Fuel pump goblins

This isn't actually a honda problem, but I hope someone here can give me
some insight into what is happening & why.

I have a 93 Nissan pickup w/ electric fuel pump in gas tank. When it works,
it works fine.. until you shut engine off. It doesn't quit when engine is
running - regardless of how long it runs - 1 mile or 50. but after turning
engine off, fuel pump may or may not run. If it doesn't, it won't work
again until it sits a day or so.
Based on the schematic, I thought the problem was with the ECU to the fuel
pump relay, so I pulled the relay & jumped the circuit. It seemed to work
fine - started it several times over next couple of days - even let it run
& get up to operating temp, shut off & restarted fine.

Then drove it about 5 mi., and it wouldn't start afterward. Still wouldn't
start 3 hrs later, but started & drove it home about 20 hrs later. Turned
off & wouldn't start.

I guess I need to replace fuel pump, but I'm baffled as to why pump works
fine and continues to run as long as engine is running. It seems like a bad
pump would quit on the road instead of only when engine is turned off.

 

honda have been plagued by the solder on their main relay cracking. and
the symptoms are exactly the same as you describe. [if nissan use
mitsuba relays,] go to tegger.com, check out the resolution, then see if
it works for you.

 

it's certainly a lot easier to replace or resolder the relay than to change
a fuel pump.

 

Hi Jim - thanks for the reply
I read Tegger's entry on the mitsuba relays and Michael's description of
what happens with a Dry
Solder socket. It's enlightning - but not encouragong - looks like i'll
have to drop the tank and pull the fuel pump. My best gestimate is that the
bad solder connection is somewhere whithin the fuel pump assembly. I have
power to fuel pump with my jumped circuit - so main relay isn't the
problem. I was hoping for an easier fix - but at least knowing how it
could happen is positive.

Jim

 

PS
is there anyone here who knows about elec fuel pumps? I may want to try &
fix this one. Autozone wants $199 for replacement, & Ebeay has some for
$70, but many say "all except US built King cab" which is what I have.
If I pull the pump I don't mind paying for replacement if it works but I
want it to work.

 

regardless, you need to methodical about this and eliminate known
failure points. start with the relay and then test the wiring - both
sides. you should be able to pull that without dropping the tank.

fyi, although you probably know this, it's ***EXTREMELY*** dangerous to
run fuel injection without main relay cutoff being active - what you
have with the jumped relay. crashed car, trapped inside, continuing to
pump gas onto a flaming engine... you'll take weeks to grow your hair back.