K Tuner Flex Fuel Converter box not working

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drtalon123
Posts: 3
Joined: Thu Mar 05, 2020 4:29 am

K Tuner Flex Fuel Converter box not working

Post by drtalon123 »

Hi all,

I recently purchased a K Tuner Flex Fuel Converter box and a brand new Continental flex fuel sensor with pigtail from Xenocron.com.

I've been a technician for a better part of almost 2 decades, and am familiar with these Continental sensors found on GM flex fuel vehicles. I looked at the installation details regarding this converter box and the sensor, and figured implementation was a no-brainer.

Well, I'm bench testing these devices and can't get any feedback from the converter box. Here's a private video I uploaded to YouTube describing my issue, and going over my bench test setup:

https://youtu.be/WXhijjR71uo


My bench test setup (borrowing items from my homemade injector flow bench):

-External 3 gallon fuel cell supplying a Walbro GSL392 > Flex Fuel Sensor > Return back to the cell.

-I am running the pump off of a variable voltage 30A switch mode power supply set to 12V.

-Power supply feeds the pump as well as the flex fuel sensor and converter box.

-The negative post of the power supply is the common for the entire circuit.

-My Fluke 87 ground lead tied into the common, and V+ lead monitoring VOUT1 (Yellow), meter set to measure DC


Device wiring is as follows:

Continential Flex Fuel Sensor
VCC > 12V @ Power Supply V+ post
GND > Common/Ground @ Power Supply V- post
Vout > K Tuner White Input wire

K Tuner Flex Fuel Converter
GND > Common/Ground @ Power Supply V- post
PWR > 12V @ Power Supply V+ post
INPUT > Vout @ Continential Flex Fuel Sensor
VOUT1 > Fluke 87 V+ lead


With everything wired and setup like above, turning the power supply on starts the pump, which starts circulating E85 through the hose loop back to the fuel cell return. The Continential Flex Fuel Sensor is teed into the pump loop line. The fuel circulates in a closed loop through the sensor. At this time, the K Tuner device is also appears to be powered on with a greenish/yellow looking status LED visible through the side of the case near the electrical connector.

I would expect to receive a 0-5V scale signal from VOUT1 of the K Tuner device, as the sensor should be attempting ethanol content measurement, and the converter box transforming the frequency signal generated by the sensor into a linear 0-5V range signal.

I get 0V at my meter when the power supply gets switched on. If I unplug the Continental sensor while the K Tuner device is powered on, then reconnect the Continental sensor, I receive a steady state 0.5V. Out of curiosity, I checked VOUT2. This continually outputs a 1V signal no matter what.

I'm not sure what might be going on. These flex fuel sensors are 12V devices, confirmed through multiple variants of GM schematics as well as many an internet search. My first thought was I might have fried the sensor if for some reason it was a 5V sensor, but I have never seen one of these Continental sensors use a 5V V+ input, they've always been 12V.

I wanted to bench test this stuff before installing things on my car, because I'd like to verify the ethanol content readout/output in a controlled manner to see a comparison with the American Petroleum Institute's ethanol content water separation test method. I performed a few tests with my batch of pump E85 and did the water mix separation method to determine ethanol content from nearby pumps. The water separation method shows my last purchase of E85 to have roughly 70% ethanol content in it. I bought 5 gallons in my VP fuel transfer container and filled my bench fuel cell with it as a way to test this sensor and converter box.

I know for a fact that there is a significant volume of ethanol in this fuel, so 0V is not accurate. Is there anything else I can try to troubleshoot these devices before contacting Xenocron to determine what I should do next? I couldn't find much information about troubleshooting the Flex Fuel Converter box, because it seems like such a simple hassle free device, I just don't know what to do next other than start replacing parts/components to isolate what might be the issue. I can break out the scope if necessary and test the flex fuel sensor native output directly if necessary, because if the sensor is dead, then the converter box rightly won't do anything to output a signal.




Thank you for any help/responses!

