Builds Mitsubishi 4D34-3AT3B diesel swap into 94 FZJ80 (1 Viewer)

[SuperHatch]

JL,

I have a plan, and this is up to you to try and figure out.

In the FSM, there are resistance values to check the primary rack position sensor. There is a specified range that is acceptable. Since this is an external test, it only gives the resistance value for when the rack is in the fully closed (engine off) position.

Can you please check the same pins, but slide the rack through its range and report the changes in resistance? I am curious if one of them is an on/off switch or closed/open or not, and how the values change throughout the travel (linear or not)

We can't simply move the sensor within the housing to change the values, since it would effect the low load fueling.

But we might be able to add some resistors in parallel/series to the sensor outputs, fooling the ECU into thinking the rack has not traveled as far as it actually has, giving a higher max fuel capability.

See attached picture...

 

[Fromage]

It will take me a bit of time to do this as my spare pump actually has a siezed rack. It's soaking in pen. fluid, and the rack does move, but the plungers are stock to the barrels in a bad way. I do think you are on the right track. We might only have to change the resistance of the main sensor, the secondary can be adjusted. I am also not sure that it would be an issue at idle, as the computer regulates the fuel rate based on RPMs, and would likely have the ability to reduce the rack position accordingly. Could we put a pot. in series there for fine tuning?

Stumped by the lockup. I am hoping it is something simple...

JL

 

[SuperHatch]

It will take me a bit of time to do this as my spare pump actually has a siezed rack. It's soaking in pen. fluid, and the rack does move, but the plungers are stock to the barrels in a bad way. I do think you are on the right track. We might only have to change the resistance of the main sensor, the secondary can be adjusted. I am also not sure that it would be an issue at idle, as the computer regulates the fuel rate based on RPMs, and would likely have the ability to reduce the rack position accordingly. Could we put a pot. in series there for fine tuning?

Stumped by the lockup. I am hoping it is something simple...

JL

Yea, if not in series, maybe parallel. It all depends on what the resistances are.

Also, according to the FSM, the ECU only uses the sub rack sensor if the primary sensor fails. I am considering severing one of the primary rack sensor wires temporarily to force it to use the secondary sensor and see if power increases.

Also considering comparing the two sensors outputs to see if they are the same, and switching the roles so that it can be easily adjusted.



Let me know if you need help troubleshooting the TC issue.

 

[Fromage]

So, I tackled finishing up a few little niggles, including wiring in the power and o/d button.

The power button made a huge difference. It downshifts a lot sooner on acceleration, holds lower gears longer in acceleration, it feels like a totally different truck. SuperHatch, just run a 12V lead to the right lead straight away, even if only temporarily, I think you'll be very happy with the results. I also installed the block off plug for the pop off valve and I got 22 PSI peak boost on my test hill.

I did run into one issue in diagnosing my no-lockup condition. I have a fault code, but I can't find the fault code table for the AW450-43LE trans. I thought I had it, but I only have the Toyota manual and the Fuso manuals I have do not have the trans supplement. To make things even more annoying, I could swear I saw this posted here in the last few days, but I just can't find it anywhere. Whatever it is, it has not worked since day one, and I am hoping it's something simple, like a bad solenoid or something. I'll keep you all posted on developments, but if anyone has the Isuzu trans manual, please post up the fault codes for the trans.

Thanks!

 

[astr]

So, I tackled finishing up a few little niggles, including wiring in the power and o/d button.

The power button made a huge difference. It downshifts a lot sooner on acceleration, holds lower gears longer in acceleration, it feels like a totally different truck. SuperHatch, just run a 12V lead to the right lead straight away, even if only temporarily, I think you'll be very happy with the results. I also installed the block off plug for the pop off valve and I got 22 PSI peak boost on my test hill.

I did run into one issue in diagnosing my no-lockup condition. I have a fault code, but I can't find the fault code table for the AW450-43LE trans. I thought I had it, but I only have the Toyota manual and the Fuso manuals I have do not have the trans supplement. To make things even more annoying, I could swear I saw this posted here in the last few days, but I just can't find it anywhere. Whatever it is, it has not worked since day one, and I am hoping it's something simple, like a bad solenoid or something. I'll keep you all posted on developments, but if anyone has the Isuzu trans manual, please post up the fault codes for the trans.

