Flex Fuel Conversion

Fishbait · April 21, 2019

On 4/5/2019 at 12:51 PM, tyler.frost92 said:

I wouldnt mind some pics, If i do it the way youre talking about ill be close to the driveshaft.

I bent the metal shield on the gas tank down a little. This gave more protection for the sensor.

Mike GMC · April 27, 2019

Quick question. I was changing the oil today and I noticed this. Is this a pressure sensor or is it the flex fuel alcohol sensor? It was located just forward of the ABS unit on the driver's side frame rail.

CamGTP · April 27, 2019

Pressure sensor.

SinisterZ71 · July 17, 2019

I've got a 2018 Silverado K1500 extended cab short bed that did NOT come with the flex fuel option.

I ordered a Continental brand flex fuel sensor p/n: 13577429 and Flex Fuel Sensor Rear line p/n: 23171534:

I placed the 90 deg bend in this nylon fuel line in boiling water so I could straighten it. After I got it straightened, I ran it under cold water so it would hold its new shape. I then installed it on the end of my OEM fuel line, installed the flex fuel sensor onto it, and then plugged the nylon line coming from the fuel tank into the sensor. As you can see below, everything tucks nicely behind the metal shield and well away from the driveshaft.

Popo1984 · July 23, 2019

On 7/16/2019 at 9:37 PM, SinisterZ71 said:

I've got a 2018 Silverado K1500 extended cab short bed that did NOT come with the flex fuel option.

I ordered a Continental brand flex fuel sensor p/n: 13577429 and Flex Fuel Sensor Rear line p/n: 23171534:

I placed the 90 deg bend in this nylon fuel line in boiling water so I could straighten it. After I got it straightened, I ran it under cold water so it would hold its new shape. I then installed it on the end of my OEM fuel line, installed the flex fuel sensor onto it, and then plugged the nylon line coming from the fuel tank into the sensor. As you can see below, everything tucks nicely behind the metal shield and well away from the driveshaft.

That worked out pretty good there

bkesting · July 24, 2019

On 7/16/2019 at 9:37 PM, SinisterZ71 said:

I've got a 2018 Silverado K1500 extended cab short bed that did NOT come with the flex fuel option.

I ordered a Continental brand flex fuel sensor p/n: 13577429 and Flex Fuel Sensor Rear line p/n: 23171534:

I placed the 90 deg bend in this nylon fuel line in boiling water so I could straighten it. After I got it straightened, I ran it under cold water so it would hold its new shape. I then installed it on the end of my OEM fuel line, installed the flex fuel sensor onto it, and then plugged the nylon line coming from the fuel tank into the sensor. As you can see below, everything tucks nicely behind the metal shield and well away from the driveshaft.

So this small addition allows you to run ethanol?

CamGTP · July 24, 2019

Yes, the sensor and a tune will allow you to run E85.

Once everything in the computer is enabled it will work as if it came that way from the factory.

I'm currently running something like E60 in the tank right now because of the mix of regular fuel. Starts, runs, drives like it should and probably gains close to 20-25hp in the process when you want it.

ANDY@ADM · August 29, 2019

This is an awesome read

SinisterZ71 · May 6, 2020

On 7/24/2019 at 5:21 PM, bkesting said:

So this small addition allows you to run ethanol?

You will need to add the flex fuel sensor, plug it into the ECM harness, AND tune the ECM to enable flex fuel mode.

JONBLARC7 · May 18, 2020

Just wanted to update this thread.

Don't use the Russell fittings that I originally used. (the blue colored fitting). They will FAIL, mine did after two years of being on the truck. This weekend I went to unhook my boat for the truck and it would hardly run. When I opened the drivers side door it sounded like a shower under my truck. When I cycled the key to the on position but didn't start it. I was spraying 40 psi of fuel on to the ground. Luckily I wasn't running E85 at the time so I was able to just unhook the sensor and plumb the stock ones back together.

Use the DSX fitting or try the fuel line above. I'm going to try that one the bent fuel line. It looks OEM

scrapen · May 20, 2020

......

Edited August 13, 2020 by scrapen

lucas287 · May 22, 2020

On 7/16/2019 at 9:37 PM, SinisterZ71 said:

Flex Fuel Sensor Rear line p/n: 23171534

I can't find this anywhere! Maybe I suck at googling. Though my wife would disagree.

JONBLARC7 · May 26, 2020

You need to remove the Flex Fuel Sensor part. It's just a rear line.

Here you go

https://www.carid.com/acdelco/gm-original-equipment-front-fuel-supply-hose-mpn-23171534.html

newdude · May 26, 2020

I was able to figure out MaverickZ71's setup and gave it a go. Pardon the crappy pictures.

If anyone is going to use the 23171534 pipe, bend it VERY SLOWLY and do the boiling water deal. I might actually take the fittings out and use the nylon line tool kit at work as its a touch long for my liking. The feed line you remove from the bracket on the tank and that will let you flip it 180* to plug into the one end of the sensor. I would disconnect the big EVAP line from the canister and pull that out of the tank bracket so you can actually get the feed line out as the bracket is really tight. No leaks or kinks that I can see anywhere.

Also, I used one of these for an extension harness: https://www.fuel-it.com/48-extension-for-fuel-it-flex-fuel-analyzer/

Edited May 26, 2020 by newdude

JONBLARC7 · June 5, 2020

On 7/16/2019 at 10:37 PM, SinisterZ71 said:

I've got a 2018 Silverado K1500 extended cab short bed that did NOT come with the flex fuel option.

I ordered a Continental brand flex fuel sensor p/n: 13577429 and Flex Fuel Sensor Rear line p/n: 23171534:

I placed the 90 deg bend in this nylon fuel line in boiling water so I could straighten it. After I got it straightened, I ran it under cold water so it would hold its new shape. I then installed it on the end of my OEM fuel line, installed the flex fuel sensor onto it, and then plugged the nylon line coming from the fuel tank into the sensor. As you can see below, everything tucks nicely behind the metal shield and well away from the driveshaft.

Have you logged you fuel trims after adding this fuel line. After my Russell fittings failed I decided to use this line. But I didn't from memory remember you flipped the fitting coming from the tank. So my sensor it hanging out over the drive shaft. But it shouldn't flow much different than how you have it set up.

I've been dialing in my spark since I already had my MAF and VE fueling dialed in pretty good.

After the only thing I did to the truck last night was I added that fuel line. Now under WOT my fuel trims read much leaner. At idol and cruising it's fine but I think it's causing a bottle neck at WOT. My MAF error went from -1 to -2 to 8 to 10 and the wideband confirms it. I'm usually around .86 lambda and before I noticed it was lean I was at .95. Not good for WOT

I'm going to go out and take it off a log again and see if it goes back to the way it was be for.