Build Mitsubishi 4D34-3AT3B diesel swap into 94 FZJ80

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Fromage: You say that the test light that you have connected up to the lockup solenoid never comes on? This would indicate that the TCM is not turning on the solenoid OR there is a problem with the wiring from the TCM to the solenoid. It is also possible that the solenoid or wiring is shorted to ground. If it is a wiring or short problem, it seems that the TCM would show a code 34 but maybe not. I never got a bad VSS code even when I had them disconnected. Are you hooking up your test light at the transmission end or the TCM end? If at the transmission end, it may be worth testing at the TCM end to rule out a wiring error.

I don't think that even if you had a line pressure problem, that it would prevent the TCM from trying to lock up the torque converter. After all, there is no way that the TCM can know that there is a line pressure problem - there are on pressure sensors within the transmission that feed this information to the TCM.

It is possible that the TCM is defective, that the lockup solenoid drive circuit is fried. Can you get your hands on another TCM to try?

If you end up pulling the pan, verify continuity all the way from the TCM connector to the lockup solenoid. The lockup solenoid is the one farthest to the right.

You can easily test the solenoid. First, the resistance across the solenoid coil should be around 12 ohms. You can easily test the function of the solenoid. Remove it from the valve body by removing the one 10 mm head bolt and then pulling it straight out. Check the o-ring on the valve body end. You should be able to blow through the solenoid from the o-ring end except when power is applied to the solenoid. If you use your mouth to blow through the solenoid, be careful how you apply power. After all, the solenoid is an inductor and therefore has the characteristics of an ignition coil. It probably won't kill you, but it could be a memorable experience :D

The other thing that you may want to check is the transmission temp sensor along with the associated wiring. After all, the TCM will not command a lockup if it thinks the transmission is cold. The FSM gives the resistance values for different temps. Be sure to do the resistance check from the TCM connector so as that will also verify the wiring. You may want to substitute a 300 ohm resistor for the temp sensor. This would fool the TCM into thinking that the transmission is up to operating temperature.

Good luck!
 
It's really amazing to me how two truck with the same swap are having totally different issues! My transmission works flawlessly, but I'm struggling in the power department, yours seems to be the opposite.

I would certainly try to work out every possible trans issue as astr has suggested before swapping to a different trans. It could very well be an electronics issue that a trans swap will not solve.
 
Would it be possible to run an aftermarket transmission computer similar to what the big HP supra drag guys do? I know of at least one guy doing this on an A343F when he swapped that into his previously 5-spd 'surf.

It's not the cheapest option, but it is an option.

Products
 
Trans temp sensor, lockup solenoid, and wiring have all been checked and have all come out fine. Based on my other tests the ECU will detect an open circuit condition in the solenoid fairly quickly, it only took a few seconds when I disabled the #1 shift solenoid. The computer being fried is a possibility but that would not explain why I get no lockup with a 12V application to the (functioning and tested) solenoid. It is possible that I have both an internal trans issue and an electrical issue. At this point I am going to concentrate on the transmission side of things as I definitely have a trans-related issue, since it does not lock up with 12V applied to the solenoid, and once I get that figured out, I wil move on to the control side of things.
 
Is it possible that you have enough line pressure to run the clutches within the transmission, but not enough to engage the lockup clutch in the TC? I have no idea which would require more pressure to operate.. just throwing ideas out there.
 
Naah, I chucked all those ball bearings... :grinpimp:

During the trans overhaul I just changed the valvebody gaskets and did not mess with anything internal. It might be something caused by the bad timing sensor that I drove on for a few weeks, it might be a burned up torque converter, but I am betting on an internal leak due to the noise I am hearing. The truck I parted was non-op so it might have been a pre-existing condition, and the trans has rebuild tags on it, so maybe the rebuild shop did something wrong. I am planning on having both valvebodies on the bench when I swap them and compare locations of all the check balls and try and reverse engineer the lockup circuit to figure out what might have failed, but I hope I find a blown gasket.

I ordered another gasket set and when it comes in I'll dive in deeper but right now it works fine without the lockup, no fault codes, etc.

I have also been messing with the timing and noticed a drop in mileage with it advanced, but the truck still sounds spot on for timing. It's unexpected. I'm going to pull it back a few degrees, past the original mark. This engine and pump do not respond to timing advances like a normal diesel.

One thing I have noted is that the computer definitely cuts fuel until the engine hits op.temp. I have a climb on my way to work, it's about 5 minutes in so the turbo is hot but the coolant is not at temp. It definitely feels different when the truck is warmed up as opposed to coldish. It really seems like they designed these rigs to be indestructible - As in, trying to limit user stupidity as well!