Thanks!

Here are the Isuzu AW450 codes:

 

[Fromage]

Thanks a million Andy, but I am getting a clear 54 code from the TCM. I am wondering if there is not another table for the Fuso. I am sure I have seen it somewhere, I'll see if perhaps SuperHatch knows. I am positive it is a code for lockup, probably overspeed in lockup mode (not locking up).

 

[SuperHatch]

That is the exact chart I was about to post... since i have the Isuzu manual as well.

 

[SuperHatch]

Just check the aisin seiki code for their 6 speed trans i the newer trucks. Code 54 is for EXH Brake Cut Signal. Don't know if it is the same for this trans, but sometimes manufacturer codes cross over.

 

[Fromage]

DUH. According to the manual(which finally finished downloading), the three first pulses don't mean anything. I believe I actually have a code 24, which is the #2 VSS (which, on the fuso, is the only VSS). This would explain a whole lot. More tomorrow!

 

[SuperHatch]

The explains a whole lot, and is a whole lot easier to change than a shift solenoid!

 

[Fromage]

It's a saved code. It does not turn on the TCM light while driving, only in diag mode. I tried to clear it, but it does not clear with the 5 second disconnect. The clear procedure in the Isuzu manual doesn't work. Regardless, I don't think it is an issue. I disconnected the VSS and the trans will not shift, so I doubt that is the issue. I also dropped the pan and checked the solenoid, which is working, and established which pin it is connected to on the trans connector. I then put the truck in neutral on the T case and drove it up to OD, and tried to establish whether or not a signal was being sent to the trans to lock up, but I wasn't really able to figure anything conclusive out. I will try again later.

To be honest I am not sure if it is locking up. Without a tach, it's really tough to be 100% sure. I am not getting any codes, and I would expect a code if there was an issue, but then again the roads are so bad here, it's tough to get a straight stretch to do a run and be sure. I think I still have my Fuso cluster, I'll probably put the tach in before I move down this any further.

Nice to have the little bits buttoned up. The warm-up switch is a nice touch, and the glow plugs help it fire up quick.

 

[astr]

When I was testing my AW450, it was very clear that the torque converter was locking up - felt almost like it was shifting into a 5th gear. This coincided with the torque converter lockup indicator light coming on that I have wired up.

For whatever it is worth, it took me quite a few tries to figure out how to clear the codes using the FSM instructions. The literal translation from Japanese left a lot to be desired. I can't quite remember what the final sequence was that worked.

 

[Fromage]

So, I had it up to very fast in neutral on the T case, and no voltage switch at the pin for the lockup. As soon as I unplugged the wiring though, it flashed me a CEL, and stored code 34 (lockup sol. to ground or broken). This is a relief. It means the ECU is not switching it. I am getting a 0.00V, so there is a connection with the ECU, it's just at zero voltage.

Since I am not getting any codes, I can only assume that one of the inputs that is required for lockup is not present. The trans shifts into 4th, so I am assuming the temp sender in the pan is working, and everything else is OK (shifts fine). I am going to go on a hunch and have a look at the exhaust brake wiring...

 

[Dougal]

They haven't done something lucas-like and switched the earth instead of the power via the ECU?

 

[SuperHatch]

When I was testing my AW450, it was very clear that the torque converter was locking up - felt almost like it was shifting into a 5th gear.

Ditto, it is very very obvious that the converter locks up.

 

[Fromage]

This is not making any sense.

So, I rechecked all the exhaust brake wiring, everything is good. I actually wired up an indicator light, to tell me when the exhaust brake is supposed to be on (the wiring is there but nothing else). Not sure if you guys have experimented with this, but the behaviour is not what I expected.

It seems to be on all the time. I expected it to come on when the brake is applied, but it's on at idle (regardless of warm up switch being on or off), and as soon as the accelerator is depressed, it shuts off. It's basically like an on-off switch that is run by the accelerator.

