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4G63 Elantra Rich when warmed up

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DestinyAscension

Probationary Member
11
2
Aug 8, 2023
Sevastopol, Europe
Greetings to all the community. I apologize for my bad English since it's not my native language.

I own a Hyundai Elantra J1 1994 with 4G63 N/A swap with freshly rebuild engine without any performance mods.
I am here to ask you guys for help since the engine and electronic engine components are the same as 1G 1991

The car was equipped with an adjustable O2 sensor on the firewall that has basically 3 wires:
1-BLK Ground
2-GRN 5V to TPS and MAF.
3-WHT that goes through a variable resistor and outputs constant voltage to the ECU reading from 0.02V to 5.00V

The problem is car running extreme rich, the exhaust is insane black and smells like unburned fuel and it burns my eyeballs at idle.

I came to a thought to rewire O2 circuit making a hole in an exhaust pipe to insert a proper O2 sensor
Basically it's just voltage that comes to the ECU to a single pin.
The TMO Logger reads frequent changes in O2 sensor voltage from 0.1 to 0.9V when car is fully warmed up that seems OK to me.

But it actually did nothing.

The car starts with a single turn of key. Smells normal until it's fully warmed up. It makes it almost undriveable, the car shakes like hell on a 1st Gear from 1k to 2k RPM. When it overcomes 2k RPM it accelerates great and drives almost normal.

The fuel pressure is normal
Spark plugs are black, bought a second set of proper gapped NGK for a N/A version
Injectors are clean and function normally, color is tan. Their cc is identical to those, that came with 1.6 G4CR
I tried to adjust the ignition, but it doesn't make significant changes. The best position is almost at middle, when the reaction to slight Throttle valve opening seems normal.
Throttle body, ISC got their new gasket and O-ring
I adjusted the fixed SAS and it changes it's continuity with a slight opening of throttle valve
The EGR was cleaned, but not deleted.
The timing of cams and crank is normal.
TPS is 10%, just as an Elantra manual requires.
EngineCoolantSensor operates normal, warmed up car reads 185-190 degrees Fahrenheit

What can cause the engine to run that rich at idle?
 
You checked all of the key areas. Thanks for letting us know before we started helping.

Two questions come to mind: Are you using the Hyundai ecu? Are you using new injectors specifically for the 4G63 N/A? They should be rated for around 275.

When you say the fuel pressure is normal, can you put a pressure number on that? Strangely, low fuel pressure can cause a too-rich condition.

As far as the TPS setting, your best adjustment isn’t a number from a manual. There are great articles on here to help you correctly adjust it, but the ecu settings and injector size need to be correct first.
 
You checked all of the key areas. Thanks for letting us know before we started helping.

Two questions come to mind: Are you using the Hyundai ecu? Are you using new injectors specifically for the 4G63 N/A? They should be rated for around 275.

When you say the fuel pressure is normal, can you put a pressure number on that? Strangely, low fuel pressure can cause a too-rich condition.

As far as the TPS setting, your best adjustment isn’t a number from a manual. There are great articles on here to help you correctly adjust it, but the ecu settings and injector size need to be correct first.
Thanks, I appreciate any help!

I am using Hyundai ECU (non-EPROM) and Hyundai sensors and wiring harness.
I am using tan injectors with unknown cc. I did a search and those are used in Elantra 1.6 (4G61) Sonata 2.0 (4G63) and Galloper 3.0 (6G72 I suppose). I would assume they are 210cc

I put an AFPR between the stock FPR and fuel return line and set it up to ~3-3.3bar and roughly restricted any fuel coming back to the tank. Tried it with 3 and 3.5, It made no difference.

If injectors are a mismatch - it would make the engine to run leaner comparing to 275cc 4g63 + It would not be affected with Engine temperature. At least not that much

The % of TPS are as well within spec in Volts. For Elantra it's around 0.48-0.52V

The only thing - car doesn't run rich when idling ~140-150 degrees Fahrenheit
 
If injectors are a mismatch - it would make the engine to run leaner comparing to 275cc 4g63 + It would not be affected with Engine temperature. At least not that much.

It's all about what the ECU is configured for and if the air flow sensor and injectors match what the ECU is programmed for.

