Fuel pump priming issue - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

S-Nation S13 · 07-09-2017, 10:09 PM

The problem is that the fuel pump will prime but it will not cut off like normal.

when turned to ACC the fuel pump activates priming the fuel system (normal) but the abnormal part is that it doesn't cut off (normally after 5 sec. the fuel pump should deactivate)

what causes the fuel pump to cut off? deactivation of the relay?

Kingtal0n · 07-10-2017, 08:18 PM

Ecu -> relay -> fuel pump

Sometimes people re-wire it to get power from somewhere else. That would keep it on all the time when the key is turned.

The ECU is supposed to turn it on / off though, this is the normal way. Some ECU throw ground to the relay (Sr20det) and some throw 12V (LSx ecu) so it depends what computer you use.

S-Nation S13 · 07-10-2017, 08:44 PM

I was using a stock 62 ecu now in using a power FC but I'm still having the same issue. On ACC fuel pump turns on stays on until I turn to OFF. Which leads me to believe my fuel pump + signal is wired on ACC circuit.

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07-09-2017, 10:09 PM	#1
S-Nation S13 Post Whore! Join Date: Jan 2008 Location: LAND of the LOST Posts: 4,083 Trader Rating: (92) Feedback Score: 92 reviews	Fuel pump priming issue The problem is that the fuel pump will prime but it will not cut off like normal. when turned to ACC the fuel pump activates priming the fuel system (normal) but the abnormal part is that it doesn't cut off (normally after 5 sec. the fuel pump should deactivate) what causes the fuel pump to cut off? deactivation of the relay?

07-10-2017, 08:18 PM	#2
Kingtal0n Post Whore! Join Date: Jul 2005 Location: South Florida Age: 41 Posts: 4,829 Trader Rating: (17) Feedback Score: 17 reviews	Ecu -> relay -> fuel pump Sometimes people re-wire it to get power from somewhere else. That would keep it on all the time when the key is turned. The ECU is supposed to turn it on / off though, this is the normal way. Some ECU throw ground to the relay (Sr20det) and some throw 12V (LSx ecu) so it depends what computer you use.

07-10-2017, 08:44 PM	#3
S-Nation S13 Post Whore! Join Date: Jan 2008 Location: LAND of the LOST Posts: 4,083 Trader Rating: (92) Feedback Score: 92 reviews	I was using a stock 62 ecu now in using a power FC but I'm still having the same issue. On ACC fuel pump turns on stays on until I turn to OFF. Which leads me to believe my fuel pump + signal is wired on ACC circuit. Sent from my iPhone using Tapatalk