VL RB30ET cold start issues

[Dtaranto]

Hi guys,

Hopefully someone can help with my cold start issues.

Basic specs:

Built engine
Ported head with Crow TX1 cam, springs and 1mm o/s valves and lifters and studs
Spool Forged H Beam rods
Ross Forged Pistons
8.8:1 compression
ATR43VLT (GT3076R .82 spec) turbo
3” dump pipe and exhaust with hi flow cat
APG FFP Intake manifold (deleted iacv and AAC)
Plazmaman 72mm tb
BPP fuel rail and Bosch 1000cc injectors
GFB adjustable FPR
Walbro 460lph pump
Z32 MAF
NISTUNE computer
All new sensors, dizzy, leads and electrics checked over by auto elec

I’ve attached my tune and two logs from driving.
Car made 281rwkw at 17.5psi

In the log (1209_43) at around 12 mins onwards I started driving.
I thought it may have been a cold start problem where I needed to get the car to warm operating temperature (60* or more) but that didn’t change it, it was missing and running rough even after idling for 12mins.

I then started driving out the driveway and it stalled. (I have to clear dtc codes to start the car again or it will just keep cranking. Codes are neutral position switch and speed sensor)
I thought those codes could be causing this but apparently neutral switch does nothing on a type 1 board. Not sure if speed sensor has relation to this.

I continued to drive down the road missing and backfiring for about 1 minute then like magic it clears itself up and runs fine. Seems to have full power, and will continue to start for the rest of the day first hit of the key until left overnight then the problem starts again.

This is the problem I keep continually having.
Seems to be overfueling on cold start up as every time I pull the plugs they are completely black. It also sprays fuel out the exhaust on initial cold start every time.

The second video is later in the day giving it a few hits of throttle if anyone wanted to reference that as it was running fine then as it’s warm.

RB30 281rwkw .bin

(32 KiB) Downloaded 159 times

Nistune_2022-02-26_1209_43.csv

(1.56 MiB) Downloaded 183 times

Nistune_2022-02-26_1404_10.csv

(640.3 KiB) Downloaded 159 times

[Dtaranto]

See below dyno sheet and picture of engine setup.

[Matt]

Having a look over things
1. Cranking battery voltage is a bit low. Suggest charging your battery (9.6V). Otherwise things like this can lead to board corruption

2022-02-28 14_23_53-Nistune [VLT (RB30ET) FP1_ Flex Fuel + Launch Control (Version_ 1)].png

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2. I've mentioned in the emails it is best to modify the fuel map values directly, rather than hack the VQ map.

2022-02-28 14_28_03-Nistune [VLT (RB30ET) FP1_ Flex Fuel + Launch Control (Version_ 1)].png

(13.43 KiB) Downloaded 793 times

This may be how you do things with HP tuners on other cars, but is not the proper way with the Nissan ECUs

2022-02-28 14_29_07-Nistune [VLT (RB30ET) FP1_ Flex Fuel + Launch Control (Version_ 1)].png

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You did mention that altering the fuel map made no difference. That doesn't make sense. Try adjusting a block of cells at the highlighted load/rpm point, and watch the trace window (injection time) rather than only the AFRs

2022-02-28 14_29_59-Nistune [VLT (RB30ET) FP1_ Flex Fuel + Launch Control (Version_ 1)].png

(25.74 KiB) Downloaded 793 times

Logs show that the STFT is continuously pulling out fuel (24%) so you base mixtures are either not correct, or the O2 sensor has an issue reporting too rich

2022-02-28 14_31_20-Nistune [VLT (RB30ET) FP1_ Flex Fuel + Launch Control (Version_ 1)].png

(36.37 KiB) Downloaded 793 times

O2 feedback kicks in at 30degC. So that is not directly related to the cold start issue

2022-02-28 14_32_58-Nistune [VLT (RB30ET) FP1_ Flex Fuel + Launch Control (Version_ 1)].png

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Before / after 60 degC switchover point, the injection time looks the same

2022-02-28 14_33_54-Nistune [VLT (RB30ET) FP1_ Flex Fuel + Launch Control (Version_ 1)].png

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2022-02-28 14_34_28-Nistune [VLT (RB30ET) FP1_ Flex Fuel + Launch Control (Version_ 1)].png

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1000CC injectors are large ones to run on a dual driver RB30 ECU ( 2 x 3 banks)
https://www.nistune.com/index.php/faq#general12

Note: VLT RB30 ECUs use twin bank sequential/batch injection modes which switch at preprogrammed RPM/load limits so usually a suitable injector is recommended (about 440CC GTR - 850CC maximum recommended). We have run higher (1200CC) but switch points need to be moved so larger sizes should be avoided in this case

