It ran fine yesterday and was completely warmed up when I parked it. I tried to start it this morning and it cranks fine, but no firing at all.

I pulled the spark plugs, they were dry. I checked for spark on the leading plugs and both are sparking. I replaced both leading and trailing sets of plugs. the same condition. Cranks freely but no ignition.

The DTC's I am getting are P0661 and P2259 neither of which should prevent the car from starting. But since they indicated low voltage to the solenoids, I checked the main EG1 relay and the associated fuses because it looks like that relay also controls the fuel pump and the fuel injectors. they all checked good with a multi meter.

any other ideas?

 

I don't think the SSV and AIR solenoids would prevent your car from starting.
Try cleaning the eccentric shaft positioning sensor, this would prevent it from starting.
Might also want to check the positioning plate while you're there also.

To further help narrow it down, you can also check each plug for a consistent spark.

 

Thanks, I will take a look

 

it turns out is is the fuel pump.

interesting that it would run fine one day then be completely dead the next morning.

 

The fuel pumps in the RX8 have been shown to have failures depending on mileage and use. I wouldn't say it's as bad as the coil reputation but it's becoming a more common issue as more 8's get older.

BHR has sourced a drop in replacement pump which we've tested on both the street and on the track to ensure it can provide the necessary performance. We're in the process of providing a full pump and assembly service so we can provide you a literal drop-in unit.

The OEM pump design has not been revised so at some point it will fail again. The pump we provide won't suffer the same fate.