Punished

91 S13 with SR20 Redtop with RS Enthalpy tuned ecu. Has been running an in tank Walbro 255 set up for 5+ years with another Walbro 255 inline towards the engine bay. The intank has a pigtail relay with 20amp fuse attached to the system with a main power wire that feeds it. This then is wired in to the stock blue plug for the pump. The first owner wired this in, so I have not traced the power wire to what it has been tapped in to in the engine bay.

With that said, I have never had a problem until 2 months ago. On the highway, lost power and had no fuel. The 20amp fuse had completely burned up and melted to nothing. Replaced the fuse/holder with a 15amp and wired in a new relay pigtail to freshen everything up.

Now today, driving down the road, lost power and knew it was fuel again. Coasted to parking lot, check pigtail relay fuse and it was fine. Check main fuel pump fuse in the engine bay and it is fine. Had it towed home and have been digging through the fuel setup.

I have pulled the fuel pump and know this does work (hooked to battery). I checked continuity and everything is good. The power wire for the relay is good as well. When I plug everything in to the blue plug and check for power at the fuel pump plug for the walbro nothing comes through. Sometimes it would spike when I turn the key to ACC for a split second but then nothing.

I found a post online about removing the EGI Pump relay and jumpering 1 and 3 to see if the pumps turn on. They do not, I also switched two relays and nothing changed.

I then saw another post about using a jumper on 3 and 2. Picture below to show which I jumpered and both inline and intank pumps come on 100% and keep running (stayed on, not just a priming on). The intank plug shows 12v when this jumper is on. (yes the cable is super long)




So, my question here is. What do I need to do now?

New EGI Pump fuse? Do I need to check continuity from the ECU? (i think it is a black with pink or purple stripe wire) I'll check ground wires tomorrow coming off the fuse box. I have not touched wiring on this car in 3 years, so this i random for me to have a wiring problem pop up when nothing has changed.

Thanks

kane01

Did you have key on when u did first jumper test to get a prime. Second one u did is constant for engine running. Could be wrong, but i believe it's a double duty relay right? If it is, then just swapping a random relay would not work regaurdless unless u happen to swap another double duty relay. Sounds more likely than a random wiring problem out of the blue.

Punished

Yes, for the pumps to turn on when the jumper was connected I had to turn the key to acc. I had that for both try's with the different jumpers.

For the relay all I did was swapped the egi and egi pump relays as they appear to be the same type.

I checked pin 1 on the ego pump relay to 104 on the ecu and have continuity. So that connection is good. I did not get a chance to check my grounds which I'll try to get to tomorrow. I also opened up the ecu to verify nothing was burnt up and that is fine as well.

I'll check grounds next and then order 2 new relays from Nissan for egi and egi pump if everything else checks out.

cotbu

You confirmed the wiring to the pump and the pump is working, your problem at this point is either the relay, wiring to ecu or pin 104 burnt trace, corrosion etc.
After you confirm wire and pin 104 to be good try swapping ecu's

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LoverTechnologies "Half Broken Things!"

S-Nation S13

its your ECU this happened to me, if you car worked and then all of a sudden you have (no fuel pump prime) more than likely its the ecu

also you might have a faulty fuel pump.

Dboyizmlg

+1 on this

Punished

1) already checked ecu internals and found no burnt marks. Is there a specific spot I would see the burn that I may have missed?
2) already checked continuity from Pin 1 (EGIpump relay) to Pin 104 on ecu and this is good.
3) already checked walbro 255 out of the tank and it worked. rechecked pump out of tank but plugged in to car when I jumped EGI relay pins 3&2. It worked and ran full speed.

I do not have another ecu to swap out, so I will need to work my way through the other processes before I can jump to that one.

What I have not checked-
Grounds for the fuse box with the EGI pump relay. This will be done tomorrow.
I have not bought new relay for the EGI pump to try out yet either. Before I do so I will use a 9v battery to see if I hear the relay click open. Normally when I turn to ACC with the key I will hear a relay click, but I'm sure this the added one I have to the fuel pump itself in the trunk.
I will also check pin 2 on the EGI pump relay with the voltmeter and see if it shows 0.5V when I turn the key to ACC.
-- also will check a jumper wire between the relay socket terminal #5 and the other terminal directly across #3, and see if it primes. ( i forgot to do this last night)

Fre3_World313

Bringing this thread back.

Need help.

Pump will not prime or make any noise unless the EGI pump relay is jumped

Won’t do shit. Unless I jump it

Then runs like a top

Do I just drive it?

I don’t think my ecu pin is burnt

And my grounds are good.

What now

Syrussilvia

Make your own circuit (12v mod)