I have the Supra pump, secondary rail and aeromotive fpr. When I turn the ignition to "ON" the fuel pressure sat at 8psi. So I put the jumper from F/P to GND to see if I could hear the pump. The pressure jumped up to 32 and held steady. After that I took the jumper out and turned the key to "ON" and the pressure slowly was dropping. Is this a problem with the Fuel Pump Relay, Circuit Opening Relay or pump? Thanks.

Richard

 

ok the pump only gets voltage for like 3 sec in the key on position, the ecu needs to see a cranking signal to keep the voltage to the pump. 32 psi jumpered in the diag box seems semi normal. did you just install the aftermarket fpr? it may need to be adjusted, make sure you do it with the vac line off. but when you cycle the key you do get pressure increase correct? also the fuel pump relay only controls fp speed car will start without it.

 

Per the FSM jump the FPR & GRD pins in the dignostic connector. The fuel pressure shoud be between 36-40 psi with the key on/eng off. You can also check for pressure decay, should hold fuel pressure for quite some time.

 

It does not hold pressure for very long, about 40 seconds and it's back down to 0 psi. Skip at KD told me that the O ring on the fuel pump probably isn't seated properly and causing fuel to flow back into the tank after the pump stops pumping. I got the car to start and the fuel pressure is now very shaky around 28psi at an 850 idle. I'm guessing I need to adjust the regulator. Any tips on how that's done properly?

I'm so glad it's running, now to get those damn air bubbles out of the coolant...

Thanks for the replys,

Richard

 

Just out of curiosity, did you ever get this fixed?

 

I am also very curious if this issue was fixed. I decided to put in a new aftermarket FPR, which is adjustable, but I don't want to cause any serious problems because I installed it wrong causing too high of a pressure or something. What is the proper way of installing a new one since mine didn't come with instructions. Thanks

 

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