Flex fuel

[K44]

edit: Please see this thread for CAN Bus flex fuel support

I am playing with flex tuning the GT and ran across a switch labeled AFR Brazil OBD2 switch.

Number auF21158 in a 17 OS

 

Any idea what this switch does?

 

Thank you

Dan 

[Roland@pcmtec]

I will go digging this afternoon when the little ones goes down for a rest. I believe from memory Brazil uses e100 which is often water contaminated, so they disable locking of the fuel content, or allow it to take longer mature. 

Could be completely wrong however we have annotated that part of the assembly and I should be able to get you a concrete a answer. 

Also I noticed someone (maybe you) mentioned some scalars were drastically different between the f150 and the mustang. I believe some logic is ifdefined out in the mustang so it is possible those scalar are not actually used (hence being zero). It could also be your lynch pin however. 

Would love to see your findings on here. 

We also have full canbus flex fuel in the works so this might be a better solution for you. 

https://fb.watch/lYhg6iotqN/?mibextid=2JQ9oc

 

 

[K44]

That looks very nice.

 

You say some things are zeroed out because they don't work? Are these tables working in the GT tune?

 

auF61356
auF61359
auF61358
auF61361
auF61357
auF61360
Gen 3 or 2018 and newer

[Roland@pcmtec]

1 hour ago, K44 said:

That looks very nice.

You say some things are zeroed out because they don't work? Are these tables working in the GT tune?

auF61356
auF61359
auF61358
auF61361
auF61357
auF61360
Gen 3 or 2018 and newer

Brazil mode effectively forces the AFR to remain "unstable" at all times. Eg it disables "Adaptive fuel control" and will disable the AFR from ever reach ing mature status. Eg it will never lock. I believe due to high humidity and water contamination this is the reason they use this (E100 loves to soak up water). I would not recommend using this feature on anything but a stock car that sits around with randomly changing fuel quality (despite not refilling the tank).

That is my understand from reading the code.

If you datalog MID33922 "Flex fuel sensor reading or inferred fuel type unstable flag" I believe will remain unstable at all times.

auF61356 "Additional LBM of DFIfuel that must be consumed to allow stabilization of AFR " effectively is the amount of fuel retained in the DFI injection pump and fuel rail, it requires that this much fuel is consumed before considering what is being read by the wideband to be what is actually in the tank. What what I can see is this is always active/used.

auF61359 "Additional LBM of DFI fuel that must be consumed to allow stabilization of AFR - large refuel" is the same thing exept for when you effectively go from an empty tank to a full tank. The code differentiates between filling a tank completely, and topping it up.

You can tell if there has been a "refill event considered large enough to use auF61359" by datalogging MID02181 and seeing if its set to 1.

The table that defines a whether a full refill or a partial refill has occured is auF30944

auF61358 is a total fuel consumption required value, eg regardless of DFI or port injection, this much fuel must be consumed, this is likely the volume of the fuel lines themselves.

auF61361 is the same as auF61358 except for on a full tank refill as defined by auF30944

auF61357, auF61360 are the same as auF61356, auF61359 except for port injection.

So you basically need to sum the 3 scalars to work out how much fuel needs to be consumed before learning occurs, if you had say for example zero'd out your DFI but left a value in this scalar, you'd never reach a condition which say you can start learning the fuel as it would assume that the DFI pump was still contaminated with old fuel (or vice versa for the rail/port injection). Same goes for the defaults of 0 in a mustang, it will likely learn too early and lock on the wrong value, especially if you have larger fuel lines/rails.

Leaving them at 0 means they will likely start learning before the DFI pump has emptied, which is also likely not optimal. I would imagine setting these values similar to what you find in an F150 with factory flex would would return better results. However if you have a return system, then you'd want to tweak these values as well as the fuel will be dumped from the port system very quickly, I don't know enough about what people do with return style systems and DFI to comment on if this fuel would be returned to the tank or not.

From what I can tell these values are indeed used in all calibrations and not calibrated out/disconnected as there are xrefs in the code to use them   even in the GT500 calibration I checked (FHJJ2).

So there is lots to tweak there depending on how much you've modified your fuel system, and also how much you've changed your DFI blending.

As always testing is key, this information could be wrong (eg I made a mistake), I also only analysed the assembler in FHJJ2 (a GT500 calibration). It may change for other vehicles however I've found the GT500 has the most features "disabled" so it is a good one to start with.

[junits15]

On 7/23/2023 at 1:30 AM, Roland@pcmtec said:

Brazil mode effectively forces the AFR to remain "unstable" at all times. Eg it disables "Adaptive fuel control" and will disable the AFR from ever reach ing mature status. Eg it will never lock. I believe due to high humidity and water contamination this is the reason they use this (E100 loves to soak up water). I would not recommend using this feature on anything but a stock car that sits around with randomly changing fuel quality (despite not refilling the tank).

That is my understand from reading the code.

