LJ78 OD Limp Mode Issue

[Reedys]

Well… quick update:

1) ECU shop was booked out till the start of March.

2) Decided to take it to Toyota today, they seem to think it’s the transmission causing the issue. Funnily enough it drove completely normal from my house to the shop too. Almost as if the car knew - first time that’s happened in a very long time.

They performed a transmission stall test and unfortunately it failed. So they have advised me to take it to a transmission specialist for further testing. Booked in for the end of this month.

Losing this battle, but grateful to hopefully finally have a solution… although this will definitely break the bank. 🫩

Will update as I know more,

Thank you all for your help.
- R

 

[Reedys]

Update: Transmission shop said kick down cable was misadjusted, they fixed it but it didn’t fix the issue.

They believe it might actually be a motor/turbo/vac issue so have advised I take it to a mechanic as they can’t do any further testing till that’s fixed.

Turbo has been replaced, and I replaced the vac lines so maybe time for another compression test. Although, has passed the two most recent comp tests. Once again feel quite stumped haha.

Probably worthwhile to take it into the ECU shop once they’re back at the start of March.

Till next time

 

[AirheadNut]

That's frustrating! Hopefully the ECU shop can find something. What manuals are you still looking for? There should be a chassis/body manual and engine manual applicable to your LJ78 available in the Resources tab, I don't see one for the A343f transmission though. There are some manuals here but they may be a bit different since they're for either an 80 or 100-series. I just uploaded a copy of the Denso electronic injection pump service manual that may be helpful chasing issues with that system.

 

[Reedys]

That's frustrating! Hopefully the ECU shop can find something. What manuals are you still looking for? There should be a chassis/body manual and engine manual applicable to your LJ78 available in the Resources tab, I don't see one for the A343f transmission though. There are some manuals here but they may be a bit different since they're for either an 80 or 100-series. I just uploaded a copy of the Denso electronic injection pump service manual that may be helpful chasing issues with that system.

Hey Airhead,

Really appreciate your reply and the build thread, I’ve learned a lot from it since owning my car. I’ve honestly struggled to find working links to most of the manuals, so the Denso pump one is new to me, thank you. If you come across anything else, feel free to tag me or drop it here.

After reading through the Denso manual, I’ve decided to replace both the TPS and the coolant temp sensor, as quite a few of my symptoms seem to line up with those failing.

Hoping that, along with getting the kickdown cable sorted, finally puts this issue to bed.

Based on the manual it does seem like the coolant sensor is the more likely culprit, potentially the TPS so figured I may as well replace that too, especially since it’s missing one of the mounting screws, which can’t be helping things.

Thank you,

 

[humza0007]

Hey Airhead,

Really appreciate your reply and the build thread, I’ve learned a lot from it since owning my car. I’ve honestly struggled to find working links to most of the manuals, so the Denso pump one is new to me, thank you. If you come across anything else, feel free to tag me or drop it here.

After reading through the Denso manual, I’ve decided to replace both the TPS and the coolant temp sensor, as quite a few of my symptoms seem to line up with those failing.

Hoping that, along with getting the kickdown cable sorted, finally puts this issue to bed.

Based on the manual it does seem like the coolant sensor is the more likely culprit, potentially the TPS so figured I may as well replace that too, especially since it’s missing one of the mounting screws, which can’t be helping things.

Thank you,

Hi, i have just registered after reading all your issues with your vehicle. I have a 1992 toyota lj78 jap import 2.4 turbo diesel 2L-TE. I have. A very similar issue. Mine starts and drives perfect from cold but when it warms up so around 30 minutes of the vehicle started wether its stationary or running the red turbo light comes on and goes into limp mode.. i have checked all hoses, replaced hoses, cleaned egr, cleaned fuel system but the issue still persists. I cannot find map sensor online at all there is 1 at $500.

 

[humza0007]

Hi, i have just registered after reading all your issues with your vehicle. I have a 1992 toyota lj78 jap import 2.4 turbo diesel 2L-TE. I have. A very similar issue. Mine starts and drives perfect from cold but when it warms up so around 30 minutes of the vehicle started wether its stationary or running the red turbo light comes on and goes into limp mode.. i have checked all hoses, replaced hoses, cleaned egr, cleaned fuel system but the issue still persists. I cannot find map sensor online at all there is 1 at $500.

And forgot to mention exhaust is really smelly and smokey … smokes more when the turbo light comes on. Like a carbon sort of smell

 

[humza0007]

And forgot to mention exhaust is really smelly and smokey … smokes more when the turbo light comes on. Like a carbon sort of smell

Can anyone zoom in to the hoses and check they are routed correctly?

 

[Reedys]

Hi, i have just registered after reading all your issues with your vehicle. I have a 1992 toyota lj78 jap import 2.4 turbo diesel 2L-TE. I have. A very similar issue. Mine starts and drives perfect from cold but when it warms up so around 30 minutes of the vehicle started wether its stationary or running the red turbo light comes on and goes into limp mode.. i have checked all hoses, replaced hoses, cleaned egr, cleaned fuel system but the issue still persists. I cannot find map sensor online at all there is 1 at $500.

Hey Humza, sorry to hear that. I’m still working on my issue too. Currently waiting on a second hand kickdown cable, have a new TPS & water temp sensor. The only place I was able to find a new MAP sensor was on a random marketplace. Sorry that did take me some time, but there’ll be some out there just keep looking until one comes up. Wishing you the best of luck. Let me know if you fix yours up.

 

[humza0007]

Hey Humza, sorry to hear that. I’m still working on my issue too. Currently waiting on a second hand kickdown cable, have a new TPS & water temp sensor. The only place I was able to find a new MAP sensor was on a random marketplace. Sorry that did take me some time, but there’ll be some out there just keep looking until one comes up. Wishing you the best of luck. Let me know if you fix yours up.

No luck yet finding MAP sensor, have checked cleaned all pipes, had 5 different mechanics look at checked all turbo wastegate etc all checked cleaned but no luck. Still working on it.