1991 HDJ81 new to me, recommended maintenance, not revving past 1.5k (1 Viewer)

[stvrn6]

I just purchased a wrecked imported HDJ81 with only 108k miles. Initially was planning to keep the engine and part out the rest but I have chosen to repair the damage and keep it. I was told the BEBs, timing belt, water pump, spring and tensioner were done about 25k miles ago but that was about 9 years ago so ill be doing the belt soon. Would I be okay to just do the belt or should I do the water pump and tensioner as well? What other recommended preventive maintenance should I do?
I'm also having some issues with the truck not revving up past 1.5k at 25 mph. Truck sat for about a year so we decided to drain the tank and replace the fuel filter. After that the truck started right up but would shut off, still had air in the lines. I bleed the lines and now it wont shut off but now I have the limited revs issue.
I should mention I have no experience with diesel at all but I'm good with wrenching so I'm sure I can figure things out but I don't really know where to start here. Thank you in advance.

 

[Eurasiaoverland]

Taking off the oil filler can be misleading as the turbo will scavenge crankcase gases, pulling the ventilation hose from the valve cover is more reliable. There will always be some crankcase gases, but if it shoots out whitish vapour then that suggests problems in the engine internals.

If you're confident that it's not air entering the fuel system and have ruled out everything upstream of the pump, and if you're not getting smoke from the exhaust, then in my opinion it's starting look like the pump may need to be inspected and rebuilt.

 

[mudgudgeon]

finally I turned the main fuel screw and it did raise my rpms up to 2k full throttle

Did you notice if the idle speed changed when you added fuel? I think it's promising that max RPM increased when you did this.

Keep experimenting. Turn it in another half turn, so a full turn.
If you add too much fuel here, it'll make it smokey in normal driving conditions.
If for some reason, fuel was turned down by a PO, increasing the main fuel screw a lot will eventually affect idle speed, make it smokey at idle, and when you stab the throttle at idle, you'll see a bigger puff of dark smoke.

For the sake of testing, experiment a little. Do it in increments you can keep track off, so you can return it to where its at.

If tuning up the fuel changes things significantly, then you might just need to tune the pump. Checking IP timing would be step 1 before you start tweaking tuning.
EGT gauge is also kind of essential if you're going to self tune.

Can you guys hear something odd in this or something I missed?
1HDT Rev issue 2

Sounds ok at idle. You can here the turbo at idle which suggests the turbo is probably ok.

As the RPMs max out, it starts to stumble.
To me, this could be a few things

1. bad injectors. I think you'd see smokey exhaust, and the exhaust would stink if the injection patten was so bad it's limiting rpm to 1500-2000.
If you're committed to sorting the truck and keeping it long term, investing in fresh injectors will cross this off the list 100%

2 Air in the fuel. Connecting a bottle of fuel directly to the IP eliminates this **unless there's a leak at the fuel pump.

3. Fuel blockage at the pump. If the solenoid can't be removed, not sure how else to test this. If you persevere with removing it and damage the Solenoid, a new one will be cheaper than a pump rebuild. The big risk is damaging the pump housing.

4. Bad injection timing. Check timing per the FSM. If you have time and capability to follow the FSM, buy a SST and spend some time to check the timing. It's not difficult, but its kind of fiddly, and took me a little while to be comfortable with the process when I first did it.

If none of that solves your problem, I'm out of ideas.

The above list is stuff a competent amateur mechanic can tackle. Beyond that, I think you're looking at professional pump work.

 

[Eurasiaoverland]

Did you notice if the idle speed changed when you added fuel? I think it's promising that max RPM increased when you did this.

Keep experimenting. Turn it in another half turn, so a full turn.
If you add too much fuel here, it'll make it smokey in normal driving conditions.
If for some reason, fuel was turned down by a PO, increasing the main fuel screw a lot will eventually affect idle speed, make it smokey at idle, and when you stab the throttle at idle, you'll see a bigger puff of dark smoke.

For the sake of testing, experiment a little. Do it in increments you can keep track off, so you can return it to where its at.

If tuning up the fuel changes things significantly, then you might just need to tune the pump. Checking IP timing would be step 1 before you start tweaking tuning.
EGT gauge is also kind of essential if you're going to self tune.


Sounds ok at idle. You can here the turbo at idle which suggests the turbo is probably ok.

