HP Tuners MAF & VE tuning

ctuinstra

Goblin Guru
Thanks for sharing I have been trying to pay more attention to HPtuners and finally got my wideband to work. Here is the dyno tune file from my recent dyno session. I asked the tuner if it was ok to share and he said he didn't mind. for some reason he couldn't get the MAF to work so its all VE tuned I believe.

He said there was some false knock issues so im not sure if timing was pulled because of it. I later found the guide bolts stripped off the timing chain and cleaned it all up and redid the timing.

"this is an 07 with 2.9 pully and 60lb injectors tune"
Do you have a boost reference fuel pressure regulator? It's odd that your Injector Flow Rate is almost a straight line. Usually you see that with boost referenced system. Not trying to say is wrong, just wondering and trying to understand things. Your VE table is interesting.
 

ccannx

Goblin Guru
Do you have a boost reference fuel pressure regulator? It's odd that your Injector Flow Rate is almost a straight line. Usually you see that with boost referenced system. Not trying to say is wrong, just wondering and trying to understand things. Your VE table is interesting.
I do not but was thinking of going down that route, matter of fact I was talking to a friend last weekend that mentioned not having one may result in your tuner hating you...…

I compared my VE table to Ross's and its consistently lower everywhere. Tuner may have had a hard time, the car was on the dyno for hours but was a little less jerky afterwards.

May be going to stage2 turbo from ZZP but they are not sure when they will have the parts available from what I gathered from sales on the phone.
I attached the difference in Ross and My VE tables if I understand it correctly I'm consistently/substantially lower everywhere. Isn't the VE table a representation of how much air is coming in ? My wideband is giving me lean readings and I wonder if this table is not commanding enough gas for the amount of air.
 

Attachments

ctuinstra

Goblin Guru
I do not but was thinking of going down that route, matter of fact I was talking to a friend last weekend that mentioned not having one may result in your tuner hating you...…

I compared my VE table to Ross's and its consistently lower everywhere. Tuner may have had a hard time, the car was on the dyno for hours but was a little less jerky afterwards.

May be going to stage2 turbo from ZZP but they are not sure when they will have the parts available from what I gathered from sales on the phone.
I attached the difference in Ross and My VE tables if I understand it correctly I'm consistently/substantially lower everywhere. Isn't the VE table a representation of how much air is coming in ? My wideband is giving me lean readings and I wonder if this table is not commanding enough gas for the amount of air.
Since you don't have a Boost-referenced system, I would think it would be more accurate to have the injector flow rates on a slope much like that of the stock (only higher values). The flow is going to vary depending on the intake vacuum/pressure. In a boost referenced system, the difference in vacuum/pressure is used to modify the fuel pressure to compensate.

More like this:

14572



The VE table is used to calculate the injector pulses. The MAF is used more to provide how much air is ingested. It's not uncommon to see high AFR on a wideband at certain times. This is especially true during decel, the ECM will cut much of the fuel using the DFCO. When you run into problems is lean during accel or tip in. To really know if it's right or wrong, you need to compare the ECM's commanded AFR (or lamda) versus what you are actually getting. It would be easier to look at a scan to see, but it has to be set up to show what to look for.
 

ctuinstra

Goblin Guru
Thanks for sharing I have been trying to pay more attention to HPtuners and finally got my wideband to work. Here is the dyno tune file from my recent dyno session. I asked the tuner if it was ok to share and he said he didn't mind. for some reason he couldn't get the MAF to work so its all VE tuned I believe.

He said there was some false knock issues so im not sure if timing was pulled because of it. I later found the guide bolts stripped off the timing chain and cleaned it all up and redid the timing.

"this is an 07 with 2.9 pully and 60lb injectors tune"
It seems like they turn things off to do the tune but don't turn them back on. I noticed on yours the Piston Protection is also disabled. I just find this strange, did they mean to disable it in the final tune? And your DFCO is disabled, again this is something that you disable while tuning the VE tables and should turn back on, but it's not. Again, I'm just questioning, not saying things are right or wrong.
 

ccannx

Goblin Guru
That makes perfect sense. The way it was explained to me is that when the injectors are under normal circumstances there is a vacuum helping pulling or assisting the fuel out of the injectors. When there is boost there is pressure resisting the fuel from flowing out of the injectors as it normally would. I’m surprised that table has is so flat.
 

ccannx

Goblin Guru
Since you don't have a Boost-referenced system, I would think it would be more accurate to have the injector flow rates on a slope much like that of the stock (only higher values). The flow is going to vary depending on the intake vacuum/pressure. In a boost referenced system, the difference in vacuum/pressure is used to modify the fuel pressure to compensate.

