Help....Fuel Pump Power Problem

[SMYLDOC]

My 92 NSX 3.8 NA SOS build in 2006 w/210,000 miles won't start
I just returned from a one week vacation, battery was on a tender during the week.
It cranks, just fine, but I do not hear the fuel pump come on when the ignition is turned on
I changed the main relay, no difference and I do have power to a good 15amp fuse in the footwell for the fuel pump (Walpro 255 installed 10 yrs during the 3.8 rebuild)
My service manual page 11-06 describes checking the fuel pump resistor, but mine was removed completely during the rebuild, so I cannot jump the terminals
Next page describes checking the voltage at the BLK/RED wire going into the fuel pump. I cannot find that black/red wire to check for voltage?
Is it accessible from the engine bay, or does the fuel tank need to be dropped to check it???
I figure it is my fuel pump, or possibly the signal coming from my AEM to that pump as I read about in a previous post
Any help would be greatly appreciated
Post here, my direct email: [email protected] or my cell 214-334-0403
Thx in advance

 

[Gary W]

Do you have a fuel pressure gauge to check the pressure when the ignition is on?

When you crank the engine do you see the Tach move?

Gary

 

[SMYLDOC]

Thx for the reply
I do not have a fuel pressure gauge, but I'm absolutely positive it is not energized as I always hear it when the ignition is turned on before I crank it to start
Just tried and the tach bounces very slightly as it cranks

 

[jwmelvin]

The red-black wire is where the wires go from the inside of the firewall into the circular plate on the firewall behind the center section.

Also in the service manual, it describes how to jump the main relay so that you can engage the fuel pump for more than the two-second priming period. I would do that as part of your diagnostic process. You will need to remove the center and side panel of the firewall (rear bulkhead) lining.

 

[Larry Bastanza]

The wire you are looking for is behind the drivers seat. Remove the inside rear panels, and you will find the circular plate that the fuel pump wiring goes through.

HTH,
LarryB

 

[SMYLDOC]

Thx for your help
I re-read pages 11-103 thru 11-105 about the main relay and did not see the method of jumping terminals to extend that signal to the fuel pump
Tonite I'll pull that driver side rear passenger panel and check for signal to that Blk/red wire

 

[jwmelvin]

I re-read pages 11-103 thru 11-105 about the main relay and did not see the method of jumping terminals to extend that signal to the fuel pump

I have a 2000, so use the later service manual. At 11-142 (page available here) it describes a jumper on the two connections to the main relay:

 

[SMYLDOC]

Question......why am I not determining current to the fuel pump at the fuel pump????
I removed the trim panel behind the drivers seat. Pulled up the rubber cover up, removed the 3 screws on the round cover revealing a 3 prong plug that goes directly into the fuel pump. The three wires in that plug are solid yellow in the center, a Yellow with blue stripe on one side and a solid black on the other side.
Wiring diagram #14 indicates that YEL/BLU comes from fuse No. 18 (20 amp)
YEL goes to F ??? SPOOL SOLENOID VALVE
BLK is ground
By checking for current at this plug, wouldn't I then be checking everything in that circuit including the main relay, the AEM, the wiring thru the BLK/RED plug ???
I don't see this as a diagnostic test in the service manual, but why not?? what am I missing???
So, I just checked voltage with the ignition on and it read 11.72 volts when the YEL/BLU plug to the BLK plug
So, wouldn't this mean that the 10 yr old Walbro pump is bad???
Thx , jv

 

[SMYLDOC]

Well it's DONE, replacing the fuel pump cleared up my non start problem!
It stars and runs great
To clear up a few things as my above post is NOT correct
Checking that YEL/BLU wire in the panel directly behind the drivers seat does not test the fuel pump
As stated above in the responses, you must check that BLK/RED wire as that's the one that does directly to the fuel pump
In retrospect, this was my most ambitious project in the 19 yrs I've owned this car. For some reason I cannot explain, it seemed to go back together easier than it came apart.
If I could offer 2 tips to those doing this in the future
I took a permanent marker and drew lines on the upper housing of the shift and clutch cables male post to orient the hole direction for the cotter pins, I also sharpened the tip of the cotter pin to make it easier to them insert thru the holes
Also, when putting the fuel tank back into position, I had trouble trying to get the fuel line with the banjo connector that goes into the fuel filter. So, I dropped a small gauge wire from the engine bay down thru the opening for the two fuel lines and tied it thru that banjo fitting. I have my wife pull up on that wire as I lifted the tank into place.. No problem it went right thru that opening.
Good luck, if I can help anyone in anyway please ask as I'm no expert having done this only ONCE but I'll help if I can
Thx jv

 

[jwmelvin]

Nice work! I've heard it's a pain to replace the pump. Glad you got it sorted.

 

[comtec]

Good work. I just did this too and it was a pain. Didn't have any trouble with the pins, did them on and off by feel with just my fingers. Before I dropped the tank I taped the hoses together with a little pull rope to get them back up. 2 hoses on the passenger side and 5 on the drivers side of my 02. Didn't expect 5 from the manual and they were in a hard location to get to.

Mike