Sunday, December 13, 2009 - 09:07 am, by: Cihan Aday(Cihan)
Damian Ware wrote on Saturday, December 12, 2009 - 10:26 pm:
What makes you think it does Cihan?
Does dyno tuning experience count or should i just take your word for it?
TPS = Green INJ DURATION = Yellow RPM = Red Notice what happens to the yellow line when the green line goes to zero. (White box)
Box 1 - throttle deadband for re-engagement. Box 2 - enough throttle is applied, injection commences again. Box 3 - TPS goes to zero but RPM is under fuel cut re-engagement limit. No decel cut occurs.
Notice the RPM blip up when injection commences post deceleration fuel cut in box 2. This is what Peter feels.
The example above is from a 91 UZZ30 3 plug ECU, tuned with an Emanage Ultimate using the Etuner S1 turbo kit. The 'feature' still works without the AFM connected.
Sunday, December 13, 2009 - 01:13 pm, by: Damian Ware(Frozenpod)
That is very interesting Cihan, with a 91 V8 factory ECU with all sensors connected I have not seen this happen.
I have tested 10 or so ECUs in more than one car and found them to regulate under closed loop to stoich AFR even under decelleration. Where as my N16 pulsar will run 17-21:1 AFR under the same test and sometimes the AFR reading will go of the scale lean.
I have also used a CRO (on my own cars) to see that injection stops on the pulsar but doesn't stop on the 1uz. Sure the 1uz injection pulses under decelleration are very minimal and they are probably the same size as the typical injection lag but it doesn't completely stop and it still maintains with the AFM connected stioch mixtures.
I believe this feature was only added in with the 94 update but I have not tested a 94 to find out.
As per the above log the pulsar also requires a bit more than low to idle RPM to run fuel cut and it drops out of fuel cut mode at about 1400-1500rpm.
Perhaps with the AFM disconnected combined with modified output of the EMU (I assume due to the larger injectors and AFM disconnected significant fuel trimming) this results in zero injection under those conditions.
Sunday, December 13, 2009 - 05:53 pm, by: Damian Ware(Frozenpod)
Matt Petersen wrote on Sunday, December 13, 2009 - 02:06 pm:
leans out heavily at idle
This is a sign that your wideband is being effected by air and is not measure exhaust gases correctly which is very common under light load and idle conditions if they are not located correctly.
Sunday, December 13, 2009 - 07:23 pm, by: Cihan Aday(Cihan)
Damian Ware wrote on Sunday, December 13, 2009 - 01:13 pm:
Perhaps with the AFM disconnected combined with modified output of the EMU (I assume due to the larger injectors and AFM disconnected significant fuel trimming) this results in zero injection under those conditions.
No, box 2 & 3 wouldn't be possible if that was the case.
Its obviously deceleration fuel cut activating, all the signs are there.
Sunday, December 13, 2009 - 09:27 pm, by: Damian Ware(Frozenpod)
So the setup is not remotely close to factory with the factory sensors used for fueling no longer being connected.
Hardly a reasonable comparsion to make to a stock setup.
With the factory ECU running as factory with all sensor connected under deaceleration the factory ECU maintains a stoich mixture. I have tested this again tonight just to make sure and it does maintain stoich an indication that the factory ECU is not shutting off the injectors completely.
There is a small blip where it appears as though the injectors are being shut off or running very minimal duty cycle with a very rapid change in TPS. After this blip less than 1 second the AFR returned to stoich.
The test was done by accelerating to 100km/hr locked in second gear then backing off to zero throttle and gradually slowing the car to a complete stop over a period of about 10 seconds. RPM range was about 5000 to idle.
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