Need a second opinion/look at cruise log....

[Dustin792]

Hello everyone,

Here are my engine specs:
CA18DET (using Feature Pack 1)
800cc Deatschwerks low impedence injectors (currently set to 800us)
Z32 MAF Sensor (authentic)
HKS SSQV Recirculated BOV

So I have some questions about the current tune I am working on and was hoping someone could take a look at my .bin and log I have attached for any possible issues before I start going further along(log is at 2000 rpm, cruise, 3rd gear. Have only worked on idle and cruise so far).

1a) I noticed my engine will idle low when cold(650rpm and rich around 11.5), shouldn't the O2 closed loop kick in and raise the idle higher to warm the engine before it drops down to a reasonable idle?

1b) O2 sensor is reading when engine is cold but does not oscillate until warmed up, is this normal?

**Note: When the engine finally warms up it will idle around 650 to 800 rpm but the if I press the gas and leave it, it stalls. Also when warm it has 14.7 AFR.

2a) Figured I would get a decent amount of fluctuation in terms of AFR and short term trim(long term trim not showing, not available for CA18DET?), at cruise but are these values in the 14.7 AFR and 0% trim for cruise good or do I need to do adjust TIM more? Also for what its worth the cruise power band felt good.

2b) If the cruise tune looks good should I go back and readjust injector latency to acquire a better idle? If so should this most likely help with the stalling at idle or will it take more manipulation later on?

3) I do not have the neutral safety switch wired up, can this create issues with idle or does the idle switch on the TPS sensor handle all of that alone?

BTW, this is the setup I am running, I realize that the BOV is not recirculating back to the turbo, but it is away from the MAF is this setup ok? Also I boost tested to 25 PSI without any leaks.

recirc-BOV-cropped.jpg

(1.61 MiB) Downloaded 1104 times

I appreciate the help just want to make sure I am taking the right steps here.

[Matt]

1a. Closed loop only starts working about 65-70degC and normally I don't see it operating at idle. Watch your STFT to see if this is happening. I'll add LTFT as an extra parameter for 1.3.30 when it is released

1b. Yes as per above. It will oscillate (closed loop) once it hits the above temps. Looks like it is doing that in the log

Try disconnecting the O2 sensor and reset LTFT by disconnecting the ECU and see if it still has 14.7:1 AFR with no trims (no closed loop)

2a. Not avaialble at this time. I've just found it (yesterday!) after some research and added it to the firmware. I've put in a hotfix into the software to read this from boards without it in the firmware for next release. See here:
viewtopic.php?f=7&t=3799

2b. Of cruise mixtures look fine and STFT is near 0% then maybe adjust latency. Its currently at 800uS which isn't that high but the timing/AAC are responsible for maintaining idle control too

3. Yes I think this might contribute. The vehicle thinks it is 'in gear' if it is not seeing the neutral input. It might not be entering idle closed loop mode, so fix this if possible

4. Normally the idea with a BOV is to vent pressured airflow back into non-pressured (before the turbo). By putting the BOV pressured airflow back into post turbo pressured airflow as it is trying to release pressure is interesting... you are basically feeding it back into itself in the same pressure stream. Really should be before turbo on the non pressure side

[Dustin792]

Thanks for the quick reply Matt, you've been very helpful.

So I think my best bet is going to be fixing that neutral switch and getting that BOV recirculating to low pressure. I basically was just working with what I already had available to me, but this makes to much sense to not fix...

Then I will go ahead and reset trim and unplug O2 and see if I am still running 14.7:1.

I guess this is just a check to make sure that mixtures and trim are still good without O2 connected?

and if mixtures and trim are not good should I be making adjustments with the O2 unplugged until they are?

[Matt]

If you unplug the O2 sensor and reset the ECU (remove the ECU for several hours, or disconnect battery) then there will be 0% to long term trims so when you get in the cruise area it will be 14.7:1 AFR when you have base mixtures set correctly

Once I get LTFT reporting in the next version then you can monitor that afterwards and double check that there is not much change to the trims as it starts learning

[Dustin792]

So I went to go about trying to wire up the neutral safety switch and noticed the wiring specialties PRO harness I have does not come with a neutral safety switch harness at all so I emailed them asking why they decided to leave it out and they basically said it doesn't have any significance toward the EFI system and therefore they leave it out on all of there PRO harnesses. So looks like that isn't a concern on the CA18DET and most likely other Nissan engines they provide PRO harnesses atleast.

Also I did get around to resetting the ECU O2 fuel trims and at cruise(with the O2 sensor unplugged) I adjusted TIM until I was at 14.7 AFR(it was a but rich), plugged in the O2 again and now STFT is reading high like 20%(I think it may still be relearning....didn't let it run too long yet, but hopefully it goes down again).

correct procedure, or did I bust that up? Either way I will have to look again after LTFT is avail. Thanks for the help again...This build is just gonna take forever, already come to terms with that!

[Matt]

doesn't have any significance toward the EFI system and therefore they leave it out on all of there PRO harnesses

This is not completely true, and they should have added it. The neutral switch may not be 'significant' but it does make the ECU switch to other maps and will affect things like idle hold up when in going into gear. Nissan added a bunch of code and maps which are based from neutral switch selection (or not selected)

Neutral switch will stop VCT working on later model ECUs if it is enabled

STFT is quite short in its measurements (like within 20 seconds) where LTFT will move 1% for each cycle of STFT

Just try for 14.7:1 AFR without the O2 connected for now. At least you know it is right without the narrowband then readjusting things

[Dustin792]

Had a feeling that maybe they decided to just leave the switch out, but I appreciate the clarification....Maybe I will look into wiring it up. The 200SX CA18DET FSM I have has the neutral switch going to an inhibitor relay, but I think that is for the auto trans...does the manual trans neutral switch just wire directly to the ecu?

[Matt]

I don't have the FSM for that one but probably does. An example of neutral used for limiters here

Code: Select all

A2FC : D6 53 		" S"		ldab	DIGITAL_CONTROL_1
A2FE : C5 40 		" @"		bitb	#$40
A300 : 26 16 		"& "		bne	BRA_A318_Neutral
A302 : C5 04 		"  "		bitb	#$04
A304 : 26 0A 		"& "		bne	LA310
A306 : B1 BB 36 	"  6"		cmpa	XBB36
A309 : 25 0D 		"% "		bcs	BRA_A318_Neutral
A30B : B6 BB 36 	"  6"		ldaa	XBB36
A30E : 20 08 		"  "		bra	BRA_A318_Neutral
				;
A310				LA310:
A310 : B1 BB 37 	"  7"		cmpa	XBB37
A313 : 24 03 		"$ "		bcc	BRA_A318_Neutral
A315 : B6 BB 37 	"  7"		ldaa	XBB37
A318				BRA_A318_Neutral:
A318 : C5 10 		"  "		bitb	#$10
A31A : 27 38 		"'8"		beq	BRA_A354_Higher_Idle_RPM_Limit
A31C : C5 44 		" D"		bitb	#$44
A31E : 26 0A 		"& "		bne	LA32A
A320 : B1 BB 38 	"  8"		cmpa	RAM_BB38_Idle_Speed_RPM_Limit
A323 : 24 2F 		"$/"		bcc	BRA_A354_Higher_Idle_RPM_Limit
A325 : B6 BB 38 	"  8"		ldaa	RAM_BB38_Idle_Speed_RPM_Limit
A328 : 20 2A 		" *"		bra	BRA_A354_Higher_Idle_RPM_Limit