P59 12562918 OS Issues

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03-18-2023
Fast355

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P59 12562918 OS Issues

My Express van with this OS has me ready to blow this P59 to pieces, rewire the entire van and start with an E67, DBW and 58X or an aftermarket standalone controller. The thought of swapping an E67 and a 6L90E is heavily on my mind. I am that sick of the P01 and P59s issues running this basic 383.

1.) I thought I had the Park/Neutral vs Drive idle table issue sorted out. However, I do not. It seems to use the Base Idle Tables as well as the LTIT learned values whenever it feels like running on them. I have seen it update the LTITs in Park/Neutral because they change from data log to data log sometimes, but I noticed it seems to mainly stick in the Drive learned cells.

2.) When the van was 24X I had no issue adding a flex fuel sensor to it with the same OS. Now that I have the Mexican L31 engine and engine diagnostic segment swapped into it the PCM does not see the flex fuel sensor. I applied the Flex Fuel patch after segment swapping in the L31 engine tune. The sensor is still correctly wired and has a frequency output approximating the Ethanol content to C1-56 but the Alcohol percentage is stuck at Zero even after reapplying the Flex Fuel patch. With the Patch set and the DTCs enabled it does not go to the Default 38% ethanol nor does it set a Flex Fuel Sensor low code with the sensor disconnected. I had to set the stoichiometric value to 11.8:1 just to get it to run well enough to make it home after I put E85 in the tank last night. I have added the flex fuel patch on several 24x setups with this operating system without issue, but the Mexican 4x calibration is being a total PITA and has me ready to pull my hair out. My buddy has a L31 with 24x running a 2005 6.0L van base tune with the Flex Fuel patch that I setup for him and the Ethanol % updates perfectly.

Any ideas? What am I missing? Then again maybe I just expect and want too much out of this antiquated platform and should just go find me a L8T and a 6L90E to drop into it.

Current Tune file is attached.
03-19-2023
Fast355

Any ideas on the flex fuel? I logged 139C and the frequency is reading ZERO. Then I am also puzzled as to why it is not setting a DTC for low frequency input nor is it defaulting to 38% ethanol content. Something must be missing with the E85 patch on this OS.
03-21-2023
kur4o

I can only speculate that the bin is missing something. Is the bin from an l31 with manual transmission and only trans segments are changed. to suit your needs.
Other reason could be the x4 vs 24x crank trigger. Lots of code can be omitted based on non sequential part of x4 signal.
System segment also have vital data. Only a disassembly can reveal the issue, and if there is a settings for the crank signal, will speed up tracing.
03-21-2023
Fast355

Quote:

Originally Posted by kur4o

I can only speculate that the bin is missing something. Is the bin from an l31 with manual transmission and only trans segments are changed. to suit your needs.
Other reason could be the x4 vs 24x crank trigger. Lots of code can be omitted based on non sequential part of x4 signal.
System segment also have vital data. Only a disassembly can reveal the issue, and if there is a settings for the crank signal, will speed up tracing.

So it is a L31 manual calibration with a 2005 6.0L Express trans, trans diag, fuel system and system segment swapped in. The crank is set to low res in the system file. My buddies truck has a near identical calibration but he has 24x and his has the 6.0L engine tune. His flex fuel sensor works. I basically copied everything except the engine and engine diag segments from a 6.0L van for the bin above. I tried swapping the system option matrix to a GMT800 thinking it had something to do with the flex fuel given vans do not havw flex fuel woth a P59 and nothing changed. Sadly I have been unable to find a L31 file with a factory automatic because I believe they only optioned the Mexican trucks with the L31 with the P59 when a 3500 with a 5spd was optioned.

I am hoping it is as simple as a small code patch, but I have not worked with GM coding newer than $OD and my expertise there ends with $OD and $99 that I worked on a lot 15 years ago or so. It would be nice to make the flex fuel and idle routine work correctly with the P59 4x Automatic though because it would give people an easy E85 upgrade path for small blocks and big blocks. My 10.65:1 383 loves E85 and it was $2.42/gal when I filled up a few days ago. Even without adding timing the engine makes alot more torque on E85 and is smoother running. Going from an 0411 to a P59 is practically plug and play.
03-21-2023
G-Body

Do you have a fuel level sending unit hooked to the PCM and in the tank? I know the 9405 OS requires the fuel level to work with the flex fuel sensor. IIRC it does read the sensor, however, it does not use the reading from the sensor to update the ethanol percentage unless the PCM sees the engine shut down, the fuel level increase, then the engine restart. I put a couple of resistors and a time delay relay in so that every time the car starts the PCM sees about 3/4 of a tank, then after a minute or so of the ignition being on it drops to 1/4 tank. Once I did that it would update the flex fuel percentage on every start. I`m not sure if the 2918 OS does that as well.
03-21-2023
Fast355

Quote:

Originally Posted by G-Body

Do you have a fuel level sending unit hooked to the PCM and in the tank? I know the 9405 OS requires the fuel level to work with the flex fuel sensor. IIRC it does read the sensor, however, it does not use the reading from the sensor to update the ethanol percentage unless the PCM sees the engine shut down, the fuel level increase, then the engine restart. I put a couple of resistors and a time delay relay in so that every time the car starts the PCM sees about 3/4 of a tank, then after a minute or so of the ignition being on it drops to 1/4 tank. Once I did that it would update the flex fuel percentage on every start. I`m not sure if the 2918 OS does that as well.

