# Fuel pump fuse keeps blowing



## vett66guy (Apr 14, 2009)

Hi ,on my 96 Kingcab XE I have a frustrating problem. The 10amp fuse to the fuel pump keeps blowing fuses. It started a few weeks back...was driving when all of a sudden the truck just died out. Found that the 10amp fuse maked fuel pump was blow. I put in a new one. Truck starts right up, but only runs for about a half minute, then fuse blows again. I first though maybe the fuel pump was going , causing the fuse to blow shortly after startup. So I replaced fuel pump. Put in new fuse, truck ran for 30 -45 seconds, pow, fuse blows again!....I can't figure it out...Is there a short somewhere!....fuel relay checked out good. Could it be the fuel regulator? Anyone have any ideas!....thanks...Mike [email protected]


----------



## zanegrey (Dec 5, 2005)

crap in the fuel tank .

or a power wire that is frayed and shorting out..


----------



## vett66guy (Apr 14, 2009)

, Thanks for reply and suggestions......Nothing in tank, was taken down and cleaned when new fuel pump was installed.....as to wires, found nothing so far as to broken or frayed. The fact that it starts right up & runs for that 30 seconds to a minute at best every time I throw in a new fuse ( then blows the fuse again) really puzzles me!


----------



## zanegrey (Dec 5, 2005)

the filter could be bad ..

the pump could be defective..

it is drawing to many amps .. try a 15 amp then a 2o amp fuse..


----------



## vett66guy (Apr 14, 2009)

Pump is brand new..... Fuel filter was changed too. I tried a 15amp, ran and blew just like the 10amp...didn't try a 20 amp......Only thing not changed was fuel regulator. My one friend thinks it maybe building up too much pressure, thus blowing the fuse, so I changed the filter ( $11.00) but fuel regulators are $75-$90 bucks.....so hate to buy and change if not it. Think he may try a pressure test before we buy it.


----------



## CMax03 (Jan 17, 2009)

unplug the fuel pump harness and measure the chassis harness for a ground be sure to remove fuse while doing this...if the chassis harness has no short to ground then check the short harness going to the tank


----------



## 4X4D21 (Mar 9, 2009)

zanegrey said:


> the filter could be bad ..
> 
> the pump could be defective..
> 
> it is drawing to many amps .. try a 15 amp then a 2o amp fuse..




DONT put in a higher amp fuse, thats how half my harness melted and it was a bitch to fix and you do not want to go through it especially if you have someone else do it (i wired it in myself 200 bucks later) If you got water on the fuel pump wires theres a good chance something is shorted out. Take a power probe and test all the wires. even if you find a short right off, test them all just in case, because the outer coating on these wires are really not that waterproof


----------



## cjserio (Mar 18, 2008)

4X4D21 said:


> DONT put in a higher amp fuse, thats how half my harness melted and it was a bitch to fix and you do not want to go through it especially if you have someone else do it (i wired it in myself 200 bucks later) If you got water on the fuel pump wires theres a good chance something is shorted out. Take a power probe and test all the wires. even if you find a short right off, test them all just in case, because the outer coating on these wires are really not that waterproof


Agreed...fuses are not there to annoy you or create another thing for the dealerships to make money on, they're there to prevent the wires from acting like fuses!! If the pump is drawing enough current to burn up the fuse then there's a short somewhere allowing too much current to flow.


----------



## CMax03 (Jan 17, 2009)

Darn it man!


----------



## tuner_toolman09 (Apr 16, 2009)

:waving: i'm 100% it's electrical problem, your's pump will be on ignition power wire obviously and since it's shorting out like that that often it's rubbing on something it shouldn't so.....

NOTE: CHECK ALL FUSES FIRST make sure nothing else is shorting out too, if something else is shorting at same time then the point of contact of the fuelpump harness and that has rubed through and ***ing your s**t up lol


1. See where the pump harness grounds out to the frame or a common ground plug.

we need to find this so can check for ohms, this is going to tell us if the wire is good or not.

2. so once find the ground, need to put the ground side of the multimeter connect it to it using test lead ( long wire with aligator clips, can be made or bought fromlocal automotive parts store) and put your positive ( RED or + ) to the fuel pump harness side of the fuse.

we are looking hopefully for 1400 to 2500 ( go to local nissan dealer and ask a technician what is supposed to have for resistance ( ohms ) just to make sure, don't worry there not going to charge you for information)

3. so if it's in range than it's not that harness that's making it blow but in your case it's probably the only thing that's not working ( IF NO OTHER FUSES ARE BLOWN)

IF not in range then need to find where it's rubbing on other wire and wore through.

IF and when you find it rubbed wire what your going to have to do is to repair both wires and tie them in loom in a way that there not going to rub on eachother. or on the chasis ( frame, brake lines, suspension).


So go from there and let me know. tell me everything you find and will respond as soon as I can.


----------



## vett66guy (Apr 14, 2009)

Thanks for info......I don't know alot about electrical on cars.....I'll see if I can get a friend over who knows electrical better to check what you said to . Will post what we find ...thanks again...Mike


----------



## CMax03 (Jan 17, 2009)

Go to the connector @ the fuel tank and disconnect it! ither measure the chassis harness with a VOM or install a new fuse and let it rip,...Try to start it and see if the fuse blows! If it does the chassis harness or relay is faulty! If it doesn't then the fuel pump is more the likely your ground source!


----------



## vett66guy (Apr 14, 2009)

First thanks for all the reply's and ideas!. My friend who's an motor head and a Heating & AC guy by trade. I bought real nice wiring diagrams and he used those to trace down the problem to the connector on top of the fuel line assembly. I don't know much of electrical stuff, but he wiggled the wire and connection and was getting different amp readings or something like that. Anyway he says top of unit where it connects is too rustly and gone, so I'm in need of replacement. 
Anyone out there know or have a good used sending unit assembly. I already have the new fuel pump, but buy the looks of this unit, it's electrical is all bonded to the top gas tank seal, thats what I really need. So if anyone knows of one or where to get one that fits a 96 Nissan EX King Cab, 2 wheel drive, manual 4 cyl......please let me know...Thanks Mike


----------



## 94_nismo_freak (Dec 17, 2008)

that makes two of us mine is the same way. the lead wire next to the ground on the top fuel pump assem. was moving around and arking on the ground took 5 min to take a piece of vacuum hose and cut it in half hotdog ways raped the conector and a zip tie and that was over 9 months ago no high draw any more and now blow fuses better than spending around 300 dollars on a new one.


----------



## vett66guy (Apr 14, 2009)

Hi,Thanks for info, just got mine fixed over weekend...I friend who's good with electrial stuff came over. He tested my fuel pump assembly and found that I had a short ( bad wire connector) going into the top of the unit. When wire under connector was wiggled , he'd get unstable volts or amps ( forgot what he told me) , thus the short and blowing fuses he said. He clipped it out and rigged up another connector with new wiring spliced in. Works great , no more blowing fuses!....again thank all for ideas and info to this promblem.......Mike


----------

