I had an issue with the fuel pump not priming in a Z I had just gotten. The PO had pulled all kinds of stuff off in an effort to get the car to run again.
Turns out, after I got all his other issues solved, the pump would prime then it wouldn't. I checked the wiring harness just above the ECU. There was a factory splice in the wire that had turned to green dust. The ECU would work or not depending on how it was sitting in the car. Just a thought.
Fuel Pump Not Priming
Moderator: Matt
There are three plugs that plug into the ECU. They join into the main cable less than a foot from the ECU. Take the black tape wrap off the outside of the wire bundle. I think the wires were green with a white stripe. They were the power lines from the top fuse in the fuse panel to the EUC. There were 5 wires joined in a brass connector that was crimped to hold them, then wrapped with black tape.vagabond wrote:Interesting.
Where was this "splice"? I have a plan of attack, but thats not on list.
Follow pin#34 from the ECU in the wiring digram
Hope it helps
So at the times when the fuel pump isnt priming, Nistune is still communicating okay?
Just need to check that. Because if at the times where you have the glitch where the fuel pump isnt priming and Nistune isnt talking then there is an install problem
If the green wires are cut then the LED should be flashing diagnostic codes also. But it never does this? Even with Nistune is running okay?
You should get a 5 second prime when first switching on the ECU
If Nistune works all the times, even when the fuel pump relay isnt and you suspect a problem with the fuel pump controller inside the ECU or the wiring. If you cannot find/fix the wiring problem, another alternative is to drive the relay from another line
This is for an R31 but applies for the Z31 also
http://wiki.r31skylineclub.com/index.ph ... U_into_R31
Just need to check that. Because if at the times where you have the glitch where the fuel pump isnt priming and Nistune isnt talking then there is an install problem
If the green wires are cut then the LED should be flashing diagnostic codes also. But it never does this? Even with Nistune is running okay?
You should get a 5 second prime when first switching on the ECU
If Nistune works all the times, even when the fuel pump relay isnt and you suspect a problem with the fuel pump controller inside the ECU or the wiring. If you cannot find/fix the wiring problem, another alternative is to drive the relay from another line
This is for an R31 but applies for the Z31 also
http://wiki.r31skylineclub.com/index.ph ... U_into_R31
use these connections to a relay to drive the fuel pump* Pin 30 Earthed
* Pin 87 White wire (joined to loom side)
* Pin 86 White with black stripe (spliced into)
* Pin 85 12v Ign power
Re: Fuel Pump Not Priming
I rewired my fuel pump to bypass the ecu and it primes now.
Re: Fuel Pump Not Priming
Car still isn't running, but that may be unrelated. With that in mind;
When I turn the car to on, the ecu powers and blinks, fuel pump primes
Then one of two scenarios occurs.
1. Turn ignition to off, ecu does final blinky thing, tung ign on, ecu powers and blinks, fuel pump primes.
or
2. Turn ignition to off, ecu does final blinky thing, tung ign on, ecu powers and blinks, fuel pump does not prime again.
Is there a certain amount of time when the ecu is powered down, that the fuel pump wont prime when the ecu is immediately powered on?
When I turn the car to on, the ecu powers and blinks, fuel pump primes
Then one of two scenarios occurs.
1. Turn ignition to off, ecu does final blinky thing, tung ign on, ecu powers and blinks, fuel pump primes.
or
2. Turn ignition to off, ecu does final blinky thing, tung ign on, ecu powers and blinks, fuel pump does not prime again.
Is there a certain amount of time when the ecu is powered down, that the fuel pump wont prime when the ecu is immediately powered on?
Re: Fuel Pump Not Priming
10 seconds after power ECU relay should click off then ECU powers down completely, after that another restart should result in priming again