R32 RB26 - After start timing advance vs. temp

Nistune topics related specifically to the 6303 cpu

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moltenice
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Joined: Mon Oct 12, 2015 12:53 am

R32 RB26 - After start timing advance vs. temp

Postby moltenice » Tue Jul 24, 2018 1:28 am

Lately I've noticed my R32 GTR has trouble staying running after cold starting. It will fire fine when cranking, but I have to give it some throttle to keep it idling until it warms up a bit.

I'm running the attached Feature Pack bin file. I noticed during logging that the After start timing advance vs. temp table doesn't seem to be accessed. I distinctly remember in the past (possibly before installing the Nistune board? Can't quite remember) that the timing after start would be advanced by the amount in this table, and I could watch the amount of advance decrease as the car warmed up until it reached the base 20 degrees of timing at around 70 degrees ECT, which matches the values in this table.

My min/max warmup timing temp parameters are both set to -50 (I think this is the default for feature map packs?). I tried increasing the max warmup timing temp to see if it would affect this issue, but nothing changed. Is there anything else I'm overlooking? I've also attached a log file for reference.
Attachments
20180723_read_from_car.bin
(32 KiB) Downloaded 15 times
NIStune_2018-07-23_2247_53.csv
(79.6 KiB) Downloaded 9 times

Matt
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Re: R32 RB26 - After start timing advance vs. temp

Postby Matt » Tue Jul 24, 2018 12:42 pm

AFRs in your log are showing super lean idle (18.4:1) which would be causing your main issues

Warmup timing tables seem disabled (from temp max settings) and its sitting on 20 BDTC at around 36 degC so looks like its using the idle/decel tables (rather than closed loop idle target RPM table)

I would look into why at this time you are getting such lean mixtures, and what those look like once car is warmish (around 80 degC coolant temp)

moltenice
Posts: 3
Joined: Mon Oct 12, 2015 12:53 am

Re: R32 RB26 - After start timing advance vs. temp

Postby moltenice » Wed Jul 25, 2018 2:32 am

Thanks for catching that, Matt. I wasn't watching my wideband during that log. As it turns out, the wideband configuration I had loaded was incorrect. Once I loaded the correct configuration the wideband shows the car idles at around 14.2-14.3:1, as seen in the attached log. Not sure what's going on with the richness towards the end with the strange short term fuel trim, though; my factory narrowband sensors are disconnected.

This time I also noticed that during log playback, the After start timing advance vs. temp table is highlighted green, but when actually recording the log, it wasn't. Below is when I was recording the log:
screenshot.png
screenshot.png (102.61 KiB) Viewed 366 times

But, if I pressed the accelerator slightly, the after start timing advance vs. temp table would be highlighted, and then immediately turn white again once I let go and the TPS idle indicator lit up. Any ideas?
Attachments
NIStune_2018-07-24_2128_16.csv
(442.41 KiB) Downloaded 10 times

Matt
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Re: R32 RB26 - After start timing advance vs. temp

Postby Matt » Wed Jul 25, 2018 1:43 pm

STFT/LTFT may change when outside closed loop mode on some ECUs. This is not indicative of an actual trim however (so can be ignored). I've noticed some ECUs will change these settings for acceleration enrichment for instance

With the table highlighting, the software looks at the consult inputs (start switch, neutral switch, TPS idle etc) and then will change table highlighting based on those inputs. Its a best guess representation of which tables are used. That may fluctuate on when and where you click in the log, so don't use that as a definitive 'its using that table'

moltenice
Posts: 3
Joined: Mon Oct 12, 2015 12:53 am

Re: R32 RB26 - After start timing advance vs. temp

Postby moltenice » Fri Jul 27, 2018 1:12 am

FYI for anyone with a similar issue: After messing around with some settings, I found that returning the Warmup timing temp min. value from the feature pack default of -50 to 30 seems to fix this issue. The car now adds timing at low coolant temperature and removes it as it warms up.

The Warmup timing temp max. and Warmup timing RPM max. tables seemed to have no effect, so set them to 31 and 500, respectively. Wasn't sure if having the max. temp below the min. would mess anything up so I erred on the safe side. I didn't have time to actually drive the car so I don't know if the actual warmup timing table is now effective again or not, but hopefully the RPM max value will keep it ineffective.


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