Have 87 Rx7 Turbo2 not getting fuel pressure when key is on witch I had earlier. Is there a fuse some where that I don't know about? I put jumper wire for purge fuel lines good fuel pressure. Turn key on nothing can anyone send me in right direction. Ready to start engine.

 

the fuel pump runs when the 'circuit opening' relay is triggered. the relay is turned on when the ignition switch is in the start position, or the ECU will turn it on when it sees rpm, or you can bypass the ecu with the test connector and it will turn on when the key is in the on position. there is also a safety switch in the air flow meter, so if the AFM is closed it turns the pump off, or the car won't start with it unplugged

pump doesn't prime like some other cars

 

So if the key is in the on position there will be no pressure. So I need to have it the start position for pressure correct?

 

I’m not saying you’re wrong but you might be, or I’m wrong. I know my s5 primes for 2 seconds with key to ignition on, but my car has an apexi power fc ecu and a lot of aftermarket stuff. I can hear it since I’m running a louder walbro pump.

My thought was key to ignition on allows fuel priming, then the fuel pump shuts off and awaits airflow signal through the maf.

 

Disregard my post above. Only s5 and fd primes the fuel, not s4.

I confirmed this by reading banzai racing’s thread on the apexi power fc patch harness.

so s4 does not prime fuel when key goes to ignition on.

 

You will also want to apply 12V and a ground to each fuel injector and confirm that each one clicks when 12V and a ground are applied. When these cars sit for some time as yours has, the fuel caramelizes in the injector and the injector seizes. When that happens they will need to be cleaned and flow tested. You can clean them at home with the proper equipment but know that it likely needs done. It may not be the issue you are having now but I wanted to chime in and mention it to possibly save you some trouble down the road when you're ready to start the engine.

 

Thanks for replying back.

 

wouldnt that fry S4 injectors if you bypassed the resistor pack ?

 

I have done it without any issues what so ever. I also use an injector pulse generator that applies the needed voltage and cycles the injector rapidly. Never an issue

 

then why the heck are they there?
i threw em away anyways since i got new injectors!