Fuel issues

[Wootang]

So I'm on a bit of a time crunch since I was supposed to drive to Calgary tomorrow morning, but that's clearly not happening any more.

What happen : I drove my car to my mums house today no problem, but when I went to leave, my car fired up instantly but then died.

My tests: Turned ignition to "on" and listened for the pump to prime - nothing.
Double checked the fuel pump fuze - it's good.
Located the green relay in the trunk and used my highbeam relay to test that the relay isn't toast - still didnt start.
Undid the fuel line at the fuel rail and had the car cranked over - no pressure
I undid the fuel tank and removed the entire sending unit. I connected the pump to the positive and negative terminals of the battery to for a split second - powered on

Ok so my fuel pump is clearly not getting any power. Awesome.

Should I rip out my interior and start tracing this gremlin?
OR
Since my battery is located in the trunk, I could run a new power wire off of the battery with an 15amp fuze to the power wire at the relay?

What do you guys suggest I do now?

I've never experienced a wiring gremlin quite like this, and since I'm supposed to be in Calgary on Saturday/Sunday.

[nimblestix]

Quickly hardware it in with a new relay. Search how to hardwire the fuel pump. There's pre cut relay harnesses to make it simple.

Good luck dude, bad timing for something like this but its better it happens before you leave rather than in the middle of nowhere.

[Wootang]

Haha yeah this is terrible timing, but much better to have it happen in her driveway than say the ferry deck, or the peak of the Rockies.

I tested the relay with wire connected to the positive and negative terminals of the battery and it clicked. I also ran my multi meter to the other two prongs on an ohm setting and it bounced around a lot. It's showing resistance, so it's still functional, yeah?
I stuffed my multi meter into the wire side of the rely with the ignition on and never picked up a reading of 12v. I actually never picked up any reading - 9 or 12V
The relay seems to be functional? But just not getting power.... Would getting a new relay are wiring it directly be a benefit? Or could I just re use the green one?

Our fuel pumps are told to turn off after a certain amount of seconds of the engine not running and the ignition set to "on". Is this done via the ECU, or the relay? How would I wire that back in??

Aaahhh!!!

[nimblestix]

The ecu sends a signal voltage to the relay causing the relay to switch on the 12+v from the battery. Once the signal stops the relay switches back to open and no more power is given.

It wouldn't be considered a common issue for the ecu to suddenly stop sending the fuel pump signal unless somehow it was unlikely wiped clean, which is why I believe the relay is the cause. Relays can and do fail in completely random times.

Which green relay are you testing? Did you follow the fuel pump wiring to said relay? Perhaps you are testing the wrong one?
Just throwing some ideas out there.

Best of luck!
Brent.

[Wootang]

I googled where the fuel pump relay was, and nicoclub, and skylines australia (yet nothing from GTRC popped up) both mentioned that it's the green relay in the trunk, between the trunk latch and the drivers tail lights. I ripped the interior bits out of my trunk and only found that one relay.
I didn't follow the specific wires, so I guess there is a chance I was testing the wrong one... Only one Relay in that location though.

Alright, so I guess with those 4 wires in the back of the relay, it should look something like this... (not in particular order)
1) Power from battery
2) Ground
3) Power going to fuel pump
4) Switched power from ECU

Seeing how the original relay isn't working correctly, I can toss the idea out of using the test light.... Off to google to find the wiring digram.

[Wootang]

No one else has any ideas or input?

[Skym]

The wiring diagram is usually in the instructions with fuel pump hardwire kits you buy, so doesn't need to be posted, but from memory there is a few threads on this subject (hardwiring GTR fuel pump) on GTRC.

You can buy a Deatschwerks fuel pump hard wire kit with all the parts you need including wiring diagram -

http://www.deatschwerks.com/products/accessories/fuel-pump-hardwire-installation-kit-detail

Tomei sell a similar hardwire kit (usually with instructions / wiring diagrams).

[Wootang]

Yeah, all those kits will take time to arrive, and I was supposed to be on a ferry at 7am this morning.. Time is pretty much my biggest enemy at the moment.

I understand how the fuzed battery wire will go to 30
chassis ground goes to 85
fuel pump power goes to 87
but I don't know which wire on the OEM relay harness goes to 86 on the new relay

I've searched for a diagram, but havent found anything that is skyline specific.
The closest i've come to is finding out that pin 18 on the ECU is going to the fuel pump relay. Short of removing my entire interior and tracing this one wire all the way back to the trunk, I'm stumped as to how to find it

[Skym]

I see what you mean, the 12V feed (as you mentioned above that you couldn't find via multimeter, etc) from OEM fuel pump relay to 86??? -



This is for a R33 GTR (should be the same on R32 GTR) -

[Wootang]

Ok I'm really confused now.

Fuel pump is wired, and I can hear it prime every time I turn the ignition to "on". Will the motor start though? Of course not. It just cranks and cranks and cranks.

[Wootang]

I pulled the ECU out with the red light facing towards me, and turned the ignition to "on". The ECU isn't flashing any codes - the red light just stays constant 'till I turn the ignition off.

[nimblestix]

Check for spark and fuel at the engine if you know the pump is priming now.

[Wootang]

Yeah, I checked the fuel line as soon as I heard the pump prime. It's definitely supplying fuel to the rail.

As for spark, I removed the clip going into the igniter pack (is that it's name?) on the engine harness harness side and slid my test light into a slot and had the motor cranked over. Nothing lit up. Hhhmmmmmm

[Wootang]

I swapped all 4 blue relays under the dash with the fan relay since I know that one is working, but it still never started.
I also checked those small square fuzes that are located in the engine bay, but none have been blown.

I didn't have a chance to stick my test light in the injector harness before I had to head out, but I'll do that as soon as I get back to the car tomorrow. I doubt I'll see any pulsing, and combine that with how I'm not getting any spark, it screams CAS.
if I do see pulsing, I'm really in a pickle..

[Wootang]

I had some one crank the car over while I used the test tight to check for pulsing at the injectors. As I suspected, no pulsing.
I removed the CAS and had some one crank the car just to make sure the exhaust cam was rotating - it was.
rested the coil pack and spark plug against the valve cover as I rotated the CAS by hand to check for spark and to see if the injectors would fire. There was no spark, and the injectors clicked while the fuel pump primed the system again. I quickly checked other spark plugs to see if the tip was damp or if I could smell fuel, and while there was no wetness to the spark plug I could smell fuel. Not sure if this was my brain playing tricks on me or not though.

Besides temporarily swapping in a different CAS and ignitor pack, I have done everything my knowledge bas covers. I'm now waiting on a tow truck to get the car back to my house. I'll take the grey hound to calgary and deal with this problem when I return.