No Power To Fuel Pump Issue - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Megagwar · 09-23-2019, 08:18 PM

I haven’t seen or read up on an issue like I’m having. At least nothing in what I’ve found yet. Previous owner did a hack job in wiring... been working on fixing all of it.

Car: 1995 S14 OBD1

I’m getting no power to the plug that connects to the fuel pump.

I was following a “no fuel” issue how to. Here’s the how to: http://driftbasic.com/troubleshootin...prelay-issues/
When I came to this step...
“Pin #2 is ground signal from ECU, it can be verified by checking for continuity between Pin #2 and a ground point while key is in the ON position (it will only work for couple seconds after turning the key)”

I get continuity when the key is in the OFF position. When I turn to the ON position, I get nothing. This is backwards from what it says it should be. Any ideas why? I’ve been stumped on this for the past few days.

All relays check out and work, fuses are good, everything else I’ve check seem to be in working order.

Megagwar · 09-25-2019, 03:28 PM

It’s looking like my ecu is not grounding the relay. Is there a way to fix this or will I need a new ecu?

S14rebuild · 09-25-2019, 03:34 PM

Check soder points in ecu

S14rebuild · 09-25-2019, 03:36 PM

What u can do, is just bypass the ecu ground and add ur own ground to that pin. So when key is turned on, the fuel.pump relay will be grounded and power sent to fuel pump. Easy solution

Megagwar · 09-25-2019, 03:38 PM

Quote:

Originally Posted by S14rebuild

What u can do, is just bypass the ecu ground and add ur own ground to that pin. So when key is turned on, the fuel.pump relay will be grounded and power sent to fuel pump. Easy solution

Sounds easy enough.
That won’t cause the pump to run at all times?

jroll · 09-25-2019, 03:36 PM

look up the ka24de fuel pump wiring diagram

S14rebuild · 09-25-2019, 03:44 PM

With key off there "should be" no voltage sent to the relay so no running fuel pump till key on

Megagwar · 09-25-2019, 03:48 PM

Quote:

Originally Posted by S14rebuild

With key off there "should be" no voltage sent to the relay so no running fuel pump till key on

Guess I meant to say... while the car is on and running, will the fuel pump be running during that time? Asking because the fuel pump relay is normally open, having no current go to it unless ECU activates it.

S14rebuild · 09-25-2019, 03:50 PM

Key on
.pump will run.

Usually stock way..ecu primes the pump..if it gets to crank signal it shuts off. Thats all

But if u ground it..fuel pump stays running nonstop till keys turned off.

Its a cheap easy fix and car will run

Megagwar · 09-25-2019, 03:53 PM

Quote:

Originally Posted by S14rebuild

Key on
.pump will run.

Usually stock way..ecu primes the pump..if it gets to crank signal it shuts off. Thats all

But if u ground it..fuel pump stays running nonstop till keys turned off.

Its a cheap easy fix and car will run

Appreciate your help. Gonna give it a go right now. I’ll see if I can get some to let me try out their ecu and see if it boils down to an ecu problem as well.

S14rebuild · 09-25-2019, 04:01 PM

Ok, long as ur diagnosis is correct with ecu ground issue, that will work.

09-23-2019, 08:18 PM	#1
Megagwar Join Date: Sep 2019 Location: Houston, Tx Age: 27 Posts: 5 Trader Rating: (0) Feedback Score: 0 reviews	No Power To Fuel Pump Issue I haven’t seen or read up on an issue like I’m having. At least nothing in what I’ve found yet. Previous owner did a hack job in wiring... been working on fixing all of it. Car: 1995 S14 OBD1 I’m getting no power to the plug that connects to the fuel pump. I was following a “no fuel” issue how to. Here’s the how to: http://driftbasic.com/troubleshootin...prelay-issues/ When I came to this step... “Pin #2 is ground signal from ECU, it can be verified by checking for continuity between Pin #2 and a ground point while key is in the ON position (it will only work for couple seconds after turning the key)” I get continuity when the key is in the OFF position. When I turn to the ON position, I get nothing. This is backwards from what it says it should be. Any ideas why? I’ve been stumped on this for the past few days. All relays check out and work, fuses are good, everything else I’ve check seem to be in working order.

09-25-2019, 03:36 PM	#6
jroll Join Date: Jun 2015 Location: Stockton, CA Age: 42 Posts: 11 Trader Rating: (0) Feedback Score: 0 reviews	look up the ka24de fuel pump wiring diagram Last edited by jroll; 09-25-2019 at 03:37 PM.. Reason: messed up

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09-25-2019, 03:28 PM	#2
Megagwar Join Date: Sep 2019 Location: Houston, Tx Age: 27 Posts: 5 Trader Rating: (0) Feedback Score: 0 reviews	It’s looking like my ecu is not grounding the relay. Is there a way to fix this or will I need a new ecu?

09-25-2019, 03:34 PM	#3
S14rebuild BANNED Join Date: May 2019 Location: Florida-FAIL Posts: 2,497 Trader Rating: (8) Feedback Score: 8 reviews	Check soder points in ecu

09-25-2019, 03:44 PM	#7
S14rebuild BANNED Join Date: May 2019 Location: Florida-FAIL Posts: 2,497 Trader Rating: (8) Feedback Score: 8 reviews	With key off there "should be" no voltage sent to the relay so no running fuel pump till key on

09-25-2019, 03:50 PM	#9
S14rebuild BANNED Join Date: May 2019 Location: Florida-FAIL Posts: 2,497 Trader Rating: (8) Feedback Score: 8 reviews	Key on .pump will run. Usually stock way..ecu primes the pump..if it gets to crank signal it shuts off. Thats all But if u ground it..fuel pump stays running nonstop till keys turned off. Its a cheap easy fix and car will run

09-25-2019, 04:01 PM	#11
S14rebuild BANNED Join Date: May 2019 Location: Florida-FAIL Posts: 2,497 Trader Rating: (8) Feedback Score: 8 reviews	Ok, long as ur diagnosis is correct with ecu ground issue, that will work.