Shooting for Lean Cruise on stock PCM
08-09-2006 | 10:20 AM
#21
From what I gather the code -is- in the PCM, but
there is a "platform check" which sees your US
domestic vehicle info and says "no cookie for you".
People have succeeded in hacking this and getting
a clean lean cruise operation inclusive of the time,
RPM, etc. qualifiers. It's been explained to me as
simply bypassing this specific check routine, along
with the other stuff you have to do to make the
PCM like the change (checksums blah blah blah).
If you wanted to do some hardware hacking I
think you could make a simple op-amp circuit to
buffer the O2 voltages, and have a TPS, RPM,
maybe even time-at-steady-cruise (or, maybe
evenr something straight off the cruise control)
enabled current summed in to jack the "xO2"
voltage pivot-point slightly positive which will
drive the closed loop leaner. The amount of
current injection, use a trim-pot and dial it in
with Mr. Wideband.
Running full time open loop might be easier
especially if your fingers are already in it and
you don't like soldering.
there is a "platform check" which sees your US
domestic vehicle info and says "no cookie for you".
People have succeeded in hacking this and getting
a clean lean cruise operation inclusive of the time,
RPM, etc. qualifiers. It's been explained to me as
simply bypassing this specific check routine, along
with the other stuff you have to do to make the
PCM like the change (checksums blah blah blah).
If you wanted to do some hardware hacking I
think you could make a simple op-amp circuit to
buffer the O2 voltages, and have a TPS, RPM,
maybe even time-at-steady-cruise (or, maybe
evenr something straight off the cruise control)
enabled current summed in to jack the "xO2"
voltage pivot-point slightly positive which will
drive the closed loop leaner. The amount of
current injection, use a trim-pot and dial it in
with Mr. Wideband.
Running full time open loop might be easier
especially if your fingers are already in it and
you don't like soldering.
Originally Posted by RedWS6 00
Yep thats right, I cant enable the true 'lean cruise' as the code isn't in my PCM. So what I have done is forced open loop constantly by uping the close loop ECT threshold to somethnig that wont be reached. Therefore while in open loop it uses the EQ ratio table, have made it about 16 AFR up to 20kpa, 14.6AFR up to 50kpa then richer above.
The thing is with runnine lean, or even rich for that matter is that it woundt [pass the emmision test, too lean I think produces NOx gas. When I'm due for an emmision test I'll put it back in closed loop and put the cats back on.
My next thing is to work on DFCO to reduce the entry time. Looks like its the 'Entry Blending vs RPM' table if you double them values it will enter DFCO twice as quick by the looks of it.
Quick question, when in Open Loop is the MAF used in any calculations at all?
The thing is with runnine lean, or even rich for that matter is that it woundt [pass the emmision test, too lean I think produces NOx gas. When I'm due for an emmision test I'll put it back in closed loop and put the cats back on.
My next thing is to work on DFCO to reduce the entry time. Looks like its the 'Entry Blending vs RPM' table if you double them values it will enter DFCO twice as quick by the looks of it.
Quick question, when in Open Loop is the MAF used in any calculations at all?
