Alright, let me start this by saying if you're not familiar with the subject, or have nothing to add please don't comment. I don't need people telling me that alcohol will corrode fuel lines, which it's not going to in almost any modern car, especially a G8, or that it's going to void my warranty, I'm not concerned about either. Seems most threads I run into just shut the idea down, and tell people it's a terrible idea and to go away, I'd like to keep this informational and purely technical.

With that being said, i believe that the E38 PCM can out of the box be capable of Flex-Fuel if the right calibration/tables were available to be changed. I have hp-tuners, but I don't believe all of the tables I need are available in it.

The flex-fuel Vortec 5.3L doesn’t even require a special fuel sensor. The first flex-fuel engines used a light-reactive sensor to measure fuel composition from 100 percent gasoline to 85 percent ethanol. The Gen IV has a virtual sensor—software programmed in the E38 ECM with no separate physical sensor. Based on readings from the oxygen (O2) sensors, fuel level sensor and vehicle speed sensors, the ECM adjusts the length of time the fuel injectors open for the type of fuel used. Within a fuel miles after filling up, the E38 controller determines what fuel is powering the Vortec 5.3L and manages the engine accordingly.

^The same is true of all other Gen IV v8's with the E38 PCM.

Running E85 is easy enough, change stoich, fill it up and be done, but it would be nice to not have to worry about a re-tune between fuels, or not being able to find 93/E85. There's also timing adders for alcohol, etc.., so you'd be able to have a E85 tune side-by-side a 93.

I was able to enable the flex-fuel field in hp-tuners, and fill up with e85, and the trims just go out of control and the command AFR doesn't change like it does in other Flex-Fuel vehicles. I assume this is because the necessary calibrations/tables aren't filled out in our PCM's. Does anyone have any insight or ideas on this? I'd really like to be able to jump between E85/93, since there's over a 70 cent difference a gallon here in st. louis. I think it would also be very nice for tuners to have the ability to throw 3-4 more degrees of timing at a motor when it's on alcohol and when not.

Anyway, discussion? Ideas?

Thanks,

Mike

 

The Flex Fuel E38 GEN IV Commodores (G8) we have all run a fuel sensor. Got me stuffed why Holden went this way when GM uses software to do it. But I'm not complaining as I personally prefer the hardware way of detecting Ethanol. Perhaps look into acquiring one of the fuel sensors we use and then turn it on in the tune to see if that works.

 

Macca that's great information. Do you have anymore details, part numbers? Is the wiring already there, need a harness or to run wire?


Thanks,

Mike

 

No doubt you will have to run wire. Flex Fuel only came out in Series II (a few months ago). Prior to that our cars are pretty much the same as your G8.

I haven't looked into part numbers for them yet.

 

Good deal. Thanks for the info. I'm still surprised, as you are, that it isn't done in software. Every other E38 Gen IV here is. Is the series II still a 6.0l L76? Thanks again for all the info. Let me know whatever you find out.

 

Yep still a 6.0L but they are calling it an L77 probably due to it having AFM and Flex Fuel. I've already seen one pulled down to a short motor, its the same as an L76 as far as I can tell.

 

Do you have a PN on this sensor?

 

Nope but on the AUS LS1 fourm there are a couple of parts interpreters that are members. May want to ask there.

 

here's something you will want to read:

http://forum.efilive.com/showthread....one-interested

 

Wow, that is great info. I wish hptuners had the tables that EFIlive does. I would think you could then add the sensor, throw it on pin 40, fill out the calibration tables and be on your way.

 

I was hoping more information would be available on the virtual sensor.

GM talks about it here, but there is little data aside from this:

http://www.gmpowertrain.com/Powertra...10_LZ4_LZE.doc

 

HPTuners has all the tables needed to fully enable a physical sensor on most all E38/40/67 OS's now. Some OS's are still being worked on but it's there.

 

More info please!!! Is the physical sensor needed/better than the virtual sensor? It seems that is GM's new MOO. Is it ineffective? We have E85 in the city, but I don't want to be chained to the city, and running two tunes is plain silly if not needed.

 

The virtual function just doesn't work worth a poo IMO. There is a switch to select between virtual and physical sensor. Physical sensor is needed on the return line to keep from restricting flow but keep a good reading on fuel composition. There are various other related tables that need to be setup to make full use of its capabilities.