I do not have the level sensor wired through it. I will check with my buddy and see if he happens to. His truck is a 95 but he built an OBD2 24x harness for it.
03-22-2023
kur4o

I think you need to use segments engine,engine cal,system,fuel, from original file and tune from there.

There is a 2006 OS that can be used too, if you want to test other options

I am still looking for 4x-24x switch in bin. Do you know how it is named.
I am sure in 4x mode it goes to batch fire mode.
03-22-2023
Fast355

Quote:

Originally Posted by kur4o

I think you need to use segments engine,engine cal,system,fuel, from original file and tune from there.

There is a 2006 OS that can be used too, if you want to test other options

I am still looking for 4x-24x switch in bin. Do you know how it is named.
I am sure in 4x mode it goes to batch fire mode.

It is in the system option matrix. Low resolution crank sensor bit. Checked is 4x. Unchecked is 24x.
03-23-2023
kur4o

Great, Finally found it. I should have took more attention. I will try to trace that switch and its impact on code flow.
03-23-2023
Fast355

Quote:

Originally Posted by G-Body

Do you have a fuel level sending unit hooked to the PCM and in the tank? I know the 9405 OS requires the fuel level to work with the flex fuel sensor. IIRC it does read the sensor, however, it does not use the reading from the sensor to update the ethanol percentage unless the PCM sees the engine shut down, the fuel level increase, then the engine restart. I put a couple of resistors and a time delay relay in so that every time the car starts the PCM sees about 3/4 of a tank, then after a minute or so of the ignition being on it drops to 1/4 tank. Once I did that it would update the flex fuel percentage on every start. I`m not sure if the 2918 OS does that as well.

2918 apparantly does not require the level sensor to update. Just checked with my buddy and his is not wired through the PCM.
03-23-2023
Fast355

Quote:

Originally Posted by kur4o

Great, Finally found it. I should have took more attention. I will try to trace that switch and its impact on code flow.

When I get home I will attach a file that the flex sensor works on. It is a non flex fuel 6.0L 24x engine calibration that was patched with the Flex Fuel patch. Maybe comparing the un-defined areas will help turn something up.
03-23-2023
Fast355

I made the first 58x swap move last night. Snagged a discontinued from GM, 2016 Express engine harness new in the box on Ebay for $350. Going to slowly acquire the parts to 58x and 6L90E swap the van as time allows. For simplicity and not having to deal with demanded torque it will probably be running on a 2009 TBSS E67 rather than the E78 GM put in the later 6.0L/6L90E vans.

I have a couple other setups I am looking to keep 4x on, but wanting a 6L90E trans the move to 58x only makes sense on the van.
03-27-2023
bobcratchet555

Quote:

Originally Posted by Fast355

I made the first 58x swap move last night. Snagged a discontinued from GM, 2016 Express engine harness new in the box on Ebay for $350. Going to slowly acquire the parts to 58x and 6L90E swap the van as time allows. For simplicity and not having to deal with demanded torque it will probably be running on a 2009 TBSS E67 rather than the E78 GM put in the later 6.0L/6L90E vans.

I have a couple other setups I am looking to keep 4x on, but wanting a 6L90E trans the move to 58x only makes sense on the van.

i have an e67 and harness from a 2009 LS4 (impala SS) - not sure if that would've helped ya or not but i would take a lot less for it
03-27-2023
kur4o

I did some tracing of x4 vs x24 switch, Lots of IF code jumps, than might set even much more subswitches. Full tracing will take lot more. I am almost sure that if you switch to x24 sensor whell it will work as it should. Low res only can be very tricky to use.
03-28-2023
Fast355

Quote:

Originally Posted by kur4o

I did some tracing of x4 vs x24 switch, Lots of IF code jumps, than might set even much more subswitches. Full tracing will take lot more. I am almost sure that if you switch to x24 sensor whell it will work as it should. Low res only can be very tricky to use.

I figured it might possibly be that kind of scenario. Honestly I just adjusted the stoich, threw some extra timing in it above 0.52 gm/cyl and it runs well for now. I got 243 miles to 17.2 gallons of E85 mostly cruising around town. Torque is up, power is up, the engine runs noticeably smoother and seems happy even without the flex fuel sensor being utilized. This is what my fuel trims and wide band looked like at hot idle this evening. E85 is ~2.40-2.70 gallon and pump premium is over a $1.00 more a gallon. With my E85 availability, ~250 mile round trips and 31 gallon tank I will just keep pumping E85 into it and adjust stoich as needed for now.

https://youtu.be/2zP2xdXIQmw