Understanding Decel Enleanment settings in 12P

[Charlescrown]

Can someone enlighten me on the decel enleament settings in 12P.
The reason I ask is when tuning my car it goes super rich when I back off to the point of lower than 10:1 and off the scale.
I would think that if it's working it should show a very lean reading.

[Holden202T]

does your log show 20kpa on decel, and if so what is the 20kpa column like, in a stock tune its way lower than the column beside it ... ?!?!

[VL400]

There are a few things at play with DE and DFCO. The VE still needs to be set in that area as it is still the basis for calculating the inj PW.

As you initially lift off the throttle the closed throttle and high vacuum pulls any condensed fuel from the intake walls and/or vapour from the plenum. This can often show as a rich spike. In 12P and 11P this is referred to as manifold fuel, the ECU tries to calculate what it thinks is condensed and then when AE and DE are started takes this in to account as extra fuel not delivered by the injectors.

DE is triggered from throttle movement (Decel Enleanment Param - DE delta throttle angle threshold,), after other conditions are met will then got to DFCO which will show as a lean area and 0 inj PW. DFCO needs a speed sensor installed, DE does not.

If you want to disable DE, max out "Decel Enleanment Param - DE delta throttle angle threshold" and then get your VE closer. Shouldnt have to play with other settings once the VE is done. Once your done set "Decel Enleanment Param - DE delta throttle angle threshold" to 0.03 as it can help with fueling during general running, the TPS can hover between two values causing light DE while cruising.

Can see here, top monitor green TPS stable with blue inj PW stable. TPS starts to flick between 9.4 and 10.2 % and from the 4min mark DE started changing the inj PW. Bottom monitor has blue wideband AFR showing what happens. Changing the DE throttle angle threshold to above 0.01 fixes it.

DE.png (37.29 KiB) Viewed 4174 times

[Charlescrown]

Thanks for the advice. I looked at the log and the MAP does not go below 25 but I have some serious lean areas on acceleration so I best concentrate getting that right before I start being concerned with decel. The problem I have is this engine is throttle body and there is no change in fuel pressure till boost starts. I tried to find a Camira TBI XDF but no such luck. I did see where you can change the ECU file to an XDF with Tunerpro but every time I tried Tunerpro stopped working. I wanted to see what the VE tables looked like on a TBI engine. I can assume quiet a bit different to a Multipoint.

[VL400]

If you have not done so already, remove the cyl select jumper on the NVRAM board to enable TBI mode and halve your injector rate in the cal. This injects fuel on every reference pulse instead of every second and will help with AE and general fueling.

When the engine is running and your logging you will see the cyl flags in list view, memcal selection will have nothing next to them and the bin setting will say 4 cyl still.

[Charlescrown]

Unfortunately I don't have a Nvram (yet) so I have to log and change. I already have it on the fire every rev setting. I used a bin file I have almost got right from my other car with the same engine but in multipoint and as the injector flow rate is not definite (I used the settings from my old Adaptronic ECU) I found it was extremely rich to the point of not running. I dropped the VE values as well as the injector flow rate and it now starts easy, idles nice but is lean when I accelerate but I am getting there. The first drive it just stalled and after raising the VE table it's getting better and better.