camopaint0707
camopaint0707 Reader
12/11/23 2:21 p.m.

My car is dead at a customer of mines parking lot.  It's not a huge deal but they'd like it gone sooner rather than later.  I thought it was the battery, replaced that no dice.  The fuel pumps aren't priming, I hear nothing.  I have the back seat ripped up and I tried giving the pumps direct power and nothing.  It's one of those dual pump setups but I can't get either to kick on at all.  It's a 2011 Infiniti G37x coupe.  The main pump has 5 wires (pink white red yellow black), 3 of them are grounded (pink yellow black).  I jumped to the red and white and got nothing.  It will crank and it seemed to sputter with a splash of starter fluid.  I'm all open for ideas to suggestions please.  Thank you.

WonkoTheSane
WonkoTheSane GRM+ Memberand UltraDork
12/11/23 2:27 p.m.

If it's 5 wire, is it possible that it's PWM?  I.e., the ECU is controlling how much pressure it's generating?    If so, a traditional jumping wires isn't going to work.      

Just to ask the obvious, you did check fuses and such, right?

camopaint0707
camopaint0707 Reader
12/11/23 2:32 p.m.

In reply to WonkoTheSane :

I checked every fuse in the engine bay, not a single blown one.  Including the fuel pump fuse.  What is PWM? forgive my ignorance.  I'm also not that familiar with this car or nissan/infinitis in general

Tom Suddard
Tom Suddard GRM+ Memberand Publisher
12/11/23 3:01 p.m.

Yeah, sounds like the pump is expecting a PWM signal to turn on. It's a computer signal to tell the pump how hard to pump. 

triumph7
triumph7 HalfDork
12/11/23 3:04 p.m.
camopaint0707 said:

In reply to WonkoTheSane :

I checked every fuse in the engine bay, not a single blown one.  Including the fuel pump fuse.  What is PWM? forgive my ignorance.  I'm also not that familiar with this car or nissan/infinitis in general

PWM is Pulse Width Modulation.  By varying the width of the square wave sent to the pump the ECM can vary the fuel pressure/

camopaint0707
camopaint0707 Reader
12/11/23 3:09 p.m.

well that's a new term for me.....So where on earth do I begin looking for that issue?  A bad ecu?

AngryCorvair (Forum Supporter)
AngryCorvair (Forum Supporter) GRM+ Memberand MegaDork
12/11/23 3:14 p.m.

In reply to camopaint0707 :

google to find which sensors or other connections must be present for fuel pump to run.  i'd suspect one of those before the ECU, unless google also tells you about ECU problems that disable the fuel pump.  sorry i don't have any vehicle-specific suggestions. 

93gsxturbo
93gsxturbo UltraDork
12/12/23 12:40 p.m.

Try to start it on starting fluid.  If it runs - fuel.  If it doesn't - spark.  Check that and report back.  

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