80 series computer code?

[landcruiser3DP]

"This is why AI is still bullshǐt and why human knowledge and experience is still indispensable in certain fields of technical knowledge."

Agree 100% about AI. Often when I ask Grok a complicated question it gets it wrong so have to ask it again and again, then it may get confused and stop responding. You can see by closely reading some of Grok's responses he was making a lot of assumptions and guesses.

The main purpose of posting what Grok said for anyone thinking about messing with the ECM/ECU was to give them a general idea (from what Grok dreamt) of how difficult it might be to try to reverse engineer anything that old. IME currently Grok works best as an advanced search tool that can review information from dozens of websites in seconds, but it's not yet a human brain replacement or thinking tool.

As OGBeno said, it doesn't have human experience so IME it seems to work best when the person asking the question is already
a subject matter expert (@TrickyT ) in the area of the question and can call BS and catch errors, which in this case I'm absolutely not that guy.

I do find it interesting however to watch how Grok thinks through a problem particularly if you give it a complicated math or physics question, it seems
fairly good at those.

FWIW

i find it interesting to talk to people and just using grok i find very interesting. so irrespective of what your actual results are i find it nice to be able to talk to people freely. because it's always interesting to see where people take productive discussion.

 

[landcruiser3DP]

I think Grok is misleading you badly about the FZJ80 ECU. It's providing general background knowledge about ECU's and trying to say that it applies specifically to the FZJ80 when it doesn't have any direct information about that ECU. Why do I say this? Because the FJZ80 is completely proprietary.

The FZJ80 ECU was designed and manufactured by Fujitsu Ten Limited. It uses custom silicon for which no datasheets are available. The heart of the FZJ80 are four Fujitsu Ten integrated circuits. The part numbers of those ICs are 211923-2040, 211923-5300, 211923-6340, 211923-6690. You can search all day for information on those ICs and you won't find anything. They obviously make up some kind of CPU, but the architecture and instruction set are unknown and so are whatever algorithms Fujitsu Ten used in the implementation. I've attached a photo of the processor board from a 89661-60652 ECU, which is the updated 1997 OBD-II automatic transmission version manufactured from 03/1997 - 12/1997, so you can get an idea of the technology used in that era. As @jonheld said, it's 1990's or earlier technology. Common home computers of that time frame were things like the Commodore 64 or the Amiga, and they typically used Intel 80286 or 80386 CPUs that were implemented on a single IC. So if Fujitsu Ten was using four custom IC's instead of one, then they could have easily been using 1980's tech. At any rate, without access to internal Fujitsu Ten documentation you're never going to be able to decode the details of what's going on inside this ECU.
View attachment 4015306

thank a lot. i also find the wiki links kindly provided to be very helpful but of course it's a lot of information.
can i just ask a couple more here?
is there a way to coherently explain what is happening?
there is a proprietary fujitsu ten central processing unit (which is the silver enclosed thing buried in the dash?) that contains a processor board or boards (with integrated circuit chips) that were encoded (?) with some computer language telling everything how to behave?
and then there are various physical and computerized sensors and actuators of various kinds with microcontrollers that are connected via the harness?
or is there a good way to explain this?
also - well this guy lutz that does a speedo adjuster module (and there are earlier ones) - they must be hacking into something, no? or he's just hacking into the signal going to the actual speedometer i guess so he's just hacking between the input and output basically since the signal goes directly from the input to the output? so it's just adjusting the electrical signal independent of anything else?(!)

 

[TrickyT]

...
there is a proprietary fujitsu ten central processing unit (which is the silver enclosed thing buried in the dash?) that contains a processor board or boards (with integrated circuit chips) that were encoded (?) with some computer language telling everything how to behave?

Yes, that's it.

and then there are various physical and computerized sensors and actuators of various kinds with microcontrollers that are connected via the harness?
or is there a good way to explain this?

