Drivetrain Correcting MPG readout after installing larger injectors?
Thread Starter
|
OVERDRIVE
Joined: Aug 2006
Posts: 7,201
Likes: 8
From: Norfolk, VA
Correcting MPG readout after installing larger injectors?
Another NAM'er brought up this question, and I thought it might make for a good thread.
If you install larger injectors without re-tuning the ECU, the average MPG readout in the OBC will be overly-optimistic (too high), because the OBC will be underestimating the amount of fuel being fed to the engine. This is because the OBC measures fuel consumption by multiplying the injectors' flow rate by their duty cycle (the percentage of the time the injectors are "on and spraying").
I'm sure that the factory can fix the discrepancy with ECU tuning, because the JCW cars have larger fuel injectors, and presumably their OBC MPG readout isn't any less accurate than the readout on a stock 'S'.
But does an aftermarket ECU tune like one you would get from someone like Jan correct the OBC MPG readout as well?
If you install larger injectors without re-tuning the ECU, the average MPG readout in the OBC will be overly-optimistic (too high), because the OBC will be underestimating the amount of fuel being fed to the engine. This is because the OBC measures fuel consumption by multiplying the injectors' flow rate by their duty cycle (the percentage of the time the injectors are "on and spraying").
I'm sure that the factory can fix the discrepancy with ECU tuning, because the JCW cars have larger fuel injectors, and presumably their OBC MPG readout isn't any less accurate than the readout on a stock 'S'.
But does an aftermarket ECU tune like one you would get from someone like Jan correct the OBC MPG readout as well?
4th Gear
Joined: Apr 2002
Posts: 444
Likes: 0
From: wherever
2nd Gear
Joined: Aug 2008
Posts: 68
Likes: 0
From: SoCal
I have this problem after larger injectors and tune. Last fill-up showed 515 mile range and 36 MPG avg on the OBC! Manual calculation shows my mpg is about the same as bone stock (24.5 mpg).
I haven't contacted the tuner yet...maybe they have a way to correct this.
Is the method below a means of correcting the fuel consumption readout?
The IKE has 21 test functions you can access by holding the trip button down while turning the ignition key. Press briefly to advance through menu options, press and hold to access that option. Tests 1&2 are always unlocked, Tests 3-21 are locked. Test number 19 is the "Unlock" function for getting to the rest of them.
Try subtest 2.0 (hold trip button, turn on key, press repeatedly to scroll up to 2.0, then hold). It runs a test that activates all gauges, LED's, and indicators.
A complete list of functions is below, this example is how to get into the menu number '7'.[/FONT]
1. With the key in the ignition, but in the off position, press and hold down the odometer reset button, while holding the button down, switch the key in the ignition to position 1.
2. The screen will say 'Test' and a number.
3. Scroll through, (pressing reset button) through to test 19 and wait a moment.
4. Wait and the message will say "log i-off" then "log i-on" and back to "log i-off" again. When "log i-off" appears, press again. You are now in the system.
5. You can (if you wish) start the ignition any time from now.
6. Scroll through to test 7.0 (or whichever from the list below) and wait a moment, after a pause you will enter the test 7.* range of information.
7. You can scroll through now (7.1,7.2,7.3 etc.) using the reset button.
8. You can exit each menu by pressing, holding for a few seconds, then releasing the reset button.
9. To leave the system scroll to 19 and leave it for a few moments.
Switching off the ignition also exits the system.
Test:
1.0 Chassis number
1.1 Kilometer count
1.2 Parts number
1.3 Coding-, Diagnostic- and Bus-index
1.4 Production Date (Calender week/year)
1.5 Hard- and Software status
1.6 Injectorstatus, Cylinder count, Engine factor.
2.0 Combisystem Test
3.0 Service interval counter
4.0 Actual fuel consumption in l/100km. eg.0154 = 15,4 liters/100kms.
4.1 Consumption in liters/100kms.
5.0 Distance consumption in l/100kms.
5.1 Actual rest distance with available fuel in Kms.
6.0 Actual amount of fuel in tank. eg. 123321 =12,3liters left 32,1 liters right
6.1 Total amount of fuel in tank.
6.2 Show value of Fuel guage. 1= both senders OK, 2= sender failure, 3=ti signal unplausible (no reading)
7.0 Actual coolant temp.
7.1 Actual outside temp.
7.2 Actual engine revs.
7.3 Actual speed
8.0 Hexadecimal readings of menu 7.0 to 7.3
9.0 Actual on board voltage (Battery)
10.0 Land codes
11.0 Unit codes
12.0 No function
13.0 Gong test
14.0 - 14.4 On board diagnostic codes. eg 000000 = no failures
15.0 - 18.0 No function
19.0 On/Off for Test menu.
20.0 Correction factor for Fuel consumption
Formula for correction:
Shown consumption x 1000 / user defined consumption
Push the trip reset button to begin the correction. Numbers count up from 0-9, when correct number shows push trip reset button.
20.1 Sets 10ths. for consumption factor
20.2 Sets 100ths. and 1000ths. for consumption factor
20.3 Saves the new consumption factor and shows new value
21.0 Software reset. (Same as disconnecting battery)
Enjoy your MINI....
