rbj1234

Hey this is my first post and need some help. I have a 04 Mazda rx8 that won't start... Has 100k miles and all stock. I was on my to payson from Phoenix when my car left me stranded on the side of the highway .. got it towed home it had a dead battery from trying to start it the day it broke down. Charged the battery and car started rite up. Drove it for about two weeks and car dies again and now won't start at all. It has new plugs wire coils and e crank sensor . The only code it's giving is u0073

Loki

iTrader: (1)

u0073 sounds like electrical issues with the ECU. I'm not too familiar with this code.

So what happens when you try to start? It turns and turns but doesn't fire? It doesn't turn at all?

rbj1234

It just cranks and cranks

RIWWP

iTrader: (2)

U codes are communication codes, it just means that your code reader doesn't recognize some of what Mazda is telling it. Ignore it.


When the engine shut off each time, did it shut off while you were idling? clutch in and coasting? or while you were in gear at speed? It can be a big clue as to the problem.

rbj1234

First time it shut off I was driving going about 65 shut off with no noise at all just cut out.. the secound time I was at a red light stopped not in gear and it just died

RIWWP

iTrader: (2)

Fuel pump failure.


The most common symptom of failure that our fuel pump has is that the engine suddenly shuts off when driving (almost always on the highway after 20+ minutes of driving), and won't restart for at least 15-20 minutes, then when later tried, it starts up as if nothing was wrong. This is due to the most common failure method, and that is the fuel pump siezes when it overheats, but then un-siezes when it cools down. It will work at near max performance right up to the point that it shuts off, causing an abrupt shut off of the engine.

The only other possible way that the first shut off could be anything other than the fuel pump is if you suffered a significant electrical failure. But you haven't given us a single sign that you might have, so I am discounting that.

rbj1234

The fuel pump is about a month old one from eBay but when I turn the key on I can hear it turn. I was thinking it might have been electrical but font know where to start looking.

RIWWP

iTrader: (2)

I hear ebay and I immediately start questioning whether it was a good pump or not. I've seen people selling 40,000 mile plugs on ebay when you should be changing them every 20-30k, if not 15k.


Pump failures are common in our car. If you don't have 100% positive proof that it was a new pump (and "the seller told me it was" isn't proof), it's still suspect.

rbj1234

Ok I'll check to see if it has pressure.. but if it does are there any electrical problems that you know of that could be causing this?

tgbmurf

Is the battery dead again? If so, get your alternator tested, probably on the way out.

rbj1234

No battery stayed charge. Died because of me trying to get it started over and over again.

BigCajun

iTrader: (1)

Mine started dying on me 2 days ago, but I was able to make it home after it died about 6 times at different speeds from accelerating in low gears to highway cruising speed.
I'm assuming it's the fuel pump dying.
Please update if you find out what's wrong.

rbj1234

It's the pump. both times the car died it was below a quart tank. The pump that eBay had sent me is a little bigger then the oem one so for some reason it would stop spraying fuel when the tank was low. today I added two gallons to my tank and car started. Sounds crazy I know but thanks for the help guys

BigCajun

iTrader: (1)

Good news.
Thanks for the update.