Chev/Holden 1.4L Cruze E85 FlexFuel Conversion

Hi All,

As you may have seen in our latest newsletter, EFILive now has a 2012 1.4L Turbo Cruze, the first R&D project we wanted to do on this car was a conversion to make it a true 'FlexFuel' vehicle, you can't buy one from GM like this so it seemed like a good starting point. Admittedly this wasn't as hard as it might appear because at least in the case of the 2012 Holden Cruze, the E85 Ethanol fuel tables are already set up, it's just a matter of turning the E85 function 'on'.

Traditionally GM have used an ethanol estimation system to detect the ethanol content of the fuel, however, in the last few years they have moved away from this method and started fitting real ethanol percentage sensors. This is the route we've chosen as the sensors are very accurate and they instantly tell the ECM what the ethanol content is without the need to drive the vehicle for a while so the ECM can figure it out. Not only that, the new ones they are using are very cheap, you can find them online for about $70.
There is two E85 sensor part numbers that could be used, we ordered both and it appears the difference is just in the type of fittings on the fuel lines.
The other thing that needs to happen is the injectors must be changed, the standard ones are rated at 23lb/h (or around that), so we chose to use the 42lb/h Bosch 'Green Giant' injectors #0280155968. For us they were 'almost' a direct drop in. The size is fine but on our car the injector clips didn't fit the same, no big deal to get around that though.

It will be interesting to see how this engine runs on E85, they knock pretty bad on low grade fuel, on our local 98 Octane they aren't too bad, still some knock every now and then, especially on the stock tune!

These photo's aren't intended to be a step by step guide on doing this conversion, but it at least will give you an overall feel on what needs to be done.

The Flex Fuel Sensors:
There is two part numbers for these, 13577394 and 13577379. The first one seems to be fitted to V8 cars, the second shows up on some SIDI applications. We chose to use 13577379 (on the right).

http://download.efilive.com/Staff/GM...uelSensors.jpg

Wiring in the Sensor:
The first step was to wire up the Flex Fuel sensor to the ECM. The sensor requires +12V, Ground and then it's signal output.
The +12V for the FlexFuel sensor we obtained from the Powertain Relay switched +12V IGN feed to the ECM, this is the same +12V that supplies other EFI related sensors so it seemed like the best choice. This connection needs to be made in the ECM wiring harness as there is no +12V output on any ECM pins. On our Cruze this +12V feed can be found on two wires in the harness to the 'Black' Connector, (Red with Dark Blue stripe).
The other two connections can be made on some ECM pins. Both are on X3, the 'Grey' Connector.
Pin 20 = GND
Pin 34 = Flex Fuel signal (called 'Out' on the sensor).

X1 = Blue Connector
http://download.efilive.com/Staff/GMPX/E78_X1.png

X2 = Black Connector
http://download.efilive.com/Staff/GMPX/E78_X2.png

X3 = Grey Connector
http://download.efilive.com/Staff/GMPX/E78_X3.png
Below you can see the harness partially pulled apart to run the new wires off to the sensor now the ECM connections have been made.

http://download.efilive.com/Staff/GM...CM_Wiring1.JPG

With the loom all taped up like factory new.
http://download.efilive.com/Staff/GM...CM_Wiring2.JPG

Fitting the FlexFuel Sensor:
GM seem to fit the flex fuel sensors all the way at the back of the vehicle, usually next to the fuel tank, probably for simpler packaging purposes when dealing with the same vehicle where one can be FlexFuel and the other isn't.
We chose to mount the sensor in the engine bay, which thankfully on the Cruze is very simple. However, the fuel line Holden used from the under car fuel line to the injector rail is just standard rubber fuel line (not good with E85), on this day we didn't replace it with the correct ethanol compatible fuel hose, we will revisit that shortly, so for the moment the FlexFuel sensor has just been spliced in to the existing rubber line and held in place with some cable ties (it was one of those 'Git-R-Done' moments)? From what we could see this was the only rubber part in the fuel line.

http://download.efilive.com/Staff/GM...e_FuelLine.jpg

http://download.efilive.com/Staff/GM...lexSensor2.jpg

Swapping the Injectors:
As I mentioned above, we replaced the factory injectors (Bosch #0280158205) with some higher flow 42lb/h Bosch 'Green Giant' injectors #0280155968, due to the additional fuel demands needed to run E85.

http://download.efilive.com/Staff/GM..._Injectors.jpg

Before we fire it up:
Prior to fitting the new parts I had put a significant quantity of E10 fuel in the tank (10% Ethanol), this seemed like a safe way to ensure the ECM was reading the sensor correctly and making any minor adjustments to the fueling with the slight change in Ethanol content. Filling up with E85 was too much of an unknown at this point.
The first thing that needs to happen is we need to tell the ECM that this car is a FlexFuel vehicle. EFILive has grouped these calibrations in one area, of course from factory this is configured for a non FlexFuel vehicle.