I haven't contacted the tuner yet...maybe they have a way to correct this.
Is the method below a means of correcting the fuel consumption readout?
The IKE has 21 test functions you can access by holding the trip button down while turning the ignition key. Press briefly to advance through menu options, press and hold to access that option. Tests 1&2 are always unlocked, Tests 3-21 are locked. Test number 19 is the "Unlock" function for getting to the rest of them.
Try subtest 2.0 (hold trip button, turn on key, press repeatedly to scroll up to 2.0, then hold). It runs a test that activates all gauges, LED's, and indicators.
A complete list of functions is below, this example is how to get into the menu number '7'.[/FONT]
1. With the key in the ignition, but in the off position, press and hold down the odometer reset button, while holding the button down, switch the key in the ignition to position 1.
2. The screen will say 'Test' and a number.
3. Scroll through, (pressing reset button) through to test 19 and wait a moment.
4. Wait and the message will say "log i-off" then "log i-on" and back to "log i-off" again. When "log i-off" appears, press again. You are now in the system.
5. You can (if you wish) start the ignition any time from now.
6. Scroll through to test 7.0 (or whichever from the list below) and wait a moment, after a pause you will enter the test 7.* range of information.
7. You can scroll through now (7.1,7.2,7.3 etc.) using the reset button.
8. You can exit each menu by pressing, holding for a few seconds, then releasing the reset button.
9. To leave the system scroll to 19 and leave it for a few moments.
Switching off the ignition also exits the system.
Test:
1.0 Chassis number
1.1 Kilometer count
1.2 Parts number
1.3 Coding-, Diagnostic- and Bus-index
1.4 Production Date (Calender week/year)
1.5 Hard- and Software status
1.6 Injectorstatus, Cylinder count, Engine factor.
2.0 Combisystem Test
3.0 Service interval counter
4.0 Actual fuel consumption in l/100km. eg.0154 = 15,4 liters/100kms.
4.1 Consumption in liters/100kms.
5.0 Distance consumption in l/100kms.
5.1 Actual rest distance with available fuel in Kms.
6.0 Actual amount of fuel in tank. eg. 123321 =12,3liters left 32,1 liters right
6.1 Total amount of fuel in tank.
6.2 Show value of Fuel guage. 1= both senders OK, 2= sender failure, 3=ti signal unplausible (no reading)
7.0 Actual coolant temp.
7.1 Actual outside temp.
7.2 Actual engine revs.
7.3 Actual speed
8.0 Hexadecimal readings of menu 7.0 to 7.3
9.0 Actual on board voltage (Battery)
10.0 Land codes
11.0 Unit codes
12.0 No function
13.0 Gong test
14.0 - 14.4 On board diagnostic codes. eg 000000 = no failures
15.0 - 18.0 No function
19.0 On/Off for Test menu.
20.0 Correction factor for Fuel consumption
Formula for correction:
Shown consumption x 1000 / user defined consumption
Push the trip reset button to begin the correction. Numbers count up from 0-9, when correct number shows push trip reset button.
20.1 Sets 10ths. for consumption factor
20.2 Sets 100ths. and 1000ths. for consumption factor
20.3 Saves the new consumption factor and shows new value
21.0 Software reset. (Same as disconnecting battery)
Enjoy your MINI....
mike
2nd Gear
Joined: Aug 2008
Posts: 68
Likes: 0
From: SoCal
update:
I'm still seeing up to 42 mpg avg and 500+ mile range at fill-up.
I've called a couple of MINI dealers and they only offerred a cluster reset, but did not know if that would correct things.
Anyone have luck with correcting MPG readout after installing these larger injectors?
I'm still seeing up to 42 mpg avg and 500+ mile range at fill-up.
I've called a couple of MINI dealers and they only offerred a cluster reset, but did not know if that would correct things.
Anyone have luck with correcting MPG readout after installing these larger injectors?
Trending Topics
update:
I'm still seeing up to 42 mpg avg and 500+ mile range at fill-up.
I've called a couple of MINI dealers and they only offerred a cluster reset, but did not know if that would correct things.
Anyone have luck with correcting MPG readout after installing these larger injectors?
I'm still seeing up to 42 mpg avg and 500+ mile range at fill-up.
I've called a couple of MINI dealers and they only offerred a cluster reset, but did not know if that would correct things.
Anyone have luck with correcting MPG readout after installing these larger injectors?
Banned
Joined: Feb 2009
Posts: 177
Likes: 0
From: Colorado
Honestly - If you are at the point of Modding your Mini to the level of changing injectors how concerned are you about the computers MPG read out 
- After all the computer is not that accurate to begin with.
??
- After all the computer is not that accurate to begin with. ??
it seems to me, the system is set up to take changes into account, if your readings are that far off, use the above mentioned function 20 to correct it, I'm sure that's exactly what Mynes did. I went from stock 340s to 450cc injectors, no real problems with accurate mileage...
Thread
Thread Starter
Forum
Replies
Last Post
squawSkiBum
MINI Parts for Sale
15
Oct 2, 2015 09:21 AM
Minibeagle
Stock Problems/Issues
6
Aug 13, 2015 10:00 AM
