LJ78 to 1kzte (1 Viewer)

[Ash Awbery]

So I have a LJ78 with A343F trans and my wife cooked the engine (drove it overheating until it stopped) it’s not all bad as I have planning an engine swap for a while and now she is on board with it!

im thinking of going down the 1kz route as I want to keep it diesel and Auto.

i have been advised to go with a Manual pump and aftermarket gearbox controller (I’m thinking Compushift)

nearly all the donor trucks I can find are 1kzte… has any swapped a 2lte with a 1kzte?

Iv Heard the injectior pumps are nearly the same, could I just swap the engine and keep the factory ECU and gearbox management?

 

[GTSSportCoupe]

I'm pretty sure 1KZTE electronic version has been installed in place of the 2LTE. Maybe do some googling to see if you can find an example build thread where this has been done.

Advantage of the electronic motors is the variable injection timing. Makes for more efficiency, power, and easier on the motor (retards when intake temps are hot etc.). I've owned both 2LTE and 2LT-II, and the electronic version blew away the mechanical one.

I'd highly recommend getting a 1KTE from a KZJ78 with wiring harness, ECU, and everything you can from the engine bay. This should make it a pretty direct install besides different engine mounts and exhaust.

Have a look at the electrical manuals to determine the exact differences: Found Japanese 1990-1995 70 series wiring manuals! - https://forum.ih8mud.com/threads/found-japanese-1990-1995-70-series-wiring-manuals.959266/

 

[Ash Awbery]

I'm pretty sure 1KZTE electronic version has been installed in place of the 2LTE. Maybe do some googling to see if you can find an example build thread where this has been done.

Advantage of the electronic motors is the variable injection timing. Makes for more efficiency, power, and easier on the motor (retards when intake temps are hot etc.). I've owned both 2LTE and 2LT-II, and the electronic version blew away the mechanical one.

I'd highly recommend getting a 1KTE from a KZJ78 with wiring harness, ECU, and everything you can from the engine bay. This should make it a pretty direct install besides different engine mounts and exhaust.

Have a look at the electrical manuals to determine the exact differences: Found Japanese 1990-1995 70 series wiring manuals! - https://forum.ih8mud.com/threads/found-japanese-1990-1995-70-series-wiring-manuals.959266/

Thanks for the info, I have done quite a bit of searching but most people are looking to ditch the auto gearbox but I planning to keep it.

i would love you use the KZTE from a KZJ78 but that’s not really an option, they are super rare here and parts are not easy to come by so I will likely use the 1KZTE from a hilux surf.

 

[GTSSportCoupe]

Thanks for the info, I have done quite a bit of searching but most people are looking to ditch the auto gearbox but I planning to keep it.

i would love you use the KZTE from a KZJ78 but that’s not really an option, they are super rare here and parts are not easy to come by so I will likely use the 1KZTE from a hilux surf.

The Surf 1KZTE wiring loom is probably close enough it could be made to work in the LJ78 ok. The motors are very close, but I'm not sure the 2LTE ECU would run the 1KZTE that well. Would be interesting to know though - as I was thinking of installing a 1KZTE injection pump to my 2LTE for more max fuel ability (12mm pump vs 10mm).

There are a couple of ECD V3 manuals from Denso out there that explain in detail the operation of the two motors ECD systems. If you had a read through it would probably help you understand exactly what needs to be done. Between those and the LJ78/KZJ78 manuals that is.

Here's the earlier ECD V3 manual:

Here's the later ECD V3 manual:

 

[GTSSportCoupe]

Any other manuals you need, let me know. I can host them for you. I have the 1KZTE one too.

 

[Ash Awbery]

Thank for the help and the Manuals it will make some good bed time reading. So looking at it I have a couple of options

1.try the 1kzte with my LJ78 management (engine and gearbox)

2. Fit the engine and loom from the surf into my LJ78 then manage the gearbox by:
a. Using the surf gearbox management
b. Using an aftermarket controller

3. put an manual pump on the 1kzte (either a 1kzt or 4m40) and run an aftermarket controller.

I suppose I can just try it in that order, I will have the whole vehicle to pull the loom and management from so I can get everything I need.

I’m not looking for loads of power, but if a can keep the 1kzt management that would be great. It’s currently sitting on 35” landdragons, but I do have the 4.88 ratio diffs so it should hopefully pull ok.

 

[roscoFJ73]

i would love you use the KZTE from a KZJ78 but that’s not really an option, they are super rare here and parts are not easy to come by so I will likely use the 1KZTE from a hilux surf.

Lots of 90 series Prados use the 1KZTE, I thought they were common in the UK

 

[Ash Awbery]

Lots of 90 series Prados use the 1KZTE, I thought they were common in the UK

Hi, yeah 90 series prados are no issue to find in the UK little more money than a hilux surf, but the sump isn’t ideal on a 90 series because it hits the front axle. So easier to use the surf engine, sump has slightly less capacity than a KZJ70/78 but it’s workable.
Getting the engine is easy, the main head ache is the auto trans as every thread I read is either unfinished or they have swapped out to a manual gearbox.