More like this:

View attachment 14572


The VE table is used to calculate the injector pulses. The MAF is used more to provide how much air is ingested. It's not uncommon to see high AFR on a wideband at certain times. This is especially true during decel, the ECM will cut much of the fuel using the DFCO. When you run into problems is lean during accel or tip in. To really know if it's right or wrong, you need to compare the ECM's commanded AFR (or lamda) versus what you are actually getting. It would be easier to look at a scan to see, but it has to be set up to show what to look for.
I tried to change value and it appears 63.5 is set max value. looking at similar tunes they do adjust that chart incrementally from 38-63.5 . I have also noticed on Ross's shared file I can go into the transmission values and I cannot on my files. I have toggled back and forth to advance mode and even reinstalled VCM suite also tried the Beta version. For some reason I am getting limited views....... Since the parameters are visible it may be that I'm not pulling all the data from the ECM when I read.

I have tried several more times and cannot seem to pull certain data like transmission values. Starting to think my eBay Ecu is fouled up somehow or not even an LSJ ecu.

Also found a config file that seems to work well with VCM scanner. It’s the starting config file shared by the Tuning school here : https://thetuningschool.com/pages/course-downloads
 
Last edited:

Rauq

Goblin Guru
...I am tempted to wire [the wideband] to the AC pressure sensor, just to get rid of the Windows10 communication issues.
Then again, I was thinking the AC pressure sensor might be better utilized for the oil pressure sender that I added to my LSJ engine. I wonder if there is another unutilized 5v sensor on my ECM/Powertrain Control Module that could be repurposed.
Didn't want to hijack someone else's thread, so I thought I'd drop a couple ideas/thoughts here.

First, what are you going to do with an oil pressure sender input going into the ECM? Pull that sender value back out with an OBDII gauge for realtime monitoring? Or just watch it while you're tuning?

Second, could you get a 5v sensor input on the second O2 sensor input?
 

Ross

Goblin Guru
Didn't want to hijack someone else's thread, so I thought I'd drop a couple ideas/thoughts here.

First, what are you going to do with an oil pressure sender input going into the ECM? Pull that sender value back out with an OBDII gauge for realtime monitoring? Or just watch it while you're tuning? -Both of those. It would require a flexible OBDII gauge to be able to reprogram the display.

Second, could you get a 5v sensor input on the second O2 sensor input? -I had the same thought, but realized that the PCM has a bunch of fuel logic associated with the 2nd O2 sensor, so I was avoiding that. Not sure that I can turn off all the logic with HP Tuners.
 

Rauq

Goblin Guru
I had the same thought, but realized that the PCM has a bunch of fuel logic associated with the 2nd O2 sensor, so I was avoiding that. Not sure that I can turn off all the logic with HP Tuners.
Have you confirmed this? On one hand that was my original hesitation, on the other hand can't you run catless in a regular Cobalt with no penalties other than a CEL? It's not like it's going to run the engine richer or leaner just because cat efficiency sensor is skewed, but on the other hand, if it were that easy, I'm assuming everyone on LS1Tech would be doing this instead of running to the AC pressure sensor. I know we can turn off the CEL in HP Tuners, but I agree, I have no idea what else is going on behind the scenes. Just another thing to add to the list of things I need to try instead of just speculating...
 

Ross

Goblin Guru
No, I haven't done independant testing, only have read about it. My understanding is that the engine does run rich when the PCM wants the catalytic converter to be running hotter, and it does use the sensor to tell it how efficient the cat is. Turning off a check engine light doesn't turn off all the PCM fuel logic, just turns off the trigger for the instrument cluster light. Again, all speculation, as I don't test everything I read.
 

Rauq

Goblin Guru
There are cat over temp protection tables, I wonder if that's about all the impact the second O2 sensor would have? They can be zeroed out.
 
Top