Hello everyone,

I have been slowly but surely planning a installation of the Gen5 flex fuel sensor. After measuring everything 5 times and mapping out all the wiring, I'm please to say im done minus a tune. I'm attempting to work with the Trifecta team to finish the tune, and I'm very anxious to share the results. As soon as it's all dialed in I will be heading strait to the dyno to get before and after numbers.

Current mods:
ARH LT Headers, aFe intake, trifecta Tune

Wiring:
First things first, I wanted to start with the wiring, and how we planned out where/how we will be getting power to the Flex Fuel sensor. We decided to use the location that the Gen5 truck motor uses. After further research within GM's truck wiring blue prints we found it to be the O2 sensor power lines.

We used the image below to help us find the correct wire. I have highlighted the most important information in the image.



This is where we will locate the wire within the fuse box:



With this information we were able to locate this wire:



We chose to not plug into the fuse port, but rather actually splice into the line. Should be much better for long term reliability purposes.



Next we needed to find a ground - Easy, found a nice bolt right next to the intake system



Wednesday we need to put it on a lift to get the single to the ECU. Based on our wiring diagrams, we chose to piggyback onto the O2 sensor on the passenger side header. Just so every knows, we have confirmed that the Flex fuel sensor is getting power, and everything is working perfectly.

Any suggestions on how to get the signal to the ECU, please feel free to share. Thanks!

ECU Pin Install:
OK guys, I was able to finish the final wire to get the signal into the ECU.

The location of the ECU is in the front passenger fender, and can be accessed without removing the fender from the car, however you must be VERY careful to not over flex the fender and crack the fiber glass.

-Turn the wheel all the way to the right to expose the inner fender Bolts

-Remove all the moldings on the bottom of the fender, and the T-bolts located under the hood that connect the fender to the car. Additionally, there is one bolt within the door jam to be removed.





-Once all is lose, you will need to pull the fender out (just a little), and pull back the inner fender to expose the ECU. If you look past the ECU you will see one more bolt that you can access with a long ratchet extension.





-Next you will want to remove the ECU from the body of the car (2 clips that can pressed back easily to remove all tension within it's grip)

- Once removed from the body, you will remove the X1 wiring harness (this harness is the one closest to the passenger side wheel well). When removed you will know it's correct by seeing a blue plastic clip board ( see picture for example ).

- slip the wire harness (X1) out where the door meets the fender. Should be plenty of room to wiggle it out





- Next remove all the plastic holding the wires together. Simply cut the zip tie, and the housing unsnapped very easy. I had to cut some of the electrical tape to loosen up some of the wires to investigate.

- Please review the picture below to see where the new wire will go. If you have a diagram handy ( I don't have it at this time ), you will see it needs to go in Pin 38. This space is currently not occupied by any other wire.





- Once you have located the hole, it will need to be punch out as a plastic piece is taking its place.





- Now feed the single wire from the Flex fuel sensor into the inner fender.





- Next, from the back of the wire board insert the pig tail into it's new location.





- When installed, you will need to snap on the blue plastic clip board back on the wiring harness. If done correctly, the new wire you have installed will not come lose when you try to pull it out from the back of the harness.

- rezip-tie the area from earlier, and replace the electric tape you removed earlier

- OK now put everything back together.

Please work slowly, and take your time to do this properly. It's not an extremely hard job, but anything that has to do with wires should be taken with caution.

My car started up perfectly, and I have had ZERO issues with anything. Now I just need to find someone willing to help me tune!

 

Very cool. Looking forward to hearing how it works out.

 

Awesome, are you grounding it at the ECU at well or just running to the Flex fuel pin in the ECU?

Looks good, but I bet hardline would look SICK and more compact

 

Power and ground are in and near the fuse box, and i'm wiring the sensor directly to the ECU. Still working on a tune with Trifecta now.

 

Looks like a clean installation to me. I'm curious to see your dyno results.

I'm presuming that you are pretty familiar with the C7 fuel system which leads me to ask you a question. Do you know how I can drain the fuel from the fuel tank(s)? I have a full load of fuel in the tanks and I do not have the option of driving the fuel out. Trying to siphon out the fuel is also not an option owing to the fact that our cars have two tanks and the bridge tube between them is near the top of the tanks. So even if you were able to get a siphon tube pass all the tank baffles, which is doubtful, you could only get the fuel out of the driver's side tank while leaving behind all the fuel in the passenger side tank. Not a good solution. Any suggestions would be appreciated.

 

Well I never really worried about the pump gas, because this sensor enables the car to be "flex Fuel". I can put any mixture of E85 and Pump 93 in I want, and it just changes the values on the fly like all the other cars.

 

Are you running some form of tune for E85 or a mix like e30? I have been looking to see if this exists for the corvette but have seen very little info.

 

Like he said, it is flex fuel. ECU adjust from zero to 100% ethanol.

 

Is this Bens flex fuel setup or a different setup?

 

I have been working with Ben to make this kit be available for the market. Has taken me some time, but I wanted to make sure I had the most stable sensor location for long term driving. I'm currently trying to log some miles, and zero in a reliable tune. Once the R&D is done, Ben will take over next steps.

 

Dave Steck also posted pictures of his kit. He is sourcing all the connectors and uses hard SS line. They look really nice. He has photos on the DSX tuning facebook page.

 

In interested in buying this..

 

Would love to see Dave's kit. Might see how he ran a few things to make sure i'm mapping everything as good as possible. So far zero leaks, and the sensor has not budged. I'm 90% sure this location will be the final resting spot, but I want to keep my options open just in case.

 

I'm buddies with Dave, he sent me a pic of his kit he did on an LT4. He uses hardline and looks really good. I've been talking to the original poster here too about this kit as well through pm. The sensor n plug above are around $70 and I bought an oem c5 braided hose to do my setup with. I have less than $100 in the whole thing.
Good discussion guys, I could always post hp tuner screen shots of what needs to be changed!!

 

Not sure if its been answered in a thread or not, but what are the HP limits on E85 before the stock fuel system needs to be upgraded?

 

Thanks for the info T/A, and please share anything you have available.

That's a great question Hawk, because I know on pump gas some of the larger HP guys (600+) are installing upgraded lobes on the cam shafts to get more fuel out of the system. I don't believe that I will have issues with my basic bolton's but if I do, I will share my findings.

 

Well blower cars max out on pump around 580ish, so take 25% off that and you are probably going to max out the stock fuel system in the low 400s. So I think these would work great on a mild bolt on car, or using it to blend for octane, but without fuel upgrades I don't see a stock fuel system c7 making 500+ on e85. Maybe I'm wrong though.

 

That would be great!

 

Well I hope it can do more than that... I dyno'd 431 with intake and tune only, and that was before I had headers... I'm sure i'm around 450whp as the car sits now before E85

 

I'm at work, but there are some tricks to make decent power on a NA LT1 with e85 on the stock fuel system, more room than you would think.