If you datalog MID33922 "Flex fuel sensor reading or inferred fuel type unstable flag" I believe will remain unstable at all times.

auF61356 "Additional LBM of DFIfuel that must be consumed to allow stabilization of AFR " effectively is the amount of fuel retained in the DFI injection pump and fuel rail, it requires that this much fuel is consumed before considering what is being read by the wideband to be what is actually in the tank. What what I can see is this is always active/used.

auF61359 "Additional LBM of DFI fuel that must be consumed to allow stabilization of AFR - large refuel" is the same thing exept for when you effectively go from an empty tank to a full tank. The code differentiates between filling a tank completely, and topping it up.

You can tell if there has been a "refill event considered large enough to use auF61359" by datalogging MID02181 and seeing if its set to 1.

The table that defines a whether a full refill or a partial refill has occured is auF30944

auF61358 is a total fuel consumption required value, eg regardless of DFI or port injection, this much fuel must be consumed, this is likely the volume of the fuel lines themselves.

auF61361 is the same as auF61358 except for on a full tank refill as defined by auF30944

auF61357, auF61360 are the same as auF61356, auF61359 except for port injection.

So you basically need to sum the 3 scalars to work out how much fuel needs to be consumed before learning occurs, if you had say for example zero'd out your DFI but left a value in this scalar, you'd never reach a condition which say you can start learning the fuel as it would assume that the DFI pump was still contaminated with old fuel (or vice versa for the rail/port injection). Same goes for the defaults of 0 in a mustang, it will likely learn too early and lock on the wrong value, especially if you have larger fuel lines/rails.

Leaving them at 0 means they will likely start learning before the DFI pump has emptied, which is also likely not optimal. I would imagine setting these values similar to what you find in an F150 with factory flex would would return better results. However if you have a return system, then you'd want to tweak these values as well as the fuel will be dumped from the port system very quickly, I don't know enough about what people do with return style systems and DFI to comment on if this fuel would be returned to the tank or not.

From what I can tell these values are indeed used in all calibrations and not calibrated out/disconnected as there are xrefs in the code to use them   even in the GT500 calibration I checked (FHJJ2).

So there is lots to tweak there depending on how much you've modified your fuel system, and also how much you've changed your DFI blending.

As always testing is key, this information could be wrong (eg I made a mistake), I also only analysed the assembler in FHJJ2 (a GT500 calibration). It may change for other vehicles however I've found the GT500 has the most features "disabled" so it is a good one to start with.

Thanks for this reply, can't wait to try this out!

Once my dongle finally arrives lol

[Roland@pcmtec]

flex stategies.csvI ran a query on all non zero strategies for the following auF IDs. Hopefully this is useful

auF61356
auF61359
auF61358
auF61361
auF61357
auF61360
auF28820
auF28819

~1200 strategies defined there. 
 

[mejohn50]

On 7/31/2023 at 2:09 AM, Roland@pcmtec said:

flex stategies.csvI ran a query on all non zero strategies for the following auF IDs. Hopefully this is useful

auF61356
auF61359
auF61358
auF61361
auF61357
auF61360
auF28820
auF28819

~1200 strategies defined there. 
 

I didn't realize gen 2 had different parameters than gen 3 (auF28819 and auF28820) and they appear to be populated. Very helpful in determining values to try in the gen 3. Thanks. 

[engineermike]

I’m working on flex tuning and it’s going well except the part that’s driving me nuts is that the learning just stops (not “paused” status”) often.  Flow is within range and fuel trims might be steady 20% or more.  Then suddenly it starts adjusting stoich again.  Any idea how to keep it adjusting constantly at least until it matures?

[Roland@pcmtec]

@engineermike I'd love to get you to try out the proper can bus flex fuel system if you have time to wire it up. Would you be interested in giving it a go?

[K44]

If he is not I am.

[junits15]

I know I haven't been as vocal on this but if you need more testers I volunteer as well

[Roland@pcmtec]

We will let you guys know. Do your have the ability to wire up and install as per the following instructions? 

edit: Please contact support for the flex fuel install guide.

[K44]

I was an ASE master tech, still have all my tools.

 

Yes I can install this

[Kirby@PCMTec]

On 8/31/2023 at 7:06 AM, Roland@pcmtec said:

We will let you guys know. Do your have the ability to wire up and install as per the following instructions? 

 

Just a note for anyone that is interested in this and runs off and buys a ECA-2 from Zeitronics.

You will also need to buy their serial cable adapter (and a RS232 port or USB to RS232 Adapter) for a one time programming of the CAN ID of the device.

AEM make an acceptable OBD sandwich plate that just breaks out the can-bus - this is suitable in this case because we source the power from the fuse tap in the above document.

 

On 8/2/2023 at 3:36 AM, mejohn50 said:

I didn't realize gen 2 had different parameters than gen 3 (auF28819 and auF28820) and they appear to be populated. Very helpful in determining values to try in the gen 3. Thanks. 

When they went from PFI (Gen2) to DFI+PFI (Gen3) there was a big behind the scenes change, not just in hardware. The Gen2 fuel model was more-or-less in-house code, which had been progressively built up since probably the EEC-V days - but realistically has a lot in common with the CopperheadB Gen1s. In some parts of the assembler we can see similarities or variables that we even had here in the "Australian" PCM's from 20 years ago.