If the ECU is setup for 210cc injectors @ 3bar then based on how much air it's measuring it will open the injectors long enough to provide for it. If the ECU thinks the injectors should be some other size you get more or less fuel.

When the car is idling it likely in closed loop using the O2 sensor feedback to adjust the fueling. It's not the actual O2 sensor voltage that's important with a narrowband sensor but the switching around 14.7:1 AFR and how fast it reacts. I'm not sure what the variable resistor setup was for unless it was part of a wideband O2 sensor circuit. We don't have any ECUs that support those natively.

What is the TMO logger reporting for fuel trims?
 
Thanks, I appreciate any help!

I am using Hyundai ECU (non-EPROM) and Hyundai sensors and wiring harness.
I am using tan injectors with unknown cc. I did a search and those are used in Elantra 1.6 (4G61) Sonata 2.0 (4G63) and Galloper 3.0 (6G72 I suppose). I would assume they are 210cc

I put an AFPR between the stock FPR and fuel return line and set it up to ~3-3.3bar and roughly restricted any fuel coming back to the tank. Tried it with 3 and 3.5, It made no difference.

If injectors are a mismatch - it would make the engine to run leaner comparing to 275cc 4g63 + It would not be affected with Engine temperature. At least not that much

The % of TPS are as well within spec in Volts. For Elantra it's around 0.48-0.52V

The only thing - car doesn't run rich when idling ~140-150 degrees Fahrenheit

Are you setting the fuel pressure with or without the manifold vacuum source connected?
 
Are you setting the fuel pressure with or without the manifold vacuum source connected?
Vacuum is connected, but the ignition turned off, I am simply putting 12V to fuel pump check connector so there is no vacuum.

It's all about what the ECU is configured for and if the air flow sensor and injectors match what the ECU is programmed for.

If the ECU is setup for 210cc injectors @ 3bar then based on how much air it's measuring it will open the injectors long enough to provide for it. If the ECU thinks the injectors should be some other size you get more or less fuel.

When the car is idling it likely in closed loop using the O2 sensor feedback to adjust the fueling. It's not the actual O2 sensor voltage that's important with a narrowband sensor but the switching around 14.7:1 AFR and how fast it reacts. I'm not sure what the variable resistor setup was for unless it was part of a wideband O2 sensor circuit. We don't have any ECUs that support those natively.

What is the TMO logger reporting for fuel trims?
Well, in Elantra manual there is a heater circuit to ground and MPI relay. And a signal circuit which is basically a ground and + wire with voltage that o2 sensor generates.

Is there a fuel trims in TMO Logger? Can you please show where it is in DRB2?

The fuel related measurements that I remember are MAF Hz, injector pulse width, barometer maf, intake and engine temperatures.
 
Well, in Elantra manual there is a heater circuit to ground and MPI relay. And a signal circuit which is basically a ground and + wire with voltage that o2 sensor generates.

Sounds the same as the 1G 4G63 NA narrowband. What I didn't get was the point of the modification.

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Is there a fuel trims in TMO Logger? Can you please show where it is in DRB2?

The fuel related measurements that I remember are MAF Hz, injector pulse width, barometer maf, intake and engine temperatures.
From TMO's old web pages.

TMO Datalogger 101

Since you purchased a TMO Datalogger, you are probably familiar with what it can do for you. Using the TMO Datalogger to "fine tune" your engine is where it really shines.

Using the information from the datalogger you can "tune" your car to run better and run closer to that fine "edge" of performance. This page will only touch base on the functions of the TMO Datalogger, the variables you can select and how to read those variables.

Now lets look at some of the data you can select to monitor with the logger.

NOTE: If you have some kind of piggyback fuel computer (VPC, AFC, PMS, MASC etc.) that gives a false signal to the ECU, that false signal will be reported by the Datalogger to you. Keep that in mind when interpreting data.

Under the label "DATA" on the toolbar you have SELECT, TRIGGERS, and QUICK SELECTS.

Select lets you pick all the variables you want to monitor

Triggers lets you select different combinations of variables and conditions (e.g. rpm>4000, TPS>50%) that will trigger the datalogger to start recording.

Quick Selects is a user-defined collection of variables. Instead of the tedious process of selecting each individual variable every time you want to use the TMO Datalogger, you can just choose a Quick select and start logging almost immediately. There are 6 Quick selects you can define, so be creative!

