DMS Flex Fuel Kit Installation Guide
 

The Flex Fuel sensor from DMS has been installed and has been verified to be working properly.

I will be updating this as I go and should serve as a guide to installing the kit as well as the necessary ECM changes in HP Tuners. Hopefully the moderators will make this a sticky when complete.

DMS Flex Fuel Kit

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Kit Installation

1. Please read through the instructions supplied with the DMS kit before starting the installation. It is critical you tighten the AN fittings per the instructions or you will leak fuel. Also, do not try and remove the crossover fuel hose immediately after running the vehicle. Let the vehicle sit for an hour or two so the pressure in the line will bleed off.

2. Unclip the cross over hose retaining clips and remove the valve covers.

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3. Remove the fuel hose QD fitting retainers.

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4. Place rags or paper towels under each of the QD fittings and then using the DMS supplied QD tool remove each end of the crossover fuel hose.

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5. Remove the retainers from the QD fittings on the DMS hose.

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6. Install the DMS hose on to the factory fuel lines and reinstall the retainers.

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7. Verify all of the fittings have been tightened properly. Start the engine to confirm there are no fuel leaks before proceeding to the wiring harness connections.

8. Disconnect the battery.

9. Locate the ECM X1 connector.

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10. Pull out the red locking tab. While pushing down on the area indicated by the yellow area pull the connector lever up and over to the other end of the connector. This will disengage the connector from the ECM module.

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11. CAREFULLY pull the X1 connector out and up to gain access to the connector.

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12. Remove the X1 connector cover by disengaging the locking tabs indicated by the yellow arrow. There is a tab on each side.

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13. Using a small flat screw driver pry up the blue pin alignment cover at the slots indicated by the yellow arrows. The cover has built in stops so do not try to remove it.

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14. Locate pin 38 and simply remove the gray plug with a pair of needle nose pliers. Route the Flex Fuel sensor signal wire to the ECM connector and install the pin at the 38 location. The pin is keyed so make sure it is rotated correctly before inserting. Pay very close attention to your signal wire routing. You want to make sure that once the signal pin is inserted into the connector the signal wire will not prevent you from reinstalling the X1 connector back on to the ECM.

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15. Remove the existing zip tie and install a new zip tie to secure the signal wire to the X1 connector.

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16. Reinstall the X1 connector cover.

17. Reinstall the X1 connector to the ECM. Ensure the connector lever is seated properly and the red locking tab is pushed in.

18. Plug the Flex Fuel harness connectors inline with the #8 coil connectors.

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19. Reinstall the valve covers and secure the hose locking clips.

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20. Reconnect the battery and restart the engine to double check for fuel leaks.

21. Secure the signal wire with zip ties. You may want to acquire some black convoluted tubing to protect the wire.

22. Done! Now on to the ECM modifications...

ECM Modifications (HP Tuners v3.2.x required)

23. The attached zip file contains a baseline HPT file for reference on enabling the Flex Fuel sensor only. All performance related tables are stock in the baseline file. The changelog.txt file will indicate what is required and what is optional (but highly recommended). I have not looked at a 2017 file so I do not know if everything for the 2016 will translate over. The stock Flex Fuel tables are very good from a performance perspective so you will realize a high increase in torque across the board without actually doing a dyno tune. If you make it this far take the time after installation to monitor knock retard and adjust accordingly. Depending on ambient conditions you might need to lower timing in the higher g/cyl areas of the high octane spark tables. GM did not optimize the timing when you start getting past 0.92 g/cyl.

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Tim

Awesome info. I think the future is alky driven hp.

The installation guide is complete. It's no Sledge blockbuster but should suffice ;)

Tim

You are to be commended my friend Great write up.

Kudos to DMS for putting together a great quality kit.

Thanks! Hopefully this helps some people out that choose to go the DIY route.

Very informational. great job

Nice Write-up!! Thanks!!

Great write up and pics. Mine (E67) only came with the pin instructions and I had to figure out the rest. Well done.

Thanks for the great write up and pictures!! Also thanks for taking the time to test the system and making the necessary tweaks. Once installed and the tune added is there any tweaks we need to make?

Valid question... I will have to write up a relatively lengthy response to address it properly. If you choose not to implement the optional changes (except for the cranking tables) you will be good to go but may not be maximizing the torque output. If you implement the optional changes (not including the cranking tables) you will likely have to tweak the high octane table at the upper load, upper RPM areas to minimize knock retard. Those areas of the tables are extrapolations more than anything. As the weather gets cooler you may hit areas of the table that need some tweaking. When I say tweaking it could literally be just a degree or two of timing to clean it up in specific spots. I've got many many logs under my belt on this and my personal tune was meticulously done to get things as perfect as possible on my car. My personal tune also blends my E10 tune and E85 tune in a way that I didn't compromise one for the other.

Shift points on the A8 are another area that don't "need" to be changed but should be changed if you are maximizing everything. The stock shift points may no longer be ideal. I created a Matlab script to read in my Dynojet torque curve and calculate the new shift points based on that curve.

Enabling the Flex Fuel sensor is relatively straight forward but as you start getting into more advanced issues of blending gas and E85 tunes, or trying to maximize everything, there are a lot of subtleties that I don't think most would pay attention to. I learned a lot when doing the straight E85 tune.

Best thing to do is just ask questions as you go. Trying to explain how/why would take too long ;)

Tim

What HPtuners version do you recommend? Is the professional version worth it?

Yes if you are going to use a non OBDII based WB sensor.

No if you are going to use OBDII based WB sensor like the new AEM unit.

Are you for hire. I don't even think E85 is readily available here in Canada.

One place in Vancouver BC sells it. They are closing their doors. Another is opening in the lower mainland.