Flexfuel sensor turning off kpro board

[fonzeka]

2003 S2000 with K-Pro4 serial 42646, kmanager 4.5.5
I've been running with this ecu for several years, right now it is on a SC setup.
Latest modification was new EV14 1500cc 8.5Ohm injectors and GM #13577429 flexfuel sensor.
After this I have had major problems when trying to start the car.
At first I thought it was a low cranking voltage problem so replaced battery, ground cables etc but no change.

Now I have found and isolated the problem to the flexfuel sensor.
Sensor is powered on with ignition.
If I turn on ignition with sensor unplugged, kpro board turns on like normal.
If sensor is plugged in no led's light up on kpro board, only one green led on the S2000 adapter board closest to ecu plugs turn on.

What's even more weird is if I have a laptop connected via usb and turn on ignition, kpro boards starts up like normal.
Laptop has to be turned on but I do not need to have kmanager running.

As long as I can get through the starting problem sensor is working and reads correctly.
I also found this seems to be a known problem since many years ago viewtopic.php?t=21028
Is it some kind of hardware problem and what is the best known solution?

[Hondata]

There was a fix for V4.4.2 (10 Jul 2019)
• [KPro4] added option to update KPro boot firmware to fix ethanol input problem

You should be able to update the boot firmware from the online menu *if* your kpro has the older boot firmware. If not, it is some other problem.

[fonzeka]

Thanks for the quick support, that seems to have fixed the problem!

On my first try I did get an error message and it didn't work on second try either.
But after unplugging ethanol sensor it did work.
I never turned on the ignition so second popup message after the success was a bit confusing.
In the future maybe fix ignition spelling and use some different words than "un-plug and re-plug Kpro" my guess was it just referred to the USB cable?

msg.jpg

[Hondata]

Glad it solved your problem. Thanks for the feedback.