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350matt, Engineer
Category: Mazda
Satisfied Customers: 21868
Experience:  Mechanical Engineer BEng Hons22 years experience
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I have 07 mazda rx8 that has no acceleration after

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I have 07 mazda rx8 that has no acceleration after installing new starter and fuel pump relay. In park it idles but when pressing down pedal it does nothing.


This sounds like a lack of fuel and could be a lack of fuel pressure from the electrical pump at the tank.

1st thing to try is to remove the fuel filler cap and then flick the ignition on whilst listening for the brief ‘buzz’ of the pump

If the connections to the pump are corroded or damaged then the pump could stop at any time or could not be running at full speed. Check that its relay switches in and out and the relay contacts are clean and bright – replace the relay if in any doubt and do the same for the fuse,

Ideally measure the pressure at the injector rail (should usually be around 3Bar / 45psi +) and if this is low check the pump as described and also consider changing the fuel filter as if this partially blocked this too will reduce pressure.

Customer: replied 10 months ago.
The fuel pump was replaced before the starter and all the connections are good also.


Ok can I ask if you've measured the fuel pressure with the engine running?

if you have and its OK ( 3bar) then its possibly an pedal sensor fault or a MAF sensor fault

Customer: replied 10 months ago.
No. How do I do that?


you'll need a pressure gauge and then check if your rail has a schrader ( tyre) valve on it some cars do some don't

if there's no valve then you add the gauge on a Tee piece where the fuel line is plumbed into the injector rail


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