1.5T Guide to DIY Flex Fuel Kit for Hondata or KTuner

shibles

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I broke both of the clips that hold the fuel line to the chasis.
Any one know the part number for them?
Thanks
I did too when I installed it. Unfortunately it looks like you can't get them as separate parts, they come with the fuel line when you order it.

 

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Question: the plug on the left is my ECT2 plug from my flex fuel kit, the one on the right is the factory one that plugs into the radiator. Isn't the flex fuel kit supposed to plug into the radiator? Seems like the wrong plug if so. Or do these plug in to each other?

20210527_095350.jpg
 

whoisJSR

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Reason I asked is that I assumed these were supposed to plug into each other (and nothing plugs into the radiator) since the harness that came with my Flex Fuel kit came with what I think is the wrong type plug (male instead of female). I suppose if that's the case I could just cut the factory plug off and splice it onto the flex fuel kit, but jeez... please tell me I was correct initially, and these plug into each other!

Unfortunately I don't believe that to be the case; I throw a CEL every time I do. :(
 

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between the two connectors, the new one for the flex fuel kit will only plug into one. It left me with a little doubt at first too.

As for the CEL... did you flash a tune with the ECT2 (and any other indicated) disablement(s)?
 

whoisJSR

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between the two connectors, the new one for the flex fuel kit will only plug into one. It left me with a little doubt at first too.

As for the CEL... did you flash a tune with the ECT2 (and any other indicated) disablement(s)?
Just the ones the install PDF told me to. I just reflashed it, and I'm taking it for a test drive now. We'll see if that fixes it. I know it's that sensor because when I plugged the stock one back in, I just got smog tested and it passed.
 

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Just the ones the install PDF told me to. I just reflashed it, and I'm taking it for a test drive now. We'll see if that fixes it. I know it's that sensor because when I plugged the stock one back in, I just got smog tested and it passed.

FYI.... my personal experience lead to an understanding that not having ECT2 enabled prevents at least the evap self-test from being run. For jurisdictions where one not-ready is allowed, if you already have P0420 or something else disabled, the car is unlikely to pass a legit inspection.

I never got around to it, but it someone can fabricate a Y-splitter pigtail with a remote fuse or toggle-switch atop the engine bay.... You'd be my hero, and will receive my monies for such a unit.
 

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UPDATE: Changed my tune to the Phearable Stage 2.5. While flashing the ECU I disabled the P2185 (Secondary ECT), P0128, and P0138/P0139 (O2 slow response) codes and the CEL has not returned.

I have 2 theories: either my Flex Fuel Kit shipped with the incorrect plug fitting (mine is male instead of female, which is required to plug into the radiator where the OEM plug goes in), or the PRL instructions to install the Flex Fuel Kit is incorrect (They say in their instructions that the dongle from the Flex Fuel Module plugs into the Radiator, but the only thing that fits into is the OEM 1-wire plug, and NOT the radiator.)

It seems to be running just fine... in fact, outstanding. My car is insanely fast and runs fantastically. So I dunno...
 

IronFusion

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UPDATE: Changed my tune to the Phearable Stage 2.5. While flashing the ECU I disabled the P2185 (Secondary ECT), P0128, and P0138/P0139 (O2 slow response) codes and the CEL has not returned.

I have 2 theories: either my Flex Fuel Kit shipped with the incorrect plug fitting (mine is male instead of female, which is required to plug into the radiator where the OEM plug goes in), or the PRL instructions to install the Flex Fuel Kit is incorrect (They say in their instructions that the dongle from the Flex Fuel Module plugs into the Radiator, but the only thing that fits into is the OEM 1-wire plug, and NOT the radiator.)

It seems to be running just fine... in fact, outstanding. My car is insanely fast and runs fantastically. So I dunno...
If you're getting an Eth% reading now, the plugs are correct. It was likely a matter of a code/sensor disablement missing. If you have other mods, the PDF may not be enough.
Assuming you didn't provide what the CEL Code was bc you don't have a way to read... Get yourself a BT obd2 tool and an app you like. I like Carscanner unpaid on android, but many will do.

You can easily read and clear codes with one of these tools. They're inexpensive and super handy. You can also know, in advance, the ready status of emissions systems. If you live in a state where 1 or two not-ready's are allowed, it's a good idea to confirm before heading for an inspection.

Unless my car is a unicorn, I have identified an issue for inspections that should impact users of the flex fuel kit... You lose ECT2 when swapping plugs at the radiator. From what I have guessed/figured out, ECT2 is needed for the evap self-monitoring test to run. So, if you have any disablements, like those O2 ones, you may already have a not-ready. If the evap can't run, you will have another. Where I live I only get one not-ready, and need P0420 for my catted DP, so I can't pass inspection without crawling under the car a week ahead of time and swapping the ECT2 wires at the radiator back, and reflashing to a different tune.
I don't recall if I needed a non-ethanol tune, or a "compatible" one that just had ethanol disabled. It was months ago.

I haven't had anyone confirm they ran into the same ECT2 Issue though. If I don't drive a ? it'd b great to have a breakout board+box to pin a dedicated sensor line for the ethanol sensor and not have to lose ECT2. Otherwise, I'm eventually going to buy a switched/fused Y-splitter product that keeps me from changing wires under the car... If someone starts selling one, or just fab my own when I've had enough.
 

Ozzie

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Hello everyone,
I have been lurking for a long time and have been following this thread mainly because I like gauges and want to install the ethanol gauge in my 2017 Si Sedan. Also, I’m from TX so I need a yearly inspection and had to switch back to non-ethanol tune and reconnect the ECT2. I finally went back to the flex-fuel tune and decided to splice the connector from the flex-fuel to the ECT2, that way the evap self- monitoring pass (hopefully).
One thing I noticed is that once I flashed the tune, ethanol content was around 9-10% which is typical from any gas station and the ECT2 was reading 168-ish degrees. Once I filled up with E-85, the ethanol % went up and the ECT2 reading went down. Right now, my car has 29% ethanol (I forgot how much I needed, it’s been a while lol) and the ECT2 was at 127 degrees. I don’t know why it went that low, so any insight will be greatly appreciated.
 

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I think if you're going to run ethanol, you should be ignoring the ect2 reading. The voltage on the wire for ect2 is coming from your ktuner converter. I'm not sure if it takes precedence over the thermostat reading, but if anything, if it's spliced together, ktuner is connected to both your ktuner converter and your thermostat. I don't think you can get an accurate reading for both eth% and ect2 temp through one wire.

I'm no electrical engineer, and I just got my diy flex fuel kit working today so I'm no expert.

 

 
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