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fuel sending unit Question


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#1 ToxicDepression

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Posted 10 January 2017 - 10:43 AM

so, I decided to get a new fuel gauge and decided to rewire it, ( the previous owner thought that they were an electrician and completely messed with the wiring) I am going to drop the fuel tank and rewire the fuel sending unit and the fuel pump, which leads me to this question.... Does any one know if there are common problems with the fuel sending unit going out, or are they pretty durable? the reason I am not fixing the old one is because the previous owner also screwed with the wiring inside the engine as well. and if anyone has a wiring diagram for the sending unit and pump to gauge and power please let me know,, Thanks

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#2 Lockleaf

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Posted 10 January 2017 - 10:47 AM

Fuel sending units are pretty durable in these. I'm not sure I've come across a single person who had to replace one.

What year is your truck?

Half Pint ('71 510 Goon) http://community.rat...agon/p?=1269361

 

Tiny Havok ('85 720 DIY built Crewcab 4x4) http://community.rat...ache/?p=1395455

 

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#3 ToxicDepression

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Posted 10 January 2017 - 11:06 AM

its a 1984 4X4, with the z24 engine 



#4 asid99

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Posted 12 January 2017 - 08:36 AM

so, I decided to get a new fuel gauge and decided to rewire it, ( the previous owner thought that they were an electrician and completely messed with the wiring) I am going to drop the fuel tank and rewire the fuel sending unit and the fuel pump, which leads me to this question.... Does any one know if there are common problems with the fuel sending unit going out, or are they pretty durable? the reason I am not fixing the old one is because the previous owner also screwed with the wiring inside the engine as well. and if anyone has a wiring diagram for the sending unit and pump to gauge and power please let me know,, Thanks

ToxicDepression

Im not sure about the sending unit, but mine had a problem with the pump. It lost its compression abilities. It would make sound when you turned it on, but didn't have the power to keep up with the engine's needs, causing it to bog out. I however need to redo my gauges so if you could, please show how you do it. I am shitty when it comes to gauges.



#5 la_leo

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Posted 14 January 2017 - 11:59 AM

I have a question on this issue. Where do the wires from the fuel sending unit go? I think I'm getting a short in between the fuel sending unit and the guage. It worked intermittently for a while but now not at all.

#6 Lockleaf

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Posted 14 January 2017 - 12:03 PM

They go to the top of the fuel tank, through a hole under the passenger seat in the cab.

Half Pint ('71 510 Goon) http://community.rat...agon/p?=1269361

 

Tiny Havok ('85 720 DIY built Crewcab 4x4) http://community.rat...ache/?p=1395455

 

720 Shenanigans http://community.rat...20-shenanigans/


#7 la_leo

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Posted 15 January 2017 - 03:50 PM

And then directly to the dash ? Or is there a relay

#8 Lockleaf

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Posted 15 January 2017 - 04:13 PM

There is a voltage regulator built in to the back of the gauge bezel, but other than that, it is a straight shot I believe. Look up a wiring diagram, or a FSM for your truck.

Half Pint ('71 510 Goon) http://community.rat...agon/p?=1269361

 

Tiny Havok ('85 720 DIY built Crewcab 4x4) http://community.rat...ache/?p=1395455

 

720 Shenanigans http://community.rat...20-shenanigans/


#9 ToxicDepression

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Posted 20 January 2017 - 09:58 AM

so I got everything wired and put together but I believe I have the wrong fuel gauge, does anyone know what resistance I will need on the fuel gauge ( or type of gauge)



#10 Lockleaf

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Posted 20 January 2017 - 11:33 AM

Do you have an aftermarket gauge?

Half Pint ('71 510 Goon) http://community.rat...agon/p?=1269361

 

Tiny Havok ('85 720 DIY built Crewcab 4x4) http://community.rat...ache/?p=1395455

 

720 Shenanigans http://community.rat...20-shenanigans/


#11 ToxicDepression

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Posted 20 January 2017 - 12:53 PM

yes, I believe they gave me the wrong one



#12 datzenmike

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Posted 20 January 2017 - 05:07 PM

I have a question on this issue. Where do the wires from the fuel sending unit go? I think I'm getting a short in between the fuel sending unit and the guage. It worked intermittently for a while but now not at all.

 

Intermittent. Well if not reading, then not a short. A short would read FULL all the time. No reading would be an open circuit. Like a lose connection.

 

Nissan fuel senders are wired this way ...

 

battery....> ignition switch...> gauge voltage regulator... > gauge... > sender in tank...>  ground.

 

The sender varies a resistance to ground with

 

10 or less ohms..... FULL (a wire that is grounded will read this)

24.5 ohms.............. 3/4

37 ohms................. 1/2

56.5 ohms.............. 1/4

80 or more ohms... EMPTY (a broken or disconnected wire will read this)


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