Other than the trans lockup it's been behaving well, only one working glowplug though :D
 
Fromage said:
One thing I have noted is that the computer definitely cuts fuel until the engine hits op.temp. I have a climb on my way to work, it's about 5 minutes in so the turbo is hot but the coolant is not at temp. It definitely feels different when the truck is warmed up as opposed to coldish. It really seems like they designed these rigs to be indestructible - As in, trying to limit user stupidity as well!
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That maybe what is happening with Supertech's engine, maybe the coolant temp sensor has gone bad leading to his sudden loss of performance seemingly overnight.
 
Fromage said:
Naah, I chucked all those ball bearings... :grinpimp:

During the trans overhaul I just changed the valvebody gaskets and did not mess with anything internal. It might be something caused by the bad timing sensor that I drove on for a few weeks, it might be a burned up torque converter, but I am betting on an internal leak due to the noise I am hearing. The truck I parted was non-op so it might have been a pre-existing condition, and the trans has rebuild tags on it, so maybe the rebuild shop did something wrong. I am planning on having both valvebodies on the bench when I swap them and compare locations of all the check balls and try and reverse engineer the lockup circuit to figure out what might have failed, but I hope I find a blown gasket.

I ordered another gasket set and when it comes in I'll dive in deeper but right now it works fine without the lockup, no fault codes, etc.

I have also been messing with the timing and noticed a drop in mileage with it advanced, but the truck still sounds spot on for timing. It's unexpected. I'm going to pull it back a few degrees, past the original mark. This engine and pump do not respond to timing advances like a normal diesel.

One thing I have noted is that the computer definitely cuts fuel until the engine hits op.temp. I have a climb on my way to work, it's about 5 minutes in so the turbo is hot but the coolant is not at temp. It definitely feels different when the truck is warmed up as opposed to coldish. It really seems like they designed these rigs to be indestructible - As in, trying to limit user stupidity as well!

Other than the trans lockup it's been behaving well, only one working glowplug though :D
Click to expand...

What I meant was, did you check the schematic in the AW450 manual for where the ball bearings go, or did you just trust that they all stayed in the correct spot or were in the correct spot from the last rebuild? Or better yet, that they were all there...



From the sound of my engine, i think i might have the timing too far advanced now, but the mileage is good. I'm going to finish this tank and then mess with bringing the timing down a hair before running another tank through.
 
So, I think I found my problem and I am NOT happy.

I dropped the pan and the valvebody and decided to test the clutches and OD pistons with some compressed air. I have a leak in the rear clutch circuit, it looks like it's the O ring between the support and the case. It's a slight leak, but it would likely decrease the line pressure enough to affect the lockup.

What's weird is I pressure tested the circuit when I built the trans, and it was perfectly airtight. Now I have a leak that is definitely noticeable.

So, it looks like I am going to pulling this trans ASAP...
 
Fromage said:
So, I think I found my problem and I am NOT happy.

I dropped the pan and the valvebody and decided to test the clutches and OD pistons with some compressed air. I have a leak in the rear clutch circuit, it looks like it's the O ring between the support and the case. It's a slight leak, but it would likely decrease the line pressure enough to affect the lockup.

What's weird is I pressure tested the circuit when I built the trans, and it was perfectly airtight. Now I have a leak that is definitely noticeable.

So, it looks like I am going to pulling this trans ASAP...
Click to expand...

Wow, well that just sucks. I'm sorry man...



I feel terrible asking on the back end of such lousy news, but it is a super-simple questoin to answer.

When you start your truck cold, like 30*F outside and the truck has sat overnight. Does it immediately idle at 750RPM, or does it have a high idle until the engine is warm? This is with the warmup switch off BTW. Just curious...



Again, sorry out your trans. Are you going to attempt to repair that one, or just swap in an A442F if you can find one?
 
That is a real bummer! I've heard of other people running into problems with those O-rings. It is so easy to cut them when you slide the assemblies into the case.

Make sure that you have the little sleeve that goes in the center of the o-ring properly seated and that there are no burrs around the hole in the case that mates with the o-ring. As a precaution, I use Parker O-ring lube along the whole path that the o-ring will take as you slide the assembly into the case.

Good luck!
 
SuperHatch said:
Wow, well that just sucks. I'm sorry man...

I feel terrible asking on the back end of such lousy news, but it is a super-simple questoin to answer.

When you start your truck cold, like 30*F outside and the truck has sat overnight. Does it immediately idle at 750RPM, or does it have a high idle until the engine is warm? This is with the warmup switch off BTW. Just curious...

Again, sorry out your trans. Are you going to attempt to repair that one, or just swap in an A442F if you can find one?
Click to expand...

Plan is to suck it up and do it. I would try an A442F but honestly I don't have time to find one and pick it up. I have the spare 450-43LE too, and to fix the o-ring I only need to take the front apart, don't need to change the rear cover/spacer gaskets, so it should go relatively quick.

I wanted to ask you the same question. Mine high idles until warm. It's odd, so far the warmup switch doesn't seem to do anything. I have not really seen any change in behaviour with it on or off.

