03 350Z - First tune from a first timer

[Adamw]

On 5/14/2022 at 7:33 PM, Timboj said:

The issue I'm dealing with now (I don't think it was introduced with the previous fix) is I'm experiencing momentary rev spikes shortly after coming off the throttle and disengaging the clutch. You can see here:

Sorry for the slow reply.  It looks like it is related to the dashpot to me.  I find it difficult to tune dashpot remotely from logs as the RPM doesnt always respond how your intuition says it should.  I usually, have a page set up with a time plot with RPM & idle target overlayed, then a few basics like idle position, idle status, idle ign running live.  Give the throttle small blips watching how the RPM comes back down to idle and tweak one of the dashpot settings at a time until you see little undershoot and little rebound.  I think it is mostly your decay value, but you really just need to experiment.   

Example page set up below.  This log was from our LS3 race car.  It is showing return to idle before dashpot tuning, 400RPM undershoot, then a 400rpm overshoot afterwards. - but you can see the throttle and ignition timing is sitting relatively still during this big oscillation - it is not caused by anything the ecu is doing, it is just some pressure wave dynamics in the large plenum.  The pink line I have drawn on is the hold period and the green line is the decay period.  dashpot offset is small.  

 

 

 

And here are a couple of blips after 10minutes of dashpot tuning.  Since it is a race car I was happy enough with that.  You can see how different the hold and decay periods are (plot time scale is roughly the same) and offset is quite a bit bigger.

 

[Timboj]

@Adamw Thanks a bunch. I'll give that a shot.

Nothing to apologise about. I was just worried I'd broken a cardinal rule lol

[Timboj]

On 5/18/2022 at 2:10 PM, Timboj said:

In the meantime, I was going to repurpose pin 16 on the main ECU harness for my AEM oil pressure sensor gauge (I'm using An Volt 8 for fuel pressure already). Which ground pin would you recommend connecting the negative wire to? Exp 1, 78? Doesn't matter?

Any advice on this one, guys? Cheers

[Adamw]

Yep that would be fine.  If your fuel pressure sensor already has a ground and 5V wire then it might just be easier to splice into those.  

[Timboj]

Thanks Adam. Now to figure out how to pull the ECU harness apart...

[RobPhoboS]

Hey Tim - just wondering if you've wired your IAT sensor in yet ?
I'm presuming you'll do what I intend to do, chop off the MAF plug and repurpose it for the IAT ?

I'm just trying to do a little homework on what the pinout might be for the MAF, I've only found this old thread:
https://my350z.com/forum/tuning/572332-iat-and-mafs-terminals-pinout.html

[Vaughan]

6 hours ago, RobPhoboS said:

I'm just trying to do a little homework on what the pinout might be for the MAF

Maybe try looking at the wire colours out of the ecu and matching them up to MAF wires?

[Timboj]

@RobPhoboS Not yet, mate. I've got a few weekends of distraction ahead of me and then I'll begin installing the blower. At that point I'll be doing exactly what you're doing.

That said, I've got my ECU connector opened up right now so when I get a moment I'll see if I can ID the colours.

@Vaughan Speaking of, I'm trying to add my oil pressure sensor to the G4x. It's via an AEM X-series gauge (30-0307) which has 0-5V analog + - out. I spliced + into pin 16 (An Volt 11) and - to pin 78 (Ground 02 signal).

The ECU has recognised it, but it's reading too high. At cold start it's reading 120psi, where the gauge is reading closer to 80. As it warms up I'm seeing ~80 on the ECU and ~50 on the gauge. You get the idea.

My fuel pressure sensor shares the same voltage/pressure scaling (which you can see above is correct for the supposed voltage) so I've set them both to reference the same calibration table:

Any idea what's going on here? Is this an issue with my chosen negative pin?

[Timboj]

Assume you guys are already across this but just in case:

[koracing]

On 5/27/2022 at 2:16 AM, Timboj said:

Any idea what's going on here? Is this an issue with my chosen negative pin?