As the RPMs max out, it starts to stumble.
To me, this could be a few things

1. bad injectors. I think you'd see smokey exhaust, and the exhaust would stink if the injection patten was so bad it's limiting rpm to 1500-2000.
If you're committed to sorting the truck and keeping it long term, investing in fresh injectors will cross this off the list 100%

2 Air in the fuel. Connecting a bottle of fuel directly to the IP eliminates this **unless there's a leak at the fuel pump.

3. Fuel blockage at the pump. If the solenoid can't be removed, not sure how else to test this. If you persevere with removing it and damage the Solenoid, a new one will be cheaper than a pump rebuild. The big risk is damaging the pump housing.

4. Bad injection timing. Check timing per the FSM. If you have time and capability to follow the FSM, buy a SST and spend some time to check the timing. It's not difficult, but its kind of fiddly, and took me a little while to be comfortable with the process when I first did it.

If none of that solves your problem, I'm out of ideas.

The above list is stuff a competent amateur mechanic can tackle. Beyond that, I think you're looking at professional pump work.

I think the OP mentioned that the problem persists with the pump taking diesel straight from a jar, and that there is not much smoke. As you mention, if the injectors were so bad, or the timing so wrong, I think we would expect a lot of smoke.

It was also initially mentioned that the engine kept running after turning the key off - with a rotary injection pump this can only be an electrical fault (very unlikely as the solenoid needs power for the pump to run, not to stop it) or physical obstruction of the solenoid plunger, which would also explain the restricted fuel supply.

I would be taking the pump off the engine (I assume it's the same as a 1HZ where the timing cover has to come off and tool made/purchased to lock the IP pulley. With the pump off you can open it and hopefully buzz the solenoid out. Unfortunately, if there is junk in the plunger bore below the solenoid, there is likey to be further damage to the pump, unless it clogged up with diesel bug.

 

[mudgudgeon]

It was also initially mentioned that the engine kept running after turning the key off

I think this was misunderstood, and not the case.
OP can confirm though.

I assume it's the same as a 1HZ where the timing cover has to come off and tool made/purchased to lock the IP pulley.

Yes, it's the same

 

[stvrn6]

Sorry,
Have you changed the air filter?

yes, new air, fuel and oil filter.

 

[stvrn6]

Did you notice if the idle speed changed when you added fuel? I think it's promising that max RPM increased when you did this.

Keep experimenting. Turn it in another half turn, so a full turn.
If you add too much fuel here, it'll make it smokey in normal driving conditions.
If for some reason, fuel was turned down by a PO, increasing the main fuel screw a lot will eventually affect idle speed, make it smokey at idle, and when you stab the throttle at idle, you'll see a bigger puff of dark smoke.

For the sake of testing, experiment a little. Do it in increments you can keep track off, so you can return it to where its at.

If tuning up the fuel changes things significantly, then you might just need to tune the pump. Checking IP timing would be step 1 before you start tweaking tuning.
EGT gauge is also kind of essential if you're going to self tune.


Sounds ok at idle. You can here the turbo at idle which suggests the turbo is probably ok.

As the RPMs max out, it starts to stumble.
To me, this could be a few things

1. bad injectors. I think you'd see smokey exhaust, and the exhaust would stink if the injection patten was so bad it's limiting rpm to 1500-2000.
If you're committed to sorting the truck and keeping it long term, investing in fresh injectors will cross this off the list 100%

2 Air in the fuel. Connecting a bottle of fuel directly to the IP eliminates this **unless there's a leak at the fuel pump.

3. Fuel blockage at the pump. If the solenoid can't be removed, not sure how else to test this. If you persevere with removing it and damage the Solenoid, a new one will be cheaper than a pump rebuild. The big risk is damaging the pump housing.

4. Bad injection timing. Check timing per the FSM. If you have time and capability to follow the FSM, buy a SST and spend some time to check the timing. It's not difficult, but its kind of fiddly, and took me a little while to be comfortable with the process when I first did it.

If none of that solves your problem, I'm out of ideas.

The above list is stuff a competent amateur mechanic can tackle. Beyond that, I think you're looking at professional pump work.

When i turned the screw the idle rpms went up, i didn't pay attention to the smoke.
Ill look into checking the time and ordering any needed tools and such.
I will have the injectors serviced soon.
If none of these works ill be sending in the pump for servicing and or ordering a replacement.
I read somewhere that someone was sucking in air throw the ACSD rod, Would that be possible?

