Nistune and Zeitronix Ethanol content discrepancy

[adamky]

Nistune shows 25%
Zeitronix display shows 9% (pump gas)

Nistune v1.2.62 - S13 KA24DE ECU - Feature Pack
Zeitronix ECA-2
GM Continental 13577394 ethanol sensor

See video for more info:
https://youtu.be/KXTbG93ajwY

[Matt]

Thanks for the video. I'll go through this once I get back and see what is going on. The Zeitronix converters the frequency to volts. We use the voltage to work out the frequency to voltage conversion (0-5.12 volt) which effectively becomes to 0-100% percentage for display purposes. From memory the zeitronix did not use the entire 0-5.12 volt ranges. Will check this out once I get back from vacation

[adamky]

Thanks Matt. Enjoy the rest of your vacation!

[Matt]

This takes some setting up to do. Getting to this today:
Setup 1. Zeitronix ECA-2
Setup 2. Nistune Flex fuel cable

Set frequency input to 59% (9% ethanol) same as video

ECU input line
Matts => 5.12 volts (floating AD input - pulled high)
Yours => 5.2 volts
[Changes here might be difference in ECU power or volt meter calibration. Normally it should be 5.12 volts maximum input to the AD converter]

Zeitronix (white/blue) outputs disconnected
Matts => 0.510 volts
Yours => 0.485 volts
Nistune Flex => 0.438 volts

Zeitronix connected to ECU changes
Matts => 1.27 volts
Yours => 1.31 volts
Nistune Flex => 0.44 volts

Display
Matts => 25%
Yours => 25%
Nistune Flex => 8%

So the Zeitronix input is being pulled up by the ECU output (but does not affect the AD output from the Nistune flex cable)

[Matt]

Remove pull up resistor on the back of ECU near board header (R225) with '112' resistor. This is the 5V pullup which is forcing the Zeitronix to show a higher voltage

I got 9% displayed in Nistune after removing this part

[Matt]

100 ohm pull down to ground on the line will counteract the 1.12K pull up also, but best to remove the pull up resistor. I'll update the FP documentation

[Matt]

I've identified the vehicles affected:

S13 SR20DE/B13 SR20DE/P10 SR20DE/S13 KA24DE
- Remove resistor '112'

S13 SR20DET
- Remove resistor '112'

Z32 VG30DETT
- Remove resistor '112''

Updated the Feature Pack hardware install manual to include this step for only Zeitronix ECA-2

Zeitronix unit was tested on other models so the voltage increase was not noticed (only really problematic around the lower end as you noted)

[adamky]

Awesome, thanks Matt! I'm going to make a video showing me removing the resistor and I'll include a link to this thread in my original video.

[adamky]

The R226 resistor on my S13 KA24DE (manual) ECU says "203" on it. Removing this only dropped the % from 25 to 22. So, I put that one back and removed the one @ R225 marked "112" and that did it. I'm seeing 9% from both sources now. Sweet!

Nissan Part # 23710-53F01

[Matt]

Thanks for the update. Definately 112 part. I'll update the document to reflect this. Hardware markings must have changed

[Grant Smith]

When I was using the nistune flex converter board, I would always get 2% ethonal readout when in free air or zero E content gasoline in my Ka24de 53f0F ecu. All other content was accurate just the baseline was 2% instead of zero. I removed the 112 resistor and the baseline went down to zero

[Matt]

thanks for the update. Whilst it is a small amount, we might update the document just to remove those resistors regardless