Once you are in the menu Select, you will see a bunch of values to select including FUEL, AIR, SPARK, IDLE, MISC, TMO, and TRIGGER.

FUEL, under fuel you have;

ACCEL ENRICHMENT (range of 0 to 100%)

This is the amount of fuel that is initially squirted into the engine during quick movements from the throttle. It gets its input from the Throttle Position Sensor. When the TPS voltage increases rapidly it shoots a little extra fuel in to help with the throttle response. Too much or too little will affect drivability.

COOLANT TEMP (range of 100 to 300 degrees)

This is just what it says, your coolant temp from the temp sensor for the ECU (not the one for the gauge, they are both located in the thermostat housing). The ECU uses this to tell when to go into closed loop after warmup. It also has an affect on timing.
ENGINE SPEED (range of 0 to 8000 rpms) (may be 8500 on some loggers)

The actual engine rpms the ECU sees from the information it gets from the TDC sensor and Cam angle sensor.

FUEL TRIMS HIGH, LOW, MIDDLE (range of 60 to 140% for 91+ cars, 80 to 120% on 90's)

These are the "long term" memory fuel tables in the ECU. When you drive the car in closed loop (normal to low-boost driving, rpm<4500), the ECU is constantly updating these trim values. The ECU takes the signal from the MAS and calculates how much fuel to add to maintain an a/f ratio of 14.7:1, then compares the O2 readings against the value it calculated and adjusts the fuel trims (adding more fuel or taking away) to try and stay at a constant "stoichiometric" value (14.7:1 air/fuel ratio). A trim value of 100% is stoichiometric, anything greater than 100% and you are running lean so the ECU is adding fuel, anything less than 100% and you are running rich and the ECU is subtracting fuel. The ECU always tries to run at a stoichiometric 14.7:1 ratio under closed loop operation and the values will be reset to 100% when the ECU is cleared.

These values will always be changing up or down a little depending on the air conditions and many other variables. Low, middle, high refer to the amount of airflow that the ECU sees while in closed loop. When the ECU goes into open loop, none of the fuel trims are updated.

INJECTOR PULSE WIDTH (range of 0 to 25 milliseconds "ms")

This is the actual amount of time that the injectors are open, not duty cycle. Duty cycle is roughly defined as the ratio of the amount of time a signal is "active" to the amount of time available for the signal to be active.

NOTE, once again every car seems to be different. I have personally run my 450cc's to 27+ ms and had a smooth pattern, great flow and no knock.

The one thing I will add is you want a value somewhere around 20ms at WOT. It must be a smooth, straight curve. If the value is jumpy at all your injectors are not squirting a smooth pattern and you will get detonation from this. It is more important that the signal be smooth than the actual number as on 91+ ECUs this number is what the ECU is "trying" to do, not that the injectors are actually open for that amount of time.

OXY FEEDBACK TRIM (range of 60 to 140%)

Just like the fuel trims, this is also a closed loop value only this is the "short term" value and it determines the adjustments made to the "long term" fuel trims. As you drive along it will switch (cycle up and down) just like the O2 sensor voltage. It should be a nice, smooth and even switching rate, not jittery or jerkly up and down. If it is switching from say 80% to 120% then you are right at 100% value, there's that stoichiometric word again. :) If it's switching above 100% it's showing lean, and if it's switching below 100% you are running rich. Based on this info, under certain conditions the ECU will adjust the appropriate fuel trim until it sees the oxy trim switching closer to stoich.

OXYGEN SENSOR (range of 0.0 to 1.0 volts)

The oxygen sensor is what the ECU to determine whether the engine is running rich, lean, or just right. 0 volts is lean, 1.0 volts is rich, and stoich is ~0.47v. Once again you want a good smooth pattern of peaks and valleys. At idle you will have a nice and slow switching rate. The higher the rpms and throttle position under a load (driving) the faster the switching rate until it stays constant at a higher reading. Once it stops switching that shows that you are not in closed loop anymore. Most importantly you want a smooth switching rate.

Once you go into open loop, it will show a constant reading. Under WOT you always want as low of O2 voltage reading as you can go WITHOUT any detonation or knock sum on the logger.

