Fuel Pump not pumping after hitting a rain puddle

[Xproject187]

I got caught in a hard rain & hit a puddle in my 92 Sentra 1.6L(GA16DE)A/T doing about 40. It ran fine until I stopped at a friends & turned it off. After that it wouldn’t start no matter what I tried,so I got a tow.

The next day was sunny,so I broke out my compressor & spent the whole day checking out connections as I tried to find the problem. I finally realized there was no humm coming from the Fuel Pump. You know when the key gets turned to on position). well it wasn’t humming. So I put a tiny bit of gas into the intake & Varrooom it started rite up(but of course it died). Anyway I’m poking around aimlessly now without knowing where to look next,so please can you direct me to a “Flow-Chart” or maybe suggest a next step.

In short,I’d need to ask,what would make the Fuel Pump on a 1992 Nissian Sentra stop pumping after hitting a big puddle. I’ve put new Bat terminals & new fuel pump relay,checked all fuses & the bottom of fuse blocks(2) in engine compartment for moisture/corrosion,evey connection I could find,including my Oil Sending Unit(which looks interestingly questionable to me).

Topic

[college man]

Maybe the fuel pump itself quit. check for 12v to the fuel pump.

[Xproject187]

Thank you for answering my request for help,I’m very greatful.
Please know that I don’t mean to be disrespectful & if I get a lil confusing,it’s only because I’m confused. Allow me to say that your question is kinda tricky. Because first you say “Maybe the fuel pump itself quit”. But then you ask me to
“check for 12v TO the fuel pump”. (As in,is 12v being sent to the fuel pump).

So
To the first part of your question my answer is “No the fuel pumps not dead”(I tested it today).

To the second part of your question my answer is “No, 12v is not being sent To the fuel pump & if it is,then it’s getting cock-blocked somewhere along the way.

Today I removed the metal protection plate & unplugged the plastic connection exposing the Fuel Pumps Positive & Negative terminals. I used my battery jumper box to run Ground & 12 Volt test leads to those terminals. I flipped the switch on my battery jumper box & of course my fuel pump purred. But you already knew that. Rite ? I know I did.

I mean after all,my car was running great,till I hit that puddle. Now it won’t start. To me that doesen’t sound like a faulty fuel pump. It reeks of an electrical issue(like a short). I know it’s not getting fuel,but what would make my fuel pump not pump(loss of signal?)

Anyway no bigg,I too wanted to be sure the fuel pump was working. So now that that’s outta the way,hopefully we can get on to some sort of flow chart or get a look at a wiring diagram. Because I really don’t know where to look next & I feel as though I’m just wasting time.

I’d like to add two new possible points of intrest.
While installing my new battery terminals,I noticed a slight spark,should I see a spark?

Secondly; Late last nite(2am) I went to my car & turned on the key to listen for the familiar humm of my fuel pump. Instead I heard a single clunk comming from my ECU when I turned off my ignition. Never noticed such a noise before,should my ECU clunk after turning off & removing the key ?

[college man]

Did not mean to trick you up with answer. Maybe means
a possibility.I can’t confirm that your fuel pump is bad
over the internet. Thats why I asked for you to confirm that
the pump Is either getting 12v or not. Anyway. now that you have
confirmed the pump does indeed work. we can continue trouble shooting.
see if this link helps you.pull up wiring diagrams at the bottom.

http://www.nicoclub.com/FSM/Sentra/1993_Sentra/

[Xproject187]

Thanks for understanding & being available,I’m at the page you linked but truth is I don’t really know where to start troubleshooting. I mean sure,I know how to look at a diagram but I don’t know exactly what step to perform next. So I guess I’ll go poke around a bit & wait for your next reply.

Since I know the fuel pump is working,I’m going to go check & see if a 12v current is making it back to the connector that plugs into the Gas Tank Lid(like you asked).

PS:
I downloaded the entire manual to my hard drive. However,I noticed it’s for the “1993” Sentra. No Biggie Rite ? And what do you think about my questions regarding the lil spark at my Batttery Terminal & the faint clunk at my ECU ?

Thanks again College Man.
Xproject187.

[college man]

Yes it is normal to see a spark when reconnecting the
battery terminals. As for the wiring being for a 1993
sentra and not 1992.The manuals I reference stop at 1993
should be the same.A clunk/click sound is the ecu being
powered.Have you looked at the ecu for water damage?
According to the diagram.There are two fuses for the
fuel pump relay. remove the fuel pump relay.with the key
on engine off.jumper the two line side terminals with a
piece of wire.blk-red and brn does the fuel pump run?
there also is a ecm relay to check.

