BMmonteSS

Ok I want to be able to disable BLM correction on my 747 at idle. From my understanding of the Open loop idle parameters, these only modify the AFR if your in open loop. Once in closed loop there really isn't any way to completely disable the BLM correction at idle.

The code does have a Max rpm for BLM parameter, what would it take to change this simple greater than parameter to a less than parameter. Is this somthing I can do by "twiddling the bits"?

;
; CK BLM RPM QUAL'S
;
EEF7: LDAA L001C ; RPM/25
EEF9: CMPA LD29D ; 3500 RPM UPPER BLM THRESH
EEFC: BCC LEF02 ; BR IF RPM GT MAX RPM THRESH
; ... else
EEFE: ORAB #$02 ; SET b5
EF00: BRA LEF04
EF02: LEF02 ANDB #$FD ; CLEAR b1, BLM ENABLE
EF04: LEF04 STAB L000E ; A/F MODE Word Flag
EF06: RTS
;--------------------------------------------------

I've been running open loop for awhile, and the car runs great, other than getting about 1-2 mpg worse milage. Without temperature corrections and such it's hard to run the engine lean consistantly. I notice that my BLM's start out around 128 and slowly go rich by about 10 BLM on my daily commute. In closed loop this is corrected for, but not in open loop. I'm guessing it's a heat soak thing. I can't get the fueling correction to work well at idle at all, the motor just idles so much better at 13 to 1, it gets real chopy at 14 to 1, if I could keep open loop at idle and go closed everywhere else I would be good to go till the speedreader comes out.

RBob

iTrader: (1)

A nice feature of the '747 is an open loop idle mode. A lot of the big block cal's are set up to run open loop while in idle. Check some of them for the parameters. Here are the cal terms (in disabled mode):

RBob.

Ronny

iTrader: (1)

I too would like to do same just i cant comprehend code change right now.

My tunercat program has three constants that may allow me to do just that. One is Speed to Enable Open Loop Idle and that is set at 2 MPH. Another is % TPS to enable OL set to 5%. I am lost as to which way to move those constants if in fact they will allow OL idle.

It would appear i already have set them to allow OL idle?

i guess i will need to check winALDL tonight. I thought i was seeing CL idle last i looked?

BMmonteSS

I'm double checking myself tonight, I thought for sure the last time I tried it I still had CL idle.

BMmonteSS

No go on the open loop idle for me. I double checked my parameter and they are set as followed.

LD29E FCB 4 ; 4 MPH, OPN LP IDLE THRESH---------same
LD29F FCB 5 ; 2%, OPN LP IDLE THRESH TPS--------4%
LD2A0 FCB 1 ; 25 RPM, Open loop RPM thresh IDLE OFF-----1200
LD2A1 FCB 2 ; 50 RPM, Open loop RPM thresh IDLE ON-----50
LD2A2 FCB 160 ; 8 Sec's, Open loop IDLE AFR Ratio enable TIME DELAY-------0
LD2A3 FCB 100 ; 5 Sec's, Open loop IDLE AFR Ratio TIME DELAY----same
LD2A4 FCB 137 ; 13.7 Open loop AFR MAX AT IDLE---------17


It's my understanding that you set your off rpm to the upper limit and your on rpm limit is your lower limit. You have open loop idle if your RPM's are inbetween these limits, correct? I'm not sure how the max AFR works. The way I read it, if the camanded AFR exceeds this number, open loop idle is stoped. Also there is a Open loop MIN AFR at LD2A9, I assume it also plays a role here, correct?

RBob

iTrader: (1)

The RPM values are an upper and lower to go into and go out of OL idle. Try these values and see if it works:

0029E 10
0029F 6
002A0 38
002A1 48
002A2 0
002A3 0
002A4 135

The timers are set to 0, no delay. And the RPM terms are at 950 and 1200 RPM ( go in less then 950, exit above 1200, along with the TPS & MPH quals).

Then the 13.5 AFR is as lean as is allowed while in open loop.

RBob.

BMmonteSS

Ohh ok, I see where I had the rpm qualifiers confuse, and the AFR limit doesn't disable OL idle, it just caps it at a particular AFR.

BMmonteSS

Works great now, just need to do some tweaking to make it seemless, right now the BLM's will dive into the 11* range below 1600 at part throttle while I'm still moving, once I stop it goes into open loop, but it will hold the last BLM value stored in that cell. I think I'm going to disable the speed limiter and TP limit and just have it go open loop anytime it's below 1600. The way I have it set up now it idles at 13-1 and I have the right off idle cells a little rich to make up for AE. This works great in open loop, but in closed loop it tries to tune itself around this. Shouldn't be too hard to tune around.