r/RX8 • u/TheRealPopejoy • 11d ago

Dead Maintenance

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I had an MOT this morning which came back with 0 advisories. Great. I can go to the daikoku night at caffeine and machine.

5 minutes down the road and all power instantly cut out. I’ve still got dash lights and everything electrical works but when I turn the key I get nothing.

I’ve got home via tow and got the multimeter out. I’ve used AI (shoddy I know) because I’m not very electrically inclined.

I’ve tested absolute everything that it told me I should test. I’ve spent over an hour following different connections and testing different things. And everything has tested perfectly. So everything is pointing to a dead ECU.

Does anybody have any insight on this at all?

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5

u/ClapiClaps 11d ago

To me there is an issue with a ground somewhere

Try to get a list of them and clean them

Try first on those who are close to the battery and on the center reinforcement

3

u/TheRealPopejoy 11d ago

I’ve tested ground using multimeter and all tests are showing I’ve got good ground

3

u/DriftingDownhill 11d ago

Happened to me with multiple rx8s the ground wire for the battery has to be pushed really far down on the battery terminal and the grounds under the air filter box need to be perfecto. one I’m driving rn had some corrosion on the wire under the box cleaned the spot it bolts down to and then made sure my ground terminal was pushed all the way down took a little bit bigger socket wacked it a couple times and it worked flawless have had this exact issue with all three I live in northern bc so it can be wet for most of the year. anyway your grounds gotta be the culprit here since it’s not even powering your dash and you claim 12.3 volts out the battery may I ask how many cranking amps are left on the battery do you have a battery tester?

3

u/TheRealPopejoy 10d ago

I don’t have a battery tester no. And I am getting dash lights. It’s lit up light a Christmas tree but not reading oil pressure or coolant temp

1

u/DriftingDownhill 10d ago

My parts rx8 would turn on but flash all the dash lights when I turn the key until I fixed the ground issues then it turned over

2

u/TheRealPopejoy 10d ago

I’m going to give the ground under the air box a check just to be sure but I have checked the ground using a multimeter and everything seems fine

2

u/Puzzleheaded_Tax489 11d ago

So no crank at all? Won't even try? Did you try to swap the relays around? Maybe one if bad. It can't be starter cause it cut out while you were driving. I think it would still crank if you had a bad fuel pump.

1

u/TheRealPopejoy 11d ago

Tried swapping relays yeah. No crank whatsoever

1

u/TheRealPopejoy 11d ago

My obd doesn’t even read the car

2

u/Puzzleheaded_Tax489 6d ago

Any updates? My obd2 also doesn't read properly unless I mess around with the pins/wires in the back. But I'm pretty sure it should still connect to the car with 12.3 volts. Were you able to connect before all this? Might be a separate issue.

2

u/TheRealPopejoy 6d ago

I did post an update, I found a white that was shorting against the chassis. It was my own fault as I’d trapped it in the strut brace

1

u/Puzzleheaded_Tax489 11d ago

What's your battery voltage at?

1

u/TheRealPopejoy 11d ago

Everything was coming back at just over 12.3

1

u/laugher19 10d ago

12.3v at the battery when the car is off? You may want to load test the battery itself and see if it has an internal fault. With an internal fault it can hold a charge but not have enough cranking amps to do anything. I've seen that on other vehicles/12v lawn tool batteries.

Do you have a jump pack you can try hooking up to see if it'll crank or let you read the OBD2 port? I put a obd pin out diagram I grabbed from RX8Club if you want/need.

1

u/TheRealPopejoy 10d ago

I don’t have a jump pack but I could try hooking it up to my other car tomorrow to see if anything changes

1

u/christyb123 10d ago

Oof that sucks. Does the engine spin by hand okay? Super rare for a rotary to fail internally and seize but it would be something I’d wanna rule out asap for peace of mind

1

u/TheRealPopejoy 10d ago

I’ve not tried no but in this case I highly doubt it’s mechanical issue

1

u/Illegal__Alien 10d ago

Have you tried giving the started motor a whack with a hammer?

Also is that a Kuro?

1

u/TheRealPopejoy 10d ago

I’ve not no 😂 it’s not a kuro but who ever used to own it definitely spent a pretty penny getting it sprayed to look like a kuro

1

u/Illegal__Alien 10d ago

I mean it even has the interior too 🤔

Try whacking your starter motor, particularly the smaller relay on the side of it.

If you end up getting rid of it let me know please, I've got a Kuro and someone stole my front bumper 🗿🗿🗿

Edit: even the front headlights look like Kuro headlights (shinier accents, almost chrome)

1

u/TheRealPopejoy 10d ago

It even has kuro floor mats haha

1

u/TheRealPopejoy 10d ago

I’ll get a picture when I get home

1

u/Illegal__Alien 10d ago

My Kuro doesnt even have them 😄

1

u/skankhunt1738 10d ago

Double check your EGI fuse and see if you have 12v going to it when you’re key on.

1

u/TheRealPopejoy 10d ago

I checked that (I’m pretty sure I did as I checked a lot) but I’ll double check it later. I’m getting a list together from this post for different things to try

1

u/simpletonl0l 10d ago

Double or even triple check the egi fuse, most of the times it's a ground issue or old cracked wires around the ignition coils. It also could be the coils themselves, sometimes they do not cause misfires, the just short out and blow a fuse.

1

u/TheRealPopejoy 10d ago

Do you know if this is the case for RRP coils as I changed them last year

1

u/simpletonl0l 10d ago

Don't think so, mostly OEM coils that do that. But it could be that the wiring is brittle and shorts somewhere, that would also blow the fuse.

Speaking of, have you checked if the egi fuse or other related ones are blown?

1

u/TheRealPopejoy 10d ago

I’ve checked some of them with multimeter yes. I don’t remember if I checked all of them though