99' MSPNP2 Blown Up Battery / Voltage Regulation Issues
 

I've already blown up my recently purchased MSPNP2 for my 99' and the main board replaced. When i got it back, I ran the car for a day on the MSPNP2 with the battery boiling over causing a rotten egg smell because it was being overcharged by the alternator. From what I understand, the stock ecu handles vreg of the car. I bought a new battery after the old one blew up from overheating (the fuel pump burst fuel lines from running off 14+ Volts) and installed the stock ECU for now and it runs perfect. I just want my megasquirt to work for more than one day you feel????? There is no setting for vreg in Tuner Studio and the board has no jumpers or dials to adjust anything related to voltage regulation. What is the fix for this problem? do i have to make my alternator internally regulated??? What am I not clearly seeing in this bullshit. Why do NA miata owners have it so easy wiring up their MS. I cant even figure out how to wire up the AEM wideband to the MSPNP. I cant even wire it through the options port for fucks sake. Can someone please for the love of god help me?????

The MSPNP2 should regulate voltage by itself, 14.5V is normal. Your fuel lines wont burst with high voltage, there has to be some other electrical problem.

As for the AEM wideband, it should have 4 wires:
1. 12V - tap cig lighter
2. Ground - anywhere on chassis or also from cig lighter
3. 5V Wideband - wire to options port or wire where the stock front o2 sensor connector is. The stock connector also has 4 wires, you want to use the signal wire (solid black or solid blue).
4. Narrowband - dont use with MS

Thank you curry, the Wideband will be easy now, but the problem with the MS is still on my mind. If the stock ECU does a perfect job with voltage regulation, why would a brand new MSPNP2 have an issue with vreg? I also sent a pic of the burst line. It gave me a headache and left me stranded on a mountain when the battery blew. I tried swapping in a new battery and the stock ecu on the mountain but it still wouldnt start due to low fuel pressure. Im mainly looking for someone who has successfully got a MSPNP2 to work well with a 99' miata. I would love to see how they did their settup.
https://cimg4.ibsrv.net/gimg/www.mia...4c98f84e5d.jpg
line from walbro 255 burst after voltage spike

Post your tune.

There is a voltage calibration on the MS2. Are you running e85? Kind of looks like ethanol damaged hose to me.

The hose also looks kind of kinked right at the pump.

You're barking wayyyyyy up the wrong tree with that fuel line. With the assumption that the line is actual EFI hose, there is no way possible the line burst due to pressure caused by pump.

Also: Your Megasquirt is not controlling the alternator correctly because it doesn't have native alternator control.

You bought a brand new Playstation 2 in the year 2020.

It absolutely has alternator control it's just done by a separate circuit. It still requires a certain output to be on which is why I asked to see the tune.

Edited post above for misleading info

Which output? tach out?

Yes.

heres the tune i was running. The car ran awesome on it. the windows rolled up super fast and the fuel pump whined like crazy (more than normal)

i am not running e85. im 18 dude i just learned how to get my car running on MS

Then it must be what Neb said. PCV or heater hose maybe?

Was there any resolution to the high DC voltage issue in this thread? I'm hunting for a solution to a voltage regulation issue.

I am getting Battery voltage readings of 17-19 vdc since the MSPNP2 installation (in my 2000 NB with FM Turbo) which I believe is causing these problems and I suspect also could affect my tuning. The problem has blown multiple headlight filaments and shuts down the radio due to excessive voltage.

I have completed the following troubleshooting steps:
- Confirmed fully charged battery
- Confirmed voltage at battery (with a high quality multimeter) is matching Tuner Studio indicated battery voltage
- Removed and bench tested alternator at a parts store, confirming 15.1 vdc output
- Double checked block, chassis grounding with the MS and alternator connections

Is there a pot or something on the circuit board which I can use to adjust the voltage down? My MS dealer thought the MS had an adjustment point but i can't find any documentation to verify that. The MSPNP2 does not have any of the small blue adjustors like I've seen on other MS boards.

Yes I found the problem a while back, sorry for not posting it. The MSPNP2 for the 99 Miata regulates voltage within the ecu itself. The problem was that when I received my ecu from Diyautotune after completing repairs, the voltage regulator was set to always output the maximum voltage. According to them, it can only be adjusted by one of their engineers. I sent the ecu back and they fixed the problem for free.

I (kinda) wish I had known about this when I first got my MM9900 years ago. I had some problems w/ voltage regulation, gave up and installed an alternator from a RX7 (self-regulated, and higher output) and haven't looked back.

I was seriously considering this too. Its never too late to go back!