TOYOBD1 :: quickest way to test TPS operation

!! After doing this test procedure make sure to erase ECU error codes because unplugging the TPS while Ignition key is ON will store an error code. !!

This technique is only meant for 4 wires analog type TPS.

Typical 4 wires Toyota TPS

4 wires are reaching the TPS

1. E2 is a sensor ground 
2. IDL is telling the ECU if the throttle is at rest
3. VTA is the output signal telling the throttle opening angle
4. VC  is a sensor reference voltage, should be 5v or pretty close

First make sure the IDL switch is working inside the TPS

Without the Ignition key ON, unplug the TPS connector.

Using a multimeter you will test for continuity between E2 and IDL when the throttle is at rest. if you open the throttle plate big enough continuity will be loss, this is expected.

using a multimeter I'm testing for continuity between E2 and IDL

Testing with TOYOBD1 the ECU and wiring for proper operation

notice the absence of IDL flag here

With the Ignition key ON and engine not running, 

unplug the TPS connector. 

Launch TOYOBD1 and connect to your OBD1READ device. 

make sure you look at the TPS cell.

with no TPS connected you should get such readings

The IDL flag will not be shown, this is expected.

BE CAREFUL NOT TO BRIDGE E2 WITH VC OR ECU DAMAGE MAY OCCUR 

LOOKING INTO THE TPS CONNECTOR. with a jumper in place

notice the presence of the IDL flag

Now using a jumper wire you will bridge E2 and IDL.

you will get this reading in TOYOBD1, the IDL flag will be present.

if you don't get the IDL flag to show something is wrong with the wiring between TPS and ECU, or the ECU is damaged( less likely )

 

!! After doing this test procedure make sure to erase ECU error codes because unplugging the TPS while Ignition key is ON will store an error code. !!

Mandatory skills before ECU tuning

Lots of people want to tune petrol EFI engines for themselves

As modern and software oriented it may seems, it requires of people godly troubleshooting skills when things don't go as planned. Without all of those skills you will always depend on a skilled folk with dwindling patience who'll end up terminating your friendship with him.
Here are the most important to me

When creating something new it's rarely expected to work right the first time

Be the person who can take on challenges, not the one asking others to fix it for free and take the glory.

Buy yourself a fire extinguisher if is not done already.

General DC electrical skills

- master iron soldering, twisting wire is not allowed
- understanding the wire colour naming convention.
- understanding how fuses work and enjoying their benefits
- understanding how relays work, there will be an awful lot of them ahead
- understanding your engine wiring diagram perfectly, if you can't say why it is rigged this way try again.
- being able to use a multimeter to read voltage,impedance,frequencies and capacitance.

IGNITION skills

0- understanding engine firing order and being able to place spark plug wires accordingly
1- being able to test for spark events at the spark plugs (getting a spark occurring outside the cylinder head for tests)
2- being able to tell when an engine does not run on all it's cylinders and locate which ones
3- being able to read spark plugs colours. (being oily, rich, lean, and more importantly variance accross cylinders)
4- being able to properly install a timing belt or timing chain
5- know what is ignition advance and ignition retard.
6- being able to use an ignition timing light
7- being able to locate TDC on the reference piston on an engine with a test rod(making sure the reference point on the harmonic dampener is true)
8- being able to adjust an ignition distributor

FUEL INJECTION skills

- understand what composes the fuel delivery system and identify which part on your car is each one(appearance varies from one implementation to another)
- identifying fuel leaks and fixing them appropriately
- being able to measure fuel pressure with a gauge
- understand how to adjust a fuel pressure regulator if needed
- knowing the various smoke colours that can come out of a tail pipe and their origins
- knowing what is a rich and lean mixture
- detecting various bad analog sensor readings
- being able to test injector impedance
- understanding how the universal narrowband oxygen sensor works and testing
- understand how to install and read a wideband oxygen sensor/gauge
- rough injector operation testing
- understand what the injector duty cycle means ,measuring/calculating it would be even better

