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Not sure what I've done but I have had no luck getting it to start again. I've loaded my original tune without the VE adjustment and made sure the MAF pin was set correctly but the car just keeps cranking.

Just giving this one a bump incase you still need assistance.

Maybe it is worth posting your tune and a log of cranking to rusEFI.com/online and posting a link?

Hopefully someone will be able to take a look through and advise some things that may help you get unstuck.

Hi guys,

Can anyone check out this log and help me with no start?

Log: https://rusefi.com/online/view.php?log=196

Tune: https://rusefi.com/online/view.php?msq=481

Thanks, hoping to get this running soon.

I see perfect cranking RPM. I see that RPM does not go above cranking i.e. engine does not even attempt to start.

it could be more or less anything

please confirm that you have spark. please try running on starting fluid. at this point it could really be anything. fuel pump is controlled by vane door. MAF moves so vane door is probably controlling the fuel pump.

Hi Andrey,

I hope you are doing well! I want to add that the car runs perfectly fine when I put the stock ECU back in, so I don't think it's a spark or fuel delivery issue, I'm thinking it's something with the tune or board?

Thanks

starsky wrote: ↑

Sat Aug 28, 2021 8:02 pm

it's something with the tune or board?

I agree completely that it looks like something with the tune or board.

in order to isolate what it is "something" with the tune or the board my suggestion is to check if you get spark WHILE RUNNING THIS TUNE AND THIS BOARD.

In my opinion it would also be valuable to see if car would fire up on starting fluid while same running this tune and this board.

at the moment I am trying to collect more data. "Does not start" is just too many possibilities unfortunately need a way to narrow it down.

Ok, I was able to get it to start, after 3 cranks, ran rough.

Please see logs and tune:

log: https://rusefi.com/online/view.php?log=335

tune: https://rusefi.com/online/view.php?msq=631

Thanks for the help!

What has changed?

Please remind what wideband controller are you using and if it's wired somehow into rusEFi

I reset the board to the base map, corrected the MAF pin as suggested earlier in the thread and let the car warm up really good with the stock ECU.

I currently do not have a wideband installed, it's running on the stock o2 sensor.

Thanks,

Ok, so it runs, thats good. Now you MUST get a wideband installed before moving forward. You wont have any way of knowing what the engine is doing so you can tune it.

Ok thanks, I actually have an AEM wideband AFR gauge installed for my future turbo project, I just have to wire the output to the o2 wire going to the ECU.

I did make one interesting discovery doing some research. My miata is a 1993 California model. Apparently this 93 CA model is the first 1.6 miata with stock sequential fuel injection, and is different from all the other 93 1.6 federal models outside of California. This was due to California's emissions requirements.

Here is a quote from the miata.net forum:

"1993 California Miatas were the first to use sequential fuel injection. The ECU, front wiring harness, and fuel injection harness are all different from the Federal Miatas (which did not change to sequential injection until the 1994 model)."

So is it possible, that my MRE ECU is not running smooth due to this? Can the tune be configured for the sequential fuel injection, and more importantly does the pinout still work?

Thanks!

This is golden info! This totally looks like a possible explanation!

I see that https://rusefi.com/online/view.php?msq=631 is already set as if injectors are wired individually.

Ask #1: please post a picture of the top-right corner of your rusEFU ECU let's confirm how jumpers are set

Ask #2: with ignition key ON and car NOT running please use "bench test" buttons and tell us if you hear injectors clicking when you click all four buttons or else.

Do you mean top right with the connector pointing up or down?

Thanks

Note the difference between https://github.com/rusefi/rusefi/wiki/Hardware/pnp_microRusEFI_48na/Whole_PCB_top_view_0_4_NA6.jpg and https://github.com/rusefi/rusefi/wiki/Hardware/pnp_microRusEFI_48na/Whole_PCB_top_view_0_4_NA94.jpg in the "fire extinguisher" general area.

I assume that your board is set more like 93. it sounds like your board would have to be set more like 94.

Here is the pics of my board.

Next step Ask #2: with ignition key ON and car NOT running please use "bench test" buttons and tell us if you hear injectors clicking when you click all four buttons or else.

