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.

 

[Squash]

Not revving could be sucking air/vaccum, pooched ACSD and the gauze thin filter under the fuel solenoid.
Not shutting down...faulty circuit, try to disconnect the one wire to fuel solenoid, it should click as you power on and off.
Lastly is your starter staying engaged, and the engine only stops if you remove a battery cable.

 

[stvrn6]

Not revving could be sucking air/vaccum, pooched ACSD and the gauze thin filter under the fuel solenoid.
Not shutting down...faulty circuit, try to disconnect the one wire to fuel solenoid, it should click as you power on and off.
Lastly is your starter staying engaged, and the engine only stops if you remove a battery cable.

sorry I meant to say that after I bleed the lines, the truck stays on and doesn’t die like before. Truck turns on and off with no issue now.
Where should I start looking for a potential vacuum leak?

 

[rick_d]

Has the truck sat for 9 years? when was last time running on the road? was accident a roll over by any chance?

 

[stvrn6]

Has the truck sat for 9 years? when was last time running on the road? was accident a roll over by any chance?

I believe the truck was only used locally and just sat for about a year after the crash. Timing belt done at 139k km and now it sits at 175k. The crash was a rear quarter panel, nothing to severe like a roll over.

 

[Squash]

Our units use fuel hose from the firewall to the injection pump. Therefore all hose and clamps are suspect. If you fiddled with the fuel filter primer....suspect.
I use clear hose starting from the injection pump to fuel filter and ideally with the engine running check for air bubbles.
Bubbles mean that your system is sucking in air.
Your Primer bulb should stay firm or firm up in a couple of pumps. Having to pump often indicates sucking air.
New hose and good clamps.
If you are in a quiet place you can often hear the vaccum leak while priming. Find the leak with you fingers.

 

[mudgudgeon]

If you replace the timing belt, replace the tensioner pulley, and spring too.

It's unlikely the water pump needs replacing IMO.
Two things in the water pump that can fail are the sealed bearing, and the shaft seal.


In regards to lack of RPM, is the air filter good?

Was the fuel you drained clean? There's a filter screen on the in-tank pick up that can get clogged up

Does it run rough when you rev it? Like is it stumbling or spluttering?

Does it blow smoke? What colour smoke?

Do you have a boost gauge? How much boost are you seeing?

 

[stvrn6]

Thank you guys for the help.

If you replace the timing belt, replace the tensioner pulley, and spring too.

It's unlikely the water pump needs replacing IMO.
Two things in the water pump that can fail are the sealed bearing, and the shaft seal.


In regards to lack of RPM, is the air filter good?

Was the fuel you drained clean? There's a filter screen on the in-tank pick up that can get clogged up

Does it run rough when you rev it? Like is it stumbling or spluttering?

Does it blow smoke? What colour smoke?

Do you have a boost gauge? How much boost are you seeing?

Air filter is brand new, the fuel drained was clean but smelled a bit funky, it kind sputters when i rev it (posting video), doesn't really smoke, and lastly I do not have a boost gauge yet.

 

[stvrn6]

Not revving could be sucking air/vaccum, pooched ACSD and the gauze thin filter under the fuel solenoid.
Not shutting down...faulty circuit, try to disconnect the one wire to fuel solenoid, it should click as you power on and off.
Lastly is your starter staying engaged, and the engine only stops if you remove a battery cable.

im not sure if its the ACSD, but i will order a plate and delete it anyway. not sure about the solenoid.

 

[stvrn6]

1HDT Rev issue
Here is the video, both of these are full open throttle, id assume its a fuel issue. I will check the in-tank filter tomorrow. When should I consider having the pump and injectors serviced?
Also the truck starts right up, no longer need to prime the filter or anything, just turn the key.

Edit: In the first video please ignore the sound of a ratchet in the back lol

 

[Squash]

You could run some hose into a container of fresh fuel and see if this makes a difference just because you mentioned having suspect diesel.

 

[mudgudgeon]

Sounds OK idling.

Definitely sounds like its starving for fuel.

If fuel was dirty, you could have a blockage somewhere. Check the filter screen in the tank
There's also a wire mesh screen where the fuel hose connects to the fuel pump. Remove the banjo bolt, then the bush screwed into the pump body.

Also, check the main fuel adjustment screw on the pump. Does it still have the anti-tamper collar on it? This prevents the fuel screw setting from being changed. If the collar is gone, someone may have messed with it. It may be limiting fuel delivery.

With it idling, stab the throttle hard for 1-2 seconds. You should see a dark puff of smoke at the tail pipe, and the engine should rev up in response to aquick burst of fuel.

This test gives a good initial indication of the state of tune.

it kind sputters when i rev it

If its stumbling and spluttering, it could be because you have air getting into the fuel system.

Search for "clear hose", a clear hose can instantly tell you if fuel has air in it.
If your see air in the clear hose, start replacing rubber fuel hoses, clamps etc

 

[stvrn6]

You could run some hose into a container of fresh fuel and see if this makes a difference just because you mentioned having suspect diesel.

The fuel tank was drained and filled with about 10 gallons of fresh diesel. Is there any additive I can add that may help?

 

[mudgudgeon]

A fuel additive isn't going to magically unblock a restriction severe enough to limit unloaded RPM to 1500ish rpm.

The suggestion to run clean fuel from a bottle directly to the fuel pump is a good one.

A couple of feet of hose, and an empty oil bottle or small jerry can will get the engine running enough to see if fuel starvation is the issue.

Skip the filter, go straight to the pump. This eliminates everything from the system, but the pump.

 

[lowenbrau]

What did the old fuel filter look like? Black? If it was sitting in a warm climate you might have algae in the fuel. Go get some Biobor JF and run it though everything.

 

[stvrn6]

A fuel additive isn't going to magically unblock a restriction severe enough to limit unloaded RPM to 1500ish rpm.

The suggestion to run clean fuel from a bottle directly to the fuel pump is a good one.

A couple of feet of hose, and an empty oil bottle or small jerry can will get the engine running enough to see if fuel starvation is the issue.

Skip the filter, go straight to the pump. This eliminates everything from the system, but the pump.

will try this when I get home. Will update after. Thank you.

 

[stvrn6]

What did the old fuel filter look like? Black? If it was sitting in a warm climate you might have algae in the fuel. Go get some Biobor JF and run it though everything.

Fuel filter didn't seem to bad but I'm in Southern California so definitely a possibility.

 

[Squash]

"Stanadyne" diesel is a decent product.
Recommend by a Toyota diesel rebuild shop.

 

[stvrn6]

A fuel additive isn't going to magically unblock a restriction severe enough to limit unloaded RPM to 1500ish rpm.

The suggestion to run clean fuel from a bottle directly to the fuel pump is a good one.

A couple of feet of hose, and an empty oil bottle or small jerry can will get the engine running enough to see if fuel starvation is the issue.

Skip the filter, go straight to the pump. This eliminates everything from the system, but the pump.

So unfortunately, the issue was not resolved by running fuel directly from a bottle to the pump. The fuel adjustment screw does look to be missing the tamper seal (not certain what that looked like but I assume it went in the little hole?). And after a hard acceleration, barely any smoke puffed up but whatever did was black. That means my issue is on the pump or injectors correct?

 

[Eurasiaoverland]

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.