ENGINE MATH THEORY skills

- understand the concept of engine volumetric efficiency ( VE )
- understand the concept of [RPM x VE ] and  [RPM x pressure] mapping for fuel and ignition
- understand what is engine air flow
- understand what an air flow meter outputs and interpret it's reading
- understand what forced induction does to engine air flow

SOFTWARE use skills 

- know what is a COM port on a laptop computer
- being able to find the COM port # you'll be using when tuning. those things change from time to time :)
- being able to use the data logging interface offered by the ECU,if available
- being able to locate data log files on your computer and read them with a spread sheet software

With those skills you should be able to troubleshoot many basic engine related issues and should avoid being a pain in the ass to someone else who does know. there is far more to be known than this, If all of this is already boring, don't bother going deeper. :)

Simplest Narrowband OX sensor simulator

BUILDING IT

 Hi, today I'll be sharing with you how to build a very simple narrowband oxygen sensor simulator, this thing is only useful to troubleshoot how an ECU reads the 2 states of an oxygen sensor. it does not simulate an oxygen sensor heater. On your left you will see the sensor curve for all NB oxygen sensors. the tool is simply a switch that outputs a ground path, or about 0.75 to 1V. allowing the user to simulate a rich or lean reading.




The Parts needed are very simple, and should be found at all local electronic parts shop.

4 X 1K resitors. 1/4w is fine
2 x 10k resistors. 1/4w is fine
3 x wires of different colors ,about 2 feet long gauge 20
1 x single pole double throw switch, something with 3 pins
2 x shrink wrap tubing for protecting the circuitry , or electrical tape

optional parts
shrink wrap to hide all of the 3 wires and the circuitry
3 x crocodile connectors

 Here you can see how I built it. very simple to do, twisting the resistors together and soldering it all in the end. adding the wires.

 complete tool ready for use

AND NOW PLAYING WITH IT

 I went ahead and proved the tool on my own like all mad scientist should be doing. Test subject is a 1997 toyota corolla, AE102 at birth , converted with an 92-93 3VZ-FE running a Canadian OBD1 A/T ECU with an OBD1READ device used in conjunction with TOYOBD1.

the tool sits on the front engine bank with the orange wire connected at the alternator pole, and the green wire connected to the chassis ground. white wire leads to the front bank ox sensor wire

 

First I warmed the engine up. then when ready ,toggling the switch with one hand an data logging in toyobd1 with the other I was able to fool my ECU into thinking the sensor reading was either rich or lean.

Summary

This tool can be used to make sure the wiring and  ECU are correctly working. leaving the only possible culprit to the sensor itself if something is wrong.

Inifiniti G35 2003 :: Wet IPDM issue, how to fix it

Introduction to the wet IPDM issue

The Infiniti G35 is a technology filed car. as early as 2003 it already had a CAN bus and a few computers that take advantage of this network. This complexity comes with the cost of horrible situations when a failure of the CAN bus occurs. the problem described below affects the G35 after heavy rain fall. the I.ntelligent P.ower D.elivery M.odule cannot do it's job properly at that time and it affects the whole CAN bus. so all communication between the other computers in the car is not working. This kind of issue is really annoying on a luxury car and can lead to a loss of confidence in the car itself if not fixed.This situation occurred to me after a heavy rain, a quick search on the web revealed a few Youtube videos showing the trouble but no clear solution or understanding, people are stating that the trouble goes away by itself after a while. That is no answer for me, hopefully all those hours spent on understanding the G35 wiring diagram before buying the car was worth it!

Symptoms

 

*The video is not mine btw

the list of symptoms were noticed on a single drive home lasting about 35 minutes and totaling 50 km. the list is quite exhaustive and so was the situation. not the kind of crappy behavior you would expect from a luxury car.... 

