CA18DET deceleration issues

Nistune topics specific to the 6802 cpu

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mattlovo
Posts: 8
Joined: Fri Jan 01, 2016 10:56 pm

CA18DET deceleration issues

Postby mattlovo » Mon Oct 02, 2017 8:26 pm

Hi guys,
I have a stock CA18DET with a GTX2863 and 550cc R35 injectors.
ECU is
Car idles fine and drives fine except when off throttle. AFRs are good in boost and on cruise.

Upon releasing the gas pedal, there will be a pulling sensation as the engine rpm drops and AFR runs into rich 10s before going to 22.
Once it reaches idle rpm of 1k, it will snap out of that deceleration mode. If you add gas to it while the engine is deceleration, rpm goes up and it smoothen out then goes back into that draggy feel as it drops again.

Not sure if it has to do with timing.
No error codes. Done my boost leak test as well.

Any input is appreciated =)

louiswun
Posts: 217
Joined: Tue Apr 07, 2009 1:11 am
Location: Hong Kong

Re: CA18DET deceleration issues

Postby louiswun » Wed Oct 04, 2017 1:45 am

what injector latency on your setting , me and my customers are running the same injectors, usually 850ms works fine.

louiswun
Posts: 217
Joined: Tue Apr 07, 2009 1:11 am
Location: Hong Kong

Re: CA18DET deceleration issues

Postby louiswun » Wed Oct 04, 2017 1:52 am

most of my tuned CA18 do the same, when let off throttle, not just R35 550cc injectos, AFR runs into rich to around 13s before going to 22, R32 444cc do the same thing, no matter how I try different setting, the off throttle fuel cut always delay a hair, what I thought is the injected fuel on the runner wall wetting, while throttle closed, it consume the rest of the fuel on the runner, but most others newer ECU like S13 SR or S14 SR does not have this symtom.

Matt
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Re: CA18DET deceleration issues

Postby Matt » Wed Oct 04, 2017 4:39 pm

Can we have a log file please with AFRs included showing the issue?

mattlovo
Posts: 8
Joined: Fri Jan 01, 2016 10:56 pm

Re: CA18DET deceleration issues

Postby mattlovo » Thu Oct 05, 2017 11:10 am

Hey matt, will get to it.
I am lacking the db9 male to connect the innovate to it.

Louis, k values and Injector latency same as yours.
Cruises and accelerates well. Only on deceleration, it's rough.
Tapping the pedal when decelerating results in a slight jerk.
Clutching in when decelerating (zero gas pedal) results in a clunk as well. Doesn't clunk or jerk when u let the rpm fall to near 1k rpm before your clutch in.

Rpm still does that dip to 500 600 rpm in free rev.

Tps shows idle switch engaged and neutral switch ok.


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