None of the sensors on the FZJ80 contain microprocessors that I'm aware of. But they all emit some type of signal that varies with some aspect of engine operation. The simplest is the coolant sensor. It's essentially a variable resistor whose value depends on temperature. If you look on page EG-166 of the 1997 FSM there's a graph of the resistance value versus temperature. The value ranges from about 20 kilo-ohms at -20°F down to about 200 ohms at 212°F. One terminal on the sensor is connected to vehicle ground and the other goes to one the ECU inputs and is used, along with other sensor inputs, to control how the engine behaves depending on coolant temperature. The EGR temperature sensor works similarly.

As engine technology has advanced over the years, more and more sensors have been added. Off the top of my head, the FZJ80 has a throttle position sensor, a mass air flow sensor, an air intake temperature sensor, the aforementioned coolant and EGR temperature sensors, crankshaft and camshaft position sensors, 2 knock sensors, 2 oxygen sensors, 2 speed sensors, and a A/T temperature sensor. The ECU uses all of these as inputs to sophisticated algorithms executing in the ECU to control things like when and for how long each injector is open for, when the ignition coil fires so that it can advance or retarding the timing, how much to open the idle air control valve, what speed (high or low) the fuel pump runs at, when to open or close the EGR valve, etc. And the ECU also decides when somethings is not working right (like a sensor input that is out of range) so it can turn on the Check Engine lamp and throw an OBD-II code.

also - well this guy lutz that does a speedo adjuster module (and there are earlier ones) - they must be hacking into something, no? or he's just hacking into the signal going to the actual speedometer i guess so he's just hacking between the input and output basically since the signal goes directly from the input to the output? so it's just adjusting the electrical signal independent of anything else?(!)

Yes, you got it. The #1 vehicle speed sensor generates a series of pulses the frequency of which varies with vehicle speed and this signal is both displayed on the combination meter and serves as an input to the ECU. The "Yellow Box" gets connected between the speed sensor and the combination meter as shown in your diagram. The circuitry in the box then just divides the pulse frequency by the ratio you set it to. So, for example, if the ratio is set to 1.042 and the sensor is sending 50 pulses per second into the box, the box outputs 50 / 1.042 = 47.98 pulses per second and this modified signal is what then gets sent to the combination meter and ECU. I don't know if it's still sold, but Slee Off Road used to sell a small plastic gear that you would replace your stock transfer case speedometer gear with. It had a different number of teeth than the stock speedo gear and thus would effectively also decrease the pulse frequency sent by the speed sensor. The Yellow Box is more effective because you can choose any number of different ratios, but Slee's gear worked on the same principle only doing it mechanically instead of electronically.

View attachment 4015429

View attachment 4015430

 

[NeverFinis]

Yes, you got it. The #1 vehicle speed sensor generates a series of pulses the frequency of which varies with vehicle speed and this signal is both displayed on the combination meter and serves as an input to the ECU. The "Yellow Box" gets connected between the speed sensor and the combination meter as shown in your diagram. The circuitry in the box then just divides the pulse frequency by the ratio you set it to. So, for example, if the ratio is set to 1.042 and the sensor is sending 50 pulses per second into the box, the box outputs 50 / 1.042 = 47.98 pulses per second and this modified signal is what then gets sent to the combination meter and ECU. I don't know if it's still sold,

Lutz Auto sells one and it is very good. I have it installed.

 

[landcruiser3DP]

here's this lutz speedo adjustment thing. i guess he grabs the signal from the microprocessors unit or mechanical electrical unit or whatever at the crank (?) and modifies it before it gets to the speedometer.

Microsoft OneDrive

onedrive.live.com

 

[landcruiser3DP]

Yes, that's it.

None of the sensors on the FZJ80 contain microprocessors that I'm aware of. But they all emit some type of signal that varies with some aspect of engine operation. The simplest is the coolant sensor. It's essentially a variable resistor whose value depends on temperature. If you look on page EG-166 of the 1997 FSM there's a graph of the resistance value versus temperature. The value ranges from about 20 kilo-ohms at -20°F down to about 200 ohms at 212°F. One terminal on the sensor is connected to vehicle ground and the other goes to one the ECU inputs and is used, along with other sensor inputs, to control how the engine behaves depending on coolant temperature. The EGR temperature sensor works similarly.

