Waveing AFR and bad warm start - SR20DET S14a Blacktop

[Rev-Vid Filmwerks]

Hello guys,

I`m owning my S13 now for nearly 13 years, had done nearly 98% of the work by my own, why Im really disappointed about the mapping, which wasn´t done by myself due to lack of practise (even I'm a mechanical engineer). So first of all, the mapping was done 1 year ago, but it´s unfortunately unfinished. The boost and mid boost is finished, off boost isn't, why the engine has very high fuel consumption. I´ve driven the car only for about 600 or 700 km, because the AFR is too high for me (around 12,2 to 13). On boost, everything is fine with 11.5.

Fortunately I have a nistune licence, why I'm able to update the numbers in the fuel map and write them on the ecu. But now it's going to get a bit tricky. As I have just one lambda thread on my turbo elbow, I spoke with my tuner last year and he told me to install the wideband PLX Gauge with the Bosch LSU instead. He told me, that he will deactivate the OEM Nissan one, but I think therefore I'm facing now a problem.

So first of all, let's talk about the issues I'm facing to:

• AFR-values are waveing, which means the car is running, but the AFR values go from 12 to 13, sometimes even to 15 up to 18 or 19. I think, that it depends on outer temperature differences, due to the missing OEM Nissan lambda sensor (the PLX wideband AFR isn't connected to the ecu, but I can connect it to my pc. The guy, who tuned the ECU set off the lambda control in Nistune.

• I tried tuning the car, when I'm driving. That worked sometimes, but after a while the AFR values went crazy. My idea is, that due to the missing OEM Nissan lambda, the control loop isn't working. Right now only the ECU can work with the Z32 AFM and the TPS in terms of control loop and I think that´s the reason why the AFR values are going crazy. I assume that changing weather conditions, like driving through the warm city or driving through the cold wood, makes the difference.

• When I turn on the interior ventilation, the AFR values will change rapidly, for instance from 12 (ventilation off) to 15 (ventilation level 3)

• When the car is warm, the start is realy bad. To turn of the car, I have to turn the key from position 0 to position 2 very fast and pumping the gas pedal a bit. Cold start is okay. I don´t know why this is happening...

Now let's go to the speclist:

- Newly built SR20DET Blacktop with original stock parts (unless otherwise described below)
- S14a ECU with Nistune type 4 board (ordered it from Matt
- PLX combination display for AFR and exhaust gas temperature with touchscreen (I managed connecting it today with my Nistune software on my PC)
- Brand new OEM Nissan ignition coils
- GK-Tech expansion tank
- NGK Iridium IX spark plug BKR7EIX
- KTS Low Down Big Capacity Oil Pan - S14 / a & S15 SR20DET
- Tomei Poncams 256 degrees (new model with modified geometry for better response)
- Tomei Nissan M32x3.5mm Forged Piston oil cap
- Tomei Expreme manifold
- Garrett GT2871R Ar0.86
- Nismo 740 sidefeed fuel injectors
- The Driveshaft Shop one-piece aluminum driveshaft incl. ABS
- 3 "from turbo - turbo knee & downpipe Japspeed
- Catback Invidia g200 with titanium end
- 100 cells cat
- HDI GT2 FMIC with high-strength clamps from Turbozentrum Berlin (tested with a little over 2 bar)
- BLITZ ZS water cooler
- OEM Nissan Fanshroud for S13 SR20DET water coolers
- Yashio Factory radiator hose (drain)
- OEM Nissan new radiator hose (inlet)
- Greddy Suction-Kit
- Z32 AFM
- Greddy Oled boost controller
- Competion Clutch Segmented Ceramic Sport Clutch
- Competion Clutch lighweight flywheel
- S14a SR20DET 5-speed
- Kazama: Shift Knob & Spin Turn Release Knob Set (S13 / S14) 5-Speed
- Nismo 32839-RN540 Solid Short Shifter
- Nismo reinforced engine mounts
- Nismo reinforced transmission mounts

I wrote it in the list, but here again. Today I managed connecting my PLX wideband and EGT with my Nistune on my Laptop. Is there a possibility, to fix the above listed problems? I`m considering to do the "auto adjustment AFR" for the low TPS map area.

