How to put native E85 on your G8

[Greg@PacePerformance]

How to put native E85 on your G8
This will allow you to run any mix of E85 and pump gas. The sensor tells the ECM the ethanol content and adjusts the timing and fueling on the fly. You will need to make sure your fuel pump and injectors are up to the task.

The Caprice PPV is set up to run E85 out of the box but it is equiped with the ZL1 fuel pump and fuel pressure controller.

Gather your parts:

Required parts depends on where you plan to install your sensor, but this is how I installed mine.
I installed my sensor in the engine compartment between the stock metal feed line and the Magnacharger fuel rail inlet.

1. You will need an E85 fuel composition sensor. I used the 13577429 sensor because it is inexpensive and compact. The PPV and Holden Commodore use the 13577379 sensor and mount near or on the tank.

2. Sensor harness/pigtail – GM doesn’t offer a pigtail connector for this sensor for any car so I did a few hours digging around and found two different harness that are inexpensive and have the correct connector for any of the above sensors. 13352241 is the least expensive and short along with 20954434 which is about 2 or 3x as long and about double the price. All you need is the connector and leads for the sensor so just cut off the other end that is not needed.

3. Quick connect 3/8” to AN fuel fittings. Something like the Russell 644123. I used 3 of these but you may need to use 4 depending how you plumb your system.

4. -6AN hose ends. I used 2 but again it depends on how you plumb your system. If using standard AN hose something like the Russell 610025 will work, but I used quality Techafx PTFE lined hose. These require the special PTFE specific hose ends AFX600006DTBK and specific hose AFX630006.

5. You will either need to make or buy an ECM lead. I had one laying around, but you can also buy 13575575. That wire has the correct E38 terminal. You need to insert this pin into the X1 connector (black) pin 40 on the ECM. This was a PITA on my GXP but made the install worth it.

6. About 18 foot of small gauge wire again depending on where you mount the sensor. I have a few junk engine harnesses I use to for projects like this.

7. Some basic wiring skills (soldering iron and heat shrink) I also used some Painless 70950 classic braid wire wrap. This made my 6’wire harness blend right in with the stock harnesses.

8. HPtuners to activate the native E85 capibility

I will try and update this ASAP with some pictures but I wanted to get this started.

Plumbing:
This is how I mounted/plumbed my sensor.

From the metal fuel line by the firewall I used the following parts.

3/8” -6 quick connect(RUS644123) -> -6 straight coupler (RUS640003) -> 3/8” -6 quick connect(RUS644123) -> E85 sensor (13352241) 3/8” -6 quick connect(RUS644123) -> PTFE hose end (AFX600006DTBK) ->about 8” of black PTFE hose (AFX630006) -> PTFE hose end (AFX600006DTBK) -> to -6 fitting on my fuel rail. This is where you might need to add another 3/8” -6 quick connect(RUS644123) if you are using the stock rail.

Note: I used a good PTFE hose here because of the E85 and how it might react with standard rubber line. Do some reading on the TechAFX hose. Very good read. The black braided hose is actually easier to use than their fabric braided hose IMO.

Wiring:
Connect the pigtail to the sensor and measure around the back of the engine down to the ECM connectors staying away from any moving parts and high heat. Also make it look good while you’re at it. I used about 6 feet of wire for each of the 3 wires.

The sensor pigtail has a black (ground), pink (switched 12v), and a white (signal to ECM). I wired the white wire to the #40 cavity on the X1 ECM connector (Black) You may need to pop out a cavity plug or snap out a small piece of plastic that seals it off to get the terminal inserted correctly.

The switched 12V wire I tied into a wire under the fuse block that the Caprice PPV uses for the sensor.
Ground I just tied into my ground for my intercooler pump but any good ground will work.

That is about it for the hard stuff.

HPTuners:
Here is what will need to be changed in HPTuners.
These are what needed changed in the 2009.5 G8 GXP ECM. When pulling files from the Holden .bin you may need to do some adjusting so don't just throw it in and think you're done.

Here is some info from HPTuners. Some of it is refering to not running E85 and just sending a signal to the ECM to change the spark and fuel tables with a item Dave Steck is selling.

So here's what you need to know:

1. you have 2 PIDs to log:
- Alcohol % (SAE)
- Fuel Composition (Hz)

2. Spark, the params of interest are:
- Flex Fuel Spark (this is multiplied by the below then added to spark). It can be positive or negative so you can do all kinds of interesting stuff.
- AFR Correction Mult vs. Composition (this is used for all gas/alcohol spark blending Flex FUel Spark and PE/COT Spark) - typical numbers here are 0, 0.25, 0.5, 0.75, 1.0 (cals that are all 0's need to be fixed up)

3. Fuel params:
- open loop tables and PE tables on newer OS's blend between gas and alcohol tables using blend factor below
- blend factor 0 is gas table, 1 is alcohol, 0.5 is middle, you get the idea. (usually this has values in it, again fix if all 0's)
- Note: if your stoich table has a flex fuel cal in here you need to set it to something constant across the whole table (ie. gas numbers) otherwise as you change the freq, the stoich will change.
- obviously you need to be open loop for the fuel stuff to work.