As engine technology has advanced over the years, more and more sensors have been added. Off the top of my head, the FZJ80 has a throttle position sensor, a mass air flow sensor, an air intake temperature sensor, the aforementioned coolant and EGR temperature sensors, crankshaft and camshaft position sensors, 2 knock sensors, 2 oxygen sensors, 2 speed sensors, and a A/T temperature sensor. The ECU uses all of these as inputs to sophisticated algorithms executing in the ECU to control things like when and for how long each injector is open for, when the ignition coil fires so that it can advance or retarding the timing, how much to open the idle air control valve, what speed (high or low) the fuel pump runs at, when to open or close the EGR valve, etc. And the ECU also decides when somethings is not working right (like a sensor input that is out of range) so it can turn on the Check Engine lamp and throw an OBD-II code.

Yes, you got it. The #1 vehicle speed sensor generates a series of pulses the frequency of which varies with vehicle speed and this signal is both displayed on the combination meter and serves as an input to the ECU. The "Yellow Box" gets connected between the speed sensor and the combination meter as shown in your diagram. The circuitry in the box then just divides the pulse frequency by the ratio you set it to. So, for example, if the ratio is set to 1.042 and the sensor is sending 50 pulses per second into the box, the box outputs 50 / 1.042 = 47.98 pulses per second and this modified signal is what then gets sent to the combination meter and ECU. I don't know if it's still sold, but Slee Off Road used to sell a small plastic gear that you would replace your stock transfer case speedometer gear with. It had a different number of teeth than the stock speedo gear and thus would effectively also decrease the pulse frequency sent by the speed sensor. The Yellow Box is more effective because you can choose any number of different ratios, but Slee's gear worked on the same principle only doing it mechanically instead of electronically.

man thanks so much. also thanks to the moderator for tagging you.
so can i just ask you if there is a list that you can think off off the top of your head for "purely mechanical" sensors or mechanisms? actually i am not even sure how to ask this but like on the side AC fluid clutch (or whatever) there is like that bimetallic spring that opens and closes the size of the fluid holes?
then the speedo sensor senses a magnetic strip in the crank? so is that like a hall sensor in my old BMW motorcycle?
sorry maybe you answered this already but are some of these purely - well the the coolant sensor is a "variable resistor" so this is like inherently an electronic component? but are there others that are sort of more physical?
sorry if that's a bad question just kind of curious about this physical and electronic sensor and actuator (if that's even a good term) thing too...

 

[landcruiser3DP]

Yes, that's it.

None of the sensors on the FZJ80 contain microprocessors that I'm aware of. But they all emit some type of signal that varies with some aspect of engine operation. The simplest is the coolant sensor. It's essentially a variable resistor whose value depends on temperature. If you look on page EG-166 of the 1997 FSM there's a graph of the resistance value versus temperature. The value ranges from about 20 kilo-ohms at -20°F down to about 200 ohms at 212°F. One terminal on the sensor is connected to vehicle ground and the other goes to one the ECU inputs and is used, along with other sensor inputs, to control how the engine behaves depending on coolant temperature. The EGR temperature sensor works similarly.

As engine technology has advanced over the years, more and more sensors have been added. Off the top of my head, the FZJ80 has a throttle position sensor, a mass air flow sensor, an air intake temperature sensor, the aforementioned coolant and EGR temperature sensors, crankshaft and camshaft position sensors, 2 knock sensors, 2 oxygen sensors, 2 speed sensors, and a A/T temperature sensor. The ECU uses all of these as inputs to sophisticated algorithms executing in the ECU to control things like when and for how long each injector is open for, when the ignition coil fires so that it can advance or retarding the timing, how much to open the idle air control valve, what speed (high or low) the fuel pump runs at, when to open or close the EGR valve, etc. And the ECU also decides when somethings is not working right (like a sensor input that is out of range) so it can turn on the Check Engine lamp and throw an OBD-II code.