THROTTLE POSITION (range of 0 to 100%)

This just simply shows the position of the Throttle Position Sensor (TPS) on the throttle body. You can use it to watch the accel enrichment while you open the TB or to tell when your WOT pass starts or watch your shifts when you let off the gas during the shift. You should see a nice and smooth increase with a slow and steady increase from your right foot on the gas pedal. If it's not smooth your TPS could be going bad. The actual lowest the reading will show is somewhere around 10%.

AIR, under air you have;

AIR FLOW HZ (range of 0 to 1600hz)

This is the actual signal the Karmann Vortex generator in the Mass Air Flow sensor (MAF or MAS) sends to the ECU. This tells the ECU the amount of air moving through the intake. Please note that this is not equal to air mass - the ECU also needs the barometric pressure and intake temperature (also located in the MAS) to determine the actual air mass entering the engine and the corresponding amount of fuel to deliver. Unfortunately, current limitations in the TMO Datalogger limit the reported result to 1606hz. However, the MAS is capable of sending out a signal up to ~2200hz or so to the ECU.

AIR TEMPERATURE (range of 0 to 200 degrees)

This is the temperature of the air at the MAS. It's great for seeing if your cold air intake or heat shield is working. On a 45 degree day I had temps of 120 degrees at the filter with just a K&N and cut air can. After making a cold air setup and a heat shield I now see 75 to 85 degree temps. This also has an affect on timing.

AIR VOLUME (range of 0 to 255, actually 0 to 7)

This is the number that the ECU uses internally for air flow. It is derived from Air Flow Hz, air temperature, and barometric pressure. This value has far more precision inside the ECU (11 bits) but due to technical reasons, the logger only sees the top digit of the whole value (technically, the top 3 bits). This gives us a visible range of only 0-7. Because the resolution is so poor, Air flow Hz is usually used instead to monitor air flow.

BAROMETER (range of .7 to 1.1 bar)

This is also in the MAS . It shows the barometric pressure of the air to the ECU. This combined with other readings helps the ECU to know how dense the air is therefore to determine total air mass entering the engine.

ISC STEPS (range of 0 to 130)

This is your Idle Speed Control servo motor on the throttle body (you know, the one that goes bad!). It is a stepper motor that opens or closes the TB plate to control the idle speed due to load changes, i.e. turning on the a/c or using the power steering, brakes etc. It opens up in steps and closes in steps to control the idle. This value is useful to tell if the ISC is working well or not.

SPARK, under spark you have;

KNOCK SUM (range of 0 to 43)

This is an important value! The knock sum scale is given to represent the signal from the knock sensor to the ECU. The ECU then calculates the amount of detonation present. The higher the knock sum the more the ECU retards timing to get rid of the knock.

With a knock sum of;
3 or below, the ECU will advance timing.
Between 3 and 7, the ECU leaves timing alone.
Higher than 7, the ECU will begin retarding timing. Higher knock = higher retard, with the possibility of seeing less than 4deg total advance at the maximum knock sum of 43.

One important note to remember is the knock sensor can detect "false" knock and retard timing. This is most commonly caused from the noisy lifters but anything it can audibly pick up could cause this.

TIMING ADVANCE (range of 0 to 50 degrees)

This is the real-time spark timing the ECU is using. While at cruise speeds at low throttle settings it can maintain as high as 40 or more. This is a very useful tool as you can really "see" the timing affect power. The more advance the better up until knock occurs. Ideally you want to maintain around 15degrees advance at WOT high rpms. Any higher advance and you probably can afford to increase boost a little bit, any lower advance and you are knocking and it's being retarded too much. It's very easy to see the relationship between the knock sum and the timing advance.

IDLE, under idle you have;

A/C SWITCH, (on or off)

This just simply tells you when the a/c switch is on or off. Nice for seeing if your TMO ECU is turning if off under WOT or above 5000rpms.
IDLE SWITCH, (on or off)

This is the single wire switch on the TB. It tells the ECU when the throttle plate is fully closed. If this switch is faulty it will cause idle problems. This tool is an easy way to tell if it's working correctly.
PARK/NEUTRAL SWITCH, (on or off)

This is simply the park/neutral switch on auto tranny cars. For the manual tranny cars, it's the clutch switch. This can be used to see how long your shifts take as it will show the switch being made the entire time the clutch is engaged (not counting pedal travel).
POWER STEERING SWITCH, (on or off)

This shows you when your power steering is being used. Normally off until you move the steering wheel.

