3bar COS only logging to 255kpa

[BAD BOB]

Basically when logging it will go to 255 kpa and flat line. Not sure if the tune is still following above that point and just not logging above or if it's a issue with the v2 not reading the map correctly. The map is scaled correctly as well.

[joecar]

The PCM's range for reporting the MAP pid is upto 255 kPa.

The COS's Boost VE table ranges upto 285 kPa regardless of what the MAP pid reports.

But this still leaves the range 255-285 kPa hard to tune.

[GMPX]

Off the top of my head there is another MAP PID that will read beyond the SAE.MAP 255kPa limit.

[BAD BOB]

Off the top of my head there is another MAP PID that will read beyond the SAE.MAP 255kPa limit.

Can you recall the pid name by chance?

[picnic_george]

The PCM's range for reporting the MAP pid is upto 255 kPa.

The COS's Boost VE table ranges upto 285 kPa regardless of what the MAP pid reports.

But this still leaves the range 255-285 kPa hard to tune.
Is this a limitation of the OS itself or the PCM?

[joecar]

The pid SAE.MAP ranges 0-255 kPa... I believe it's the OS.

Like Ross said, there is another MAP pid, but I don't see it...

[GMPX]

Can you recall the pid name by chance?
No sorry I don't remember.


Is this a limitation of the OS itself or the PCM?
It is a limitation of the SAE defined PID, not the PCM.

[tirefryin_s10]

Any update on this? Need to be able to log to the end of the map sensor.

[tirefryin_s10]

Anyone?

[RADustin]

Can you log MAP voltage? and scale it yourself with a custom PID?

[ScarabEpic22]

I think that's going to be your only bet, just because it's a 3 Bar MAP doesnt mean the PCM can see the whole range. There are hardcoded limits (like the 255kPa limit you found) that you cannot get around, the PCM will never be able to see it. If you HAVE to have it, you're going to need to scale everything and get creative on how to display everything. FWIW, I see this being a huge can of worms and would not suggest it, likely way more headache.

[tirefryin_s10]

I think that's going to be your only bet, just because it's a 3 Bar MAP doesnt mean the PCM can see the whole range. There are hardcoded limits (like the 255kPa limit you found) that you cannot get around, the PCM will never be able to see it. If you HAVE to have it, you're going to need to scale everything and get creative on how to display everything. FWIW, I see this being a huge can of worms and would not suggest it, likely way more headache.

If someone can help me build a custom pid I would just like to at least be able to log to the end of the map sensor voltage.

[RADustin]

I think that's going to be your only bet, just because it's a 3 Bar MAP doesnt mean the PCM can see the whole range. There are hardcoded limits (like the 255kPa limit you found) that you cannot get around, the PCM will never be able to see it. If you HAVE to have it, you're going to need to scale everything and get creative on how to display everything. FWIW, I see this being a huge can of worms and would not suggest it, likely way more headache.

this isn't completely true. The SAE pid is limited to reporting up to 255 as it is one byte(0-255). I believe the ecm can read in and perform math with up to 285.

Is raw MAP voltage available as a scan tool item?

If not you could run the map sensor into one of the analog in's on the V2- and scale it from there.

[ScarabEpic22]

this isn't completely true. The SAE pid is limited to reporting up to 255 as it is one byte(0-255). I believe the ecm can read in and perform math with up to 285.

Is raw MAP voltage available as a scan tool item?

If not you could run the map sensor into one of the analog in's on the V2- and scale it from there.

Hmmm interesting, I figured that 0-255 range = 256 unique values or 2^8 applied to both the PID and what the PCM/ECM can do. Be interested to know, even more so if this changes per ECM/PCM...

[RADustin]

its the way the packets come across the data lines. It doesn't have to do with internal PCM processing.

[GMPX]

What controller are you working with? The LS1 has a PID called 'GM.MAPBOOST_DMA', that will read past 255kPa. If you are talking later model ECM's (E40, E38 etc) then forget it, the ECM's internal calculations do not allow past 255kPa.

[Highlander]

Simple

Create a custom PID with your sensor's equation and log map.voltage and custom convert.... also log VE table dma and you will know where you are .