disabling lean spool
 

Hi Guys,

Now we all know about using the min/max rpms to disable lean spool.

But has anyone found anything about using Periphery 0xFBA bit 0 (ie 0x1) to enable/disable it?

Cheers
David

If I am not mistaken, Lean spool is there to compensate for EGR solenoid opening,
the EGR can be disabled via bit 12 in Periphery 0 (faa), I cannot confirm that bit 0 of Periphery1 (fba) has this effect.

On an evo 7 ecu, changing the above along with 0xFCA bit 0, doesn't fully disable lean spool.

It does to a certain extent, but it also mess's with the comms to the ecu.

i.e you can't read or clear DTC's.

So I would imagine the same would happen with the 8 and 9 ecu's.

I can't remember if I have tested only changing 0xFBA bit 0 or not though.

why FCA?

I tested FBA this morning - no discernible difference between using the RPM method and fba_bit0.

if anyone wants I can post up the XLS with the two logs.

I havn't tested setting the RPM's back to default and using bit0, however the code indicates once you set bit0 the RPM's are no longer even checked.

I think from pure ECU performance perspective we will get more cycles available by disabling FBA bit0.

It was something I was told to do, before we found the lean spool start and stop address's.

But as said, it messed with the comms in the ecu, so you couldn't check or clear dtc's.

I have the original mod using addresses 1285 and 1281 documented in PD1's thread. I think I will put it back to stock and just disable it through the periphery bits though.

1285 and 1281 are the direct byte addresses for lean spool.

Since all Evo ECU's use words we change that to 1284 and 1280 (using a word size).

Its more consistent and just better...

But yes - I think if we use the FBA bit0 method from now on it will become even simpler.

For the 96530006 ROM I see the Lean Spool bit labelled as Bit 7 in FBA.

Yeah I queried that in the thread about bit's.

I think its wrong.

Alright - so I changed my rpm's back to default 2500/7000 and left the bit disabled. and my AFR stayed the same.

I think we should make this the preferred method for disabling lean spool.

If anyone else with a 7/8 ROMID wants to give this a go then that would be great :)

and it was definitely bit 0 not 7?

yup. 0x0009 -> 0x0008

I will be disabling my buddy's 8 tonight but it was previously/currently enabled. I cant wait to start from square 1 on the fueling again :crap:

And this will reduce the amount of time the ECU wastes doing calculations that no one uses anyway correct?

yeah...