WORKING SYSTEMS ( QUITE SHORT LIST INDEED ... )

• Engine ECU works fine
• Radio works fine
• ABS works fine
• Sunroof works fine
• door lock works fine
• SRS seems fine
• interior car lighting
• the only thing in the dashboard that works is the fuel level gauge, alternator warning light, ABS system is OK

NOT WORKING SYSTEMS( CHOOSE YOUR PICK THERE'S PLENTY FOR EVERYONE! )

All other gauges are not moving or being totally erratic.

• Tachometer
•  Speedometer
•  Engine temperature
• Check engine light flickers
• VDC light is on all the time
• SLIP light on all the time
• CAN bus communication is down or erratic across all systems,  

Additionally those systems are not working properly.

• -all systems relying on the CAN bus are in fail safe mode, some shut themselves down, some try to cope with the situation
• -dashboard clock stops working
• -VDC and traction control are OFF
• -Transmission ECU is in fail safe mode since the CAN bus is down, gear shifting is extremely harsh at all engine loads,
• -gear shifting is relative to car speed only
• -transmission will never down shift no matter how hard you step on the accelerator
• -manual gear shift mode is not working,
• -while cruising on the highway the transmission down shifts hard for no reasons on constant engine loads.
• -headlights are jumping from low to hi beam (people are thinking you want to tell them something ). you cannot engage hi beam yourself, it's like being epileptic.
• -electric radiator fan control, this one I can't confirm but it is sufficient to say this is quite critical as this is controlled by the IPDM and if the fans don't work when they should, you would get an overheating engine due to a bad CAN bus... what a lovely feature!!

Explanation 

( spoiler alert :: 2003 NISSAN ELECTRICAL ENGINEERS ARE DUMB ASSES!!)

Battery compartment without battery , IPDM and fuse box plastic cover

On older cars a 'gutter box' of some sort was draining the rain water coming to the bottom of the windshield and conveniently channeled it to the bottom of the car, it is called a cowl dash.on conventional design, only the wiper arms mechanism and wiper motor are installed there, end of the story. Nissan on the G35 decided they wanted to save weight and probably some money so they designed the car WITHOUT a cowl dash. Result:: when it rains, or you wash your beloved car, there is a waterfall running on the firewall inside the battery and Brake booster compartment. at the bottom of those boxes are holes meant to drain those boxes.

You can notice dirt marks around the top wiring harness, it indicates water flows there often then around the IPDM, this is a rust hazard to consider too..

First problem: the IPDM sits low cramped in the battery compartment adjacent to the firewall, there is always a humidity risk for this device since the water flow is in it's back, common sense suggest to never place critical electrical components in the way of water ...this is only common sense though...

IPDM with it's plastic cover, fender side fuse box out of the way

Second problem: the battery compartment is only equipped with one drain hole at the bottom and IT COMPLETELY CLOGS WITH THE YEARS! this lead to water accumulation in the bottom of your battery compartment, with sufficient water input it can get high enough to disturb your IPDM and voila You reproduced the problem on your otherwise pristine G35! (mine was completely clogged with mud and the water level was about 1/2" high.) looking down the battery compartment does not show much, you need to bend out of the way stuff and go there with your fingers to tell.

unclogged drain shown,IPDM out of the way, the drain is visible now

Third problem - the plastic battery tray gets filled with water under the battery and there is no drain holes in it.
( the blame goes to the cowl dash less design ) so you carry around about a glass or two of water that splashes here and there on hard accel/braking/cornering. Removing the battery tray and drilling holes at the bottom would drain that water accumulation when it fills.

The battery tray gets filled with stagnant water as the years are passing...

