Hard wire fuel pump problems - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

seg24life · 11-11-2013, 07:57 PM

Hey guys, I need some help pretty quick on my DD 240! I did the Dual cam swap, and the wiring harness was somewhat hacked up so i had no other option than to wire the pump to a fuse on the switch, kicks on accessory power and continues through the start and run etc... I never leave the accessory power on alone, because the fuel pump runs, but lately after turning off my car and going back to start it, it very quickly floods itself out and i have to unhook the fuse, crank for 10 seconds with full throttle to start the engine, and the quickly hook the fuse back up for it to run, then no problem! it seems it happens mostly when i have just cut the car off and 10-15 mins go back to start it. overnight i dont really have any problems. anything will help guys, ive tried searching the forums but couldnt find anything very helpful.

Hashiriya415 · 11-11-2013, 08:28 PM

Leaky injectors. Fuel pump has nothing to do with being on. It can't flood the cylinders unless injectors turn on or either leak.
BUT you are in a FUCKING huge risk in case of accident you have nothing that will shut off your pump. Buy an aftermarket switch that will cut power to pump.

twinspool · 11-11-2013, 08:48 PM

^what he said or get a FSM and start tracing wires and hook that junt up legit style yo.

seg24life · 11-11-2013, 10:22 PM

Quote:

Originally Posted by Hashiriya415

Leaky injectors. Fuel pump has nothing to do with being on. It can't flood the cylinders unless injectors turn on or either leak.
BUT you are in a FUCKING huge risk in case of accident you have nothing that will shut off your pump. Buy an aftermarket switch that will cut power to pump.

Thanks for that, I didn't even think of the accident part when wiring the pump that way. I'll try to invest in a switch in the very near future and that should solve my problem hopefully, because the injectors were working properly. Thanks you guys again, if anyone has anything else to add or to try feel free

OnTheChip · 11-12-2013, 08:20 AM

I would wire it properly so the ECU controls the fuel pump. It automatically turns the fuel pump off within 5 seconds after the engine stops turning, even with ignition switch ON.

suspectu1 · 11-13-2013, 03:08 PM

all you really need to do in order to wire it properly is use a 30amp relay that gets power AND trigger (86 and 30 on the relay) with the IGN ON.
you then connect the 85 (which grounds the relay) to pin 104 from the ECU(pink/black). and 87 to your fuel pump +
what happens is simple: whenever the key is turned to ON, you get power to your relay that controls the fuel pump but ONLY when the ECU wants so it provides GROUND for this relay so basically this is the same way the OEM has it wired up.

11-11-2013, 07:57 PM	#1
seg24life Join Date: May 2013 Location: TN Posts: 33 Trader Rating: (0) Feedback Score: 0 reviews	Hard wire fuel pump problems Hey guys, I need some help pretty quick on my DD 240! I did the Dual cam swap, and the wiring harness was somewhat hacked up so i had no other option than to wire the pump to a fuse on the switch, kicks on accessory power and continues through the start and run etc... I never leave the accessory power on alone, because the fuel pump runs, but lately after turning off my car and going back to start it, it very quickly floods itself out and i have to unhook the fuse, crank for 10 seconds with full throttle to start the engine, and the quickly hook the fuse back up for it to run, then no problem! it seems it happens mostly when i have just cut the car off and 10-15 mins go back to start it. overnight i dont really have any problems. anything will help guys, ive tried searching the forums but couldnt find anything very helpful.

11-12-2013, 08:20 AM	#5
OnTheChip Zilvia Junkie Join Date: May 2013 Location: Burgaw, NC Posts: 317 Trader Rating: (0) Feedback Score: 0 reviews	I would wire it properly so the ECU controls the fuel pump. It automatically turns the fuel pump off within 5 seconds after the engine stops turning, even with ignition switch ON. __________________ NismotronicSA - Speed-Density Tuning for Nissans

11-11-2013, 08:28 PM	#2
Hashiriya415 Zilvia FREAK! Join Date: Jun 2007 Location: San Francisco Age: 36 Posts: 1,007 Trader Rating: (22) Feedback Score: 22 reviews	Leaky injectors. Fuel pump has nothing to do with being on. It can't flood the cylinders unless injectors turn on or either leak. BUT you are in a FUCKING huge risk in case of accident you have nothing that will shut off your pump. Buy an aftermarket switch that will cut power to pump.

11-11-2013, 08:48 PM	#3
twinspool Zilvia Junkie Join Date: May 2006 Location: mississippi Posts: 349 Trader Rating: (7) Feedback Score: 7 reviews	^what he said or get a FSM and start tracing wires and hook that junt up legit style yo.

11-13-2013, 03:08 PM	#6
suspectu1 Join Date: Mar 2008 Location: Montreal Age: 33 Posts: 37 Trader Rating: (0) Feedback Score: 0 reviews	all you really need to do in order to wire it properly is use a 30amp relay that gets power AND trigger (86 and 30 on the relay) with the IGN ON. you then connect the 85 (which grounds the relay) to pin 104 from the ECU(pink/black). and 87 to your fuel pump + what happens is simple: whenever the key is turned to ON, you get power to your relay that controls the fuel pump but ONLY when the ECU wants so it provides GROUND for this relay so basically this is the same way the OEM has it wired up.