Gen3 represents a huge departure in the fuel/spark model as to implement this Ford started to use, what appears to be, somewhat "off-the-shelf" software models provided by Bosch, which means all new parameters and tables, and the code is quite different - as is the order of execution.  Effort has been made on Fords' part (probably to save the sanity of the calibrators there) to create tables which somewhat align in function to the old PFI tables, in name etc, but the way we identify them they look completely different to us hence the different ID's.

[junits15]

15 hours ago, Roland@pcmtec said:

We will let you guys know. Do your have the ability to wire up and install as per the following instructions? 

PCMTec Flex2CAN Prototype.pdf 1.57 MB · 8 downloads

I can pull it off, the install looks straightforward enough.  Mostly wiring it seems.

I know mike and k44 have been more active and involved in this, so if you only need one or two testers then I have no issues letting the opportunity pass and waiting for a final release.  

[junits15]

23 minutes ago, junits15 said:

I can pull it off, the install looks straightforward enough.  Mostly wiring it seems.

I know mike and k44 have been more active and involved in this, so if you only need one or two testers then I have no issues letting the opportunity pass and waiting for a final release.  

Actually I'm looking through the install and I wont likely do it exactly as written.  So I think I can't help create the writeup you guys need.

I ran CAN, power and signal wires to my trunk for a previous install that has since been de-activated. I will be reusing all that and will be mounting the analyzer-CAN bridge back there to save headache from re-wiring. My install will not be typical, so I will back out.  

If you guys need someone to test out the functionality of the software I can absolutely do that, but my writeup would be very atypical and not useful as instructions for others.   Apologize for any confusion!

[Roland@pcmtec]

6 hours ago, junits15 said:

Actually I'm looking through the install and I wont likely do it exactly as written.  So I think I can't help create the writeup you guys need.

I ran CAN, power and signal wires to my trunk for a previous install that has since been de-activated. I will be reusing all that and will be mounting the analyzer-CAN bridge back there to save headache from re-wiring. My install will not be typical, so I will back out.  

If you guys need someone to test out the functionality of the software I can absolutely do that, but my writeup would be very atypical and not useful as instructions for others.   Apologize for any confusion!

We want to test the actual flex logic itself primarily so this would still be very useful. 

We can tweak the firmware based on feedback from users. So the first ones to use it will get dibs on what they want changed. 

[Kirby@PCMTec]

13 hours ago, junits15 said:

Actually I'm looking through the install and I wont likely do it exactly as written.  So I think I can't help create the writeup you guys need.

I ran CAN, power and signal wires to my trunk for a previous install that has since been de-activated. I will be reusing all that and will be mounting the analyzer-CAN bridge back there to save headache from re-wiring. My install will not be typical, so I will back out.  

If you guys need someone to test out the functionality of the software I can absolutely do that, but my writeup would be very atypical and not useful as instructions for others.   Apologize for any confusion!

This was a guide I wrote as an example of how it *could* be done. its not the way it must be done. we expect every shop to come up with their own preference based on the car type, fuel system type, packaging etc.

The key part is that you have a compatible Flex to CAN converter, that is configured correctly and is connected to the correct can-bus so we can receive the messages at the PCM.

[junits15]

17 hours ago, Roland@pcmtec said:

We want to test the actual flex logic itself primarily so this would still be very useful. 

We can tweak the firmware based on feedback from users. So the first ones to use it will get dibs on what they want changed. 

 

10 hours ago, Kirby@PCMTec said:

This was a guide I wrote as an example of how it *could* be done. its not the way it must be done. we expect every shop to come up with their own preference based on the car type, fuel system type, packaging etc.

The key part is that you have a compatible Flex to CAN converter, that is configured correctly and is connected to the correct can-bus so we can receive the messages at the PCM.

Understood! I'm willing to beta test then. Just to confirm, you guys are looking to test this functionality in the PCMTech DIY software package?  Or the full Workshop package?  Just want to double triple check everything so there's no confusion😅  

Edited September 1, 2023 by junits15

[Kirby@PCMTec]

On 9/2/2023 at 12:36 AM, junits15 said:

 

Understood! I'm willing to beta test then. Just to confirm, you guys are looking to test this functionality in the PCMTech DIY software package?  Or the full Workshop package?  Just want to double triple check everything so there's no confusion😅  

Request duly noted.

[K44]

@ Rolland

Is there something in the 21 and newer Mustangs that disabled the flex logic?

 

Thanks

[Roland@pcmtec]

On 11/17/2023 at 7:34 AM, K44 said:

@ Rolland

Is there something in the 21 and newer Mustangs that disabled the flex logic?

 

Thanks

I missed this.

The logic is still there as far as I know, it just does not work very well from what we have been told from various tuners (eg the process to get it to lock properly is confusing for many end users and it can lock on the wrong content). We highly recommend utilising our user flex logic instead, or ultimately using a flex fuel sensor. This will mean instant 0°C cold starts and that your extra timing is added immediately. You don't have to worry about it learning the wrong content and adding too much/too little timing and relying on the knock sensors.