MISC, under misc you have;

A/C CLUTCH RELAY, (on or off)

Indicates whether or not the A/C clutch is engaged (ie the A/C compressor is working).
BATTERY, (range of 8.0 to 16.0 volts)

Useful to see what your battery is putting out. Also testing the alternator. You monster stereo guys should like this one. The ECU uses this along with other inputs to actually control the fuel injectors.
EGR TEMPERATURE, ( range of 100 to 400 degrees)

Nice to know info on how hot the air is going through the EGR valve. Not all cars have this sensor, and it certainly won't work if you have a blockoff plate installed.

TDC SENSOR, (on or off)

The ECU uses this to determine the engine rpms, ignition and fuel injector firing. The ECU assumes that the engine timing is set for 5deg BTDC, and this signal is the only way it knows where the engine is in its rotation.

TMO, under tmo you have;

TMO ENGINE SPEED, (range of 0 to 10,000rpms)

This is a little more accurate tachometer and you get the added plus of reading up to 10K!! If you try and see if you can get the line graph to reach that high, you're on your own. Don't say I didn't warn you! :)

Last but not least, TRIGGERS, (user set functions)

These are created by you and are recalled by selecting the trigger you save it as.You can select a value or a group of values that you want to datalog but only under certain parameters. Then have that value(s) only come on when you are in those set parameters.
 

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From TMO's old web pages.

TMO Datalogger 101

Since you purchased a TMO Datalogger, you are probably familiar with what it can do for you. Using the TMO Datalogger to "fine tune" your engine is where it really shines.

Using the information from the datalogger you can "tune" your car to run better and run closer to that fine "edge" of performance. This page will only touch base on the functions of the TMO Datalogger, the variables you can select and how to read those variables.

Now lets look at some of the data you can select to monitor with the logger.

NOTE: If you have some kind of piggyback fuel computer (VPC, AFC, PMS, MASC etc.) that gives a false signal to the ECU, that false signal will be reported by the Datalogger to you. Keep that in mind when interpreting data.

Under the label "DATA" on the toolbar you have SELECT, TRIGGERS, and QUICK SELECTS.

Select lets you pick all the variables you want to monitor

Triggers lets you select different combinations of variables and conditions (e.g. rpm>4000, TPS>50%) that will trigger the datalogger to start recording.

Quick Selects is a user-defined collection of variables. Instead of the tedious process of selecting each individual variable every time you want to use the TMO Datalogger, you can just choose a Quick select and start logging almost immediately. There are 6 Quick selects you can define, so be creative!

Once you are in the menu Select, you will see a bunch of values to select including FUEL, AIR, SPARK, IDLE, MISC, TMO, and TRIGGER.

FUEL, under fuel you have;

ACCEL ENRICHMENT (range of 0 to 100%)

This is the amount of fuel that is initially squirted into the engine during quick movements from the throttle. It gets its input from the Throttle Position Sensor. When the TPS voltage increases rapidly it shoots a little extra fuel in to help with the throttle response. Too much or too little will affect drivability.

COOLANT TEMP (range of 100 to 300 degrees)

This is just what it says, your coolant temp from the temp sensor for the ECU (not the one for the gauge, they are both located in the thermostat housing). The ECU uses this to tell when to go into closed loop after warmup. It also has an affect on timing.
ENGINE SPEED (range of 0 to 8000 rpms) (may be 8500 on some loggers)

The actual engine rpms the ECU sees from the information it gets from the TDC sensor and Cam angle sensor.

FUEL TRIMS HIGH, LOW, MIDDLE (range of 60 to 140% for 91+ cars, 80 to 120% on 90's)

These are the "long term" memory fuel tables in the ECU. When you drive the car in closed loop (normal to low-boost driving, rpm<4500), the ECU is constantly updating these trim values. The ECU takes the signal from the MAS and calculates how much fuel to add to maintain an a/f ratio of 14.7:1, then compares the O2 readings against the value it calculated and adjusts the fuel trims (adding more fuel or taking away) to try and stay at a constant "stoichiometric" value (14.7:1 air/fuel ratio). A trim value of 100% is stoichiometric, anything greater than 100% and you are running lean so the ECU is adding fuel, anything less than 100% and you are running rich and the ECU is subtracting fuel. The ECU always tries to run at a stoichiometric 14.7:1 ratio under closed loop operation and the values will be reset to 100% when the ECU is cleared.

