[rusEfi] red 2003 VVT test mule Miata NB2 #27

[AndreyB]

I've decided to unify my test fleet, please welcome this automatic 1.8 VVT 2003 Miata.

First step would be locating the OBD-II port and fixing check engine, the price considering nice interior was good to ignore the check engine light.

https://svn.code.sf.net/p/rusefi/code/trunk/firmware/config/engines/mazda_miata_vvt.cpp
http://rusefi.com/wiki/index.php?title=Vehicle:Mazda_Miata_2003

JimStim reference https://rusefi.com/forum/viewtopic.php?p=40438#p40438

Tune status:
+ stats reliably
+ stars reliably without throttle application
- 80C engine idles close to 14.7 with manual idle control
- smooth warm-up with manual idle control
- smooth warm-up with automatic idle

[stefanst]

Awesome!
OBDII Port is right above the fuse panel.

[kb1gtt]

Sweet. Is this waiting for that connector that I'm nearly done with?

Is that "drive by wire" or "drive by the seat of your pants"

[AndreyB]

First it is waiting for a spot in the garage (depends on Neon rolling out either dead or alive, hopefully alive by the end of this week), after that yes the connector would help In the mean time I will have a chance to find the ECU, it must be somewhere...

Simple throttle cable, just with a VVT on the intake side.

[AndreyB]

codes

[kb1gtt]

Sounds like an exhaust leak or an intake leak for the P0420. I've checked for intake leaks by using a vacuum to lightly pressurize the intake, then listen for whistling noises. Often people will do this with a "smoke" device. Another way to look for intake leaks on natural aspirated engines is to spray the engine with starter fluid. It will typically increase revs when you find the leak, as it sucks in the starter fluid.

Does the retarded CAM return after you clear the codes? Also when was it's timing belt last done. You had that issue with the Neon. Perhaps they just had the belt replaced and perhaps the mechanic couldn't get it properly adjusted.

[AndreyB]

Looks like p0012 pretty much means "vvt system is not happy, either o-rings are gone or just too much crap in the oil passages". Looks like first step is trying Rotella T6 high in detergents oil (dual rated but the larger label says "heavy duty diesel") to wash it out, if not swapping some rings like http://miataroadster.com/miataroadster/miataroadster-vvt-system-viton-seal-rebuild-kits/mrvvtrk/i-1964289.aspx

[kb1gtt]

seafoam is also good about dissolving carbon garbage.



http://www.kmart.com/seafoam-motor-treatment-16oz/p-02801507000P?sid=KDx01192011x000001&gclid=COTntpDpv88CFYYmhgodcKQGHg&gclsrc=aw.ds

[stefanst]

On the NB1 the ECU is under the steering column in the driver-side footwell. I believe the same is true for the NB2.b

[stefanst]

Are you going to convert to manual before going all rusefi on its' behind, or are you keeping it auto? I don't think the tranny control needs much from the ECU, so I *guess* you'd be OK keeping it auto.

[AndreyB]

I want to at least attempt rusEfi before manual conversion. But before that I need to fix VVT and ideally pass inspection

[ItaloManyak]

Check the oil pressure and o-rings if it is good then
Try to clean the valve or replace it

[stefanst]

I'm going to add my '03 (manual trans) Miata with VVT rusefi-conversion to this thread if that's OK, since there's going to be a lot of overlap.
Updated the wiki on NB2 (2001 to 2005) Miatas: http://rusefi.com/wiki/index.php?title=Vehicle:Mazda_Miata_2003
Will also add suggested wiring including WBO2 and MAP sensor.

[stefanst]

Just to make sure I got this right: The only way that the ECU know what angle the VVT is advanced by, is by comparing the CAM sensor signal to the CRANK sensor signal - correct?

[AndreyB]

The only way that the ECU know what angle the VVT is advanced by, is by comparing the CAM sensor signal to the CRANK sensor signal - correct?

that's my understanding of this, and that's the kind of logic I have for the toyota vtti.

[Abricos]

[kb1gtt]

Gotta love 3D printers.

[AndreyB]

Really confusing +12 running / +12 constant / main relay, got couple of wires wrong, diagram is a labyrinth, got tired added an unneeded wire which made power supply side really funny, nearly fried some sensors but somehow these survived, the ex-Neon board had a non functioning 5K resistor which was not used on Neon but was important on Miata... Thank you @ for doing half of the work!

But now I have both cam and crank, four injectors, fuel pump and main relay. Open question trigger shape but that should be available online.

[stefanst]

Eating burritos with @ and his wonderful wife is a real treat Thanks for lunch!

On the VVT trigger shape, I found the following on Miataturbo.net:

So it's the same as NB1 without VVT, the CAM signal just moves relative to the CRANK signal. Should be OK to run just using NB1 setup.

[Abricos]

[AndreyB]

On the VVT trigger shape

just realized that we had an NB1 running - see http://rusefi.com/forum/viewtopic.php?f=3&t=467&start=33 see http://rusefi.com/wiki/index.php?title=Manual:Software:Trigger#Mazda_Miata_NB

[stefanst]

Earlier this year we also had my NB1 running http://rusefi.com/forum/viewtopic.php?f=3&t=987

[stefanst]

Managed to simulate Miata NB2 VVT cam/crank signals with an arduino. rusefi accepts the signal and reads rpm. I can also see the crank signal moving relative to the cam signal, but am not sure how to use Miata VVT with rusefi in Tunerstudio. Will play some more tomorrow.
It only gets up to 3670rpm, because arduino is soooo slow, but it should be good enough!

[AndreyB]

Unfortunately no VVT code for Miata yet. This signal is too complex for the current implementation - current implementation only works with one teeth cam sensor (we have three) and distinct crank signal (we only have 180 degree precision, not 360 degree because the wheel is symmetrical)

I think I have a plan how to implement this trigger, I just need to sit and do it.

[AndreyB]

I've got some useful UK parts but UK-specific wiring diagram seems impossible to find

http://www.mx5nutz.com/forum/index.php?showtopic=324257

[AndreyB]

From http://www.miataturbo.net/megasquirt-18/msiii-v3-57-no-cas-cam-60824/page2/

[AndreyB]

I think VVT Miata trigger support is ready - version 20161114

Crank is primary trigger - shaft position is based on that channel. Cam sensor is only used to detect intake cam position and engine phase (that's especially important with this symmetrical shape of crankshaft pattern). Special VVT mode is needed since three teeth, CAM gap ratio setting is temporary - once we confirm the numbers on a running engine these would be hard-coded.

[stefanst]

Success!

Running the new VVT code with a stimulator we get VVT-angle feedback. We can sweep approx. 50 deg, which correctly mirrors what the simulator does. There is one issue though: The angle feedback from rusefi goes from 382deg to 432deg.
MS3 reports -5deg to 44deg.

[AndreyB]

Great news
I wonder what is the meaning of -5deg to 44, is it in relation to where cam is on NB1 maybe?

[stefanst]

My simulator has more freedom than the actual actuator on the intake cam. I believe the intake cam has a total range of 38 deg. I assume that MS3 just sets "full retard" at 0deg and "full advance" then at 38deg or so.