I remain at your disposal!

Best regards from Germany!

[Matt]

Just wrote a big reply, but lost it, so here we go again

Vehicle: S14A SR20DET 740CC/Z32 MAF

Please post tune file (or email to me) and also log files showing the issues

I´ve driven the car only for about 600 or 700 km, because the AFR is too high for me (around 12,2 to 13)

AFRS should be around 14.7:1 when cruise (around 1/4 load and 2000-3000rpm steady load)

AFR-values are waveing, which means the car is running, but the AFR values go from 12 to 13, sometimes even to 15 up to 18 or 19

This is a problem. Need to trace the AFRs and see where the mixtures are where, log file will show this. Where is the 18-19 on deceleration?

My idea is, that due to the missing OEM Nissan lambda, the control loop isn't working

Watch from the log what the trims are doing. If they are near 0% then should be 14.7:1 AFR. Also sensors get old and dont work properly. Normally about 80,000kms is their life

When I turn on the interior ventilation, the AFR values will change rapidly, for instance from 12 (ventilation off) to 15 (ventilation level 3)

This is my main concern. Electrical problems will cause all sorts of issues. Sort this firstly. Check grounding and electrics. Check no change when headlights on, AC and fan systems on/off. Monitor log during changing these condiitons

Make sure you are getting 14.7:1 at cruise firstly. Disable O2 feedback if you think the sensor is a problem. You can also use the 0-1V output from wideband units and feed into your narrowband ECU input

[Rev-Vid Filmwerks]

Cheers Matt,

thank you for your fast reply! After I started this topic, I managed to connect the PLX AFR and EGT gauge with Nistune. But let's go ahead and share some results.

Today a friend and I had a ZOOM session and this was the result:

• Please find attached the log file, you will find the issue of waveing/Jumping afr values

In the attachments you'll find some screenshots in comparison mode and of course a log file. A lot of values were far from Nissan OEM settings, why we decided to update them to the stock ones. Now the start works without any issues, but my AFR-values are jumping/waveing. The log file was recorded after we changed the values to OEM NIssan.

What do you think Matt? If you want, I can share my map directly with you via PM.

Take care.

Ps. I will have to post more than just one post, because of attachment limitations (3 pcs)

[Rev-Vid Filmwerks]

Further attachments:

[Rev-Vid Filmwerks]

Last but not least. Furthermore you'll find the log-file here. Drove max. 1,42 bar in the highway once (1:42 - 1:52 min). Rest was driven without pushing the gas pedal too much.

[Matt]

Thanks for the update

Posting the BIN file is more useful than the logs, that way I can trace the tune with the log file

What we can see is the entire tune is around 10-11:1 AFRs which means that you need to think about reducing the total injection muliplier (around 10-20%)

Then monitor your log around cruise. Around 2000rpm at 1:00 in the log we see here around 10:1 AFR, so want about 14.7:1 AFR

I can see it a little wavering but it is very rich

[Rev-Vid Filmwerks]

Hello Matt,

I appreciate your support, thanks a lot!

Regarding the .bin file- are you talking about the map? I can share it with you by mail. Could you please give me your address?

It is really annoying to have rich AFR, while driving the car off boost (which corresponds to 80-90 % of my driving profile). Do you have Zoom? Otherwise we can meet there and talk about the issue, while you take a look on the map.

Best regards, take care!

[Matt]

We don't offer individual tuning advise. We do provide documentation on our website including a tuning guide which runs through how to make changes to setup for your tuning. These forums offer more specific advise where you have a particular issue

As mentioned before, it appears your whole map is rich. Get the vehicle at cruise (around 2000rpm) and check the mixtures here. If they are too rich then pull back TIM/K until it is stoich (for your base mixture settings)

Then adjust the rest of the map after

Yes the BIN file is the effectively the maps. My email is info@nistune.com