My glowplugs are all dead :hillbilly: It starts a little ruff at 15*F.
 
Fromage said:
Plan is to suck it up and do it. I would try an A442F but honestly I don't have time to find one and pick it up. I have the spare 450-43LE too, and to fix the o-ring I only need to take the front apart, don't need to change the rear cover/spacer gaskets, so it should go relatively quick.
Click to expand...

Good plan, just sucks to have to go through it.

Fromage said:
I wanted to ask you the same question. Mine high idles until warm. It's odd, so far the warmup switch doesn't seem to do anything. I have not really seen any change in behaviour with it on or off.

My glowplugs are all dead :hillbilly: It starts a little ruff at 15*F.
Click to expand...

Well that is the best news I've heard in a while.

My truck idles at ~750RPM at first start regardless of engine temperature.

I also developed a new symptom this weekend.

When I hit the throttle, my Speedometer jumps up irradically. When I let off the throttle and coast, it reads correctly.

I know I have a wiring issue, and I think I have voltage bleeding off of the governor drive circuit into other systems. Basically, the electronic linear DC motor in the governor is not receiving the correct voltage to move the rack the correct amounts. This is why it always idles the same at all engine temps and doesn't give me full throttle.

I plan on re-running new wires from the ECU to the governor and see what happens. I'll report back when I get to it, which with the holidays coming up, won't be anytime soon.

EDIT: How do I test my glow plugs? Multimeter?
 
Oye, that sucks. Did you make sure to leave the shielding on all the wires?

Re - glow plugs - I pulled them out of the head and tested them with booster cables and a battery, as well as a multimeter. Sometimes they have continuity but are shorted internally and don't get hot.
 
Fromage said:
Oye, that sucks. Did you make sure to leave the shielding on all the wires?
Click to expand...

Yep, must have missed something, crap happens. I figure I'm doing ok if out of 200-300 soldering joints I only have one issue. We'll see...

Fromage said:
Re - glow plugs - I pulled them out of the head and tested them with booster cables and a battery, as well as a multimeter. Sometimes they have continuity but are shorted internally and don't get hot.
Click to expand...

I guess that's one way to do it!




Did a little experiment when I got home today. I parked the truck and rev'd the engine while not moving. The speedo stayed at zero. I thought this was weird, so I backed the truck up and then forward again and parked, tried the same thing. This time the speedo jumped all over the place. So this leads me to believe that I have stray voltage jumping to one of the leads on the speedo sensor, not sure if positive or negative yet.

Then to determine if it was the wiring to the pedal position sensor, I turned up the fast idle knob, and sure enough the speedo started jumping around again. This tells me it is something in the wiring between the ECU and the electronic governor, not between the Pedal Position Sensor and the ECU.

Then I left the truck fast idling and went under the hood and jiggled the wires where the 10 pin and 3 pin connectors are going to the governor assembly. Looked back inside the cab and the speedo wasn't jumping around anymore.

Took the truck for a drive, and the speedo was slightly irradic, but not wild like it was initially.


I think I might have some spare time on Thursday to run 4 new wires from the ECU directly to the governor. (2 positive, 2 negative) Pins 12 and 25 on ECU connector BZ26A are negative, Pins 13 and 26 on the same connector are positive. Pin 2 of the 3-Pin connector and Pin 1 of the 10-Pin connector are positive and Pin 1 of the 3-Pin and Pin 2 of the 10-Pin are negative.

I'll also check to see if any of the wires in the existing harness have continuity to ground and/or to the speedo sensor wires. Say a prayer!!
 
Update:

So, I am getting good at pulling transmissions...:D

Trans has been apart completely, valvebody too, found a blown O-ring for the 2nd brake and an accumulator piston O ring that looked a bit rough. Re-measured the endfloat for everything, put it back together, reinstalled and refilled. That took a better part of the weekend.

Other than the O ring, I didn't really find anything odd that would affect the lockup circuit. I removed the spare valvebody from my spare trans and intend to go though it with a fine tooth comb, but I ended up reinstalling the same old valvebody with new gaskets after cleaning it all, checking the check ball locations and checking to make sure all the lockup-related pistons and valves were moving.

I only had 10L of ATF on hand so it's still low on fluid (holds 15 but the torque probably holds 2 or 3 so it's likely 2L low), but I took it for a drive and it drives way better. I am not sure what exactly caused the change but the shifts are a lot crisper, and it seems to downshift a lot faster. It also feels like the truck is not working as hard as it used to - It may be because I haven't driven it in a while and have been driving gas powered trucks.

However, it did not lock up, and I haven't applied voltage to the solenoid to verify whether or not the "mechanical" side of things is working. Will try and do that tonight.
 
Between the center support and the main case. One of the three O rings right where the valvebody pressure connections are. I believe it was the center one.

Kind of an amazing feeling going from putting check balls in a valvebody to driving it around in an afternoon.
 
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