Yes, you got it. The #1 vehicle speed sensor generates a series of pulses the frequency of which varies with vehicle speed and this signal is both displayed on the combination meter and serves as an input to the ECU. The "Yellow Box" gets connected between the speed sensor and the combination meter as shown in your diagram. The circuitry in the box then just divides the pulse frequency by the ratio you set it to. So, for example, if the ratio is set to 1.042 and the sensor is sending 50 pulses per second into the box, the box outputs 50 / 1.042 = 47.98 pulses per second and this modified signal is what then gets sent to the combination meter and ECU. I don't know if it's still sold, but Slee Off Road used to sell a small plastic gear that you would replace your stock transfer case speedometer gear with. It had a different number of teeth than the stock speedo gear and thus would effectively also decrease the pulse frequency sent by the speed sensor. The Yellow Box is more effective because you can choose any number of different ratios, but Slee's gear worked on the same principle only doing it mechanically instead of electronically.

wow that Slee gear thing sounds kind of genius...

 

[TrickyT]

Oh wait, there's more. The FZJ80 ECU also decides at what vehicle speed and engine load the transmission shifts, what gear to use, and when to lock the torque converter. So there a whole lot going on in that "silver enclosed thing under the dash" as you put it. And to give you an idea of how rapidly vehicle control electronics has progressed I'll just note that my 2014 FJ Cruiser has at least 12 "Electronic Control Units" including engine control, skid control, crawl control, body control, 4WD and diff lock control, clearance warning, transponder key ECU, tire pressure ECU, occupant classification ECU, airbag control and some other simple stuff like air conditioner control. And most are connected to one another using the "body electronics area network" (BEAN) bus. And this is all in a vehicle that first hit the US market in 2007. I have no idea what ECUs are in one of the new 2024/2025 Land Cruisers, but there's got to be even more. So troubleshooting and repair now a days is mostly about electronics and understanding how all these ECUs and sensors relate to one another. It would require a lot of study to become a Toyota Master Mechanic in today's world.

 

[TrickyT]

man thanks so much. also thanks to the moderator for tagging you.
so can i just ask you if there is a list that you can think off off the top of your head for "purely mechanical" sensors or mechanisms? actually i am not even sure how to ask this but like on the side AC fluid clutch (or whatever) there is like that bimetallic spring that opens and closes the size of the fluid holes?
then the speedo sensor senses a magnetic strip in the crank? so is that like a hall sensor in my old BMW motorcycle?
sorry maybe you answered this already but are some of these purely - well the the coolant sensor is a "variable resistor" so this is like inherently an electronic component? but are there others that are sort of more physical?
sorry if that's a bad question just kind of curious about this physical and electronic sensor and actuator (if that's even a good term) thing too...

Yes, there are plenty of mechanical based controls and also several based on engine vacuum. If you've looked at the FSM you've no doubt seen references to "VSV" (vacuum switching valves). Controlling engine and vehicle operation using vacuum sensors and valves is a whole other topic. If you ever get the chance look at the vacuum hose routing diagram for, say, a 1978 FJ40. It will boggle you mind!

 

[NeverFinis]

here's this lutz speedo adjustment thing. i guess he grabs the signal from the microprocessors unit or mechanical electrical unit or whatever at the crank (?) and modifies it before it gets to the speedometer.

Microsoft OneDrive

onedrive.live.com

Lutz's device just increases or decreases pulse frequency from the speed sensor located at end of the t-case. It acts as a man in the middle. Speed sensor is just a magnetic pulse signal.

Crank isn't involved.

 

[OGBeno]

wow that Slee gear thing sounds kind of genius...

They are actually just different toothed Toyota gears from other Land Cruisers that use the same speedometer plug into the tail housing for the transfer case. Diesels received different toothed gears, as did different market FZJ80 trucks during the same time period.

I believe there are 4 different toothed gears that can be put into the same plug at the transfer case.