Your 150psig pressure sensor should show 0kpa at 0.5v and 1034kpa at 4.5v (1034kpa = 150psig).  I think it's just  a units issue.

[Timboj]

Thanks for the reply but I'm not sure that's the issue (happy to be corrected though)? You are correct though that my output values are PSI not kPa. I couldn't find a way to change this scale to imperial while I use metric for everything else.

However, the scale is set by the 0.5 input = 0 output and 4.5 input = 150 output. The units shouldn't matter because the ECU isn't making a calculation based on the output unit, that's just for the end user to derive meaning from the value.

Output value unit could be "Ham sandwiches" as long as the scale is set correctly.

[koracing]

If you disconnect the wires from the ecu do you get the same voltages as are being logged by the ecu on AN volt 11? 

Doing a little quick math as I noticed AEM offers a 100psi x-series gauge as well as a 150psi, the value offsets you are reporting are almost dead on if your sensor is 100psi, and not 150psi.  Perhaps the sensor/gauge was mispackaged?

3.7v would be 120psi on the 150psi gauge, and 80psi on the 100psi gauge.

2.5v would be 75psi on the 150psi gauge, and 50psi on the 100psi gauge.

Also if you want to see a kpa input sensor in psi, you can always do the conversion on a math channel so the data would be *more* accurate - but that's probably more personal preference than anything if one isn't doing anything critical with the data.

[Timboj]

You could be onto something there, Kris. When I've got a moment I'll check my sensor voltage coming into the gauge vs what's going out and try a few grounds.

I'm keen to hear back from Link though as to whether my chosen pins would meet AEM's criteria for an Analog + and - connection, or whether it's a potential cause for incorrect voltage reading.

[koracing]

I think your pins should be just fine - analog input and signal ground originally for the LF o2 sensor.  

[Adamw]

Yes the pins are fine.

[Timboj]

On 5/29/2022 at 12:19 PM, koracing said:

If you disconnect the wires from the ecu do you get the same voltages as are being logged by the ecu on AN volt 11? 

Doing a little quick math as I noticed AEM offers a 100psi x-series gauge as well as a 150psi, the value offsets you are reporting are almost dead on if your sensor is 100psi, and not 150psi.  Perhaps the sensor/gauge was mispackaged?

3.7v would be 120psi on the 150psi gauge, and 80psi on the 100psi gauge.

2.5v would be 75psi on the 150psi gauge, and 50psi on the 100psi gauge.

Also if you want to see a kpa input sensor in psi, you can always do the conversion on a math channel so the data would be *more* accurate - but that's probably more personal preference than anything if one isn't doing anything critical with the data.

Well this is embarrassing- it IS the 100psi version... Good eye, Kris.

A while back I'd downloaded AEM's user guide for the 150psi version, then I was so fixated on the digital readout I wasn't even looking at the analog dial... which only goes to 100psi...

That is some shocking attention to detail on my part.

I even spent a week or so trying to find where and what I'd ordered but nothing was coming up in my emails or my usual suppliers. Only just a moment ago I found it in my Amazon orders from 2020.

Anyway, thanks Kris. And thanks again for answering the stupid questions @Adamw

 

 

[Timboj]

Gauges working as expected now, thanks. I switched my gauge digital units and analog face to bar so at least there's some consistency.

Back to tuning- I've just started playing around with the dashpot so I'm hoping to get some results out of that soon.

I've got another couple of issues that I'd love some input on.

The first is my "idle" getting stuck at around 16-1700rpm. This happens with high frequency and will stay this way until I start to put load on the engine. Letting the clutch out ever so slightly (and briefly) is my workaround at traffic lights. This issue was occurring long before I touched the dashpot settings and is still happening after (I've only adjusted dashpot hold and decay between 0.5-2 secs so far).

 

 

The other issue is holding certain throttle positions is giving me unstable revs:
 

 

 

Any clues? Tune and logs here https://drive.google.com/drive/folders/1D8cuVWkbfangLsQ3i5Etf3kp4LqwyD--?usp=sharing

 

[Electredge]

3 hours ago, Timboj said:

Gauges working as expected now, thanks. I switched my gauge digital units and analog face to bar so at least there's some consistency.

