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Part of the reason they stopped making flex fuel vehicles was because they didn't need to keep doing it for the EPA/CAFE reasons. The added bonus was that they saved money not installing the parts for it or having to test the engines and get them SAE rated for those fuels.

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12 hours ago, CamGTP said:

Part of the reason they stopped making flex fuel vehicles was because they didn't need to keep doing it for the EPA/CAFE reasons. The added bonus was that they saved money not installing the parts for it or having to test the engines and get them SAE rated for those fuels.

The parts part to me didn't matter.  They basically already were set up to go down the assembly line.  Now the testing and making the ratings for using that fuel makes sense.  The vehicles have to be able to handle some ethanol or they would have more work in their service bays then they could handle.  It is just taking advantage of it is the main thing.

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It was hard to find without e85 being in the name. But for those that are interested, here it is.

 

https://www.gm-trucks.com/forums/topic/178280-k2xx-53l-pic-request-flex-fuel-sensor-mounted-on-the-frame/page/5/

 

20967866 Clip

13577429 Sensor

23171538 Hose

20967834 Hose

23158923 fuel line

23171532 fuel line

15168646 fuel line clips

 

Anyone know if e85 is ok with kooks race cats... lol

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12 minutes ago, M1ck3y said:

It was hard to find without e85 being in the name. But for those that are interested, here it is.

 

https://www.gm-trucks.com/forums/topic/178280-k2xx-53l-pic-request-flex-fuel-sensor-mounted-on-the-frame/page/5/

 

20967866 Clip

13577429 Sensor

23171538 Hose

20967834 Hose

23158923 fuel line

23171532 fuel line

15168646 fuel line clips

 

Anyone know if e85 is ok with kooks race cats... lol

E85 will not hurt the cats.

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Make sure you don't use those Russell fittings.  I had them on my truck and they failed and sprayed fuel all over the ground.  Sounded like a shower under my truck when the low side pump primed.

 

And straighten out that OEM fuel line did work for me either.  I made my truck run lean at WOT.  The other guy in the thread tried to argue with me that 02 sensors didn't show his truck going lean.  I didn't feel like arguing then, but O2 sensors aren't accurate for anything but stoich.  So he had now way to really know even with HP tuner VCM scanner with out a wideband.

 

I ran the truck right before I put the fuel line on.  And it held steady at at .87 to .88

 

Then I slapped that OEM line I straightened out on and ran the truck again.  It idle and cruising speed it was fine but when you put more fuel to it under Power enrichment my wideband jumped up to .91 to .93.

 

So I went straight back home removed the line and went right back out to log.  Wideband straight back to .87 to .88.

 

With the straight through Russell fitting I didn't have this problem.  But they failed so when I get back to running E85 again I'll just put the 50 dollar straight through DSX fitting.  I really liked E85 on my L86 that was stock except unlocking E85 and some trans tuning.  Then I had it on E85 just cam and heads and that was even better.  Then the fitting failed before I put the full bolt-ons with cam and heads.  I plan to use the DSX fitting in the next week or two.

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3 hours ago, JONBLARC7 said:

Make sure you don't use those Russell fittings.  I had them on my truck and they failed and sprayed fuel all over the ground.  Sounded like a shower under my truck when the low side pump primed.

 

And straighten out that OEM fuel line did work for me either.  I made my truck run lean at WOT.  The other guy in the thread tried to argue with me that 02 sensors didn't show his truck going lean.  I didn't feel like arguing then, but O2 sensors aren't accurate for anything but stoich.  So he had now way to really know even with HP tuner VCM scanner with out a wideband.

 

I ran the truck right before I put the fuel line on.  And it held steady at at .87 to .88

 

Then I slapped that OEM line I straightened out on and ran the truck again.  It idle and cruising speed it was fine but when you put more fuel to it under Power enrichment my wideband jumped up to .91 to .93.

 

So I went straight back home removed the line and went right back out to log.  Wideband straight back to .87 to .88.

 

With the straight through Russell fitting I didn't have this problem.  But they failed so when I get back to running E85 again I'll just put the 50 dollar straight through DSX fitting.  I really liked E85 on my L86 that was stock except unlocking E85 and some trans tuning.  Then I had it on E85 just cam and heads and that was even better.  Then the fitting failed before I put the full bolt-ons with cam and heads.  I plan to use the DSX fitting in the next week or two.

Wow, sounds like compression fittings are definitely not the way to go. I wish I had considered e85 before I put my headers on; it would have been extremely easy to install the oem lines with it all open...  

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24 minutes ago, M1ck3y said:

Wow, sounds like compression fittings are definitely not the way to go. I wish I had considered e85 before I put my headers on; it would have been extremely easy to install the oem lines with it all open...  

TSP carries a Flex fuel kit that fits up at the fuel rail.  It should be real easy to install.  If I didn't already have my wires extended and just need alittle 50 dollar DSX piece I would buy this one.

 

 

https://www.texas-speed.com/p-8612-smg-silverado-sierra-2014-flex-fuel-kit.aspx

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Does anyone know what pressure the lines operate at; it's 6AN? And are the fuel lines always full/under pressure? I'm just wondering if gm had the sensor mounted the way they did so it was at a high point and wouldn't be exposed to fuel that's not moving?

 

No idea how it works so I hope someone can chime in.  

Edited by M1ck3y
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The low side fuel pressure is going to vary between 30-80psi, it all depends on the demand of the engine.

 

There is only one line from the fuel pump to the high pressure fuel system on the engine.

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On 10/22/2020 at 9:48 PM, CamGTP said:

I didn't cut any lines. I just made a couple adapters to plumb the sensor in right by the fuel tank. It stays out of the way and doesn't move around much. I extended the harness that is already under the truck so it would reach to the tank and that was it.

 

Enabled it in the tune and setup all the flex fuel tables to how I wanted them. I don't know if the 6.2 ever had a rated E85 horsepower like the 2014-2015 5.3's did but that was good for like 25+ hp and torque just on E85.

 

Having the sensor would surely let it optimize the commanded fueling at all times and should net the best economy and performance at that given time. Just know that running any mix of fuel will probably reduce mileage by a little bit. Getting 20-21 on the freeway was still do-able on E70 in my truck but city mileage dropped to about 10-12mpg. Mileage isn't something I worried about with my short commutes anyway because even on regular 89 octane I got 14-15mpg in town.

I haven't had a chance to install it as I just got it last week, but I bought this

 

https://dsxtuning.com/collections/fittings/products/gm-fuel-line-push-connect-coupler

 

Sounds like the same idea, but this is one piece vs 3 pieces.  Less connections for leaking and a shorter overall piece for less strain on the lines.  Either will work, but I think this is a nice option.  It costs a couple bucks more though.

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