Engine>Fuel>Open&Closed Loop> Flex Fuel >Enabled
Engine>Fuel>Open&Closed Loop> Flex Fuel Sensor>Sensor
Engine>Fuel>Transient>Transient Fuel Mass Evaporation>Evaporation Factor Blend (copy from 2012 Holden 6.0L sedan file)
Engine>Fuel>Transient>Transient Fuel Mass gain>Impact Factor Blend (copy from 2012 Holden 6.0L sedan file)
Engine>Spark>Advance>Spark Correction>Flex Fuel Spark (copy from 2012 Holden 6.0L sedan file)
Engine Diagnostics>Airflow>Flex Fuel>Flex Fuel Sensor Diag>Enable
Engine Diagnostics>Airflow>Flex Fuel>Flex Fuel Diag delay >10sec
Engine Diagnostics>DTC’s>P0169> SES enable & 1-MIL on Second Error
Engine Diagnostics>DTC’s>P0178> SES enable & 1-MIL on Second Error
Engine Diagnostics>DTC’s>P0179> SES enable & 1-MIL on Second Error
Installed picture

[Greg@PacePerformance]

Here is some info from HPtuners and Dave Steck on inserting the ECM pin.

Pin 40 installation on E38 PCMs

Note: Photos shown are from a bench harness, and consequently are missing a majority of the pins, but the instructions for adding a pin are the same. The blue wire is what represents the pin to be added, and all photos show it added to the Pin 40 location.

Basic tools:
Wire stripper
Decent crimper (no need for the $500 Molex OEM one)
Very small screw driver and/or wire separation tools

Parts:
Female Molex MX64 pin (Mouser part number 538-33467-0005)
20 or 22 gauge wire



First, disconnect the battery.

Crimp the female pin to the wire. Solder if you feel necessary, but keep the solder on the crimp only.




Disconnect the J1 connector from the PCM. This is a 73 pin connector, and is on the left if looking at it on a Corvette. Pin 40 is the Flex Fuel frequency input (shown below).

[Greg@PacePerformance]

Pop the cover off of the connector by prying up the clips on the sides.



Flip the connector over and use a screwdriver to gently pry up the black plastic plug covering the pins.




Some connectors will use blue plugs to block off unused holes. These can be removed from the top side. If your connector has the black molded in plugs, you need to break them loose from the top side, but remove them from the side that physically connects to the PCM. Some gentle pressure will break these loose. Be careful not to break the retainer inside the J1 connector.

You are now ready to add the new pin. You can try pushing it from the outside in, but it is typically easier to take the bare wire and push it from the inside out, pulling the pin into place rather than pushing it. Be sure it is oriented the same way the other pins in the row are. Gently pull the wire until the pin is flush with the others. It should click into place.



Once this is done, gently push the black terminal alignment plug back into place and replace the cover on the connector.

[Kermit]

This is GRRR8 stuff Greg! I thought E85 requires a different tune also? Do you have to swap tunes depending on which fuel you put in the tank.

[LDM]

This is GRRR8 stuff Greg! I thought E85 requires a different tune also? Do you have to swap tunes depending on which fuel you put in the tank.

That's what this whole setup does:

The sensor tells the ECM the ethanol content and adjusts the timing and fueling on the fly.

[Napalm]

Damned impressive man.


Will that same connector and tuning apply for the GT - since I noticed you mention this was on your GXP

also are the wires in the same spots?


Meanwhile it sounds like from a stock GT one would have to rig a new fuel system with at least 1 size up injectors and perhaps a stonger pump.

[Greg@PacePerformance]

The 2009.5 GT would be the same PCM changes as it uses the same OS as the GXP.
As for the 2008-2009 GT your PCM would use the same pin (#40) in the ECM connector and the same tables would need to be modified. What you would have to check is if your PCM has additional fuel or timing tables that are blank or all zero compared to the newer OS.

To run pure E85 I would say yes you would need a larger pump and you may need injectors (say LSA/LS9), but to run a blended fuel you may not need to change things. It is work a try if you are interested.
If you start to see your IDC peg out stop

[Napalm]

How different are the PCM's is my concern. I think mine is a 2009 base. but I don't know is there an system, or software part number that will tell me?

[Greg@PacePerformance]

I just did a compare of a 2009 gt file to a 2009.5 GT file

I did find a few differences
Engine>Fuel>General>Fuel Density (copy from 2009.5 G8 GT 6.0L sedan file)

That just effects the fuel level gauge when different fuel compositions are in the tank.
All the other tables are loaded or the same as the 2009.5 as far as E85 is conserned.

[DSteck]

The only differences will be how much is available to edit. Later operating systems have more functionality associated with flex fuel. For example, my 2006 Corvette does not have a Power Enrichment alcohol table. Later vehicles have this. There are also other differences like the cluster fuel density parameter. Even the oldest systems have enough functionality to make true flex fuel viable.

The flex fuel parameters can also be manipulated to control nitrous or methanol timing. There are a lot of cool possibilities.

By the way, if anybody needs a wire with the proper female pin on the end, you can send me a self addressed stamped envelope along with a couple bucks, and I will mail you back a wire with the connector.