1991 HDJ81 new to me, recommended maintenance, not revving past 1.5k

[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.

 

[stvrn6]

The anti-tamper seal is a wire wrapped around the screw and through that hole in the end of the screw, sealed with a zinc press seal and collar. If injectors were bad, you would expect bluish smoke when trying to raise the engine speed from partially burned diesel from large droplets of poorly atomised fuel from dirty injectors. But as injector nozzles are a service item, it won't hurt to have them changed (making sure to use genuine Toyota/Denso nozzles, not Chinese junk from eBay). But my suspicion would be incorrect ignition timing, clogging of the particulate screen(s) in the pump, or generally faulty pump setup.

I see thank you! Looks like mine has been messed with. Truck is stock so not sure why. Ill look into the timing. Ill be removing the the ACSD when the kit arrives. When should I consider sending the pump for rebuild? sitting at around 108k miles, Just got quoted 2-3k for a rebuild so hoping I don't need to do that now.

 

[Eurasiaoverland]

The red paint marks on pump fasteners are not factory, so someone has already been in the pump.

Normally pumps get rebuilt when they leak, or when there are fuel delivery problems and other (cheaper) parts of the fuel system have been ruled out. In general these pumps last for several hundred thousand kilometres before mechanical wear becomes an issue, so if your mileage is correct it should be fine. But someone has been in there, so it's really a guess what they have done and why they opened it in the first place.

 

[stvrn6]

The red paint marks on pump fasteners are not factory, so someone has already been in the pump.

Normally pumps get rebuilt when they leak, or when there are fuel delivery problems and other (cheaper) parts of the fuel system have been ruled out. In general these pumps last for several hundred thousand kilometres before mechanical wear becomes an issue, so if your mileage is correct it should be fine. But someone has been in there, so it's really a guess what they have done and why they opened it in the first place.

Im not 100% but I believe it was opened up back in Japan. Would it worth a shot to adjust the main fuel screw?

 

[Squash]

Black smoke is common if you pound the skinny pedal.

 

[Eurasiaoverland]

As has been suggested earlier, take a 24 mm spanner and remove the solenoid to check the little filter/strainer underneath it. There may also be a second filter/strainer under the inlet banjo.

 

[mudgudgeon]

Looks like mine has been messed with. Truck is stock so not sure why.

Toyota have these a conservative tune. The tuning also varies a lot from factory.
Some tuning can liven them up a LOT even in 100% stock trim.

Ill look into the timing.

This would be high on the list for troubleshooting. I agree with @Eurasiaoverland bad timing could explain your issue, but i'd also expect to see whiteish smoke if timing was heavily retarded. Exhaust would also likely stink of raw diesel.

Ill be removing the the ACSD when the kit arrives.

I'd wait. Unlikely the ACSD has anything to do with this. Changing it now adds another layer of doubt

Would it worth a shot to adjust the main fuel screw?

Absolutely. As an experiment, loosen the lock nut, and turn the main screw in 1/2 turn. This should be enough to make a difference if this is your problem.
Just keep track of how much you turn it so you can put it back if there's no change

When should I consider sending the pump for rebuild?

There a lot of stuff to tick off before spending $$$ on the pump.

Check timing
Check filter screen in the pump

Experiment with some tuning (find "the officisl 1hd-t pump tuning thread", do some reading in tuning)

Service/replace injectors

Also, check the turbo is spinning freely.
Is it spooling up when you rev the engine? You should hear it.
Check the compressor wheel isn't making contact with the housing, and shaft doesn't have excessive play.

Keep asking questions, sharing observations

 

[stvrn6]

Toyota have these a conservative tune. The tuning also varies a lot from factory.
Some tuning can liven them up a LOT even in 100% stock trim.


This would be high on the list for troubleshooting. I agree with @Eurasiaoverland bad timing could explain your issue, but i'd also expect to see whiteish smoke if timing was heavily retarded. Exhaust would also likely stink of raw diesel.


I'd wait. Unlikely the ACSD has anything to do with this. Changing it now adds another layer of doubt


Absolutely. As an experiment, loosen the lock nut, and turn the main screw in 1/2 turn. This should be enough to make a difference if this is your problem.
Just keep track of how much you turn it so you can put it back if there's no change


There a lot of stuff to tick off before spending $$$ on the pump.

Check timing
Check filter screen in the pump

Experiment with some tuning (find "the officisl 1hd-t pump tuning thread", do some reading in tuning)

Service/replace injectors

Also, check the turbo is spinning freely.
Is it spooling up when you rev the engine? You should hear it.
Check the compressor wheel isn't making contact with the housing, and shaft doesn't have excessive play.

Keep asking questions, sharing observations

I really appreciate all the help from everyone. Thank you.
So i only had time to take apart the banjo bolt that connects to the fuel filter and I did not see any filter in there, tried with several tools but didn't see anything. I can go back in there with a small pick but I'm almost certain it was missing. How can i access the other filters in the pump? I tried find the engine FSM but could not find a working link. and finally does anyone know the proper procedure to bleed the injectors? I want to be sure I did it correctly.

