TOYOCOM :: UNIVERSAL MODE how to monitor fuel trim

Getting fuel trim into toyobd1

All pre-obd2 diagnosis box have the VF(1) contact pin.
Depending on the ECU and production years some can output the obd1 data stream ,some will only give the fuel trim.

following the theory found here https://people.well.com/user/mosk/Vfsignal.htm a toyocom sensor curve was written for it.

The fuel trim tells us how much the ECU believes the engine is out of tune, a near 0% is a perfect score.

Android app setup

With toyobd1 running and the bluetooth connection established with your toyocom.
Go to main menu /configuration / Display
in there check the VF1 checkbox

Go back to the main display, there you will find the new VF1 cell
in that cell you will find a button in it`s upper right corner. Press on it.
a dialog will appear for you to choose a sensor curve to use for VF1.
In there using the drop down menu select 'Toyota obd1 fuel trim'
then press the apply sensor curve button
the dialog will go away and the new senor curve will be applied on the VF1 display cell.

TOYOCOM :: OBD1 MODE

WHAT IS IT DESIGNED FOR

Meant to read the Toyota obd1 data stream found on a known list of vehicles
for an up to date list please have a look here

 ENGINE ERROR CODES

Engine error codes output can be triggered with the tool, depending on the car`s wiring diagram it may lack the W wire in the diagnosis box to get the codes into the toyocom, in this sitatuation one must rely on eye reading and compare with the chart built into the error codes glossary built into the android app. On cars with complete wiring the error codes are fed into the tool and the android app.

CUSTOM INPUTS

Additionally it allows to read simultaneously custom inputs from different spaces in the diagnosis box, (VF2,TS,TT,AB) This allows to replace the SPD,RPM,INJ reading with custom sourced signals which are read more often (faster on screen). It also allows to just route additional sensors into the tool.

TOYOCOM :: UNIVERSAL MODE

WHAT IS IT DESIGNED FOR

Meant for Toyota cars before the obd1 data stream. Quite limited in comparison with the OBD1 mode and more involving but still relevant on cars with nothing at all. On older cars VF (fuel trim) can be read directly off the diagnosis box, this tells us how much the engine is out of tune, with the added installation of  the 'one wire setup' one can see the injector usage in conjunction with the fuel trim at any given RPM making for a deeper understanding of the situation, useful for engine tuning on stock ECUs or health monitoring for a daily driver.

 ENGINE ERROR CODES

Engine error codes output can be triggered with the tool, depending on the car`s wiring diagram it may lack the W wire in the diagnosis box to get the codes into the toyocom, in this sitatuation one must rely on eye reading and compare with the chart built into the error codes glossary built into the android app. On cars with complete wiring the error codes are fed into the tool and the android app.

CUSTOM INPUTS

Additionally it allows to read simultaneously custom inputs from different spaces in the diagnosis box, (VF2,TS,TT,AB) This allows to replace the SPD,RPM,INJ reading with custom sourced signals which are read more often (faster on screen). It also allows to just route additional sensors into the tool.

TOYOCOM :: the one wire interface

 Allows to compute fuel consumption ,trip information and basic injector usage out of one added wire on nearly all early EFI toyotas, without the obd1 data stream.

benefits

• extremely easy one wire job, fast and simple.
• allows to get many information out of it
• -injector opening
• -engine rpm
• -injector duty cycle
• -fuel consumption
• -fill the built in trip computer
• faster refresh rate than regular obd1 mode

pitfalls

• loses RPM when injection stops, happens when deceleration fuel cut off occurs

*All pictures in this post have been highlighted in blue to improve understanding

TEST MULE

1997 1mz-fe V6 in an MR2  , without relying on obd2 or obd1, using only the Toyocom universal mode

PHYSICAL WORK ON THE CAR

• you need to have a toyocom as found on www.zf-scantools.com
• you need a diagnosis box with at least +B and E1 (grey and black diag boxes have it, obd2 cars might lack some pins)

1MZ-FE DIAGNOSIS box with added VF2 contact pin

install a new wire from VF2 in the diagnosis box to one injector wire of cylinder 1 (#1 or #10 on the wiring diagram of your engine. for this particular installation the last cylinder of the front bank was chosen due to the ease of reach.

A T-junction was made at the #6 wire where it was easy to reach

the same zone seen from a far before the new wire was tucked in

follow this link to understand how to open up the diagnosis box and add a new metal contact in there for your new wire

ANDROID APP SETUP

following this video you should be able to mimick the setup for your own car. resumed below are the steps.

