So to get things started, i just got my car back from getting extensive body work done. Car has been sitting for the better part of 4 months, but i always been able to start it up and it idles fine. Car was retuned at SOHO 5 months ago with no problems and after a full inspecting by Nik.

Fast forward til about 2 weeks ago, go to pick up car from body shop and battery wouldn't hold a charge, so turns out battery is bad. We get a new battery and turns out alternator was bad and wasn't charging it. We get the new alternator so go to pick up car. 15 minutes in to driving the car it completely dies, get it back to shop and we find out the fuel pump is dead. We replace the old walbro 255 GSS342 with another what looks to be a carbon copy Walbro GSS342, it had W stamp and p/n on it like the original and everything (I got it off amazon since all other places were on back order). Get the car back drive it again and 15 minutes in the cars dies... again. Have the car towed home scratching my head thinking this fuel pump either is trashed or my car is burning up fuel pumps for some unknown reason. After getting it home and it sitting for about 4-5 hours i investigate and check all the fuses. Turns out the "IGN CONT & ECCS" fuse has blown. Put new one in and car starts fine.

Already suspicious of maybe a bad ground i start creating my own grounding kit for the car. Tidy things up and take the car on the next day for a test drive. 15 minutes in car dies... this time i go right back to the fuse. Again it has blown, i had a large pack at this point so i put a new one in. I turn the car over and this time i hear the fuel pump prime but only for a short split second as if it cuts off before it finishes and car won't fire up... just keeps cranking. I go back and to my amazement the second fuse i put in immediately blows. So at this point i'm like WTF. I put another fuse in, and it blows it immediately like before like with every time it attempt to prime the fuel pump. 4 fuses later i decided to tow the car home, at this point i'm over having it towed. Car is staying home until i figure this out. I let the car sit over night suspecting that something is either hot (fuel pump) and needs to cool down before attempting to start again. So this morning i put in my last of 3 fuses and start the car again. This time it start right up and idle fine.

So i'm thinking that maybe i got a trash walbro fuel pump that i recently order and it is basically choking out and burning up and causing my car to die. One thing i forgot to mention, in both instances where the car blew the fuse while i was driving, the car would cut fuel once under accel and then after letting off and accelerating again it would just die. This morning as i let the car idle i immediately check the fuel pressure gauge and it's showing 51ish psi.


** this is happening on Greddy twin turbo’ed 2003 g35 coupe**

 

Disconnect the fuel pump harness, turn the ignition to ON and crank it to see if the fuse pops. If it's fine with the fuel pump unplugged but immediately pops when you plug in the fuel pump then you have a bad pump.

If it still blows the fuse with the pump unplugged then you have a wiring problem, probably rubbed through somewhere.

 

Yeah problem is getting it to duplicate the issue. I’m over test driving it and get stranded again. I’ve had this car towed 3 times in the past 2 weeks. I may let it idle and see if rev’ing the throttle when engine temps are normal mah make it happen. I know this morning she started and idled fine. I’m about to double check the connections and siphon through the harness. I feel like I need to do that anyways. Thankfully car isn’t my daily.

 

Actually scratch that, I looked up that fuse in question, fuse 77 in the IPDM does NOT go to the fuel pump. Here's a few snippets from the FSM that relate to fuse 77. Pay particular attention to the last image, everything inside that red box could have potentially failed and is causing the fuse to blow, if you have been messing with any of those systems that's where I would start, otherwise it's going to be a matter of individually unplugging components to see what's shorted out.

 

Also, there was probably never anything wrong with your fuel pump, it just wasn't receiving the signal to turn ON from the ECM so it never had power until the fuse was replaced.

I would start with things like the MAF, inspect the wiring harness to make sure nothing is melted in the engine bay, could be MAF or the cam/crank sensors, if you have the rev-up engine it has the exhaust timing stuff, if you don't have the rev-up then ignore that. Coil packs, intake timing solenoids, etc.

Basically those items all get POWER through that fuse 77 (then send their signal back to the ECM), if any of those components has damaged wiring that is intermittently shorting out it's going to blow that fuse.

It's probably somewhere in the engine bay harness. Alternately you can source a used harness from eBay or pull one from a salvage vehicle and just replace the entire harness. Sometimes it's easier to do that than it is to track down the one spot on the harness that's got damaged insulation and intermittently grounding out.

 

Hmmmm...... so before all this stuff the car has been getting evap codes! i've replaced the Evap solenoid, i've replaced the cam sensors before too..... i think you are on to something my friend.... it was weird but the codes were intermittent. Before the car was down i would drive it and car would get to half a take and throw the code, it also prevented me from filling the car up all the way. I've even gotten a new gas cap because i thought it was venting. This is such a hodge podge... but i will do what i can to track this down.

 

Also the "NATS Antenna Amp". Is that for boosting the AM/FM radio signal in our cars? I know this whole time i have had the car, the aftermarket radio's AM/FM tuner never worked! THis is definitely related! All this stuff was done by the previous owner.

 

The NATS antenna is the one mounted to the side of the lock cylinder that detects the RFID chip inside your key to allow the car to start.

Nissan Anti Theft System - NATS

As for the fueling issue, there is a vent hose that goes from the tank up to the top of the fill neck that allows air to escape the tank when filling. There is a TSB about the hose basically getting plugged up with gunk which prevents proper filling of the tank, the symptoms are EXACTLY what you're describing. This issue is unrelated to your start problems but definitely something that should be fixed as well.

Here is the NHTSA link to that TSB for the fueling issue.

https://static.nhtsa.gov/odi/tsbs/20...44497-9999.pdf

 

I wonder how much it would cost to get infiniti to work on my car via that TSB for the purge valve. But i guess first things first. I have replace all my cam and crank position sensors.... i wonder if now i just have a bad MAF. I'll inspect the harnesses tomorrow.

 

I would try to wiggle around various parts of the harness and sensors with the butt end of a long screwdriver to see if you can get it to fail while the engine is running.

 

Update, this was under neath the battery tray

Is this even worth salvaging? Also does the engine harness come in two halves? Meaning can i just replace everything outside of the firewall?

 

Harness should be one piece iirc. What's the issue with the harness besides the loom that looks torn? I'm not seeing any damage but I am on mobile at the moment

 

I'd start with all the stuff covered in electrical tape, also that coiled up grey wire with the zipties. First try to figure out why they spliced and see what was added, look for nicks/abrasions on anything.

 

The middle picture I posted in post 4 has the color codes for all the wires that come off that circuit. Here's the color code chart from the FSM.

 

Thank you very much! This is what I was about to ask if anyone had info on. I’m doing a little bit each afternoon. I will keep you updated and should make some slow progress soon.