On the P2229, normally the voltage tests are set at 40% and 90% voltages, so on a 3bar map, that would mean the low voltage test would need to see about 170kpa before being correct.Originally Posted by FL0WL0W
This is fixable if you post your calibration here, i can adjust it.
I am also able to adjust the P1101 max PR value as well.
I cant promise that it will fix everything, but piece by piece we can get through it.
Here is the tune, alot of crazy stuff going on in there, borrowing the ECM from my w204 mercedes swap to try out this OS on my 95 truck with an L84 engine controlled with L83 electronics and no TCM since it is manual. I have yet to get HP Tuners speed MPH in VCM scanner to show anything but 158 mph (even sending it a good square wave into X2 pin 8 and reading correct kph on CAN broadcast), so i've had to do alot of stuff to get throttle to act right. it revs up nice now but still slow going back to idle.
I was attempting to control BPV with a solid state relay like i saw some people do online with an aftermarket ECU. I gave up getting the ECM to work last night and instead programmed one of my custom modules to output a PWM signal and fed it into the SSR. I am convinced now that this is not a good reliable long term solutions and probably only works in their application of going down a drag strip for ~10 seconds (who knows for how long). the SSR is just too slow to turn off to be able to give it a proper PWM signal at anything below like 25hz. I might still explore this using a proper fast switching mosfet instead. Do you know what frequency the PWM output is from the E92?
Thank you for your help! Do you have a discord or slack you regularly hang out in?
you can use 4x4 truck file, use the vss wires that are used on the transfercase, that will feed ecm with speed, you need to set trans to manual, so it will go out of reduced mode.
I tried that. I can try and fight it that way some more. You have had luck doing it this way? That file is a 4x4 file, but i may have turned something on/off that is keeping it from working.
I adjusted the AAP voltage limits
Try this, and see if it is any better
Im concerned that iirc the aap when in sciap mode may be linked to the baro and the sciap sensor, so the aap linear and offset may have to match, not 100% sure
ok i did a write entire and it looks like there is no longer any AAP faults. I enabled all 3 tests and no longer get those faults.
If i rev the engine, i get a P1101 fault. Did you make the 0.97 change you talked about in the blog post? I think the error may be from filling the manifold cause i can see a spike in the MAF when throttle opens, but settles back down once the manifold is filled. I may be able to get this to go away if i increase the manifold volume under airflow>SD
I still don't have pwm output. below are my DTCs and explanations of each
0x7E8: P0073 - Ambient Air Temperature Sensor Circuit High (Permanent) - No AAT sensor is installed. I can work on this if you think it may be an issue
0x7E8: P0521 - Engine Oil Pressure Sensor/Switch Circuit Range/Performance (Pending, Current, Old) - L84 sensor is different than L83 sensor. No cal tables available in HP Tuners, so i am just going to have to switch out to a different sensor. Should i go with L83? or can i try out the LT4 sensor so that i can get Oil Temp as well?
0x7E8: P057C - Brake Pedal Position Sensor Circuit Low (Permanent) - Brake switch is not hooked up. not really that big of a deal since this is a manual swap. i will get this hooked up later when i work on making Cruise Control work.
0x7E8: P0650 - Malfunction Indicator Light Control Circuit (Pending, Current, Old) - Not hooked up
0x7E8: P1101 - Mass Airflow Sensor Out Of Self Test Range (Pending) - Only faults when revving, Not present during startup
0x7E8: P2160 - Vehicle Speed Sensor B Circuit Low (Permanent) - I can't make this go away.
0x7E8: P2635 - Fuel Pump 1 Flow Insufficient (Permanent) - No Fuel Pressure sensor hooked up on the low side. I disabled the code but now its a permanent code that won't go away.
Attached is the same tune you sent me, just with AAP1/2/3 enabled.
The .97 was already set in your calibration.
I made one more change to a SCIAP performance table that may fix your P1101 issue, but its a long shot.
What exactly are you expecting to happen?
The Supercharger bypass controls are to control the disabling of the supercharger.
Normal ~95 pwm indicates that boost is allowed, If the PWM is here, then there isnt any more you will want unless you want less boost?
The ~5 pwm value will indicate that boost is being disabled.
Its not a closed loop system like i thought originally.
This seems to have fixed the P1101 error. but still no PWM output.
Interesting that its not closed loop. so if the supercharger were to overboost, it wouldn't try and regulate down to a safer boost level? i guess this makes sense given all GM uses is a vacuum solenoid so there probably isn't a bunch of fine control there. Does the ECM command boost disabled when in vacuum? if it does then that will at least work for controlling the bypass valve. To control boost i will have to change pulleys.