Edit: Should i have the injectors serviced or replaced?

 

[stvrn6]

I think the OP mentioned that the problem persists with the pump taking diesel straight from a jar, and that there is not much smoke. As you mention, if the injectors were so bad, or the timing so wrong, I think we would expect a lot of smoke.

It was also initially mentioned that the engine kept running after turning the key off - with a rotary injection pump this can only be an electrical fault (very unlikely as the solenoid needs power for the pump to run, not to stop it) or physical obstruction of the solenoid plunger, which would also explain the restricted fuel supply.

I would be taking the pump off the engine (I assume it's the same as a 1HZ where the timing cover has to come off and tool made/purchased to lock the IP pulley. With the pump off you can open it and hopefully buzz the solenoid out. Unfortunately, if there is junk in the plunger bore below the solenoid, there is likey to be further damage to the pump, unless it clogged up with diesel bug.

No the initial issue was the truck would die after running for a short period but was resolved by bleeding the injectors. I meant to say that the truck is no longer shutting off on its own anymore but yes it shuts on and off with no issue.

 

[Eurasiaoverland]

When i turned the screw the idle rpms went up, i didn't pay attention to the smoke.
Ill look into checking the time and ordering any needed tools and such.
I will have the injectors serviced soon.
If none of these works ill be sending in the pump for servicing and or ordering a replacement.
I read somewhere that someone was sucking in air throw the ACSD rod, Would that be possible?

Edit: Should i have the injectors serviced or replaced?

On the pump, Only the inlet banjo sees negative pressure. All the rest of the pump is pressured internally, so failed seals result in external fuel leaks.

No need to replace the injectors, just the nozzles.

 

[Squash]

I did have an ACSD device grenade over time.
Unfortunately we were traveling.
Limped it home 4 hours, but only by giving her fuel because at idle she would stall.
The screen under the solenoid was full of metal shavings which obviously cut back the fuel delivery.
This was years ago...I believe one member was able to back flush the screen by forcing fuel in via the return line and out via the supply. If you attempt this check for metal.
Btw if you remove the ACSD use the best tools possible. Bottom bolt can be accessed by removing the front tire and sneaking an extension in if you remove the rubber skirting.

 

[stvrn6]

I've been busy with work but finally got around to working on it. Cant get that damn solenoid off, already ordered a new one. Considering ordering a new pump and just getting that purchase over with for piece of mind from Gturbo AUS. I decided to do a compression test before pulling the injectors. I used a tester from Harbor freight (Maddox) but due too it being a right angle, it was way to difficult to get it on with out removing the intake so i only got it around cylinder 1 and 5. I ordered a cheap no brand off amazon to redo all the cylinders and these were the numbers:
1. 480, (HF Tester 525)
2. 480
3. 460
4. 480
5. 480, (HF Tester 525)
6. 480
+/- 2-4 psi

Injectors are being sent to DFIS in Portland, Oregon to be service. Also here are how the injectors look. (1 to 6, left to right)

 

[stvrn6]

Update and HELP needed.
I was removing my pump today following the FSM, engine in BDC, belt off, held the crank to break the pump bolt no issue. I ran into an issue when using the a gear puller to remove the IP. I got in the 2 bolts in and started turning the center bolt to push the pump in. It was very tight, so tight that as I turned the ratchet it moved the gear that pulley was attached too. I don't even know but it also moved the cam pulley as well. Now my timing is all messed up and I'm not sure how to get it back in spec. Did this harm the valves? How do I get everything lining up again?
Also finally got that damn Fuel solenoid off and boy let me tell you, Never would have been able to get that thing off in the truck. Damn thing took my whole body to push on it with locking pliers to finally break loose. already got a new solenoid shipped in off of partsouq.

Edit: The filter under the solenoid was clean, sending pump in for rebuild anyway.

 

[Eurasiaoverland]

The FSM will explain how to set the timing when you reassemble the engine. I assume the camshaft and IP pulleys moved together, in which case there is no chance of any collision as the IP is hard-linked to the crank via timing gears. Even if the camshaft rocks one way or another passively, there is no way it will damage the pistons/valves. Just follow the FSM religiously when reassembling the engine.