| Author | Topic |
|---|
Registered:
May 2002
|
 MA70 and the Fuel Pump Relay setup
|
Wed, 08 December 2004 05:00
|
 |
What environment does the ECU require for the FP (Fuel Pump) output to drop its voltage, causing the relay (controlling the high/low voltage for the fuel pump) to switch to the low voltage ciruit?
When the IGN is on, the relay is tripped and current is passed through a circuit with a 0.7ohm resistor in line, dropping the voltage of the circuit therefore minimising the output of the pump. When the FP lead from the ECU is dropped, the relay switches back and the circuit now carry's the full load to the pump maximising the output.
What I want to know is the what information does the ECU require in order to drop that voltage from the FP output???
Frank
|
|
|
Location:
Mildura
Registered:
May 2002
|
|
Re: MA70 and the Fuel Pump Relay setup
|
Wed, 08 December 2004 05:34
|
|
It gets a signal from a VSV(vaccumm solenoid valve).
Marty
|
|
|
Registered:
May 2002
|
|
Re: MA70 and the Fuel Pump Relay setup
|
Wed, 08 December 2004 05:50
|
|
Are you sure...? That valve is used for when the engine has been just tuned off allowing heat-sink to occur. Although this does make sense in most ways, i've been told the actual control of the pressure is not via that soleniod.
How sure are you? I wont knock anything back as after all, i'm the one asking.
|
|
|
Registered:
May 2002
|
|
Re: MA70 and the Fuel Pump Relay setup
|
Wed, 08 December 2004 21:44
|
|
After doing some more research, that VSV valve is used in junction with the fuel pressure regulator and nothing to do with the fuel pump relay which controls the voltage to the pump.
When this VSV valve is given a voltage, the vacuum is blead out and therefore causes the fuel pressure regulator to run on max high pressure. I think the ECU activates this VSV when the engine is hot. It works with the THA in the AFM and the Water Temp sensor.
Still doesn't clarify what triggers the FP output for the fuel pump relay, arrg!
|
|
|
Location:
Perth
Registered:
January 2003
|
|
Re: MA70 and the Fuel Pump Relay setup
|
Thu, 09 December 2004 01:57
|
|
|
It is triggered when the primary load signal exceeds a setpoint, AFM signal for most MA70s, MAP for Turbo As
|
|
|
Registered:
May 2002
|
|
Re: MA70 and the Fuel Pump Relay setup
|
Thu, 09 December 2004 02:09
|
|
Thanks a lot! You have just confirmed what our good friend in the states just said. It's triggered from a load setting.
Thanks for you help! How did you come across this knowledge?
|
|
|
Location:
Perth
Registered:
January 2003
|
|
Re: MA70 and the Fuel Pump Relay setup
|
Thu, 09 December 2004 08:06
|
|
Can't really remeber, probably somewhere like this:
http://www.autoshop101.com/techarticles/technicala rticles.html
Seeing as I installed new high current relays for my new fuel system, the switching circuit will be used to trigger a water spray on the intercooler.
|
|
|
Location:
Mildura
Registered:
May 2002
|
|
Re: MA70 and the Fuel Pump Relay setup
|
Fri, 10 December 2004 13:33
|
|
Oops.
Lucky I didn't put my left knacker on it.
Marty
|
|
|
