Accelleration and decelleration

[Lawso]

Been trying to get my head around the accelleration and decelleration settings in 12P.

The following I would assume govern the accelleration enrichment settings,

AE-AE Multiplier Vs Engine RPM Table - I would assume that the higher the number the more fuel is added according to RPM?

AE-AE Temperature factor Vs Coolant Temp - Temperature compensation

Transient - AE Fuel decay factor (% of ref period) Vs Coolant Temp - Higher number is faster decay?

Transient - AE Gain Vs Manifold Fuel - I can only assume that 'manifold fuel' is a representation of the amount of airflow? IE, the amount of throttle applied?

Decelleration enleanment

DE - DE Coolant factor Vs Coolant temp - Higher number greater enleanment?

Transient - DE Fuel Decay factor (% of ref period) Vs Coolant Temp - Higher number is faster decay?

Transient - DE Gain Vs Manifold Fuel - As above?

DFCO

DFCO Params - DFCO Upper RPM Limit - Point at where DFCO must pass this RPM to enable?

DFCO Params - DFCO Lower RPM Limit -Point at where DFCO cuts out?

DFCO Params - DFCO Max map for Automatic, Maximium map for DFCO to occur ( Auto Trans)

DFCO Params - DFCO Max map for Manual, Maximum map for DFCO to occur ( Manual Trans)

DFCO Params - DFCO Multiplier Step value - Not sure what this one does?

DFCO Params - DFCO Road Speed Threashold - Point at where below this speed DFCO is disabled?

DFCO Params - DFCO Thottle Threashold - Point at where below this throttle point DFCO is enabled?

DFCO Params - DFCO Asynch AE Multiplierto BPW - Assume that this adds fuel at end of DFCO to help recovery?

DFCO Params - DFCO Temperature Threashold - Enabled above this setting?

I ask because I have no DFCO at the moment, but I believe that I have the settings set correctly, I have too fast decay on AE, and I know that DE has to be screwing around with something...

My 20 - 40 kpa VE tables are being screwed aroud with in closed loop as under decelleration, I am not seeing DFCO or enleanment.

Any assistance would be appreciated.

[VL400]

AE ..
AE-AE Multiplier Vs Engine RPM Table - Higher the number the more fuel is added according to RPM. The vacuum factor is also part of this calc but you dont get to control that.

AE-AE Temperature factor Vs Coolant Temp - Temperature compensation

Transient - AE Fuel decay factor (% of ref period) Vs Coolant Temp - Higher number is faster decay

Transient - AE Gain Vs Manifold Fuel - Manifold fuel is the fuel condensed in the manifold ie stuck to the walls. When you give a hit of AE this gets pulled in as part of the in-rush of air.






Basics of it are in order of criteria checking..
Checks for MAP malfs - code 33 and 34.

DFCO Params - DFCO Temperature Threashold - Enabled above this setting

DFCO Params - DFCO Max map for Automatic, Maximium map for DFCO to occur ( Auto Trans)
DFCO Params - DFCO Max map for Manual, Maximum map for DFCO to occur ( Manual Trans)

DFCO Params - DFCO Thottle Threashold - Point at where below this throttle point DFCO is enabled (1.17% hysteresis)

DFCO Params - DFCO Road Speed Threashold - Point at where below this speed DFCO is disabled (5kph hysteresis)

DFCO Params - DFCO Upper RPM Limit - Point at where DFCO must pass this RPM to enable
DFCO Params - DFCO Lower RPM Limit - Point at where DFCO cuts out



Then when in DFCO...
EST params - DFCO Mode Forced Advance - locks the spark advance to this when in DFCO (If commanded is already < than this value it uses the commanded).

DFCO Params - DFCO Multiplier Step value - This is the decay value for each 12.5mS pass. Rather than just switching fuel off instantly it decays to 0 over a number of code passes. The larger the number the more rapid the decay happens.



And exiting..
DFCO Params - DFCO Asynch AE Multiplierto BPW - Adds fuel at end of DFCO to help recovery, this is an async pulse so not intime with normal injection events (just like regular AE).



If you can post a log showing when DFCO should be active will take a look.

[Lawso]

After a bit of thought, I figured out why I didn't have DFCO happening.

I had all of the requirements met, bar one. When I converted the car to a manual transmission, I had earthed the Neutral/Drive wire. The ECU would be assuming that the transmission was in park or neutral.

Removed the earth and DFCO is working.

I had noticed that in the list view, it was saying that an automatic transmission was detected.

So I guess the delco looks at the drive/neutral input when the ignition is turned on to determine which transmission is fitted?

[vn5000]

It will still use dfco with an auto but obviously not in park or neutral .Well there you go aye ,never new that .

[VL400]

So I guess the delco looks at the drive/neutral input when the ignition is turned on to determine which transmission is fitted?

Sure does

[Holden202T]

that would be spinning the ecm out, its going WTF im still in park how is there speedo pulses!

[Lawso]

It was doing some funny things.....nothing too serious though. Was driving quite well.

The lack of DFCO was annoying me and had me scratching my head for a little bit.

Just another opportunity to learn something!

[VL400]

And i skipped over that little bit when posting the above info

Code: Select all

brset	*L006B,#0x04,L9F64 	; Branch and Disable DFCO if Trans in Park or Neutral
				   	; Else, in Drive or Manual...

[VK_3800]

I've had the same issue with my VK for a while - it has a VN series 1 V6 with 5 speed manual (all original including the VN wiring). I have the genuine GM-H wiring manual and it shows manual transmission models as shorting the wire to the loom earth (as opposed to going through the park/neutral switch), this wire is also tied up with the earth for the start relay. I'm guessing that this is a slight difference between VN-VR (obviously the original tune didn't use DFCO). The easiest way to disconnect it without removing necessary earths is to un-pin the grey wire at the engine harness connector (YB62) under the dash on the passenger side near the ECU, and it now registers as manual transmission. Will be interesting to see the difference in driving it.

[jacomms]

So when looking with the Tech1 it looks as this only effects the idle up for the auto when put in gear along with the start relay.
I found years ago that when I left this out on a conversion into a HQ and over looked the wiring that the IAC was going crazy on decel pulling up at lights. Hooked the wiring in and hey presto....reset the base idle and the road test was 100%....didnt log codes or effect the driving at all......but it was a 808 not $12P/VR.

Justin