Liquid LPG tune using Flex Fuel

[Wrath23]

Im looking into using the flex fuel system to change the fuel and spark maps to suit a Liquid LPG setup on an E38 controlled LS2.
I have only recently discovered the flex fuel so im not sure exactly how it effects engine operation, does it only adjust fuel and spark maps? or is there other changes made.
how much control over the system do I have with EFIlive? can I see and adjust all tables and modifiers related to flex fuel? can I use the fuel composition sensor input as a switch? can I use the input to sense LPG temp and modify the fuel map accordingly?

I been searching for as much info as I can find on flex fuel but there is next to nothing available. can anyone point me in the direction of somewhere or someone who knows the ins and outs of the system and its capabilities.

thanks

[gmh308]

Im looking into using the flex fuel system to change the fuel and spark maps to suit a Liquid LPG setup on an E38 controlled LS2.
I have only recently discovered the flex fuel so im not sure exactly how it effects engine operation, does it only adjust fuel and spark maps? or is there other changes made.
how much control over the system do I have with EFIlive? can I see and adjust all tables and modifiers related to flex fuel? can I use the fuel composition sensor input as a switch? can I use the input to sense LPG temp and modify the fuel map accordingly?

I been searching for as much info as I can find on flex fuel but there is next to nothing available. can anyone point me in the direction of somewhere or someone who knows the ins and outs of the system and its capabilities.

thanks

Do you have EFILive? If not download a demo at www.efilive.com.

And then take a look at a Flex Fuel calibration '08 5.3 litre truck at www.holdencrazy.com. EFILive has probably better access to FF control than any package and enables FF to be enabled/disabled and fuel, spark and transient tables to be adjusted.

Fuel composition sensor produces a frequency and pulse width modulated output the ECM uses to calculate ethanol content and temp. You would need to build a sensor which replicates the ethanol function for LPG.

Cheers.

[Wrath23]

Thanks gmh308.

This should work out perfectly for LPG. Now I just have to implement it.
Activating the FF is the only problem. Does anyone have a specs on the output of the fuel comp. Sensor? Is it possible to use a switch combined with a NTC thermistor without major software changes?

[gmh308]

Thanks gmh308.

This should work out perfectly for LPG. Now I just have to implement it.
Activating the FF is the only problem. Does anyone have a specs on the output of the fuel comp. Sensor? Is it possible to use a switch combined with a NTC thermistor without major software changes?

There is info on specs of the FF sensor outputs here:

http://www.megamanual.com/flexfuel.htm

As mentioned, it uses a frequency and pulse width modulated output, so that is what the ECM expects to monitor, so an NTC setup wont do it. A purpose built FF simulator would give you manual control of temp and ethanol content.

Of course the other catch here is whether there are any E38 operating systems that support connection of a hard FF sensor to the ECM and which pinouts the sensor uses. GM switched to virtual fuel sensing at some point on E38 with no hard sensor (IIRC '06) and they are still using the Virtual Sensor for '09.

[Wrath23]

I am fairly confident my 09 VE SS commodore uses the virtual system as there is no part listing for a fuel composition sensor. However I install these liquid LPG systems on many gen4 vehcles so I will need to work out something for both types.

How does the virtual system pick up when there is ethenol present? What activates the FF tables?

[gmh308]

I am fairly confident my 09 VE SS commodore uses the virtual system as there is no part listing for a fuel composition sensor. However I install these liquid LPG systems on many gen4 vehcles so I will need to work out something for both types.

How does the virtual system pick up when there is ethenol present? What activates the FF tables?

Your '09 Commodore supports Flex Fuel from the factory?

In simple terms the virtual sensing system looks at what it needs to do in terms of degree of trim to keep the mixture in stoich, using a change in tank level as a trigger to consider trim changes as a change in fuel composition.

[Wrath23]

All I know so far is that I can run E10 in my commodore, I havnt been able to confirm if it has flex fuel or not, but a few sources believe they do run FF.

If they don't run FF is I possible to update the E38 with a OS that will support a virtual or sensor FF system?

[macca_779]

All I know so far is that I can run E10 in my commodore, I havnt been able to confirm if it has flex fuel or not, but a few sources believe they do run FF.

If they don't run FF is I possible to update the E38 with a OS that will support a virtual or sensor FF system?

VE's don't run Flex Fuel compensation as yet I believe. The fact that Holden say you can run E10 is only the case because it is in the scope of the fuel trims to add enough fuel to compensate for it (E10 is only 0.6:1 richer stoich). In fact I would surmise that you wouldn't find many Closed Loop EFI setups that can't work on E10.

E85 on the other hand which determines true flex fuel capability is way out of the scope of normal closed loop setups.

[gmh308]

All I know so far is that I can run E10 in my commodore, I havnt been able to confirm if it has flex fuel or not, but a few sources believe they do run FF.

If they don't run FF is I possible to update the E38 with a OS that will support a virtual or sensor FF system?

As Macca779 notes, E10 fits within the normal trim range and is not really considered Flex Fuel.

Remote chance the native E38 operating system in your VE coincidentally supports virtual sensor flex fuel. Any other OS is unlikely to be compatible with the rest of the car (BCM/Instrument panel/etc).

[Chevy366]

Back in the 70s we had a Ford 360 ci. truck running on LPG .
After seeing this did some research on now a day LPG , seems they are several people running LPG , off road of course (most with carburetor) , saying it has a 100 to 110 octane rating .
Which kit do you use ?
I found a good source for the kits but it is on my other laptop .