1978 HJ45 Troubleshooting help needed (11 Viewers)

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I fired it up today and took the oil cap off. No pressure coming out at all. Waiting for my head gasket leak detector and will check that next. If I post glow at idle, it idles really smooth. Once I let off the glow, lumpy and low idle again.
 
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Not sure about that motor specifically, but it isn’t uncommon for glow plugs to run at half voltage for a while after the engine starts until it reaches a specific temperature.

Maybe the thermostat is stuck open meaning the engine isn’t getting hot enough for decent combustion?
 
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For what its worth.. this is a 2H I was working on last weekend.. lumpy idle, having the manifold off lets you really see whats going on.

After it got nice and hot and was run up to 3000rpm a few times briefly it cleared up. I'm guessing the exhaust valve that was left in the open position for a couple of years had some light surface rust on the seat that took a while to clean up. The engine is running nicely now.

 
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I let it idle about 2 mins and then shut it down since it was smoking pretty good. I live in the forest and did not want my neighbors thinking there was a fire. I put a brand new thermostat in it just recently as well when I changed the radiator hoses. Mine is fully manual glow now so full voltage to glow plugs when button pressed at all times.

I had the radiator cap off during my test yesterday and did not see any bubbles this time; strange. Duncan, I plan on trying the exhaust manifold off test after I do the leak test in coolant. Will shoot some video and post then so you all can hear/see what I am dealing with.

Please keep the ideas coming!
 

RufusTheDufus

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I had the radiator cap off during my test yesterday and did not see any bubbles this time; strange. Duncan, I plan on trying the exhaust manifold off test after I do the leak test in coolant. Will shoot some video and post then so you all can hear/see what I am dealing with.

That's similar to my experience. No leaks at idle. Take it out and run it down the roadat 65MPH for 30 mins and it would start blowing coolant out the overflow.

Have you tried to re-torque your head bolts? They can be a bit finicky if the holes in the block aren't chased clean with a tap and the bolts properly lubed. I was surprised how much variance there can be after running the engine for a bit.
 
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I will try re-torqueing them today. I was also wondering about that, easy enough to try. You have to remove the rocker assy first correct?
 
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OK, went out and re-torqued the head bolts to 103ft/lbs in the order the manual shows. They were all right on but 2 towards the middle that took about 1 turn to reach full torque each. Going to fire it up to see if any difference but not confident there will be. Will bleed the fuel system *again* just to make sure. Ugh
 
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As suspected, it still runs the same. I bled the fuel system until fuel was pouring out of the filter, inj pump and injectors. I did have a productive day though and replaced the axle bump stops and all motor/trans mounts. One was broken badly.

I guess I will just wait for the head gasket leak detect kit and try that next. Likely will pull the head after that.
 
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Duncan, I hope it does show a leak. Then I would at least know where to focus. Will try a warm engine compression test next. I would hope the Hi-Tech injector folks out of Australia I used set the Pop pressure correctly. I will see if any local shops can pop test them. If not a head leak issue it has to be fuel.
 
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I found a local shop that can Pop test the injectors and test the injection pump if needed. Will pull the rebuilt injectors and have tested next week.
 
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OK, big progress today! I did a Diesel Purge using the Liqui Moly brand. Unhooked the fuel feed line from the tank and dropped it into the Diesel Purge can. In about 2 mins my idle cleared up nicely, about 10mins in no smoke at idle and rev'd real smooth with a bit of black smoke at WOT. After the entire can went through even smoke at WOT was just barely there. My injection pump must have been gunked up. I am going to run a couple more cans of this stuff through it so that it gets really clean. I've never believed much in "magic in a can" but this stuff worked amazingly well!

I think I figured out the bubbles in the coolant also. I had just installed the toyota heater valve and plumbed in the coolant hoses the first time when I saw the bubbles appear. Since that original start the bubble have never returned in the radiator. There must have been air pockets or something purging through the water pump.

I took it for a spin for about 30 mins and it ran great. I got 3 thumbs up by fellow motorist and walkers :) I also spent some time and got my clutch adjusted today.

diesel purge.jpg
 
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Hmm, wondering if it’s worth putting some through my 12ht and 1hdt as a bit of a “preventative maintenance”. Glad to hear things are improving so cheaply 👍
 
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When injector pumps gunk up, where typically does this occur within the pump? I would think the delivery valves. Can you unscrew the delivery valves and clean them while the pump is still on the motor? Do they take special gaskets or seats like the injectors do and are they serviceable like the injectors are?
 
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When injector pumps gunk up, where typically does this occur within the pump? I


I've seen the fuel rack freeze up on 2H pumps that are left sitting for years.. and because of the design of the pump they gunk up in the max fuel position. The actual mechanism of what stops the fuel rail moving is not clear to me.

Here's a video of a stuck fuel rail that I made a few years ago.. a few taps with a light hammer freed it and working it back and forth with some fresh fuel in the pump fixed everything.. I wonder if this was your problem?

 
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Can you unscrew the delivery valves and clean them while the pump is still on the motor? Do they take special gaskets or seats like the injectors do and are they serviceable like the injectors are?

Here's a small guide I wrote on how to change the Delivery Valve Gaskets.. there's no reason to open your pump at the moment, there's more risk of introducing problems than solving any remaining problem at the moment I think. This is on a 2H pump, the H pump is pretty much identical though.

 
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Great info Duncan. Thank you for posting that. I will leave my pump alone for now. I did notice the #1 injector had some compression blowby at the base of the injector. My new seats must not have sealed all the way. Will have to pull it and install a new seat.

Has anyone had better luck using the newer injector seats that look like a smashed donut vs the convex original ones? The new ones look like they crush on both sides vs just the convex side on the originals.
 
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Has anyone had better luck using the newer injector seats that look like a smashed donut vs the convex original ones? The new ones look like they crush on both sides vs just the convex side on the originals.

I have not seen that new design.. I picked up a set of seats a few weeks ago for a 2H and was supplied with the usual design by a respected diesel shop. I'll ask around about the new ones. I dont suppose you have any part numbers?
 

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