 

[Ash Awbery]

So small update… so I narrowly missed out of a cut down KZJ78 (my wife was literally on the delivery suite giving birth to my daughter) so I have now bought a Hilux Surf with a 1KZTE and auto trans. I have the whole truck so my first plan is to swap out the 2LTE with the 1KZ (using the surf bell housing and torque converter) and I will see if LJ78 management will run the 1KZTE.

If this doesn’t work I then have two options:

1. Use the wiring harness and management from the surf and transplant it into my LJ78

3. Build a hybrid 2LTE/1KZTE pump - if that’s even possible?

2. Fit the 4M40 Mitsubishi manual pump to my 1KZ and use an aftermarket gearbox controller.

Watch this space.

 

[GTSSportCoupe]

So small update… so I narrowly missed out of a cut down KZJ78 (my wife was literally on the delivery suite giving birth to my daughter) so I have now bought a Hilux Surf with a 1KZTE and auto trans. I have the whole truck so my first plan is to swap out the 2LTE with the 1KZ (using the surf bell housing and torque converter) and I will see if LJ78 management will run the 1KZTE.

If this doesn’t work I then have two options:

1. Use the wiring harness and management from the surf and transplant it into my LJ78

3. Build a hybrid 2LTE/1KZTE pump - if that’s even possible?

2. Fit the 4M40 Mitsubishi manual pump to my 1KZ and use an aftermarket gearbox controller.

Watch this space.

The ECD systems between similar years 2LTE and 1KZTE are very similar from what I understand. Does your new 1KZTE injection pump have the two resistors on the side? If so, it's the early version of the motor that has closest electronics to the 2LTE.

I would think that option 1. would give you the best performance. If they're both RHD vehicles, it shouldn't be that difficult, as the harness should be a similar size and layout. Just get the wiring diagram for each vehicle, and go from there. One of the ECU plugs will need to connect to the chassis wiring, so that is the one you will have to focus on. The other plugs should mostly connect to the engine.

Option 3. is possible, but I don't think you'd gain anything. The early 1KZTE pump has the same sensors/actuators as the 2LTE as far as I know; but a 12mm head (more fuel capability).

Option 2. is also possible, but the 4m40 pump has less fuel capability, and will require some custom linkage etc. Taking the ECU out of the mix will make controlling the auto transmission potentially troublesome. So maybe not the best option.

 

[Ash Awbery]

The ECD systems between similar years 2LTE and 1KZTE are very similar from what I understand. Does your new 1KZTE injection pump have the two resistors on the side? If so, it's the early version of the motor that has closest electronics to the 2LTE.

I would think that option 1. would give you the best performance. If they're both RHD vehicles, it shouldn't be that difficult, as the harness should be a similar size and layout. Just get the wiring diagram for each vehicle, and go from there. One of the ECU plugs will need to connect to the chassis wiring, so that is the one you will have to focus on. The other plugs should mostly connect to the engine.

Option 3. is possible, but I don't think you'd gain anything. The early 1KZTE pump has the same sensors/actuators as the 2LTE as far as I know; but a 12mm head (more fuel capability).

Option 2. is also possible, but the 4m40 pump has less fuel capability, and will require some custom linkage etc. Taking the ECU out of the mix will make controlling the auto transmission potentially troublesome. So maybe not the best option.

So it would appear I can’t number probably!

It has visually the same solenoids on the side so I’m fairly hopeful.

Option 1. Is fairly straightforward but just hoping for an easier option!

Option 2. I have been speaking with a guy who went this route with good results but, I’d rather avoid the expense and complication of an aftermarket controller.

Option 3. If they are similar pumps then in theory my LJ78 management should work… one way to find out!

I will see what works and report back!

 

[GTSSportCoupe]

So it would appear I can’t number probably!

It has visually the same solenoids on the side so I’m fairly hopeful.

Option 1. Is fairly straightforward but just hoping for an easier option!

Option 2. I have been speaking with a guy who went this route with good results but, I’d rather avoid the expense and complication of an aftermarket controller.

Option 3. If they are similar pumps then in theory my LJ78 management should work… one way to find out!

I will see what works and report back!

Haha, sounds good! My guess is you might end up with a high idle, but maybe not. The 1KZTE pump will flow a lot more fuel for the same spill control valve open time. Hard to say if the 2LTE ECU will be able to cut fuel enough at idle to get a proper rpm. I'd be interested to know how this goes. Partly because I've thought of putting a 1KZTE pump on my 2LTE for more fuel capability (higher power limit).

You can tune the 1KZTE pump to some degree to match the 2LTE ECU, by using 2.5kOhm potentiometers in place of the resistors on the pump side (tunes timing and low rpm fuel), and you can use the spill valve screw to tune higher rpm fuel. This might be enough to solve any problems that come up.

 

[Ash Awbery]

So the physical engine swap is now complete, the 1kzte more or less bolted in with no issues I used the hilux surf bell housing and torque converter mounted to the LJ78 A343f gearbox but had to mod the 2LTe engine mounts.