These values will always be changing up or down a little depending on the air conditions and many other variables. Low, middle, high refer to the amount of airflow that the ECU sees while in closed loop. When the ECU goes into open loop, none of the fuel trims are updated.

INJECTOR PULSE WIDTH (range of 0 to 25 milliseconds "ms")

This is the actual amount of time that the injectors are open, not duty cycle. Duty cycle is roughly defined as the ratio of the amount of time a signal is "active" to the amount of time available for the signal to be active.

NOTE, once again every car seems to be different. I have personally run my 450cc's to 27+ ms and had a smooth pattern, great flow and no knock.

The one thing I will add is you want a value somewhere around 20ms at WOT. It must be a smooth, straight curve. If the value is jumpy at all your injectors are not squirting a smooth pattern and you will get detonation from this. It is more important that the signal be smooth than the actual number as on 91+ ECUs this number is what the ECU is "trying" to do, not that the injectors are actually open for that amount of time.

OXY FEEDBACK TRIM (range of 60 to 140%)

Just like the fuel trims, this is also a closed loop value only this is the "short term" value and it determines the adjustments made to the "long term" fuel trims. As you drive along it will switch (cycle up and down) just like the O2 sensor voltage. It should be a nice, smooth and even switching rate, not jittery or jerkly up and down. If it is switching from say 80% to 120% then you are right at 100% value, there's that stoichiometric word again. :) If it's switching above 100% it's showing lean, and if it's switching below 100% you are running rich. Based on this info, under certain conditions the ECU will adjust the appropriate fuel trim until it sees the oxy trim switching closer to stoich.

OXYGEN SENSOR (range of 0.0 to 1.0 volts)

The oxygen sensor is what the ECU to determine whether the engine is running rich, lean, or just right. 0 volts is lean, 1.0 volts is rich, and stoich is ~0.47v. Once again you want a good smooth pattern of peaks and valleys. At idle you will have a nice and slow switching rate. The higher the rpms and throttle position under a load (driving) the faster the switching rate until it stays constant at a higher reading. Once it stops switching that shows that you are not in closed loop anymore. Most importantly you want a smooth switching rate.

Once you go into open loop, it will show a constant reading. Under WOT you always want as low of O2 voltage reading as you can go WITHOUT any detonation or knock sum on the logger.

THROTTLE POSITION (range of 0 to 100%)

This just simply shows the position of the Throttle Position Sensor (TPS) on the throttle body. You can use it to watch the accel enrichment while you open the TB or to tell when your WOT pass starts or watch your shifts when you let off the gas during the shift. You should see a nice and smooth increase with a slow and steady increase from your right foot on the gas pedal. If it's not smooth your TPS could be going bad. The actual lowest the reading will show is somewhere around 10%.

AIR, under air you have;

AIR FLOW HZ (range of 0 to 1600hz)

This is the actual signal the Karmann Vortex generator in the Mass Air Flow sensor (MAF or MAS) sends to the ECU. This tells the ECU the amount of air moving through the intake. Please note that this is not equal to air mass - the ECU also needs the barometric pressure and intake temperature (also located in the MAS) to determine the actual air mass entering the engine and the corresponding amount of fuel to deliver. Unfortunately, current limitations in the TMO Datalogger limit the reported result to 1606hz. However, the MAS is capable of sending out a signal up to ~2200hz or so to the ECU.

AIR TEMPERATURE (range of 0 to 200 degrees)

This is the temperature of the air at the MAS. It's great for seeing if your cold air intake or heat shield is working. On a 45 degree day I had temps of 120 degrees at the filter with just a K&N and cut air can. After making a cold air setup and a heat shield I now see 75 to 85 degree temps. This also has an affect on timing.

AIR VOLUME (range of 0 to 255, actually 0 to 7)

This is the number that the ECU uses internally for air flow. It is derived from Air Flow Hz, air temperature, and barometric pressure. This value has far more precision inside the ECU (11 bits) but due to technical reasons, the logger only sees the top digit of the whole value (technically, the top 3 bits). This gives us a visible range of only 0-7. Because the resolution is so poor, Air flow Hz is usually used instead to monitor air flow.