[college man]

wiring

http://www.nicoclub.com/FSM/Sentra/1993_Sentra/l%20wiring%20diagrams.pdf

[Xproject187]

Yes I checked my ECU for water damage last nite,but I saw no wetness of any kind. In fact the ECU was all dusty & my carpet was completly dry. I just finished watching the videos you linked & it reminded me to tell you that my car was in an accident aprox 3yrs ago.

I clipped a Malibu from behind. So my drivers side front bumper got pushed back into my fender. My cars 2 engine compartment “Fuse Blocks” are located on that side & both harnesses run behind my the fender liner on that side. I’m currently watching the last video you linked & expect to be done in approximately 15mins.

Meanwhile please allow me to show you what I found when I checked to see if voltage was being delivered to the female plug that connects to the plastic tank lid under the back seat. You’ll notice the bottom rite terminal(Ground)is slightly blackened & melted to the point where the ground terminal is slopping back & forth(Loose) & you can even see daylight shinning through it. In other words the ground terminal is getting hot!

Attachments:

• photo.JPG

[Xproject187]

I just re-read your post & I think I understand that you’re asking me to pull the Fuel Pump Relay(Brown) located in the engine compartment Fuse Box. Then jumper the contacts inside its receptical,so as to check & see if 12v will then get delivered to the pump(is that rite?).

Please excuse me,but this is rite about where I start getting confused. So bare with me ok ?

You stated that there is also a “ECM Relay to check”.
I am not familiar with a ECM Relay,is that the brown relay located in my engine compartment fuse box ?

Because I know of only 2 fuses that control my Fuel Pump. The first is located in my “Under-Dash Fuse Box”(a small 15amp) & the second is a big brown square relay located in my engine compartment fuse box.

PS:
Excuse me but in my first post I had stated that I’d put new Battery terminals,a New Fuel Pump Relay & checked all the Fuses remember? Anyway I’m off to try the step you suggested. BRB

[college man]

[quote=”Xproject187″ post=55409]I just re-read your post & I think I understand that you’re asking me to pull the Fuel Pump Relay(Brown) located in the engine compartment Fuse Box. Then jumper the contacts inside that receptical,so as to check & see if voltage will then get delivered to the pump(is that rite?).

Please excuse my confusion,but this is rite about where I start getting confused. So bare with me ok ?

PS:
You did read the part in my first post where I’d stated that I had put new Battery terminals, a New Fuel Pump Relay & checked all the Fuses rite ?[/quote]

I have read everything that you have done and posted.
you are correct in the jumpering of the relay contacts
to see if the pump runs.If it did run.It tells me that
the fuses and wiring and pump work from that relay back.
But I see an issue in the picture. so I was right by sending
you to the pump.

[Xproject187]

Thank you & I’m sorry I didn’t mean to sound like a smartelleck. So should I go jumper the relay still like you asked ?

[college man]

you could jumper the relay to see if 12v is read at the
connector. or crank the car and see if 12v is read.this way
we can see if the circuit works on its own. leave the relay in.

[Xproject187]

I left the relay in place like you asked & placed my tester at the female connector that plugs into the Gas Tank Lid(Fuel Pump). My wife turned the ignition on & I saw +12v delivered to that Connector for 5 seconds,but then it drops to Zero. We retested it 4 times & it did exactly the same thing(12v for 5 seconds then drops to Zero). So I put the old relay back in & re-tested it & saw the same result.

So I pulled the relay out of its recepticle & probed my +Pos test lead into the first Line Side hole(big slots) & placed my -Neg test leed on my -Neg Battery terminal & I saw +12v Constant (No drop). I tested the other Line Side hole & got a 0v reading(as I should,rite ?).

PS:
I tested the smaller holes too,but I’ll wait & see if you even need em.

[college man]

If 12v was seen at the pump.That says that entire circuit works.
I believe you need to fix the pump connections.

[Xproject187]

Please realize that I’m probing my test leads into the connector that plugs into the “Fuel Tank Lid”. There is no other connection between my test point & the fuse box. No disrespect but it almost seems as if your omiting the fact that 12v is not being “Sustained” at the pump connection.

The fact that the 12v current drops to Zero within 4secs makes me think that something is shorting out & a protection device like the “Circut Breaker” shown @ 12:11 in the video you linked is shutting off the voltage.
Am I wrong in this logic,or is it normal for the 12v current to drop to Zero ?(No)

[college man]

I think whats happening here is the pump is going into prime
mode.But the ECM is getting an incorrect start signal which is
shutting down the ECM go to the service manual I sent you. look
under system component tests. find the start signal trouble shooting.

[Author]

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