 

[Eurasiaoverland]

Not all pumps have the tall strainer under the inlet banjo. But they all have one under the solenoid.

This is the thing you want to remove. I don't remember there being an FSM section on checking this filter, the official line is if you take anything off the pump which exposes any of the internals, the whole thing is serviced and recalibrated.

 

[stvrn6]

Not all pumps have the tall strainer under the inlet banjo. But they all have one under the solenoid.
View attachment 3927175
This is the thing you want to remove. I don't remember there being an FSM section on checking this filter, the official line is if you take anything off the pump which exposes any of the internals, the whole thing is serviced and recalibrated.

That was actually my next question, how do i get this off? I tried using a 24 mm wrench but its so tight it will most definitely strip it but I don't have clearance to get a 24mm socket on. Is there any trick ?

 

[Eurasiaoverland]

You can't get a socket on there unless you take the whole cover off the pump, which is not advisable while it is fitted to the vehicle. If you grind down a ring spanner or have a 24 mm union spanner you can try hitting it with a hammer to break any corrosion. You're more likely to round off the solenoid than strip the thread IMO. That said, I've had one damage the threads in the head of the pump while removing it which means I have an M24x1.0 tap in my tool collection now.

 

[stvrn6]

You can't get a socket on there unless you take the whole cover off the pump, which is not advisable while it is fitted to the vehicle. If you grind down a ring spanner or have a 24 mm union spanner you can try hitting it with a hammer to break any corrosion. You're more likely to round off the solenoid than strip the thread IMO. That said, I've had one damage the threads in the head of the pump while removing it which means I have an M24x1.0 tap in my tool collection now.

I've rounded it off.... lol I was able to fit a wrench by removing the oil filter but its on so tight its rounded now. I put some lubricant and will try again with a hammered on 23mm. I do hear the turbo spool up but that's about it. Its actually up to 1800 rpm now? I will be removing the exhaust, not sure but maybe some critters may have clogged it up? Also does this engine have a air bleed screw?

 

[mudgudgeon]

There's several links to the FSM for the 1hd-t engine in the RESOURCES section found via the forum menu

 

[stvrn6]

There's several links to the FSM for the 1hd-t engine in the RESOURCES section found via the forum menu

Thank you. But I only see the 1HDT-FT. I tried accessing an older one but shows "unavailable".

 

[stvrn6]

Update:
The Fuel solenoid is seized on. I removed the oil filter and hammered on a 23mm and 7/8s wrench and no luck. I fear ill have to take the pump cover off. It was mentioned on here that its not advisable, how come? but if this is my last resort is there anything to look out for?
Also i pulled the airbox and inspected the turbo and everything looks solid. Removed the exhaust incase it was restricting air flow but no its solid. And finally I turned the main fuel screw and it did raise my rpms up to 2k full throttle, and the turbo light turned on but that was about it. I returned the screw to where it was before.
Can you guys hear something odd in this or something I missed?
1HDT Rev issue 2
Thank you in advance

 

[Eurasiaoverland]

It's inadvisable as you open up the pump in a dirty engine bay, removing dirty pieces which can't be fully cleaned prior to removal, so there's a very good chance to drop pieces of dirt straight into the pump.

The engine sounds fine but seems to start running slightly unevenly when it reaches the limit it's willing to rev to. Have you disconnected the crankcase ventilation hose and looked for blow-by?

 

[dmjay]

Sounds like it is time to get it to a diesel mechanic.

 

[stvrn6]

It's inadvisable as you open up the pump in a dirty engine bay, removing dirty pieces which can't be fully cleaned prior to removal, so there's a very good chance to drop pieces of dirt straight into the pump.

The engine sounds fine but seems to start running slightly unevenly when it reaches the limit it's willing to rev to. Have you disconnected the crankcase ventilation hose and looked for blow-by?

Damn, that does not sound like fun. I put my finger in the hose as I revved it up and it did build up some pressure, but when I leave it open it seems normal? I don't know what normal is if I could be honest. I did put the oil cap upside down and it does a little dance than settles, doesn't come off or anything so it seems the blow-by is very minimal.

 

[mudgudgeon]

Thank you. But I only see the 1HDT-FT. I tried accessing an older one but shows "unavailable".

FSM - 1PZ, 1HZ, 1HD-T ENGINE REPAIR MANUAL

ENGINE REPAIR MANUAL for 1PZ, 1HZ, 1HD-T engines.

forum.ih8mud.com

 

[stvrn6]

FSM - 1PZ, 1HZ, 1HD-T ENGINE REPAIR MANUAL

ENGINE REPAIR MANUAL for 1PZ, 1HZ, 1HD-T engines.

forum.ih8mud.com

Thank you!

 

[Squash]

Sorry,
Have you changed the air filter?