is clear sailing....err... cruising!!

 

[JDM Journeys]

frustrating

Cold temps and condensation I feel we would have come across if what your seeing was the norm

Do you have a video of the amount of smoke ?

I live in gunnison Colorado and most of the winter it’s well below zero.
(I cringe to start an old diesel in those temps)
On my 1HZ if really I will glow x2 as you mentioned above, turn the key let the the glow light run, once the light goes off wait 5 seconds. Repeat and on the second cycle fire it up …Very little white smoke.

I’d leave the clear line in for a while until you feel you have it figured out.
Your prob not far from having clear lines everywhere if you don’t get it narrowed down.

As to what is normal on the good sized air bubble your seeing in there honestly we don’t know as there is no way to ever see it. So it’s hard to say if that air bubble should be there or not.

How would you check if air was getting in between the pump and injectors?

I’m assuming like here humidity is low.
Is there a way water could be causing it from something other then condensation?

For sure low humidity here too. I think I'm pretty much there in terms of cold starts now. Yesterday when I reached the first red light, everyone around me was producing more condensation than I was. Well, except for the Tesla.

Maybe they should've put in clear lines from the factory eh?

My valves are still on the list, since they haven't been done and the intakes are on the tight side. And I'm still tweaking fuel a Lilliputian turn (down) at a time. Egts are getting very manageable now. If I can keep the smoke down I might try to retard the timing ever so slightly back toward stock too. But one thing at a time so I know what effect each adjustment has.

Gradual results are still results, right?

 

[ATL Cruiser]

I second @African's double glow technique. Or even triple glow. I used to do that on my TDI when I lived in Iowa. It made cold starts a breeze. This would eliminate any chance that it's a "cold engine" causing your misfires. I don't think it's this, but it would certainly eliminate that possibility.

The fuel pressure should not drop AT ALL on cutoff. If you come start my truck, I barely bump the key, and it starts in like a microsecond with no smoke whatsoever.

I know I've said this already, but in order to find your air leak, you need to smoke test the system. We do this every day here at the shop on evap lines. It's the same concept on a fuel line. You just need to drain the system to the tank, cap off the line at the tank, and run smoke through the entire system. I bet you'll find that leak in 10min.

 

[Felde]

That bubble is quite big. It might be an artifact though. Keep the clear line in place and monitor. Now you know: If any air, it will surface there.
10sec of smoke might just be normal.
Don't forget to drive abd enjoy your rig!
Cheers Ralf

 

[JDM Journeys]

It seems like the bubble goes through on the next startup but then forms another if parked long enough. And probably it's small bubbles that join together at the top of that clear line, which is the highest point for fuel after the filter.

So today I replaced the next short section of rubber hose, back near the rear leaf front mount. Then I started it up and revved it some until I worked the bubbles I had introduced, through the line. Weirdly satisfying to watch the air come through. Once it seemed all the air was gone I shut it off again. Now I'll wait for it to cool down again and see if I get any more. The old line was pretty hard and decrepit looking. But of course there's another old rubber one left on the feed side, and it's back next to the tank. Not really looking forward to it. Diesel up my sleeve is losing its luster.