Back to tuning- I've just started playing around with the dashpot so I'm hoping to get some results out of that soon.

I've got another couple of issues that I'd love some input on.

The first is my "idle" getting stuck at around 16-1700rpm. This happens with high frequency and will stay this way until I start to put load on the engine. Letting the clutch out ever so slightly (and briefly) is my workaround at traffic lights. This issue was occurring long before I touched the dashpot settings and is still happening after (I've only adjusted dashpot hold and decay between 0.5-2 secs so far).

 

The other issue is holding certain throttle positions is giving me unstable revs:
 

 

Any clues? Tune and logs here https://drive.google.com/drive/folders/1D8cuVWkbfangLsQ3i5Etf3kp4LqwyD--?usp=sharing

 

Raise RPM Lockout Above Target - From 500 to 1000

[Timboj]

Thanks @Electredge I made the change and took it for a quick drive. The idle didn't hang like it was so we're on the right track re the first issue.

With the undulating rpm at a static throttle position, is that the closed loop lambda hunting (too much), or ignition timing changing too sharply across cells, or something else entirely?

[Adamw]

7 hours ago, Timboj said:

The other issue is holding certain throttle positions is giving me unstable revs:

This is due to Bank 1 intake cam bouncing around, bank 2 isnt great either but is probably usable.  I suspect you are going to need to use the custom PID option to get better control.  Possibly oil is a different viscosity to recommended or something.  

[Timboj]

Damn, didn't see that one coming. I've been using 5w40 for 10 years and never had an issue.

They're the original solenoids, any chance just getting old and need to be replaced?

[Timboj]

@Adamw I've gone back to my original map from the tuner it appears to have fixed the issue, while reintroducing some other behaviours I'd been slowly addressing.



VVT lockout is working as expected at 1200rpm and both banks are much more aligned. Looks like it was a setting (or multiple) that was causing the problem.

[Adamw]

Its still a long way off target in some areas though, I wouldnt really call that "working as expected", not even really acceptable.  

You can use the file compare function to see the difference between the two maps.  Still needs PID tuning.  

[Timboj]

Thanks @Adamw I'm going to leave this one to the next dyno tune.
 

PID tuning is a new concept to me, so just for my own understanding I went back to my pre-dyno tune maps (my home tuning) and the VVT data looks much the same (significant delta between target and actual), so there's been no real change to my VVT settings other than the target angle table.

If I'm understanding this correctly, my tuner should've picked up on this issue? Is PID tuning the cam phasers normal?

[Timboj]

I posted in 'Engine Tuning' but haven't had much of a response there.

I'm hoping for some guidance on basic configuration changes I need to make to safely get up and running after installing a super charger (low boost), ID 1050X injectors, GTR coils and E85.

If needed I'm happy to spend some time manually road tuning as I've done before, but I've read that people have had positive experiences in using Quick Tune on the road as well. Appreciate Link's input in particular on this.

I'm currently on a traditional Fuel equation, but maybe this is an excuse to move to modelled now?

I have a regulated return fuel setup, so it looks like I can use a 2D table for dead times based on voltage alone.

 

My current thought process is the following:

1. Set Stoich ratio to 9.733 (and udpate all settings in Fuel Main)
2. Set new injector dead times (@300kPa base)
3. Set injector flow rate
4. Set Pulse Width Adder figures
5. Turn off closed loop fuel trim
6. Start engine
7. Set fuel pressure with no vacuum @300kPa
8. Dial in idle
9. ...

Remaining questions:

• What am I overlooking above?
• Should I make a blanket adjustment to my fuel table (divide by xx) to account for larger injectors
• Similarly, should I make a blanket change to ignition timing?
• Do I leave coil dwell times at stock values?
• Without knowing my Fuel Charge Cooling Coeff, is 10C fine to leave until it's dynoed?