See also https://github.com/rusefi/rusefi/wiki/Miata-NA-48-pin-board-for-MRE#jumpers

Do you have a link for your 93 wiring diagram just to confirm that it looks like 94? We can assume where injectors 3 and 4 are wired but better not to assume.

Thanks, I will do the bench test a little later, still pretty early here in CA

So I have not had luck finding a 93 California specific ECU diagram, but I think I may have found the answer on Flyin' Miata's Voodoo box installation instructions on page 2 and 3.

https://www.flyinmiata.com/support/instructions/ecu/Voodoo_Box_new.pdf

"90 - 93 cars (except for 93 California cars): These cars will only use two injector wires,
not four. This is because Mazda designed these cars to run batch injection (not sequential),
meaning that two injectors fire at a time. On the earlier cars, just ignore two of the injector
wires, per the wiring instructions."

On page 3 it shows:

90-93
blue / white: yellow, pin 2U
grey / white: yellow with black stripe, pin 2V
green / white: not used, except 2Y on 93 CA cars
brown / white: not used, except 2Z on 93 CA cars

and the 94/95 cars
blue / white: yellow, pin 2U
grey / white: yellow with black stripe, pin 2V
green / white: green with white stripe, pin 2Y
brown / white: green, pin 2Z

So I would assume 2Y and 2Z on my 93 CA would give me sequential?

Thanks again!

Also found on the MS3X pinout:

Ok guys I hooked up the MRE48 again and did the Bench Test, I can hear clicking injectors when I went through each one. I just can't tell which ones are clicking.

Can I try moving the jumpers?

Success!!

I removed JP58 and JP59 and jumped JP53 and JP57

Set my injector settings to sequential.

It started right up, and sounded much better (normal) than before.

Log: https://rusefi.com/online/view.php?log=337

Tune: https://rusefi.com/online/view.php?msq=634

My next steps:

- Configure for MAP and run the vacuum line (easy since I already have a boost guage)
- Run my AEM AFR Wideband to the o2 Sensor wire and configure
- Kia TPS

Thank you for all the help thus far!

That's great! And news to us that the 93 CA is different

When I want to change to MAP, is the only setting I change in "Base Engine Settings > Fuel Strategy > Speed Density" ?

I am finally going to be able to start learning TunerStudio now that the car is starting properly!

Yes, to run with the MAP sensor (as opposed to MAF), you want "speed density". You'll of course need to mess with the VE table, as that'll be completely different in SD.

Andrey,

The 5V USB power through 2J works for me (in the MRE48 page it says it was untested), I plan to solder a permanent Micro USB female plug to the harness so that I don't have to worry about cutting a hole in the cover or vibration causing strain on the Micro USB port on the board it's self.

I was able to get a really good deal on a used boomslang harness, which will let me experiment/swap/add connections without cutting into my OEM harness and from the comfort of a workbench

Hi All,

My car is officially turbo'd with a GReddy turbo kit. I would like to look into deleting the AFM and I have some questions:

I'm assuming the fuel pump pins have to be jumped at the connector?

If so, does the MRE ECU control the fuel pump or should I look into an aftermarket fuel pump relay that reads RPM?

Thanks and Happy Holidays!

I bet your MRE has a lot of unused outputs, rusEFI can totally control your fuel pump relay as long as things are wired

The firmware has a section for the fuel pump control that will allow the ecu to power the fuel pump relay for priming and then whenever it sees rpms. I believe you need to go from 2T on the ecu to 2O on the chassis side. Easy with your boomslang. Then jumping the maf connector.

BeerMoneyMotorsports wrote: ↑

Tue Nov 23, 2021 5:52 pm

The firmware has a section for the fuel pump control that will allow the ecu to power the fuel pump relay for priming and then whenever it sees rpms. I believe you need to go from 2T on the ecu to 2O on the chassis side. Easy with your boomslang. Then jumping the maf connector.

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Awesome! This is exactly what I was looking for. Does this feature have to be "turned on" software/firmware wise or is it on by default? Thanks

Im not sure on your base map. You will see Fuel Pump under the Base Engine menu.