CA18DET deceleration issues

Nistune topics specific to the 6802 cpu

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Matt
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Re: CA18DET deceleration issues

Post by Matt »

Increasing latency adds fuel (0.1ms in this case) everywhere
mattlovo
 

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Re: CA18DET deceleration issues

Post by mattlovo »

HI Matt,
noted... looks like I have to redo the entire map since the deceleration/TPS on fueling is too lean and I cannot just adjust Min TP or the Injector Latency at all.

Is there another field that perhaps I am missing out in the software which I could use?
It just the deceleration in gear that is an issue sadly.
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Re: CA18DET deceleration issues

Post by Matt »

Start with what has changed from factory and why you are getting deceleration issues now. The maps which you need to be concerned with are

- K constant (adjust TP) and base fuel schedule (calculated from MAF / RPM)
- Min load TP (minimum base fuel schedule)
- Fuel map (read all the time) and added on top of base fuel scheule
- Total injection multiplier (multiply final injection time)
- Injection latency, add to final injection time
mattlovo
 

Posts: 42
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Re: CA18DET deceleration issues

Post by mattlovo »

- K constant (adjust TP) and base fuel schedule (calculated from MAF / RPM)

this is at 255, with the change in larger MAF (r35) and larger injectors (r35 as well).

- Min load TP (minimum base fuel schedule)
Been adjusting this from 800 - 1200 -1600 -2000 -2400 -2800
Values currently at 160 to 155 to ensure smooth transition from off throttle to on throttle.
Can't get the jerk off at the lower rpm range. Initially thought it was a lightweight flywheel issue, swap back to stock wheel recently.
Bogs at time when accelerating fast like a light weight flywheel is in it and RPMs seem to drop too soon) Low drives are ok.

- Fuel map (read all the time) and added on top of base fuel schedule
Fueling is good in cruise and low boost. Seldom go above 0.8 bars of boost.
Decent AFRs at cruise, about 14.8 to 15+
0.5 bars boost, about low 12s, 0.8 will see 11.8 (New walbro 255 genuine, new Tomei L FPR, new R34 fuel filter)

Running a GTX2863 with STOCK head STOCK block and STOCK internals.

- Total injection multiplier (multiply final injection time)
need to check this out...can't recall the figures.

- Injection latency, add to final injection time

Latency currently at 880ms. Idles at about 2.2 from what I saw yesterday night.



Lastly, I noticed my AAC values are showing 80 when TPS is on while decelerating from a rough range of 4000 rpm to 1000rpm. Feels like handbrake is on as the car decels. Once it drops to idle rpm of 900rpm, it will twitch back to the smooth engine idle.ACC will show 60 again.
(If I recall, ACC 80 is a value when it doesn't work)

Throttle open, AAC values go down to about 20 or less. I am not sure if its due to AAC.
Current adjustments have left the car idling with an AFR of 16-17, which is abit too lean when aircon is on.
My suspicious is on the AAC valve maxing out its duty cycles for now.
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