[rusEfi] 2004 Mazda MX5 1.8 VVT #50

What engine are you torturing? Is it inside some car?
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russian
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Re: 2004 Mazda MX5 1.8 VVT #50

Post by russian » Sat Aug 31, 2019 6:41 pm

Now that I am thinking about it I an not 100% sure if I got MIL to work on NB2 :( I know it's just a trivial low side driver on NA6 but no idea what's the deal with NB2 :( Need better record keeping :(
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Re: 2004 Mazda MX5 1.8 VVT #50

Post by Crazy Striker » Sat Aug 31, 2019 6:45 pm

Mine works but is very very shy, the light is very weak.
It's actually on 5v I think, maybe 12v is the answer but I don't want to burn it...

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Re: 2004 Mazda MX5 1.8 VVT #50

Post by russian » Sat Aug 31, 2019 7:59 pm

What does the wiring diagram say? I would expect it to be low-side driven, not high side driven?
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Re: 2004 Mazda MX5 1.8 VVT #50

Post by Crazy Striker » Sat Aug 31, 2019 8:59 pm

On the 2003 Miata page low side driver is specified, but on the 2003 alt which is working for me it's stated that high side driver should be used. So as I see it it's just a question of switching the wiring to an unused low side driver.

Will try that tomorrow eventually and give you some feedback on it. It would be great to change the wiki page for that

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Re: 2004 Mazda MX5 1.8 VVT #50

Post by russian » Sat Aug 31, 2019 9:38 pm

Crazy Striker wrote:
Sat Aug 31, 2019 8:59 pm
On the 2003 Miata page low side driver is specified, but on the 2003 alt which is working for me it's stated that high side driver should be used. So as I see it it's just a question of switching the wiring to an unused low side driver.

Will try that tomorrow eventually and give you some feedback on it. It would be great to change the wiki page for that
In my opinion this is a vague post. Is this about MIL? Alternator? What are the URLs of the pages you are referring to? Are you trying to report an issue? Please edit your post and provide a bit more details.
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Re: 2004 Mazda MX5 1.8 VVT #50

Post by Crazy Striker » Sat Aug 31, 2019 9:44 pm

https://rusefi.com/wiki/index.php?title ... Miata_2003 is the one stating low side should be used for CEL.

https://rusefi.com/wiki/index.php?title ... a_2003_alt is the one referring to high side driver for CEL. I used the wiring diagram from this one to build my harness and most of functions are correctly wires, but obviously not for the CEL. It glows very poorly following this wiring diagram.

I will try the low side driver tomorrow as stated by the first link and report results

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Re: 2004 Mazda MX5 1.8 VVT #50

Post by Crazy Striker » Tue Sep 03, 2019 7:45 am

So I tried the low side driver for the CEL and it is not working. Seems it should be driven using +12V as +5V seem to barely light the bulb.
As I'm dur to a 1000km trip next friday to get hoem I will not be able to test it anymore until mid September.

I had one or two questions still.
Is your engine able to idle without the IAC with the stock Throttle body idle screw settings ? I need like 30% of duty cycle for the RPM to stay at 800rpm approx, and on the stock ECU the idle is kinda instable. I'm starting to think my throttle body bypass screw is clogged up...
Otherwise, for the auto idle, do anyone have approximative PID ans such values that would work on a NB2 miata ? I tried but it was pretty instable with what probably was a positive feedback loop. I studied PID quite a lot so I understand what had to be changed but I couldn't get it to stabilize...

But so far I'm so happy of how everything turns out, I'm considering building another rusefi one day so that I can make a clean one using a reflow oven.
@russian what method do you use to place and solder components for your kits ? SMD stencil, solder paste and oven ?

Gwendal

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Re: 2004 Mazda MX5 1.8 VVT #50

Post by russian » Tue Sep 03, 2019 2:19 pm

Something is weird with that MIL, you are confirming my vague recollection :(

At the moment there are some discussions of better idle control in the 93 miata thread and in Slack chat.

I order assembled Frankenso from China, I hate soldering.
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Re: 2004 Mazda MX5 1.8 VVT #50

Post by Crazy Striker » Tue Sep 03, 2019 2:25 pm

Oh so you use pcb assembly services, what website are you using for that purpose ? I was considering getting into microrusefi but I'm not sure about the number of available low side outputs if I want to get into weird things like water/meth injection. I could as well use an Arduino over CAN but I would prefer it to be controlled by rusEFI 😅 The other option is to design a new pcb suited for my needs which considering the amount of work you've already put in validation of used technologies should be quite easy too but time consuming.

I definitely need to get into that slack thing, I'll look for that

I think it's just some lack of usage which led to the MIL issue. It would be easy to test with a paper clip and the stock harness. You plug the pin to gnd, then to 5v then to 12 v and we should have our answer. Unfortunately I can't work on that this week but as I saw you are working on the VVT test mule 😉

Cheers

Gwendal

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Re: 2004 Mazda MX5 1.8 VVT #50

Post by russian » Fri Sep 06, 2019 3:06 am

Just checked: check engine light is dim if connected to +5v and bright if connected to GND. This tells me it's a +12v bulb with LOW side control.
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Re: 2004 Mazda MX5 1.8 VVT #50

Post by Crazy Striker » Wed Sep 11, 2019 7:37 pm

Hi all !

I'm slowly preparing the "beast", starting by the fabrication of mechanical parts. After receiving the piping I cut steel for supercharger flanges and started welding today. Considering I discovered welding this morning the result is pretty good. It was done using stick (MMA) then TIG to solve small issues. I just need to cut and Weld flanges for the BMW ETB that I received today and the supercharger bypass, as well as the supercharger bracket.
One of the machinists is gonna turn my pulley so that it fits the supercharger.

For the software part I need to configure the ETB control, I received the VSH2SP30 H bridge modules. Are they driven through the PWM input ?

Cheers

Gwendal
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Re: 2004 Mazda MX5 1.8 VVT #50

Post by russian » Wed Sep 11, 2019 9:30 pm

Did you decide to keep mechanical throttle body? We shall chat about this. I am afraid if the struggle would be to pass all the knowledge related to ETB tinning, we have next to zero documentation on how to get a nice bias curve and nice PID settings
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Re: 2004 Mazda MX5 1.8 VVT #50

Post by Crazy Striker » Wed Sep 11, 2019 9:32 pm

Yup I'll leave the mechanical TB on the stock position, so it can eventually act like a failsafe.

For the TB I'm ready to try it out, I can try to tune the PID using an arduino before so that I can write a code quickly

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Re: 2004 Mazda MX5 1.8 VVT #50

Post by Crazy Striker » Sat Sep 14, 2019 4:49 pm

Hi all !

Today I had the opportunity tu try rusEFI on another car and I'm quite pleased about how it worked out. A friend of mine with a 2002 1.6 Miata has a possible alternator issue, the regulator doesn't regulate well and it sends 17v in the battery when running over 5k rpm...

So to sort out if it was his alternator or his ECU I plugged in the rusEFI without MAP or any computer and the car started right away, running a bit rich because of the 1.8 tune but overall it was fine. And considering I was still seeing 16.5V on the battery terminals I think the issue has been ruled out...

So very pleased to see it's so much reliable 😅

For now I can't use rusEFI on my car because I'm already struggling with the incoming inspection and emissions issues (no cat for now)... But as soon as I pass this part I swap my injectors for yellow RX8 and plug rusEFI in. Auto-tune will do the rest.

Gwendal

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