[Matt]

Perhaps for now disable your O2 sensor (unplug it, set the temperature to 120degC, burn and restart the car). I see a lot of 'staircasing' of the STFT going on here



Set up the base mixtures again (so around 40-48 load point, 2000rpm hold) and mixtures should be stoich (14.7:1 AFR)

Note: Temp enrich table only gets used upto 80degC
With Z32 MAF I tend to have to modify the lower end of the map to assist with idle (this was before feature pack)

I have to clear dtc codes to start the car again or it will just keep cranking. Codes are neutral position switch and speed sensor

That doesn't seem right. Maybe your board has got corrupted. It should not be necessary to clear the codes

apparently neutral switch does nothing on a type 1 board. Not sure if speed sensor has relation to this.

Neither of these really affect injection on this ECU, so not a problem

I continued to drive down the road missing and backfiring for about 1 minute then like magic it clears itself up and runs fine.

what point is that in the log? Timestamp?

Not having AFRs in the logs makes it a bit tricky to see what is going on

One thing I did find. These switch over points are crazy:

2022-02-28 14_44_41-Nistune [VLT (RB30ET) FP1_ Flex Fuel + Launch Control (Version_ 1)].png

(16.02 KiB) Downloaded 791 times

Set them to 354, 455 and the temp back to 60 (or change say to 70 for experiment to see if this matches when you have the issue)

Those numbers are 270CC/1000CC injectors to readjust where the batch changeover happens

[Matt]

LMK how that goes. If still an issue, needing to reset the DTC codes, then maybe the board needs to be reflashed

[Dtaranto]

Having a look over things
1. Cranking battery voltage is a bit low. Suggest charging your battery (9.6V). Otherwise things like this can lead to board corruption
2022-02-28 14_23_53-Nistune [VLT (RB30ET) FP1_ Flex Fuel + Launch Control (Version_ 1)].png

Will do. Terminal was loose just noticed that.

2. I've mentioned in the emails it is best to modify the fuel map values directly, rather than hack the VQ map.
2022-02-28 14_28_03-Nistune [VLT (RB30ET) FP1_ Flex Fuel + Launch Control (Version_ 1)].png
This may be how you do things with HP tuners on other cars, but is not the proper way with the Nissan ECUs
2022-02-28 14_29_07-Nistune [VLT (RB30ET) FP1_ Flex Fuel + Launch Control (Version_ 1)].png

You did mention that altering the fuel map made no difference. That doesn't make sense. Try adjusting a block of cells at the highlighted load/rpm point, and watch the trace window (injection time) rather than only the AFRs
2022-02-28 14_29_59-Nistune [VLT (RB30ET) FP1_ Flex Fuel + Launch Control (Version_ 1)].png

My tuner advised he did do that and watched pulse width and it didn’t change it.

Logs show that the STFT is continuously pulling out fuel (24%) so you base mixtures are either not correct, or the O2 sensor has an issue reporting too rich
2022-02-28 14_31_20-Nistune [VLT (RB30ET) FP1_ Flex Fuel + Launch Control (Version_ 1)].png

O2 feedback kicks in at 30degC. So that is not directly related to the cold start issue
2022-02-28 14_32_58-Nistune [VLT (RB30ET) FP1_ Flex Fuel + Launch Control (Version_ 1)].png
Before / after 60 degC switchover point, the injection time looks the same
2022-02-28 14_33_54-Nistune [VLT (RB30ET) FP1_ Flex Fuel + Launch Control (Version_ 1)].png
2022-02-28 14_34_28-Nistune [VLT (RB30ET) FP1_ Flex Fuel + Launch Control (Version_ 1)].png
1000CC injectors are large ones to run on a dual driver RB30 ECU ( 2 x 3 banks)
https://www.nistune.com/index.php/faq#general12

Note: VLT RB30 ECUs use twin bank sequential/batch injection modes which switch at preprogrammed RPM/load limits so usually a suitable injector is recommended (about 440CC GTR - 850CC maximum recommended). We have run higher (1200CC) but switch points need to be moved so larger sizes should be avoided in this case

[Dtaranto]

Perhaps for now disable your O2 sensor (unplug it, set the temperature to 120degC, burn and restart the car). I see a lot of 'staircasing' of the STFT going on here



Set up the base mixtures again (so around 40-48 load point, 2000rpm hold) and mixtures should be stoich (14.7:1 AFR)

Note: Temp enrich table only gets used upto 80degC
With Z32 MAF I tend to have to modify the lower end of the map to assist with idle (this was before feature pack)

Will give this a go and see what happens thanks.