I'm thinking there might be an issue here...

I then ran a wire from the connector on the transmission for the lockup solenoid (yellow and red), to a light inside the vehicle. I took it for a drive and it is definitely not locking up.

This is where it got weird.

I took the wire, and put it to 12V, expecting the torque to lock up and the truck to lurch forward. Nothing happened. There was a small spark (indicating that some amperage was behind the wire, IE it is connected to the solenoid), but it didn't make any difference. The truck just kept idling normally.

So, it looks like I have both a control issue, and a solenoid issue.

Question for you SuperHatch, when the trans fluid is cold, will it shift into OD, but not into lockup, or does it restrict you to 3rd until it warms up?

 

[SuperHatch]

Question for you SuperHatch, when the trans fluid is cold, will it shift into OD, but not into lockup, or does it restrict you to 3rd until it warms up?

When I leave in the AM for work, it has been about 40 degrees. I let the truck idle for a minute or less before leaving.

I am restricted from overdrive for less than 2 or 3 minutes. I am restricted from lockup for 5 or 6 minutes. So it is definitely temperature dependant.

I also have to be at a very light throttle application for it to lock up, sometimes I let off the throttle for it to lock and then get back on the throttle.



There are two main plugs that connect to the trans. The one is on the shift position sensor. The second connects to all of the solenoids inside of the trans. I'm trying to remember of one of the wires is +12V hot, and all of the solenoids are triggered by ground, or if they've all got a ground and they're triggered by power. Either way, if one some of the slenoids are working, they all should work.

But if they've all got power, then you should try giving it ground to test it out, not 12V.

 

[Fromage]

Very interesting that the lockup is at a different temp threshold than 3rd.

So, I pulled the pan. All the solenoids have but one connection, they are grounded to the trans body to complete the circuit. I noticed that the trans temp sender is in a different spot than the one in Astr's trans, so I relocated it. I also tested the solenoid, which was in spec, ohm wise, and it works fine.

Did you run your ATF cooler loop through the rad? I ran it separate. It's possible that the trans never hits op temp, but it gets super warm to the touch after a long drive, and with the torque converter slipping a whole lot, I'd imagine it would heat up really fast.

I am hoping (!!!) that the location of the temp sender has something to do with it. How much of your exh. brake did you get wired up?

 

[SuperHatch]

Very interesting that the lockup is at a different temp threshold than 3rd.

I am not 100% certain that it is different temps, it might also have to do with the speeds of the roads I drive on my way to work in the morning.

So, I pulled the pan. All the solenoids have but one connection, they are grounded to the trans body to complete the circuit. I noticed that the trans temp sender is in a different spot than the one in Astr's trans, so I relocated it. I also tested the solenoid, which was in spec, ohm wise, and it works fine.

Did you run your ATF cooler loop through the rad? I ran it separate. It's possible that the trans never hits op temp, but it gets super warm to the touch after a long drive, and with the torque converter slipping a whole lot, I'd imagine it would heat up really fast.

I am hoping (!!!) that the location of the temp sender has something to do with it. How much of your exh. brake did you get wired up?

Yes, my ATF cooler is run just like stock, through the rad and cooler. If your temp sender wasn't in the fluid, that could be your problem.

I never wired any of the exh brake, I couldn't find room to mount the fuso brake with the exh run inside the rail, so I abandoned that idea. I capped every wire... I labeled them for the option later, but no plans for it right now.

 

[Dougal]

For the exhuast brake, here is how it works on an NPR. Mitsubishi should be doing something similar.

On an Isuzu NPR there is a switch on the washer stalk for exhaust brake on/off. This is essentially the master switch. From there the clutch and accelerator pedals have kill switches which turn the exhaust brake off.

At idle the exhaust brake obviously bypasses enough that it doesn't choke the engine, but the exhaust note does audibly change. Touch the accelerator or clutch and the brake switches off. Obviously you have no clutch pedal, it may use the P/N selector switch instead.