As expected the part that hasn’t been so easy is the EDC side of things, so far I have the 1KZTe hooked up to the 2LTe ECU and harness. It’s starts and runs but pours out white smoke and Unburnt diesel and idle is far too high just like @GTSSportCoupe hypothesised.

I have tried some potentiometers in place of the correction resistors but unfortunately this has only marginally improved it.

So unless I can come up with a way to trick my ECU I now have 2 options:

1. use the wiring harness and ECU’s from the surf - my main concern with this is moving my problem from the engine to the gearbox, as the surf gearbox has some differences physically and electronically.

2. Go manual pump and aftermarket gearbox controller - this will nearly double the current build cost.

 

[GTSSportCoupe]

So the physical engine swap is now complete, the 1kzte more or less bolted in with no issues I used the hilux surf bell housing and torque converter mounted to the LJ78 A343f gearbox but had to mod the 2LTe engine mounts.

As expected the part that hasn’t been so easy is the EDC side of things, so far I have the 1KZTe hooked up to the 2LTe ECU and harness. It’s starts and runs but pours out white smoke and Unburnt diesel and idle is far too high just like @GTSSportCoupe hypothesised.

I have tried some potentiometers in place of the correction resistors but unfortunately this has only marginally improved it.

So unless I can come up with a way to trick my ECU I now have 2 options:

1. use the wiring harness and ECU’s from the surf - my main concern with this is moving my problem from the engine to the gearbox, as the surf gearbox has some differences physically and electronically.

2. Go manual pump and aftermarket gearbox controller - this will nearly double the current build cost.

Hi Ash. There is one more easy and significant thing you can try. Remove the cap from the spill valve adjust screw. Mark, or take a picture of the screw setting before doing anything. Then release the lock-nut, and turn the fuel screw OUT. Keep track of how far you've turned it. This will reduce the fueling significantly. Turn it out somewhere between 1/4 to 1/2 a turn to start. Then tighten the lock nut again.

I think what's happening is your 2LTE ECU is used to a longer injector time because of the smaller 10mm plunger in that motor. But with the 1KZTE 12mm pump, this ends up being a lot of fuel.

If the spill valve thing seems to work, it will likely take some experimenting to get it set just right.

 

[Ash Awbery]

Thanks I did wonder about the spill valve, most people
Only adjust it for top end fueling so wasn’t sure if it would make much difference, but nothing to loose by giving it a try!

 

[Tigris]

Hi there. I am in favor of option: 1. Yes, this will most likely shift your problem from the engine to the gearbox, but IIRC, you might only lose the overdrive. I know that is far from ideal but I think that the Surf ECU can be modified into a KZJ7X ECU with minor surgery. I am almost done finalizing the procedure for the conversion.

Cheers,

Moe

 

[Ash Awbery]

So I have had a bit of time off from this, 3 kids, work, moved house all the usual excuses!

So I read through all of the pump
Manuals, tried different resistors and made some adjustments to the spill valve but all in all I just wouldn’t run right

So I have gone with a 4m40 manual injection pump, I know loads of people prefer a 1kzt pump but I already had the 4m40 pump and because it was from an auto, my line pressure cable connected right up to the pump and with a few mods the Pajero throttle cable also worked. Now the 1kzt is running really well…

Next problem is the transmission….
In the short term I want to manualise it then fit a Spitronics ecu to just run the trans.

Anyone have any experience manualising a A343F in an LJ78?
Loads of stuff online but the LJ78 seems to have a different plug on the trans and I cans seem to find a ECU pin out for an LJ78.

Or better does any have a trans wiring diagram of ECU wiring diagram?

 

[GTSSportCoupe]

So I have had a bit of time off from this, 3 kids, work, moved house all the usual excuses!

So I read through all of the pump
Manuals, tried different resistors and made some adjustments to the spill valve but all in all I just wouldn’t run right

So I have gone with a 4m40 manual injection pump, I know loads of people prefer a 1kzt pump but I already had the 4m40 pump and because it was from an auto, my line pressure cable connected right up to the pump and with a few mods the Pajero throttle cable also worked. Now the 1kzt is running really well…

Next problem is the transmission….
In the short term I want to manualise it then fit a Spitronics ecu to just run the trans.

Anyone have any experience manualising a A343F in an LJ78?
Loads of stuff online but the LJ78 seems to have a different plug on the trans and I cans seem to find a ECU pin out for an LJ78.

Or better does any have a trans wiring diagram of ECU wiring diagram?

Nice work; glad to hear you have it going!

That's too bad the 1KZTE pump doesn't work with the 2LTE computer. :-( I have a 1KZTE pump and was hoping to use it as a 12mm upgrade for my 2LTE. Guess I'd have to work a 1KZTE ecu into the mix to get it working.

ECT wiring is in the manual: EWD_67341_lj78 - https://www.dropbox.com/sh/583d34p4hxjumut/AACDux1bBa7HY9cKQQ8_JfeDa/EWD_67341_lj78?dl=0&subfolder_nav_tracking=1