11p 3 Bar over fueling

[PaulR]

Hi everyone been using 11p stuff for a while but first time using a 3 bar map. So want to get some thoughts on what's happening it seems when the ecu reads over 200kpa it wants to dump extra fuel like over 20%. In the photos of the log before and after it crosses that point can see the injector BPW goes right up. I haven't touched the boost multiply table but I have leveled out the VE table. The car is a VS 5L with a sidemount blower and as the boost drops when it changes gears the BPW drops back down.
Monitor 1 red -rpm, blue -2 bar map, green -boost multipler. Monitor 2 red -tps, blue -current ve, green -injector bpw, light blue -target afr, light geen -wideband.

[antus]

Boost support is a bit hacky because the ECM was never designed for it. I cant remember perfectly the details but I think the boost fuel is calculated in part with a hard coded multiplier based on sensor type. This is to keep the rest of the code happy and keep the operating code in 8 bits which the hardware platform requires in places. So you will see more fuel as VE continues to rise even with a flat VE. I think "Something" is hard coded differently after the cross over above 200kpa. Check the tune is configured for the right MAP sensor anyway (sounds like it is), check tunerpro is showing 200-300kpa in the boost VE table, and then tune the ve down at that point to get the tuning right. Because the increase is hard coded I am 99% sure you are not missing a setting and will still have repeatable results when your tune is run in different weather.

Edit: Having said that I went and checked the code, and I cant see anything that should specifically change at the 200kpa mark. The 2/3 bar code mearly halves the values in the boost VE, or leaves as it for 3 bar, so the above does not explain why there would be a sudden fuel spike at 200kpa. Having said that, its all a bit black magic to be sure...

So, if you havnt looked at map voltage maybe check that and make sure the map is giving you analog increate in voltage with boost, incase there is something odd about the sensor. If anyone else has any ideas, it'd be interesting to hear them. But if you find nothing else and can tune around it, that may be the outcome.

This is from an earlier version of 11P which I have on hand, but it should be the same.

Code: Select all

	;**********************************************
	;
	;	  Boost Multiplier Determination
	;
	; Call with: 
	;	Nothing
	;
	; Returns With:
	;	Nothing
	;
	;**********************************************
BoostMultiplier:
	brclr	*L000D,#0xC0,BstMultClr	; Branch If 1 Bar Sensor In Use And Clear Multiplier
					; Else...	
	; ------------------------------
	; -- 2/3 Bar Boost Multiplier --
	; ------------------------------
	ldx	#Boost		   ; Boost Multiplier Vs MAP (100-200kPa or 100-300kPa)
	ldaa	BoostLV			; Boosted Filtered MAP Load Variable
	cmpa	#160			; Check If Less Than Max
	bls	BstMultLK		; Branch If < And Lookup
					; Else...
	ldaa	#160			; Use Max				
BstMultLK:
	jsr	L59CC			; Call 2d Lk Up
					;	X = Addr of table 
					;	A = Independent Var, (offset = 0) 
					; 	A = Results 
	; ----------------------------------------------------
	; -- To enable 0-100% and 0-200% Boost Comp With no --
	; -- cal changes the table by default has 0-0xFF    --
	; -- Linear. With 2 bar sensor halve this so 0xFF   --
	; -- becomes a 100% multi. XDF adjusts calc to suit --
	; ----------------------------------------------------
	brclr	*L000D,#0x40,BstMultEnd	; Branch If 3 Bar Sensor In Use And Skip Div
					; Else...
	lsrd				; Div 2
	bra	BstMultEnd		; Branch Over CLear
	
	; ---------------------------
	; -- 1Bar Boost Multiplier --
	; ---------------------------
BstMultClr:
	clra				; Clear...
BstMultEnd:
	staa	Multi   		; Boost Multiplier
	rts				; 
					; 
	;**********************************************