Talon.
KTuner
Site Admin
Posts: 3745
Joined: Mon Jul 22, 2013 8:13 pm

Re: K Tuner Flex Fuel Converter box not working

Post by KTuner »

0v and 1v for the outputs suggest no signal. If you take the top off the LED gives an indication of signal being good or not.
Divergent Concepts
Posts: 7
Joined: Mon May 13, 2019 8:37 pm

Re: K Tuner Flex Fuel Converter box not working

Post by Divergent Concepts »

if the LED inside is Yellow it is not receiving a Frequency of 50-150hz from the Sensor. when the LED is Green it means it is picking up the 50-150hz, If you have a scope i would hook it up and see what you have. Also see if you get any difference with the Pump off you might be getting interference from the pump.
drtalon123
Posts: 3
Joined: Thu Mar 05, 2020 4:29 am

Re: K Tuner Flex Fuel Converter box not working

Post by drtalon123 »

Awesome, thanks guys! Excellent responses.

I took the top off of the device and looked at the LED directly, it almost looks like green and yellow are on together inside the single multicolored LED? Its hard to tell the true color. It starts out as solid green for less than half a second then another LED turns on and they are both blended together, and it almost looks white, light yellow.

In any case, I will interrogate the FF sensor with my scope to determine if it is outputting any frequency and the overall line voltage to make sure I'm not getting a lot of noise from the pump.

Thanks again for your input! I'll update this thread again when I finish testing to post the findings.
drtalon123
Posts: 3
Joined: Thu Mar 05, 2020 4:29 am

Re: K Tuner Flex Fuel Converter box not working

Post by drtalon123 »

Broke out the scope and the fluke again, confirmed the sensor is dead. There is no abnormal noise being generated from this pump that I could see with the scope on any of the power supply lines, so it isnt noise causing issues.

Luckily I have a PWM signal generator that I use for my injector flow bench, and I was able to feed the K Tuner Converter box a 50-150 hz signal to test with.

Sure enough the LED color I was seeing was yellow, which is some sort of colors blended together, but the second it received a valid in range 50-150hz signal, it turned nice and green. It always stays yellow apparently until it receives a valid signal, that's good to know.

Feeding it the min/max frequencies this FF sensor typically generates, I was able to correlate the voltage readout from the K Tuner box on VOUT1 was in range of the install instructions, 0.5V@50hz - 4.5V@150hz.

The Continental FF sensor is getting clean power and ground, but the output is a dead solid line stuck at 5 volts+ with reference to ground. I will contact Xenocron and see if they might be able to help me out. I feel I've done my due diligence before attempting to push through a claim.


Thanks again to everyone who responded! I really appreciate it!

Here are some proof pics that the converter box is working:


Setting fluke and scope to display frequency measurements for verifying signal generator functionality, currently set out of range of K Tuner converter box input:

Signal generator desired output display settings:

Image


Fluke and scope correlation:

Image

Image


@ 10hz now:

Image

Image

Image


Feeding the K Tuner box an in range frequency, and monitoring its 0.5-4.5v output with fluke:

Image

Image


Now @ 60hz:

Image

Image


Now @ 90hz:

Image

Image


Now @ 120hz:

Image

Image


Now @ max 150hz:

Image

Image


The box works lol :)
KTuner
Site Admin
Posts: 3745
Joined: Mon Jul 22, 2013 8:13 pm

Re: K Tuner Flex Fuel Converter box not working

Post by KTuner »

Glad the box works and that you know where to go from here!
bbeem
Posts: 4
Joined: Fri Feb 08, 2019 3:30 am

Re: K Tuner Flex Fuel Converter box not working

Post by bbeem »

FFC100 worked well for a year, now I think it's failing. Was at 34% ethanol and almost empty so I filled up premium and brought it to 5% and parked the car for the week. 8 days later I start up and it reads 17-25%! I drove it 90 miles and put 3 gal premium and it still says 17-25%. It doesn't lock in +/-1% either, just swings around 20%. I plugged in an identical flex fuel sensor (in my hand not in the fuel line) and got the same 20% reading. I metered the pins and have 14.4vdc pin 2, 3.233vdc input, 0.503 output 1, 2.523vdc output 2
KTuner
Site Admin
Posts: 3745
Joined: Mon Jul 22, 2013 8:13 pm

Re: K Tuner Flex Fuel Converter box not working

Post by KTuner »

.503 is not 20%, so you have a connection issue between the box and the ECT2 input.
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