Fixing it 

tools needed to fix this

•  shop towels.
•  small air compressor equipped with a duster.
• something to unbolt 10 and 12mm nuts. (for baterry removal)
• narrow flat screw drivers can be useful to release the IPDM from it's bracket.

 things to do ( 15 to 30minutes )

1. Remove battery compartment plastic cover.
2. Remove the plastic part that meets with the lower part of the windshield.
3. take out your battery.
4. take out the water from the battery tray.
5. slide up the IPDM and fender fuse box, let the IPDM rest on the battery tray.
6. unplug the drain using fingers or better.
7. dry out as much as possible remaining droplets in the whole battery compartment with a towel.
8. reinstall IPDM and fuse boxes on their brackets.
9. remove IPDM and fuse boxes plastic covers.
10. using the duster generously dry all the wires connectors at the base of the IPDM. catch the escaping water with a towel using the other hand.
11. do the same thing in the fuse boxe.
12. do the same thing in the wiring harness behind battery tray and coming from under it.
13. install plastic covers on IPDM and fuses boxes.
14. Reinstall battery.
15. Start the car to confirm the problem went away.
16. Stop car, reinstall the lower windshield plastic cover.
17. Install battery compartment plastic cover.
18. Enjoy life.

Afterthoughts 

The IPDM is placed at what seems to me THE WORST PLACE EVER for a module as critical as it is.This module controls electrical power distribution across various systems and by placing it there endanger the CAN bus operation. I hope NISSAN was wise enough to improve on their electrical designs over the years...

TOYOTA engine swaps, avoiding wiring job traps

Since I have started developing TOYOBD1 I learned constantly about the 90s to mid 90s OBD1 Toyota ECUs, they all share similitudes.The traps we fall into while doing custom engine wiring jobs are also similar here are a few I have encountered through the years that may save you time and money.

The STA wire

STA is not to be fed with a constant 12v source like b+, it's purpose is to inform the ECU that the starter is engaged while the starter is engaged. feeding constant 12v to STA will fool the ECU into thinking it is cranking all the time, regardless of engine speed.this will make an ECU inject about 2.5 times the fuel it would have injected normaly. in all cases I have seen it is so rich the ignition cannot burn all that fuel, and of course engine performance is bad. Lots of people fall into that trap, stay aware!.

The Batt wire

This one is a constant 12v power source, it is fused and always powered regarless of ignition key position. this is what keeps the RAM (ecu memory) powered at all time. not feeding Batt correctly will result in Error codes being wiped every time the engine is shuted off, and the ECU learning process starts form scratch every time. 

Digital 3 wire TPS (PSW, E2, IDL)

On cars using this system it is important that those signal be wired correctly. those ECUs dont have a real TPS, this TPS design only tells the computer if you are at idle, at WOT , or anywhere in between. this is a lot of guessing and if the ECU senses the throttle is at WOT when it is not it may take bad fueling and ignition angle decisions. a digital tps can also simply go bad and need replacement. found on MT cars 3S-FE,4E-FTE,etc

The E2 wire

This is a special ground,This is the sensors ground, this ground must not be tied to other ground signals directly, doing so may introduce sensor noise or worst.

Testing toyota fuel injector Wiring with a paperclip

Using a paperclip you can test the basic operation of gasoline fuel injectors.

NEVER DO THIS TEST WITH A RUNNING FUEL PUMP IT WILL INJECT FUEL IN THE CYLINDERS.DISABLE FUEL PUMP FIRST

this information is targeted at TOYOTA designs but should be meaningful for many other makes.

this test can reveal:

• the injectors cannot be actuated by the ECU(if you can't manually it cannot either)
• one or many injector are clogged (don't click when powered)
• the injector you are actuating is matching the one that is  clicking, (in custom engine swaps those injector wires can be inadvertently exchanged)

this test cannot reveal:

• current applied at the positive pin of the injectors is sufficient(too low current caused by bad resistor pack or bad wires on the 12v side)

So overall it can tell you that if you can't actuate the injectors manually the ECU wont be able either...

It can be performed on a car or a bench test setup. The following video shows it on a bench setup.

Theory behind the test

On conventional designs, the fuel injectors have 12v current applied on their positive pin when the ignition switch is ON. the negative pin of each injectors is connected to an ECU which sinks that current when the ECU wants to actuate that specific injector.

Without an ECU installed but having the ignition switch at ON you can sink an injector current manually by jumping an injector contact at the ECU connector with a main ECU ground contact  at the ECU
connector. doing this will result in a clicking sound coming from that particular injector when the jumper is placed or
removed.