silverrotor

iTrader: (1)

to the Pulsation Damper when removing the hard lines aka rats nest? What are the consequences to doing this?

banzaitoyota

I would ditch the PD altogether and use an Aftermarket FPR

neevosh

The only thing plugged into the PD is the fuel line. The FPR needs a pressure source. That's the one at the end of the secondary injector rail.

NZConvertible

What he said. The PD has no vac line going to it, but the FPR does. DO NOT disconnect or cap that one. The FPR must always be able to sense manifold pressure.

silverrotor

iTrader: (1)

Man! I mean't to say the Fuel Pressure Regulator. Not Pulsation Damper thats found at the Primary Fuel Rail.

Tap directly In to a vacuum source, you say?

I understand It's actuated via a Solenoid but what causes a signal to go to the ECU resulting In the Solenoid to redirect air to the FPR (not PD)? And whats It's effects If their Is a direct vacuum source to the FPR?

NZConvertible

All FPR's need to be connected to the manifold so that fuel pressure increases with manifold pressure.

The solenoid is part of the hot-start assist system. Because if the proximity of the fuel rails to the engine, heat-soak can cause the fuel in the rails to boil while the engine is sitting and not running, which causes hard starting and poor idling.

Normally the solenoid is closed and manifold pressure goes straight from the manifold to the FPR. If the engine is very hot at start-up, the ECU opens the solenoid and the FPR vac line is vented to atsmophere. This increases the fuel pressure (FRP basically sees WOT) and stops vapour lock.

This system is only used if the coolant and air temp sensors are both showing high readings caused by heat-soak. (FYI, the FD uses a dedicated fuel rail temp sensor instead.) It only lasts for 50sec after start-up, then the solenoid closes and manifold pressure is applied to the FPR again.

You can bypass the solenoid if you want, but don't complain if your engine is hard to start when it's hot.

silverrotor

iTrader: (1)

Bravo Jason.

silverrotor

iTrader: (1)

Btw, It's history anyway when my TII Conversion and MT LT8 come through.