Stock:
http://download.efilive.com/Staff/GM...exDisabled.png


Modified for FlexFuel:
http://download.efilive.com/Staff/GM...lexEnabled.png

Calibration B0187 was important for us to change. GM would normally have this set so once the ethanol content change is detected at the sensor (normally back at the fuel tank) the engine will need to consume 'x' amount of fuel before the new enthanol mix reaches the injectors. In our case we put the sensor on the engine so there is minimal fuel useage before it actually gets to the engine.
The value we chose was a guesstimate, but it should ensure the ECM adjusts fueling right away once the new ethanol content is detected.
We also chose to enable the Flex Fuel sensor fault codes P0178 & P0179 (not shown here), we want to know if the sensor goes bad.

We also changed the injector flow table to suit the new 42lb injectors, this was easy as the 6.0L L96 truck (with the E78) uses 42lb injectors, so it was a simple copy/paste effort.

Time to fire it up:
With the V2 plugged in and the WBO2 being monitored it was time to run the engine.
It was good news all round, the Ethanol Sensor was reading perfectly (it said 6.7% ethanol with a sensor frequency of 57Hz) and the ECM had already adjusted it's target Stoich value down to 14.33:1 AFR to compensate for the small ethanol content.

So now that it appears the ECM knows exactly what is going on with the ethanol content we will put a higher E85 blend in to the car, we'll target about 40% to 50% as the final mix, if all continues to go well at that point then a full tank of E85 is next. Of course that might take a while on the Cruze, high fuel consumption isn't something it's known for.

http://download.efilive.com/Staff/GMPX/Cruze_WBO2.jpg


Can't buy one from the factory like this....
http://download.efilive.com/Staff/GMPX/Cruze_Badge.jpg

Thanks To:
Brian at Vermont Tuning for the tip on the 'Green Giant' injectors.
Guy Tripp at SoCal Diesel for organising all the parts to get over here.
Thanks to Steve down at MKAL Automotive in Melbourne for assisting (actually, doing most of the work) to the Cruze.

http://download.efilive.com/Staff/GMPX/MKAL.jpg

Text and Images Copyright EFILive 2012.

IMPORTANT NOTE: This upgrade does NOT work on 2011 Cruze's.

Thanks for the write up Ross :cheers:

I have been looking at wiring diagrams and was going to do a similar project on my VE Calais.


Ben

Nice :cheers:

Ben, depending on the year I know the E85 conversion (even with a sensor) doesn't work so good on the early VE's as there is some underlying E85 tables that aren't set up from factory. If only the E38's were like LS1 computers where you could flash in any OS you wanted.

Sweeet! Thanks for the writeup, please continue to post updates! Let's see some boost, 20+ psi seems to be the sweet spot on my 2012 1.4t. I actually desensitized the transmission downshifts so I can step into in and get a nice boost pull without downshifting which the stock tune must do to accelerate well.

I've got the E10 mix down to about half a tank now, so in the next day or so I'll be putting in some E85 to see if I can get the final ethanol percentage up around 50%. Lets hope some helpful person at the petrol station doesn't yell out "Hey mate, you can't put E85 in one of them". When it goes in for service at Holden, if they question why it has FlexFuel badges on it, I'll tell them it was a special factory order the sales guy organised for me ;)

All I've done on the transmission at this point is do drop the desired shift times way down, it's just horrid in factory tune (0.8sec part throttle shifts!!). For the most part the shift points seem pretty good except sometimes coming out of a roundabout it shifts to 3rd too early, is off boost and bogs down pretty bad. So, a little bit of work there, otherwise the trans is pretty good now.

Haha! You should try my boost tables. I know your gears are different but I will send them.

Thanks Roland, I'm willing to give that a go. I do have a tune in the car sent to me by one of our workshop customers, but unfortunately the weather is too wet here at the moment to really give it a decent blast. I don't think they are hitting 20+psi on their tunes though, again, that is probably a fuel quality issue. And to be honest, I am worried about the transmissions limits, it's not GM's strongest unit.

Of interest, I got the tank down to half full and filled up with E85. So it's now got a mix of E10 (which over here is 91 Octane with up to 10% ethanol) and the rest is now E85.
So far it looks good, the sensor has detected the change, the ECM is running a lower stoich value and the engine seems fine, no stumbles or rough running, just the sweet smell of Ethanol fumes out the back :drool:
The good part was, the E85 cost me $1.02 per litre ($3.86 per gallon), the top shelf 100 octane premium unleaded is 1.45 per litre ($5.50 per gallon). On regular fuel, highway I'm seeing about 6.0L/100Km (39MPG), city around 8L/100 (29MPG). So based on that, the octane benefits of the E85 vs Premium 100 isn't the factor here, both are good, it's the price, city cycle it will have to increase to around 12L/100 (19MPG) or worse to make it a negative to use E85 (at least on the current 50/50 I have).

Here's a shot of the log I did on the drive home after putting E85 in, it took nearly 3 minutes of driving before the new E85 mix reached the sensor at the engine (I was starting to worry), looking at the V2 going, c'mon, change, change.
But you can see the Commanded Stoich AFR start to drop as the Ethanol percentage increased.

http://download.efilive.com/Staff/GM...5_HalfFill.png

Interesting log...

Yes, I would like to see the look on Holden's faces when you take it in for servicing... :cheers:

If I was within 50 miles of an E85 station this would convince me to forgo the 328i we have had our eyes on in favor of the Cruze.
Are the stock Cruze Injectors connector type USCAR?
Did you have to re-pin the connectors or is it a direct replacement?