Side note. i dusted off my breadboard and hooked up a 555, a couple opamps and a mosfet to create a bypass valve controller that opens during vacuum and has a maximum boost limit. seems to do a decent job just revving it. Going to probably spend the rest of the night soldering it up to some perfboard.
I would assume it would do a parital closing as you get past the 'max boost kpa'
However I have not seen it personaly.
The system commands 95% duty cycle during vaccum all the way through boost.
Only commanding 5% on an Error condition.
This was very annoying for my use case as well.
I ended up fully hooking up the smoothboost to the pedal, and I use that to control boost.
This allowed me to have a 'boost knob' in the cabin with me to turn down the boost if desired.
Update Here:
HPT recently Added what I had been referring to the SCIAP Baro Smoothing Factor to their suite.
It is referenced as: ECM 32872 SC LF Constant.
They also have added the Commanded Power Table as : ECM 33008 Driver Demand Engine Torque
I am still happy to locate these, however you can now request it from HPT support if you so wish.
Wonderful~~~. I will repin the TMAP air temp signal wire to resume the IAT2 value.
Big update here.
I recently have been seeing a bunch of different performance shops offering Custom OS changes to enable different functionalities in the OS.
I took this as a challenge to revive the initiative to get the smoothboost controller to work seamlessly with the GM E92 ECM.
In my previous attempt I discovered that this was not possible due to the OS itself only having the capability to enable or disable via a ON or OFF Pwm Signal.
Long story short, I made a custom change to the OS and was able to accomplish controling the Smoothboost via PWM from the ECM.
The custom change involved re-purposing the Base DC Table for use with SC fitted vehicles.
Screenshot 2025-04-29 162552.png
Screenshot 2025-04-29 163252.png
With this custom change I was able to get the behavior that was desired from the ECM.
My Man, that's huge, GOOD JOB! How does it drive/ feel now? I see you have desired MAP as the Y axis of the table. Would this still work for vehicles that do not report desired MAP, or does your OS tweak add that in? Correct me if I'm wrong but I'm assuming desired MAP would be controlled by the DD table?
I just finished installing one of those Kaizen Speed Relays. It does what it's supposed to however, it's only active at WOT so it doesn't help with part throttle, I wondering if there would be any way to integrate it with your OS mod.
EDIT: actually now that I'm thinking about it, If it's driven off of the DD table, one would assume boost could be controlled that way instead.
Either way, exciting stuff, can't wait to learn more about it.
One of my biggest gripes with the smooth boost is the fact that there isn't a way to adjust the actual point where it starts to close, which in my case seems to be ~70% APP. In my opinion that's too late, as you know it causes a situation where the engine gets to zero vacuum like an NA car, rather quickly, then there is a large window where nothing really happens before boost finally is allowed to ramp in from 70-100%. I found myself trying to adjust the DD table to line up with the closing event, which proved unsuccessful for obvious reasons.
Last edited by GPGTP; 04-30-2025 at 08:03 AM.
2018 Camaro SS, Maggie 2650, 103 TB, Big Gulp, E85
It felt correct, there may be a slight delay transitioning into boost, but im confident that will go away once i get a bit more time to adjust where i want the ramp to start.
With OS changing, I can set the y axis to any of a vast amount of variables, i may try setting it to pedal position or demanded torque..
From what ive been able to gather, yes, desired kpa is controlled by pedal input and dd tables.
I am not familiar with that product..
However if you are having part throttle SC boost issues, you should look into the SCIAP sensor addition.
I had good luck with the smoothboost wired into the the pedal.
With this OS change however, we could have it ramp in without butchering dd tables.
I feel you on that, its annoying to get them to behave correct.
I am not currently offering this as something i openly offer, It is very risky to change the underlying OS.
HPT and VCM do not currently offer any mechanism for xdf based OS Patching.
This means that for me to do this for a customer, I have to have their ecm in person to hook non HPT tools up to it.
How did you get the boost gauge to work on the ss? Your link is broken to the blog
It took a lot of different pieces.
Had to configure the gauge pod and the serial gateway module.
On the Smooth boost controlled via PWM custom OS change,
I adapted it to use desired KPA vs actual KPA, This results in a very predictable bypass control.
It is faster to open than a normal vaccum controlled bypass.
I am working on an addition to provide modifiers for wheel sleep and knock and switching on different drive modes.
General question.
I have made progress on being able to provide custom OS changes.
Is there any interest in having this available?
If anyone is interested in Custom OS changes for Blower PWM control, please reach out.
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