• go to main menu
• go to display settings
• show GPS
• show VF2
• show VF2-2
• remove obd1 specific fields
• go back to main menu
• go back to main display
• click on VF2 cell
• apply injector opening sensor curve on VF2 (leave MS as the measurement unit)
• apply injector opening sensor curve on VF2-2 (swipe up on the cell to reach either RPM4,RPM6,RPM8)
• go to main menu
• go to device features
• set the tool to UNIVERSAL MODE
• set VF2 as frequency input
• set rpm channel to VF2-2
• set injector channel to VF2
• set speed channel to GPS
• press apply device config
• go back to main menu
• go back to main display
• you can additionally remove VF2,VF2-2 if you wish to clean the display, this won`t break your setup.

THEORY OF OPERATION

Free from the phone itself we get GPS moving speed.
By monitoring an injector wire we can get 2 different readings

• injector opening duration
• engine rpm

with those 3 key readings are computed injector duty cycle, fuel consumption,MPG and the trip computer data.

TOYOCOM:: Universal mode with a carburetor.

A LITTLE BACKGROUND

A year ago I was given a 1990 tercel DX coupe. It had issues to fix and I was glad to know how to.
It was then 28 years old while still showing under 100k km (about 60k miles) on the clock.

It got fixed here and there in the last year span; tires,suspension,brakes,body panels and exhaust system, engine valve seals and timing belt to name a few. The good old trusty 3E grew on me in that time lapse since it was so reliable, overshadowing the fact it is under powered to the extreme.

ENGINE OVERVIEW

It has got 82 hp and an A/T 3 gear transmission. starts like a charm on cold weather

It's an 1.5L 3E engine from 86 to 90. This engine uses a carburetor and a computer to control some peripherals and monitor it's overall operation. Very few existing sensors are useful on it, an oxygen sensor is there at least. all other sensors are switches. no analog sensors at all.(digital throttle position switch and digital temperature and vacuum switches)

The vacuum diagram is as complicated as a wiring diagram for a much more complex engine.it was the time where carburetors had to let got to full EFI.

Only E1(ground) and the VF (fuel trim) were available in the diagnosis box for the TOYOCOM to use. not even switched power (+B). Improvements had to be made to take full advantage of this setup.

GETTING  SOMETHING INTERESTING INTO TOYOBD1

An android car radio was installed to be able to gather data all the time from the TOYOCOM unit installed in the engine bay (blue box in the upper right corner of the preceding picture). this radio is setup to connect to the TOYOCOM every time TOYOBD1 starts.

• VF is already there
• E1 is already there
• +B was routed from the engine harness reaching the fuse box.
• Ox(oxygen sensor)  was routed into AB
• Moving speed is taken from the android car radio GPS

Even though there were still custom inputs available on the TOYOCOM nothing else was routed to the diagnosis box yet.

WHAT WAS LEARNED FROM TOYOBD1

• the alternator is poorly working but still operational. (battery voltage is low under all conditions)
• the engine runs rich while idling and lean when held at WOT for a long time in 2nd or 3rd gear. it might have fuel delivery or carburetor issues
• the fuel trim is always negative ,meaning the ECU suspects the fuel consumption is less than expected. It might be the oxygen sensor, might be fueling issues again. 
• throttle position and temperature switches are working OK, the system goes from closed to open loop following engine load and growing engine temperature.

WHAT IS COMING AHEAD

More custom sensors are to be mounted on the engine to even out MPG calculations reserved only at this time to EFI engines. more sensors will be added to monitor the engine tune and improve it along the way as possible.

• fuel flow sensors on fuel lines
• MPG calculations for a carbureted engine in TOYOBD1
• dirt cheap wideband oxygen sensor setup
• rpm input from the igniter

TOYOCOM :: Universal mode on the AW11 blue top 4A-GE

WHAT'S THE BIG IDEA

Having modern day diagnostic features on an car is very useful. On a +30 years old car it is a luxury that is rarely found. For Toyotas there is hope now. Using the toyocom 'universal mode' you can get a fair level of information out of our  mid 80s toyotas.

Doing so requires of the car owner to do some electrical work to splice into signal wires we care for. A compromise was made to leave the wiring harness untouched. It may be more ambitious but certainly not out of the reach of the DIYers.  What requires to be done is to solder wires on the underside of the ECU main board, exactly where the ECU connector are soldered. This location gives us acces to every wires going into the ECU and is conveniently labeled on most toyota ECUs.

RANDOMNESS STRIKES

Believe it or not, while working on this blog post a friend passed by with a beaten up mr2 while being in transit to somewhere else. It was shear luck,so we took the time and tried the modified ECU on it!
The car was in really bad shape but running,no exhaust with the blue top 4A-GE not running on all cylinders. we were able to get our readings while being quick at it to not wake up the city neighbors.

