J30 not starting (UPDATE)

[andre1038]

Ok i have a 94 J30t not starting this is the story. I have been driving my J30 for awhile and every morning or when it was really cold i would have to leave the ignition on "ON" position for about 5 seconds then i would hear the pump make a sound (sounded like someone knocked on the fuel tank with their fist) then i would turn the car on and the car would start fine warming up but if i try to start it before the knock sound from fuel pump it would not start. So i did the first thing possibe since the pump on the car was old and installed a new Bosch fuel pump. Car is not starting now (except once after alot of cranking) it cranks has spark and everything but not starting like something is not working right. So this is what i have installed

-New Bosch fuel pump (which is the O.E.M pump for Nissan because Unisia Jecs is Bosch's Japanese division and the part number matched the Original in the car)

This is what i have tested so far:
The resistance in the new fuel pump was in Specification, the fuel pump control modulator/unit (located in right side trunk behind cover panels) i took one from a junkyard J30 and same result so thats not it, Checked resistance in fuel pump resistor (located in trunk next to fuel pump control modulator) in Specification as well, the fuse for fuel pump is good, the relay for fuel pump (located near driver side kick panel behind Transmission computer) is good tested it by supplying voltage to it hearing it click plus i have two other fuel pump relays (the green colored ones) and still did the same thing no starting with any of the 3. So im stuck wondering something is not supplying the right voltage to pump or could it be fuel pressure regulator?? i mean i changed the one i had originally to a junkyard one to get around but im still wondering. After a few cranks i am getting pressure in the tank cause when i open the fuel cap i hear pressure escaping but it could be due to alot pressure that has build up after several cranks. And get this, after alot of cranking the car did start barely and i got to drive it fine (around neighborhood) so freaking weird. But after i turned it back off and let the pressure escape (simulating like if i was getting gas for the car) it will not start. I have tested alot of components and im left with either an ECU or Regulator. Now the reason i say ECU is because last year the ground for my AC fan from ECU i discovered was not good anymore so i had to make an external ground for AC fan circuit cause the one that was built in the ECU wasnt good and plus the ECU keeps bringing up code 13 even though i installed a new Coolant temperature sensor and i checked if the ecu is sending voltage to the sensor and it is. I also checked the ecu ground for this sensor and continuity did exist. So my Ecu is basically showing a code for something thats been fixed and my check engine light is not ON or never seems to ever light up even tho the computer shows code thru the self diagnosis mode. Now right now im trying to find out if anybody has experienced this in their J. I also already installed new injectors and o-rings 5 months ago. Just trying to get an opinion should i purchase a new regulator or buy an ECU from Ebay

[andre1038]

I think i will go with regulator since code 31 has not shown unless i have been reading the self diagnosis backwards.

[driverdriver]

Do you have any updates?

This is one of those problems that's mind boggling.

[andre1038]

Hey Driver Driver i am gonna update this as soon as i install the regulator. I found it online for 53.95 so it should be here around tuesday or wednesday the latest. Has there been a post on how to change a fuel regulator??? if not im willing to show all J members how to do it with the proper procedure with pictures and explanation

[randytrant]

been having the same thing on a 1994 J30.......did your regulator help...

[swimshark]

do you know which regulator it is?

[andre1038]

UPDATE
Ok guys i fixed the problem. So this was the problem, i had defective fuel pump from the manufacturer. So they will be sending me a new one in the mail. The only way i found out that the fuel pump was defective was the following way. Some of you will probably not believe it. Ok so my 94 J30 did not want to start at all with the NEW OEM pump so this is what i did. I took the fuel pump out of my father's daily driver a 98 Y33 Q45 (The two share the same part number until the last digit. J30 ends with T40 and Y33 Q45 ends with T45). Everything fit perfectly it was like the pump were the same regardless of the different part number. (Remember J30 in japan did come with a VH41DE like the one in Y33 Q45). So guess what when i installed the Q45 pump in my J30 i turn the key and vrooom the J30 starts up perfectly. It was a defective new pump that was my problem, but i noticed my car ran just alittle rough (probably due to old regulator) so since i bought the regulator already (for 53.95 from rockauto.com) i installed it and guess what the car runs super smooth, not once since i owned this J30 has it ran this sweet. So yea guys i have a step by step procedure how to take out the fuel pressure regulator with pictures i just dont know if you guys already have it as a sticky, I have the car software for a infiniti J30 so i will just be copying and pasting Alldata's instructions and show you with my pictures, but before i do just let me know if you guys dont have it. So in the end i took out my father's Q45 pump and installed back in his Y33 and luckly we had a good spare one for him that i ripped out a running Q45 that got crashed in the front. So yea as of now until i get my new OEM pump in the mail i will be riding around in a Q45 pump. LOL Hope this helped some people, and by the way the defective pump i tested it's resistance and it was in Specifications yet it just did not want to work so if you encounter similar it has to be the pump. My household has a Y33 Q45, 96 G20, my 94 J30, my 92 Q45, and my 90 300zxTT so yea we are a nissan family and i have alot experience with Nissan's/Infiniti's (My J30 i did a engine rebuild in my garage lol i took the whole powertrain out though so i can make sure everything was perfect lol i was tempted to drop a VG30DETT but i was like na i already got a Z so i just left it stock) J30 is a solid car and i would like to put my knowledge of the car in this forum, (I have done alot to my J bringing it back from the dead) and o dont try to install a 90-96 Q45 fuel pump because that is a completely different fuel pump that fuel pump in a G50 looks awfully similar to my Z's maybe one day i will pull both out to just experiment and see lol

[andre1038]

O and to answer swimshark's question i changed the fuel pressure regulator. the one on the right of the engine when your looking at it.

[yodawill2000]

Bravo !!!

[driverdriver]

Good to see, you got it figured out!