Chrysovalantis

My mazda rx7 2002 starts on idle around 1200 rpm for approx 1min then the engine starts to work at rich mixture
before dies.I try to start again but dont fire up until i remove the fuel pump fuse.Then run again until burns the excess fuel and then the same charastiristics when i connect the fuel pump.I have checked the fuel injectors,changed the Ecu,change the coils and and spark plugs,the Tps and i have perform a compression test.
Any ideas.
Thanks in advance Chris

Akagis_white_comet

iTrader: (4)

How old is/are the O2 sensors? It sounds like it is behaving similar to my 20B FC, though mine starts out okay and drifts leaner and leaner untill it stalls and will not restart, due to low compression.

If you do not have a wideband O2 sensor, you should invest in one as a practical tool. My personal recommendation is the Innovate LC1 or LC2 as they can simulate a stock sensor on the secondary output too.

Are you experiencing any misfiring or lack of power? My next suspect would be poor grounding for the ECU. It supplies signals to the ignition coils by providing a ground. If its ground is poor, it will run poorly, certain signals like the MAP sensor will be biased toward vRef, making the ECU think there's higher pressure inside the UIM and it will dump in more fuel as a result