I have to clear dtc codes to start the car again or it will just keep cranking. Codes are neutral position switch and speed sensor

That doesn't seem right. Maybe your board has got corrupted. It should not be necessary to clear the codes

apparently neutral switch does nothing on a type 1 board. Not sure if speed sensor has relation to this.

Neither of these really affect injection on this ECU, so not a problem

I continued to drive down the road missing and backfiring for about 1 minute then like magic it clears itself up and runs fine.

what point is that in the log? Timestamp?

Not having AFRs in the logs makes it a bit tricky to see what is going on

I will go through the log tomorrow and find it. But basically from 12 mins onwards once you see the rpm increasing from idle to cruise (3500rpm+ going through the gears), within two minutes of driving the car then ran fine.

One thing I did find. These switch over points are crazy:
2022-02-28 14_44_41-Nistune [VLT (RB30ET) FP1_ Flex Fuel + Launch Control (Version_ 1)].png

Set them to 354, 455 and the temp back to 60 (or change say to 70 for experiment to see if this matches when you have the issue)

Those numbers are 270CC/1000CC injectors to readjust where the batch changeover happens

I changed the batch switchover as per advice from a tuner that has found that sometimes works better from -10*. My tune I was running before this with the standard 60* batch changeover the car ran the same. See attached.

rb30 281rwkw.bin

(32 KiB) Downloaded 176 times

[Matt]

Setting to 10 makes it happen all the time. It was the other two numbers I was concerned about. Depends if you have latest feature pack on the board or not. Older boards don't have batch added in (only added in the last few years)

[Dtaranto]

Ok will adjust those numbers as advised.

Pretty sure I have downloaded the latest feature packs.

On the second tune I posted, do they have the crazy numbers in batch inject high and low?

[Dtaranto]

Hi Matt,

Was planning to make those adjustments today.

Decided to upgrade my fuel pump wiring as my 15a fuse had started to melt due to the bigger intank pump.
Ran a 30a rated wire with fuse to pin 30 on fuel pump relay and removed the factory 15a fuse and left the rest as standard.

Took the car for a test run before making any ecu changes to check my wiring. Strangely it started with minimal missing. Could barely notice it was missing. Start driving at 2:33 of the log. Car felt like it was running smooth at 3:10 onwards.

At 5:59 on the log I came on boost in second gear had full power all the way to about 5800rpm went to shift to third and power cut out.
From then it was low powered wouldn’t come on boost again.
Got home and car stalled.
Checked for boost leaks etc and all looked fine.
Struggled to start, would start but wouldn’t idle. Was holding accelerator but would not increase in throttle, just stayed at like 1500rpm and if I took my foot off throttle would just stall.

Then adjusted high and low batch injection to what you advised and temp to 60. No difference trying to start. If anything was getting worse.
Disconnected o2 and set temp to 120, no difference.
Although these adjustments may not be making an effect as something else is wrong.
Reset back to the tune I had originally and car is the same.
Now will start and just stall.

Could you look at that log and see if you can notice what happened?

1636-55 is trying to start it after the power cut.

[Matt]

At 5:59 on the log I came on boost in second gear had full power all the way to about 5800rpm went to shift to third and power cut out

You maxed out the MAF voltage (5.11 is the maximum)

Capture.PNG

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[Matt]

I think you still have some electrical issues

If you look at your log at 1.48 the battery voltage is stable, and MAF voltage is well... ok

but after this point the battery voltage starts dropping, and the MAF and injection time, and RPM all go all over the place. Then it clears out around 2.47 and goes to normal

This is before the 6:01 mark where you are maxing out the MAF

You still have some wierd electrical issue going on. The trace goes all over the map from this point. So you have an intermittent problem. Even around 6:14 the battery voltage drops again

Check alternator wiring, battery arounding to chasis etc

[Matt]

another snapshot

[Dtaranto]

I think you still have some electrical issues

If you look at your log at 1.48 the battery voltage is stable, and MAF voltage is well... ok

but after this point the battery voltage starts dropping, and the MAF and injection time, and RPM all go all over the place. Then it clears out around 2.47 and goes to normal

This is before the 6:01 mark where you are maxing out the MAF

You still have some wierd electrical issue going on. The trace goes all over the map from this point. So you have an intermittent problem. Even around 6:14 the battery voltage drops again

Check alternator wiring, battery arounding to chasis etc

Thanks Matt.

I will check over all electricals and let you know what we find.

Maybe the recent change of a higher flowed cat and upgrade fuel pump wiring has let the car make more power.

So you’re saying I need an upgraded MAF, something like the hpx1? What is the z32 maf usually rated at in rwkw?

[Dtaranto]

Looking at a couple logs, I’ve reached over 6.0 volts on several occasions.
It didn’t max out/power cut then, how does that work?