strix1996

My mazda rx8 sometimes turns on but sometimes it doesnt it looks like its not getting gas i looked at the fuel pump and all the fuses and relay but its all working good can you please tell me what is the source of this problem sometimes the car works for a week then it just doesnt work i already change the starter and put premium gas on it what i think it is that it is not getting spark to turn on any help?

RIWWP

iTrader: (2)

Your post is a bit confusing, since you mention "not getting gas" and "not getting spark", and supposedly to define the same symptom.

How do you know it isn't getting gas?

How do you know it isn't getting spark?

If those are just guesses, then back off of those guesses and give us the symptoms you are experiencing, not guesses at what the problem might be without any other explanation.

This thread may be of help to you to see how else to explain what symptoms you have: https://www.rx8club.com/new-member-f...causes-249529/

strix1996

sometimes the fuel pump gets power and sometimes it doesnt so i change the relays to new ones and it worked but then the problem started again and then i put power on the pump and the fuel pump started working so that is why the car sometimes turns on but it looks like the fuel pump is not getting power

RIWWP

iTrader: (2)

How did you determine that the fuel pump isn't getting power? I'm asking for a very specific reason that I'll explain once you answer.

strix1996

the reason i know because sometimes the fuel pump doesn't pump fuel and when i put power directly to the fuel pump that is when it pumps gas

RIWWP

iTrader: (2)

Gotcha, so a direct electrical test. I was just making sure, there are plenty of people that show up here saying "it's not getting gas" when they haven't done a single test of the fuel system, and it is actually a completely different problem.

What symptoms do you experience when you run into this issue? I assume that the engine just shuts off, but I'm looking for more of the circumstances around that. Like, does it operate fine sometimes and not others? Does it only stop flowing fuel when you are driving it, or does it sometimes just not flow fuel on trying to start up the car?

When you tested the fuel pump, did you have it out of the car? Did it pump for a while and then shut off? Or did it pump just fine out of the car and not with it in the car?

I have some possibilities, but most of them are contradictory so I'm trying to narrow the list by getting a better understanding of when it does pump vs when it does not.

strix1996

the only problem i see is that when i try to turn on the car the fuel pump is not receiving gas so i took the fuel pump out the car and tried it but the fuel pump worked fined. When the car does start the car runs fine it feels like there is no problem at all when its running but the problem is when i turn off the car might not start i took it to already three different mechanics and they all say something different but im certain its that the fuel pump is not getting power

RIWWP

iTrader: (2)

Ok, so the problem only manifests while the car is shut off, and only sometimes. That rules out a fuel pump failure. A failing fuel pump can pump when the pump is cold (like when it's out of the car), but seize up when it gets too hot (like when it's been working for 15-20 minutes straight, ie driving).

Where are you located in the world? Are there low ambient temperatures where this might be a problem with something freezing some days but not others?

Is the car stored outside anywhere where there may be mice/rats/squirrels nesting in the wiring harness somewhere? (don't laugh, it's happened plenty)

Have you cleaned the grounding connection points between the battery and the fuse/relay box?

strix1996

I live in the US Georgia and its summer right now the problem is that the fuel pump is not getting any power to pump fuel out I'm assuming that it is a fuse or a relay but I'm only assuming what do you think is the problem

strix1996

In my mazda rx8 sometime the fuel pump get power and sometimes it does not will that be the computer that is having problems but how do you check a computer on a 2004 automatic mazda rx8

04Green

iTrader: (1)

Whatching,

But, RIWWP is who I would hope to have helping me if I had this issue. Only thing I can think to ask is how much fuel is in the tank? The fuel cools the pump, but if you are below 1/4 tank, pump is in air. If you are above half a tank, you cannot remove fuel pump, so do not run out an fill it.

RIWWP

iTrader: (2)

This all sounds electrical in nature, and no, not the ECU. While yeah, it's possible that a resistor in the ECU circuity failed, it is exceedingly unlikely, and only ever happens with an over voltage situation.

I'd be tracing wires in the harness, looking for shorts, breaks, crimps, corrosion. Check all grounding points, both major for the car and minor for that circuit.

The only intermittant fuel pump problem that I have ever seen that is specifically a fuel pump problem doesn't fit your symptoms at all. Intermittant electrical problems DOES fit your symptoms, and corrosion is at the top of that particular diagnosis pile.

Pac-man_911

I have a similar problem when I drive it fast and come to a stop it switches off automatically then I have to restart it. When I drive for plus minus 100kms speed reduces by it self and car does not want to start. Car only starts after plus minus 10hours. I drove the car parked it the next day when I tried to start it it did not want to start.

I took the car to the Machenic they told me that it's the injectors not supplying the motor with petrol. But the car starts when I spray petrol in the intake. ..

guys please help.

Loki

iTrader: (1)

Sounds like your fuel pump is shutting down. Known to happen with age.