High Pitched Squeel What Is This??

[RXWPN]

Guys I'm getting a high pitched squeal coming from the circled black box in the engine bay when I turn the ignition on. Have had a Legnum Vr4 for years and have never heard anything like this.

Can you tell what this is and or does as I am having issues with tuning at the moment, Car maxes the injectors (100%) at 15psi boost and 4000rpm but seems to still fuel ok on dyno right through rev range.

My tuner thinks that fuel pump is on its way out, as car under max load is starting to miss badly just wondering does this black box have anything to do with fuel?

Cheers

76404

[Davezj]

that is the fuel pump relay that is used to switch in and out the resistor pack to drop the voltage going to the fuel pump at idle and stop the fuel pump flowing so hard at idle and making lots of noise.
the relay drops the voltage to the fuel pump to about 7V at idle all other times there should be battery voltage going to the pump.

you can bypass the resistor pack by shorting the two wire going to from the relay to the resistor pack. this will give battery voltage to the fuel pump all the time.

the fuel pump relay is just a standard automotive relay nothing special probably a 40A relay just replace it if it is making a noise.

the issue with the relay will probably be dirty contacts which you can clean be taking the relay apart but for cost of a new one just get the new one.

or to test if it is the relay issue swap one of the other car relays over with this one and see if the noise goes away.

[RXWPN]

that is the fuel pump relay that is used to switch in and out the resistor pack to drop the voltage going to the fuel pump at idle and stop the fuel pump flowing so hard at idle and making lots of noise.
the relay drops the voltage to the fuel pump to about 7V at idle all other times there should be battery voltage going to the pump.

you can bypass the resistor pack by shorting the two wire going to from the relay to the resistor pack. this will give battery voltage to the fuel pump all the time.

the fuel pump relay is just a standard automotive relay nothing special probably a 40A relay just replace it if it is making a noise.

the issue with the relay will probably be dirty contacts which you can clean be taking the relay apart but for cost of a new one just get the new one.

or to test if it is the relay issue swap one of the other car relays over with this one and see if the noise goes away.


Perfect Dave I thought so. Will change out today fingers crossed its why its missing under max load.

[Davezj]

I am not saying it is definitely this but it is probable.