[N111CUK]

Hello to anyone who can assist me with my Flex Fuel issue

I have setup flex fuel using a specific MHD tune from an experienced tuner (JSR) and a fuel-IT ethanol analyzer which can read over bluetooth plus on a 0-5v signal wire

My setup; The ECA analyzer wire plugged into Harness PIN#16 on the black 26 pin sub

Issue I'm having is #pin16 has 4v coming out of it which is normal based on my testing this car and others. However when I plug my ECA signal wire which currently has 0.28v (pump gas) it doesn't change the PIN16 voltage to the ECA reading but rather keeps the 4v resulting in a E reading of E80 on MHD and my JB4

My fuel-IT app shows E4 which is correct based on pump gas and 0.28v which I measured with a multimeter

My tuner has double checked the tune and seeing as I can see E content in both MHD and JB4 it looks right. But because I have a persistent 4v on PIN16 my E content is skewed

Important to note;
I installed a new DME MSD81 which came from a 135 from 2008 from the USA. I have my old mds80 but is now not coded to my CAS

I have a theory which comes from looking at the wiring diagrams attached in the PDF at the end of my thread

In the USA PIN 16 and PIN17 were used for these functions

16 E USA Signal, fuel tank leak diagnosis pump Diagnostic module for fuel tank leakage
17 E USA Signal, fuel tank leak diagnosis heating Diagnostic module for fuel tank leakage

Could I have a coding issue on this DME which means a conflict between function ????

I did also try plugging in the ECA signal only into the JB4 PIN2 on the DB25 plug and E shows up correct. the analyzer is working as intended

All I can think is at fault is the DME coding is somehow causing the issue

[langsbr]

Mine just had this same issue and it was the flex fuel box that was bad. Just got the replacement back and back to working properly.

[langsbr]

To add more context - it sounds from your post that you have both the Motiv flex fuel and the Fuel-IT ECA. If you are using the same Contiental sensor, it's taking the frequency reading from the sensor and each ECA does it's own "thing" to determine the ethanol content.

The Fuel It sensor's voltage to ethanol rating is likely different than Motiv's. Most ECAs go all the way to 4 or 4.5V for full E85, while Motiv's stops at 3 or 3.5V and 4V is an error from the box.

The sensor itself does not put out a voltage, but a frequency, thus you need the ECA to 'decipher' the ethanol content.

You could take the voltage out from your Fuel-It ECA and use that instead of the Motiv box, but your tuner would have to redo the tune for the Fuel-It ECA breakpoints.

Hope that helps.

[N111CUK]

I only have the fuel-it analyser
When tested I get 0.28v from its signal wire.
This is in-line with its reading in the app of e4

Issue happening when I connect the signal wire to my harness pin16
This pin16 is outputting 4v and once connected should be overridden by the eca signal voltage

I've since plugged in another dme and I have the same results

I think it's time to try another eca analyser