Did something break or?
 

Was driving on the High Way on Friday. Ended up hitting some plastic that 'banged' something under the car.

I noticed while still driving, that the oil temp (pressure?) gauge started to go all the way up to H. I pulled over and with another car buddy looked at the car - no leaks, oil level is fine. We decided to keep going.

Parked the car Friday, started it up Sunday morning and the gauge was already at near H. So, we kept driving and the car drove fine. Got to his house and after that, the car went to go turn the car on - got in, put the car in the ignition, put the clutch in... click. The electronics went out and everything is dead. Tried to jump the car, didn't seem the work. Anyone have any ideas wtf just happened to it?

Is the ECU stopping the car from turning on due to the gauge? Everything I read online says that the gauge is actually oil pressure, not temperature and that it's a 'dummy' switch anyways?

EDIT: 2004 RX-8 GT. Looking online I noticed some RX-8's have oil temp instead of oil pressure gauges in their cars. Mine, being a '04 probably has oil pressure right? My guess is the thing that hit the bottom of my car broke/threw off the oil sensor?

Check the fuses, perhaps whatever you hit severed a wire which then shorted on something, blowing a fuse. Whichever one is blown will tell you which circuit to chase, so you'll need a wiring diagram and some dirty clothes to get under the car and assess the damage. The internet can't do that :)

Correct, it's supposed to be pressure and correct, it's a dummy switch anyway.

The ECU isn't stopping the car, my bet is the ECU is not even getting power.

No RX-8 came with an oil temperature gauge from the factory.

The RX-8 has a dummy oil pressure gauge but it's just an on/off switch. It's literally zero or around half. The car will start and run just fine even if this isn't working (at least mine did and about gave me a heart attack).

The oil pressure switch isn't anywhere near the bottom of the engine so the likelihood of debris taking it out is slim.

The oil level sensor is in the oil pan and that could have been damaged but that will just cause a light to turn on in the dash.

Thanks everyone, that's what I was thinking. Weird though, that this happened on Friday and the car drove fine. Then started right up and drove fine Sunday until we got to my buddies place, then it wouldn't start over. Something probably was just draining the battery dead and some wiring under the car is messed up.

What's weird to me is that the "dummy gauge" is, if I'm not mistaken, a binary indicator; it should read either 1) "normal" (needle in middle of gauge), or 2) "low," indicating low oil pressure. But I don't understand how it would read "high".

Strange.

It has a valid high position, such as when it sweeps all the way when you do the 20 brake stomp. The gauge is basically just a voltmeter for an ECU signal, so if wiring got damaged and ECU reference or signal voltages went out of expected range, it could show anything.

Aren't most gauge cluster functions transmitted over the CAN bus?

The fact that you couldn’t get any power while trying to jump start it would strongly suggest that a major power fuse is blown. If there’s damaged wiring and then it shorted out later could easily explain why it was fine one moment and the ... poof ...

The thing is, you know something slammed up under there yet you didn’t bother to check it out. That’s like asking for trouble and so it seems that you may have received it. Hopefully it’s something simple like some bare wires and a blown fuse rather than say, you burned up the engine computer :uhh:

Have you put the car int he air to see if anything was damaged? That's honestly the first place I'd look.

Update. After towing the car to the shop and paying $135 for the tow... One of the guys at the shop (EK Automotive in Chicago) came out and tightened down the positive terminal Aux wiring from the battery, which then made a stronger connection and solved my issues >_>

Happy and mad at the same time.

I’m sure it feels good knowing, at least, it’s finally resolved.

It does. Now I need to fix an issue where my oil pressure gauge is now off (the cap is off the driver and just hanging out inside the dash cluster).