BAROMETER (range of .7 to 1.1 bar)

This is also in the MAS . It shows the barometric pressure of the air to the ECU. This combined with other readings helps the ECU to know how dense the air is therefore to determine total air mass entering the engine.

ISC STEPS (range of 0 to 130)

This is your Idle Speed Control servo motor on the throttle body (you know, the one that goes bad!). It is a stepper motor that opens or closes the TB plate to control the idle speed due to load changes, i.e. turning on the a/c or using the power steering, brakes etc. It opens up in steps and closes in steps to control the idle. This value is useful to tell if the ISC is working well or not.

SPARK, under spark you have;

KNOCK SUM (range of 0 to 43)

This is an important value! The knock sum scale is given to represent the signal from the knock sensor to the ECU. The ECU then calculates the amount of detonation present. The higher the knock sum the more the ECU retards timing to get rid of the knock.

With a knock sum of;
3 or below, the ECU will advance timing.
Between 3 and 7, the ECU leaves timing alone.
Higher than 7, the ECU will begin retarding timing. Higher knock = higher retard, with the possibility of seeing less than 4deg total advance at the maximum knock sum of 43.

One important note to remember is the knock sensor can detect "false" knock and retard timing. This is most commonly caused from the noisy lifters but anything it can audibly pick up could cause this.

TIMING ADVANCE (range of 0 to 50 degrees)

This is the real-time spark timing the ECU is using. While at cruise speeds at low throttle settings it can maintain as high as 40 or more. This is a very useful tool as you can really "see" the timing affect power. The more advance the better up until knock occurs. Ideally you want to maintain around 15degrees advance at WOT high rpms. Any higher advance and you probably can afford to increase boost a little bit, any lower advance and you are knocking and it's being retarded too much. It's very easy to see the relationship between the knock sum and the timing advance.

IDLE, under idle you have;

A/C SWITCH, (on or off)

This just simply tells you when the a/c switch is on or off. Nice for seeing if your TMO ECU is turning if off under WOT or above 5000rpms.
IDLE SWITCH, (on or off)

This is the single wire switch on the TB. It tells the ECU when the throttle plate is fully closed. If this switch is faulty it will cause idle problems. This tool is an easy way to tell if it's working correctly.
PARK/NEUTRAL SWITCH, (on or off)

This is simply the park/neutral switch on auto tranny cars. For the manual tranny cars, it's the clutch switch. This can be used to see how long your shifts take as it will show the switch being made the entire time the clutch is engaged (not counting pedal travel).
POWER STEERING SWITCH, (on or off)

This shows you when your power steering is being used. Normally off until you move the steering wheel.

MISC, under misc you have;

A/C CLUTCH RELAY, (on or off)

Indicates whether or not the A/C clutch is engaged (ie the A/C compressor is working).
BATTERY, (range of 8.0 to 16.0 volts)

Useful to see what your battery is putting out. Also testing the alternator. You monster stereo guys should like this one. The ECU uses this along with other inputs to actually control the fuel injectors.
EGR TEMPERATURE, ( range of 100 to 400 degrees)

Nice to know info on how hot the air is going through the EGR valve. Not all cars have this sensor, and it certainly won't work if you have a blockoff plate installed.

TDC SENSOR, (on or off)

The ECU uses this to determine the engine rpms, ignition and fuel injector firing. The ECU assumes that the engine timing is set for 5deg BTDC, and this signal is the only way it knows where the engine is in its rotation.

TMO, under tmo you have;

TMO ENGINE SPEED, (range of 0 to 10,000rpms)

This is a little more accurate tachometer and you get the added plus of reading up to 10K!! If you try and see if you can get the line graph to reach that high, you're on your own. Don't say I didn't warn you! :)

Last but not least, TRIGGERS, (user set functions)

These are created by you and are recalled by selecting the trigger you save it as.You can select a value or a group of values that you want to datalog but only under certain parameters. Then have that value(s) only come on when you are in those set parameters
Thank you very much for the information, I will definitely save it! However, It seems I can't set the Trigger correctly; it's as if nothing happens after I close its window.
Haven't found any video of people doing this...
 
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