So my rx8 has been quiet finicky lately electrical wise. Basically what happens (sometimes) is nothing will get power, except when I put my key in the ignition, the dashboard lights up. So when this problem happens, my remote won't unlock the doors, the radio doesn't turn on, my lights don't turn on, and more importantly, my starter motor never gets power.

A few weeks ago, when it was still quite cold, I seem to have had a mixture of two problems - 1. My starter motor was struggling to start the car, and 2. The issue I mentioned above. I thought the two were related. Since then, I replaced my starter motor and she starts up like a charm. It's been on for about two weeks, and since then, I've had no issues.

Today I go to get in my car, unlocks with the remote, interior lights go on, put my key in the ignition, and then when I turn it, everything shuts off. I take the key out, try again, and I was back to the original problem I mentioned. No radio power, no start, but the dash was on.

After playing with the battery cable, for some reason it started. I am now in another place, I tightened the terminal clamp to make sure that wasn't it, but now im back to the original problem.

What could be causing the seemingly random electrical problems?

Thanks,
John

 

Also, another weird thing I noticed: when I put the key in and the dash turns on, the gauges set them selves like normal, but the fuel guard dances around a bit. Not sure what that could signify...

 

Seemingly random electrical issues that affect more than 1 system are a grounding problem 99.9% of the time.

The most common grounding problem point is the negative battery terminal clamp, followed by the positive one.

And this looks like it fits the bill. You replaced the starter which (hopefully) means disconnecting the battery, and the reconnection solved the problems for a bit until the corrosion ate back through again.

Disconnect both battery terminals and clean the posts and clamps thoroughly. Make sure the seating surfaces are clean. Re-connection and make sure it's a solid seat connection.

Edit:
Your 2nd post confirms it. The dash stuff acting like that is ALWAYS a grounding problem.

 

Ok, thanks Riwwp! I will break out the baking soda and do some cleaning. I did notice corrosion on the negative clamp.

 

I've yet to clean the negative clamp, but I wanted to ask a few questions anyway. I'm again having the same issue - nothing turns on, but when I put the key in, the dash lights up. The thing that confuses me is, if there is a ground issue, how come the dash and headlights are able to turn on, but the radio doesn't and the starter doesn't turn?

 

I noticed some corrosion on my ground clamp, so I replaced the fuel pump - starts like a champ now!

 

Think about how different thickness of wiring can change the resistance level against the current traveling through it. Think about how that resistance affects the voltage of the current.

Now think about how corrosion isn't a complete instant spread, but rather something that slowly grows on/between the two metals.

There is enough of a connection to allow the lower power requirement of the dash lights, but not the single biggest electrical current demand that the battery ever sees...the starter.

 

So I just finished cleaning off the corrosion and it doesn't seem to have helped.

When my car wouldn't start, I decided to leave it there and come back a few hours later (now). When I got here, things powered on (interior lights, radio, etc). Once I went to turn over the engine, everything died and I am back to the same issue. Should I check the starter motor connections? I'm quite confused.

 

Other information:
My rear springs are dead, so whenever there's 3 or more people in my car, it rides pretty low. This leads to a hard ride on the rough northern streets. Maybe this has eventually upset some wires.

Sometimes when it starts up after being difficult, the ABS and HandBrake icon stay lit.

 

Another update:
Today, it started off well. Web I stopped to get gas, it wouldn't restart. I push started it successfully, and then about 15 min later I lost power steering. Subsequently after, the dashboard and radio display started to go crazy, and then the ECU started to lose stable control of the engine. No response to throttle, just oscillating like mad. AAA is on the way :/
There must be some short that is exacerbated by rain.

 

It's a grounding problem. If you can really confirm a solid battery connection, then start checking other grounds.

Even the rain causing more issues is more prominent with the poor battery connections.

Are you SURE they are correctly seated? Are you making sure that the clamps are actually grabbing the posts? It's possible for the posts to corrode thin enough to the point that a completely clamped clamp won't actually grab it solidly.

Both positive and negative confirmed? Are you fully disconnecting both, then cleaning, then reconnecting?

 

I had a similar problem with my old AT 8. And it turned out to be the negative terminal clamp to be too thin to seat properly. Try rotating the clamps once you have fully tightened them. If there is any play, it's time to change them.

Another place is to check the wires going in to the fuse box and also check if the fuses are seated correctly. It seems like bumps or moisture cause a short somewhere that affects all the systems together, so it must be a major circuit .

How old is the battery and the alternator?

 

So, to wrap up this thread, it turned out to be a bone-headed work around that the previous owner must have done, but that I didn't notice.

So as I was working with the mechanics, they noticed a sketchy wire jumping from the first post on the fusebox where the battery comes in to somewhere else (I don't remember). The wire was melted and burned. I'm guessing that at some point, the main fuse blew and the owner couldn't find the 120A fuse? So anyways, there was this ~16awg wire shorting past the main fuse, and there was about 4 strands of this wire still making contact with the post. Somewhere within the past month or so, I must have blown the 120A fuse, so now all of the current that was powering anything was going through this tiny wire. Additionally, the alternator wasn't charging the system because it gets power from the other end of the 120A fuse, and since that was blown... So it seems my problems were twofold: trying to power an entire car with almost no wire, and my battery slowing dying.

So, we yanked that jumper wire out of there, replaced the 120A fuse, and got some new clamps for the battery terminals just for longevity. Alls well now.

 

electrical problems are haunting me, what could cause this? i been having electrical problems so i replaced my battery and had my alternator checked= no good for both.
replaced idled the car for a while and took it for a drive. came home let the car sit for a day took it for a "spirited" drive this time car shuts off i drove it home parked it and noticed smoke coming out from the fuse box.... any ideas other than the alternator...? my fuse box melted