Fuel Pump Help
Thread Starter
Full Member
Joined: Jan 2010
Posts: 47
Likes: 0
From: Green Bay, Wisconsin
Fuel Pump Help
So basicaly i have a hacked up fuel pump harness. For some reason the fuel pump wasnt receiving any signel and the previous owner decided to hack into the harness and hot wire it in.
Right now i am just trying to get the thing started, so i am going with his approach but i cant figure out how he did it.
Here is a picture of the harness before it goes into the fuel pump:
As you can see there are four wires: Blue, Black, Red, Black/white. He had the black/white one cut and wire nutted going to the front ignition somewhere ( im asuming to a hot wire).
When i tried putting 12volts to the black/white wire the fuel pump didnt run. This is where im confused.
Is that the wire that runs the fuel pump, or does it deal with the level or something? Does the fuel pump not run on 12 volts?
There is not voltage comming from the other end of the black/white wire so there is somthing wrong before the pump. Right now though i just want to get the thing started to see if there is anything else wrong. So am is that the wrong wire? What am i doing wrong?
Right now i am just trying to get the thing started, so i am going with his approach but i cant figure out how he did it.
Here is a picture of the harness before it goes into the fuel pump:
As you can see there are four wires: Blue, Black, Red, Black/white. He had the black/white one cut and wire nutted going to the front ignition somewhere ( im asuming to a hot wire).
When i tried putting 12volts to the black/white wire the fuel pump didnt run. This is where im confused.
Is that the wire that runs the fuel pump, or does it deal with the level or something? Does the fuel pump not run on 12 volts?
There is not voltage comming from the other end of the black/white wire so there is somthing wrong before the pump. Right now though i just want to get the thing started to see if there is anything else wrong. So am is that the wrong wire? What am i doing wrong?
HAILERS
Joined: May 2001
Posts: 20,563
Likes: 27
From: FORT WORTH, TEXAS,USA
The LARGE Blue wire on the REAR harness side of the connector, is the power wire.
IT mates with a black/white wire that is part of the fuel pump PIGTAIL harness.
The other wire that MATTERS is the pure BLACK wire which is the gnd wire for the pump.
On a series four car, the LARGE BLUE wire only has power if the key is ON and the key is either HELD to START or the fuel pump check connector is jumpered, OR the AFM vane is pushed aft a 1/8" or more, or if the engine is actually running (running makes the vane in the afm move aft).
Put the key to ON. Then jumper the fuel pump check connector. Check the LARGE BLUE wire for batt power. It should be there.
The OTHER wires in that fuel pump plug have nothing to do with the pump running. Nothing at all.
IF power is not there at the large blue wire when the check connector is jumpered.....then there is another problem. Either the ENGINE fuse is blown or the Circuit Opening Relay is not configured right.
If the fuel pump did not run with batt pwr put to the black/white wire on the fuel pump pigtail, then you did not have the pure black wire going to ground or the pump is kaput one.
Put your digital meter on ohms and see if the pure black wire in the REAR harness side of the plug is going to gnd or.......not. Should read less than 0.4 ohms or so. It's a simple pump., Power on the black/white and a gnd on the pure black wire.
IT mates with a black/white wire that is part of the fuel pump PIGTAIL harness.
The other wire that MATTERS is the pure BLACK wire which is the gnd wire for the pump.
On a series four car, the LARGE BLUE wire only has power if the key is ON and the key is either HELD to START or the fuel pump check connector is jumpered, OR the AFM vane is pushed aft a 1/8" or more, or if the engine is actually running (running makes the vane in the afm move aft).
Put the key to ON. Then jumper the fuel pump check connector. Check the LARGE BLUE wire for batt power. It should be there.
The OTHER wires in that fuel pump plug have nothing to do with the pump running. Nothing at all.
IF power is not there at the large blue wire when the check connector is jumpered.....then there is another problem. Either the ENGINE fuse is blown or the Circuit Opening Relay is not configured right.
If the fuel pump did not run with batt pwr put to the black/white wire on the fuel pump pigtail, then you did not have the pure black wire going to ground or the pump is kaput one.
Put your digital meter on ohms and see if the pure black wire in the REAR harness side of the plug is going to gnd or.......not. Should read less than 0.4 ohms or so. It's a simple pump., Power on the black/white and a gnd on the pure black wire.
In the factory harness, solid blue (L) supplies voltage to the pump. Check page 36.
http://www.teamfc3s.org/main/factory...NG_DIAGRAM.pdf
http://www.teamfc3s.org/main/factory...NG_DIAGRAM.pdf
Thread Starter
Full Member
Joined: Jan 2010
Posts: 47
Likes: 0
From: Green Bay, Wisconsin
The LARGE Blue wire on the REAR harness side of the connector, is the power wire.
IT mates with a black/white wire that is part of the fuel pump PIGTAIL harness.
The other wire that MATTERS is the pure BLACK wire which is the gnd wire for the pump.
On a series four car, the LARGE BLUE wire only has power if the key is ON and the key is either HELD to START or the fuel pump check connector is jumpered, OR the AFM vane is pushed aft a 1/8" or more, or if the engine is actually running (running makes the vane in the afm move aft).
Put the key to ON. Then jumper the fuel pump check connector. Check the LARGE BLUE wire for batt power. It should be there.
The OTHER wires in that fuel pump plug have nothing to do with the pump running. Nothing at all.
IF power is not there at the large blue wire when the check connector is jumpered.....then there is another problem. Either the ENGINE fuse is blown or the Circuit Opening Relay is not configured right.
If the fuel pump did not run with batt pwr put to the black/white wire on the fuel pump pigtail, then you did not have the pure black wire going to ground or the pump is kaput one.
Put your digital meter on ohms and see if the pure black wire in the REAR harness side of the plug is going to gnd or.......not. Should read less than 0.4 ohms or so. It's a simple pump., Power on the black/white and a gnd on the pure black wire.
IT mates with a black/white wire that is part of the fuel pump PIGTAIL harness.
The other wire that MATTERS is the pure BLACK wire which is the gnd wire for the pump.
On a series four car, the LARGE BLUE wire only has power if the key is ON and the key is either HELD to START or the fuel pump check connector is jumpered, OR the AFM vane is pushed aft a 1/8" or more, or if the engine is actually running (running makes the vane in the afm move aft).
Put the key to ON. Then jumper the fuel pump check connector. Check the LARGE BLUE wire for batt power. It should be there.
The OTHER wires in that fuel pump plug have nothing to do with the pump running. Nothing at all.
IF power is not there at the large blue wire when the check connector is jumpered.....then there is another problem. Either the ENGINE fuse is blown or the Circuit Opening Relay is not configured right.
If the fuel pump did not run with batt pwr put to the black/white wire on the fuel pump pigtail, then you did not have the pure black wire going to ground or the pump is kaput one.
Put your digital meter on ohms and see if the pure black wire in the REAR harness side of the plug is going to gnd or.......not. Should read less than 0.4 ohms or so. It's a simple pump., Power on the black/white and a gnd on the pure black wire.
edit: Ok another question. When puttin the battery to the pump i connect the postive to the Black/White, then do ground the battery to the chassie or do i have to splice the black wire?
Last edited by JC6711; Mar 6, 2010 at 06:33 PM.
Thread
Thread Starter
Forum
Replies
Last Post
trickster
2nd Generation Specific (1986-1992)
25
Jul 1, 2023 04:40 PM
ChrisRX8PR
Single Turbo RX-7's
21
Oct 18, 2015 04:01 PM