2018 Accord 2.0T Sirimoto flex fuel problems

FlashPro questions & answers specific to the 2008+ Accord, Americas and international
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Gustav88
Posts: 2
Joined: Sun Sep 08, 2019 7:14 pm

2018 Accord 2.0T Sirimoto flex fuel problems

Post by Gustav88 » Sun Sep 08, 2019 8:11 pm

Hello,

I'm new to these forums, have searched but could not find any answers to my problem so I'm making a new thread.

Only mods to my 2018 Accord Sport 2.0T 6SPD besides the flex fuel kit and Hondata calibration is an Afe/Takeda intake, model 56-70003R. Will be installing a full turbo back exhaust system once all the parts arrive. RV6 black ceramic coated downpipe with high flow cat and plugged O2 bung for future CTR turbo upgrade, PRL frontpipe, and Borla S-Type "catback" exhaust. I have the race flashpro.

Installed the Sirimoto kit and followed the instructions to a "T", but when cycling the ignition on and off after installation, I noticed the gauge was not working, no power, no readings. Double and triple checked all connections, everything is hooked up as it should be. Started the engine and still nothing. Checked connections and for fuel leaks, again everything as it should be and no leaks.

Hoping it was just a bad gauge, I proceeded to upload the Hondata stage 2 with flex fuel calibration (already had stage 2 loaded, but without flex fuel support prior to Sirimoto install). I'll note that in anticipation of the install, I filled up a partial tank with what I calculated as a 30% ethanol blend. I used the calculator on the Hondata website. Upload was flawless and started engine. Ethanol reading in flashpro manager was at 29%, then dropped to 28% after a few minutes and stayed there. Given the possible variance of ethanol in e85, I figured it was working and I just got a bad guage from Sirimoto. I secured and tucked away the loose and excess wiring and filled up the rest of the tank to what should have been the recommend 40% optimal ratio. It felt more peppy and powerful, but it's hard to tell. I only had the stage 2 w/o flex fuel calibration loaded for a week before the Sirimoto install and was still getting used to it. After filling up and driving for 15 miles the reading is still at 28% in Flashpro manager (27.73% in the android app), and hasn't changed since (this was all yesterday).

I'm wondering if anyone has experienced this problem and if so any solutions, or things to try? It seems stuck at 28% no matter what fuel. I'm hoping it's just a bad sensor so the swap out will be fairly easy. I have a voltmeter to test the wiring, just haven't gotten to it yet. Really hope the wiring isn't bad, getting it through the firewall grommet was a pain! I'm not sure what else to do or try. Just hoping for suggestions or help in some way.

I'm also contacting Sirimoto to see what they might suggest, just thought I'd try here too and see what the folks at Hondata think. Thanks in advance for any help!

Gustav88
Posts: 2
Joined: Sun Sep 08, 2019 7:14 pm

Re: 2018 Accord 2.0T Sirimoto flex fuel problems

Post by Gustav88 » Mon Sep 09, 2019 11:52 pm

Update:

Contacted proimporttuners.com where I bought the sirimoto kit. They suggested running the tank out and refilling with just pump gas to see if it reads differently. In addition, to check 12v supply and ground with a voltmeter.

I was going to do that tomorrow morning before work (and wait to run out my tank of 40/60), but I was telling a guy at work about it and how it is wired (he used to be an auto tech, we work in a machine shop - tool makers). Anyway, he suggested flipping around the fuse adapter plugged into the under dash fuse box. He said he had a similar problem with an after market fog light kit he installed in his car, wired it all up correct, but did not work. He thought to try switching around the fuse adapter that supplies power and boom, worked instantly. I didn't think it mattered which way it was plugged into the fuse box, but I guess it depends on how the adapter is wired.

I tried it and I'm up and running now. Guage has power, reading 40% ethanol on it and ecu/flashpro manager/hondata android app reading 40%, too. And my fuel trims are back to normal, they were running +5~8%. So I was running lean, which make sense. Ecu thought I had 28% ethanol, but I was really at 40%.

Anyhow, I'm all good now. Glad it was an easy fix. Maybe this will help someone else if they have the same problem.

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