I am wanting to put a Flex Fuel sensor in this car and it looks like there are a couple of tables missing in the Calibration I have. Is there anyone out there that has done this successfully on a P59 ECU? Would you mind sharing your tune (Original/Custom tune) so I can have HP add the tables if they are missing?
Thanks
What exactly is missing?
Email Tunes, [email protected]
96 TA Blown/Stroked, 4L80E/Fab 9
15 C7 A8 H/C 2.3 Blower/PI
14 Gen 5 Viper
Custom Mid Engine chassis, AKA GalBen C
On all the E38 ECU's there is a Mult vs. composition table to adjust for the spark to ethanol content. I don't see it anywhere in this calibration.
Post the file... should be there
Email Tunes, [email protected]
96 TA Blown/Stroked, 4L80E/Fab 9
15 C7 A8 H/C 2.3 Blower/PI
14 Gen 5 Viper
Custom Mid Engine chassis, AKA GalBen C
the table you are looking for is the stoich fuel table under the Fuel General Tab. this sets the stoich ratio per ethanol percentage.
there is no % of gasoline stoich multiplier table.
once the sensor is active your high octane table becomes your E blend table and low Octane becomes your Knock detected table or Gasoline table.
complete a solid gasoline tune file and then when you add E fuel you can log your wideband error against stoich and modify the stoich values to make it drop into place when stoich ratio is being commanded. this is where lambda pids and wideband channels come into play because gas and blended fuels can be calibrated from the same fuel error plot.
Last edited by cobaltssoverbooster; 02-16-2018 at 03:29 PM.
2000 Ford Mustang - Top Sportsman
That file also has a Flex fuel Spark tab under MISC in the spark tab. You can use that to add or subtract spark based on alcohol content.
I way I understand it that say you put 10 degrees of timing in at .36 volume all the way up to .88+ it will add in that 10 degrees if the alcohol content is 100%. If you are using E50 it will add in 5 degrees. It's sloped like the stoich table would be. If I'm wrong please correct me there.
2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.
If you don't post your tune and logs when you have questions you aren't helping yourself.
The table you are talking about only makes sure the AFR is corrected. The table I'm talking about corrects the amount spark based on ethanol percentage. A E38 computer has the table I'm lookin for in the spark tab so that when you put your timing numbers in the flexfuel spark modifier table it can pull timing out based on how much ethanol is in the tank because obviously it will take more timing with E85 vs. E20.Originally Posted by cobaltssoverbooster
If you look up the E38 computer and go into the spark tab you will see the table I'm talking about.
You are correct, the table that I can't find will do that. If I tell it to add 10 degrees with true E85 but then if there is only E10 it will do the deduction on timing for the E10
your looking for spark blending, got it.
no there isnt a spark blend table in this OS. From what i remember in testing you select the Ignition for E85 and it has been assumed that the ignition is linearly ramped by percent of alcohol from table A to table B. (A being High Octane table and B being Flex Table)
you will have to track content vs main spark and map it against a linear blend curve that you make yourself using the High Octane and E85 tables to see how the linear blend factor is programmed in. The early computers can handle E85 but they do it with very crude basics as you are now finding out. Below is an example of the linear relationship between high and E85 tables in a bogus example where High octane cell would be 14* advance and E85 in the same cell would add an additional 12* for a total of 26* at 85% content threshold. i didn't test if the table was set to considered 100% blend or 85% blend the max content.
blend.jpg
Last edited by cobaltssoverbooster; 02-19-2018 at 04:41 PM.
2000 Ford Mustang - Top Sportsman
Thank you. I was kinda thinking the same thing. Once I have it all back together I will just turn it on and give it a try.
Conclusions to spark being added with P59 pcm?
HPT (and efi live) are missing the spark blend table in the calibration. Need a tune file that already has 'sane' values programmed in, or use user defined parameters to define that table and put in sane values. But yes, totally works fine. I'm running a P59 Corvette file with flex fuel (this file in stock form has all things flex fuel disabled).
Ive got a CAX file that gives me the Flex fuel spark blend tables on a P59.
It is named "Flex Fuel Spark Blend Factor Vs. % Alcohol"
I was going to set it up to give me a 93 octane timing table and a 87 octane timing table for my truck.
87 and 93 have same ethanol content, changing flex fuel spark blend factor won't do anything. If you want that, just set the low and high octane tables accordingly, but understand it will be a reactive system to knock
We don't have e85 anywhere around here. And yes I know the main fuels are usually 3-8% here.
I use the nitrous retard on the 99-02 trucks for a 87/93 tune. And on the P59 truck it doesn't have knock sensors. So it just going to be tuned for 93 octane and then a signal to trigger it to use the 80%E tables for 87 octane.
If you download a stock tune file that has flex enabled from the factory and flash it, the flex fuel spark table works. I'm running the only stock file that has flex enabled for a P01 (2002 tahoe) on my 2001 Silverado. The Spark modifier table and fueling are automatically adjusted based on alcohol percentage from the flex fuel sensor I wired into the PCM.
You need to change Your current OS to a Flex fuel enabled OS ( like a 2005 avalanche or 2004 Tahoe OS ) For the P59 to have the Spark tables populated and operational.
Last edited by Matt Vardaman; 12-23-2021 at 02:18 AM.
2001 Silverado 5.3 - 209/217 cam, GT45 Turbo on 7lbs, Aem x-series wideband, 50lb/hr flex fuel injectors, on E85 with content sensor
1999 Silverado 6.0/4L80E Summit Stage one camshaft, 317 heads (replaced cast iron)
03-06 trucks with the P59 Pcm have knock sensors.
2001 Silverado 5.3 - 209/217 cam, GT45 Turbo on 7lbs, Aem x-series wideband, 50lb/hr flex fuel injectors, on E85 with content sensor
1999 Silverado 6.0/4L80E Summit Stage one camshaft, 317 heads (replaced cast iron)
For the general user, using a file already flex enabled would be best. There are many many parameters that reference ethanol content. Multiple transient fueling tables, cranking fuel, spark blend factor and engine torque models are among the few.
However for some using a stock file, usually a truck/suv file, creates issues in other places whether it be traction control, gauge issues or electronic throttle control. Even using certain transmissions can be a pita because some do not have available segments to use a certain type. In this instance is where using someone that knows the ins/outs of the whole system to build a custom file to fit the individual needs.
Working on a P59 based L31 tune for my 383 to run on E85 at the moment. Don't see anything missing on the 2005 L31 GMT800 Mexican file I am working on.
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