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-   -   NB VVT MS3PNP first configuration issues (https://www.miataturbo.net/megasquirt-18/nb-vvt-ms3pnp-first-configuration-issues-99960/)

KevinK121 04-26-2019 10:52 AM

NB VVT MS3PNP first configuration issues
 
Alright, got the MS3PNP installed and the base map loaded.
Nothing works of course.

2002, 1.8 VVT, NA, square top, big TB, DIY intake, deleted MAF, soldered the GM sensor to the OEM IAT wires.
AEM Uego is wired into analog 2 and EGO seems to have figured that out on its own(thought I'd have to tell it).

If there's already a guide somewhere just tell me the site and Ill go find it. I couldnt find anything directly helpful all in the same place. Much less anything specific for the vvt engine.

1) The car doesnt run for more than a few labored seconds before dying. I know this is likely timing related. I know you cant adjust VVT motors timing like the older cars. Issue is, I cant get it running long enough to verify where the timing even is. I set the table to "fixed" and 10 degrees in both required fields. What do you suggest to get it running long enough to get a timing light reading?

2) AFR is way off between the gauge and what TS is reading. While the car is off, the gauge reads 13.9 and TS sees something like 10.3. TS doesnt have the option for the AEM 30-4110 so I used the values I found Brain had mentioned. 0 volts- 10 afr and 4.75 volts- 18.75 afr(I forget what it was exactly off the top of my head, something along those lines) should have worked according what I had read but doesnt. The aem is grounded to chassis right outside of the drivers side firewall. I wasnt able to find the location where the ECU grounds. Potentially the issue, but I doubt it.

3) How might I verify the IAT is seeing the real temperatures? Or reading at all? I wasn't able to find a value anywhere for what the IAT is reading.

know its a long one, I apologize, I just wanted to capture as much of the relevant info as I could.Thanks for any input.

KevinK121 04-27-2019 11:14 AM

Additional questions that have come up.

1) why does everything say to use the 4g63 spark mode when there's a 99-05 miata option?

2) CLT thermistor. The trubokitty guide says to use the, well...

For 90-97:
From ‘Common Sensor Values’, select: RX-7_CLT(S4 & S5).
For 99+:
Temperature F / C Resistance In Ohms
14 / -10 9000
68 / 20 2500
176 / 80 320

But it doesnt state what to use as a biased resistance. There's a "Mazda" option in which the bias resistance is 5000 and the rx7 resistance mentioned is something like 2750.

This is extremely confusing and seemingly nonsensical.

3) MAF settings, I deleted the MAF like everyone else does but it still insists on trying to read the MAF in terms of voltage.

4) "The wideband needs to be grounded to sensor ground or it will be off." I dont follow. The afr is grounded to the chassis, not sure whats meant by the sensor ground.

5) How much different is the square top manifold going to affect all of this? No vics or IACV on the square top.

SpartanSV 04-27-2019 12:30 PM


Originally Posted by KevinK121 (Post 1532711)
Additional questions that have come up.

1) why does everything say to use the 4g63 spark mode when there's a 99-05 miata option?

2) CLT thermistor. The trubokitty guide says to use the, well...

For 90-97:
From ‘Common Sensor Values’, select: RX-7_CLT(S4 & S5).
For 99+:
Temperature F / C Resistance In Ohms
14 / -10 9000
68 / 20 2500
176 / 80 320

But it doesnt state what to use as a biased resistance. There's a "Mazda" option in which the bias resistance is 5000 and the rx7 resistance mentioned is something like 2750.

This is extremely confusing and seemingly nonsensical.

3) MAF settings, I deleted the MAF like everyone else does but it still insists on trying to read the MAF in terms of voltage.

4) "The wideband needs to be grounded to sensor ground or it will be off." I dont follow. The afr is grounded to the chassis, not sure whats meant by the sensor ground.

5) How much different is the square top manifold going to affect all of this? No vics or IACV on the square top.

1. Who is everyone? Don't listen to that guy he's an idiot. 4G63 is for NA miatas. Use the 99-05 miata option which your basemap was already set for.

2. Bias resistor will be ecu dependent, but is likely 2490.

3. You should be using speed density which means the MAF isn't used for anything.

4. There is a sensor ground and a chassis ground at the ecu. Ideally you want the wideband grounded to the sensor ground.

5. You'll probably need to get your MAP source from a different location than whatever the instructions indicated, but I would hope you're past that point by now. The IACV is built into the throttle body. You'll have one even if you're running a squaretop.

WestfieldMX5 04-27-2019 06:29 PM

Have you considered looking up the AFR table in Google? Took me all of 5 secs to find it https://www.aemelectronics.com/files...GO%20Gauge.pdf
IAT is easy to test. Engine off and cold, it should indicate how hot is it outside :)

KevinK121 04-28-2019 04:20 PM


Originally Posted by WestfieldMX5 (Post 1532764)
Have you considered looking up the AFR table in Google? Took me all of 5 secs to find it https://www.aemelectronics.com/files...GO%20Gauge.pdf
IAT is easy to test. Engine off and cold, it should indicate how hot is it outside :)

I did, the question was more about the ground location and how much a grounding location can contribute off numbers.


Originally Posted by SpartanSV (Post 1532722)
1. Who is everyone? Don't listen to that guy he's an idiot. 4G63 is for NA miatas. Use the 99-05 miata option which your basemap was already set for.

2. Bias resistor will be ecu dependent, but is likely 2490.

3. You should be using speed density which means the MAF isn't used for anything.

4. There is a sensor ground and a chassis ground at the ecu. Ideally you want the wideband grounded to the sensor ground.

5. You'll probably need to get your MAP source from a different location than whatever the instructions indicated, but I would hope you're past that point by now. The IACV is built into the throttle body. You'll have one even if you're running a squaretop.

Thank you very much, a cat for you!

Updated issues

We were able to verify timing today. Its fine at a zero offset under fixed table with a fixed 10*


2 big issues remain.


1) Megasquirt is not reading any MAP vaccuum. The defaults in TS havent been altered at all, we confirmed they are on the correct sensor(internal MS sensor). We verified the hose isnt pinched and we're getting a vaccuum pull off of the manifold. TS doesnt see any reading on changes at all from the port directly from the unit.

No idea here. Really hoping its some silly sensor setting and not the MS unit

2) Wideband is still reading 13.9 whether the car is running or not. TS is reading a static 10.7 whether the car is off or running.

I relocated the ground directly into the sensor ground of the MS. In TS, AFR EGO is set to the "custom linear input" with the correct volt-afr voltages. Tuner studio knows its reading EGO from the correct pin input.

Its weird to me that it reads stoich with the car off and theres no change at all when the car is running.
Its also weird that tuning studio sees a completely static 10.7 under the correct ts settings.


KevinK121 04-28-2019 10:21 PM

The hose inside the unit was kinked :vash:

Thats a big relief for starters. It starts and idles seemingly fine now.


Tried some troubleshooting with the wideband, Im not electrically inclined enough to make any meaningful deductions from the outcome.

o2 sensor plugged into gauge harness with the car off(ignition on):
Gauge: 13.9
TS: 10.5

o2 sensor unplugged from gauge harness with the car off(ignition on):
Gauge: 14.5
TS: 10.7


These were the same with the car running ^^^ neither the gauge or TS responded to throttle blips


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