WHAT YOU CAN EXPECT IN THE ANDROID APP

mandatory features from universal mode on an early EFI toyota.

• Error codes readout
• battery voltage
• fuel trim

mandatory wires you have to solder

• B+ 12v power
• E1 ground
• T (TE1) trigger error code output
• W check engine light
• VF (VF1)  fuel trim

additional wires you should monitor before anything else

• IGT this is the igniter control (for RPM input)
• #10 this is the first injector pair control
• VS  this is the air flow meter output
• OX this is the oxygen sensor
• THW this is the coolant temp sensor

reasoning

• having RPM & injector activity allows us to get injector duty cycle
• having the air flow reading tells us about the engine load which is always useful.
• having the oxygen sensors allows us to troubleshoot fueling issues against engine load & rpm
• having coolant temperature allows us to know if we overheat and guess the fueling choices.

WHAT YOU NEED TO GATHER

• a toyocom scan tool from www.zf-scantools.com
• a spare ecu for your engine is best.
• a junk yard diagnosis box, preferably a late black one from an obd2 toyota.
• new contact pins from digikey (only usable with the late black diagnosis box)
• 10 wires of different colours. about 1' long 20ga

WHAT REQUIRES TO BE DONE ON THE ECU

To understand how to install contact pins in the diagnosis box follow this earlier post.

where each wire goes in the diagnosis box

ORANGE                =         +B
RED                        =         VF1
DARK GREEN        =         E1
NORMAL GREEN  =         AB
YELLOW                =         W
WHITE                    =        TE1
BROWN                  =         TT
BLACK                   =        TS
BLUE                      =        TC
PURPLE                 =        VF2

• install contact pins on each new wires you need  ( a feet long is comfortable to work with)
• place the wires in the diagnosis box at the specified spaces in the top cover

• Add a shrink wrap sleeve to your new bundle of wires
• Remove both top and bottom ECU cover plates
• on the TOP side,read the labels for the connector pins to know where your signals are located.

YOU WILL BE SOLDERING ON THIS SIDE

where each wire goes on the ecu connector

ORANGE goes to +B
RED goes to VF
DARK GREEN goes to E1
NORMAL GREEN goes to VS
YELLOW goes to W
WHITE goes to T
BROWN goes to THW
BLACK goes to #10
BLUE goes to OX
PURPLE goes to IGT

Overview of the work done ot the ECU

PLEASE EXCUSE THE HASTY SOLDERING

• solder each wire to it's matching pin
• reinstall the top cover plate.

• Applying hot glue with a glue gun over your work is suggested for shielding and dampen vibrations.

before installing the bottom plate you want to add washers to shim the cover and use longer bolts to compensate, doing this drops the chances of the wires cutting themselves due to friction.secure the added wires to the ECU case using hot glue, to lock them in place.

• connect your ECU to the car and the toyocom into the diagnosis box.
• at this point follow the toyocom user manual given with the tool to start using it.

TOYOCOM :: playing with contact pins in the DIAGNOSIS box

With the TOYOCOM & TOYOFAN tools it is now possible to do more than before with the OBD1READ. This takes advantage of what the DIAGNOSIS box offers by default and allows the user to expand the inputs using empty spaces when availalbe.

Sometimes, depending on engines and wiring harness variants some mandatory wires have been omitted from the wiring harness and require to be added so the TOYOCOM tool can be used at it's fullest. This can be accomplished with simple tools without removing the wiring harness from the car.

Getting contact pins, 2 ways to do it

1. cut off a spare diagnosis box at the junkyard and reuse it's contact pins.
2. use brand new contacts that you will crimp and solder to new wires.

IF YOU HAVE A GREY DIAGNOSIS BOX YOU CAN ONLY REUSE CONTACT PINS AS OF YET.

I will only describe how to work with new contact pins in this post, the theory on how to pull contact pins from a diagnosis box is described in the later steps. 

You can buy suitable contact pins online from Digikey. A123029CT-ND on digikey

The tools and parts I used.

Getting the contact pin on the wire

Soldering is used to compensate for the loose the crimp tool may leave. 

Getting the new contact pin into the diagnosis box

Hold the diagnosis box so you can read 'DIAGNOSIS' (not upside down.)

 Be careful so the contact pin 'wings' are facing up

You will hear this sound when the contact pin locks right.

Pulling out contact pins from the diagnosis box (applies to BLACK and GREY boxes)

Position the diagnosis box facing you and so the cover sits at your right

 Using the precision flat screw driver you will pry the lock teeth toward you.

 While you are holding the lock teeth with the screw driver you will use another hand to pull the wire from beneath until it is totally out of the box.

Closing the clam shell in the end.