Fuel gauge and temp

[Messi720D]

So im trying to trouble shoot fuel and temp gauge they both seem to work when ground manually but I have no resistance for them to work any ideas ? Fuse ? Connectors ? 

85 720 2.4 ST

[datzenmike]

If you ground the sender wires and they read full hot and full tank then can't be the fuse.

 

Seems like the senders are not working. Not really sending anything they are a variable resistance path to ground. Odd that they are both out. If tail lights and brake lights are working then the common ground that the tank shares is good.

 

Just a wild guess.... Make a temporary ground wire from the battery to the body sheet metal. Booster cable will do. Did that fix anything????

[Messi720D]

29 minutes ago, datzenmike said:

If you ground the sender wires and they read full hot and full tank then can't be the fuse.

 

Seems like the senders are not working. Not really sending anything they are a variable resistance path to ground. Odd that they are both out. If tail lights and brake lights are working then the common ground that the tank shares is good.

 

Just a wild guess.... Make a temporary ground wire from the battery to the body sheet metal. Booster cable will do. Did that fix anything????

Well I got fuel gauge running looks like bad sending unit cleaned it out and put it back in seems to work but trouble with grounding or just faulty, temp gauge will move once I ground the temp sensor with a wire but will not move only connected to oem wire ?? but that same wire connected to an after market temp gauge works fine wonder If temp sensor is running on different ohms

[Messi720D]

so went ahead and ordered a temp sending unit to replace aftermarket one i ordered TS111 but it too big  and thanks for all the input and great help all of you have been

 

 

 

 

This is what came out 

 

Every where i go this is what i am told it calls for 

 

This is what I'm working with unless i pulled wrong thing i see a plug next to where i pulled aftermarket temp sending unit 

[datzenmike]

Single wire is the temperature gauge sender unit. The dual wire ones are the temperature sensor unit for the  feedback carburetor. 

[Messi720D]

1 hour ago, datzenmike said:

Single wire is the temperature gauge sender unit. The dual wire ones are the temperature sensor unit for the  feedback carburetor. 

So I been look on senders online and the threads seem way to big the one I took out seems to be 1/8 npt does that sound right id figure it would be metric threads 

[datzenmike]

Nissan uses 1/8 BPT for the oil sender. Could it be BPT? They did this well into the 2000s and maybe still do. Most other threads will be metric.

[Thomas Perkins]

Look's like someone put that sender in that was not made for your 720.What year is your 720 and what size engine is it,Those senders are a one blade male sender.I looked everywhere and can't seem to see the one like you pulled out.Or that is another intake manifold.Here are mine from a 85 2.4 engine.The sensor has a new pig tail and the sender has a new female. blade connector.Both dry rotted long ago.I perty much replaced everything as you see on the date,but it ended up being a bad temperature gauge,one of the white wires melted away.What it was doing,was giving a real low reading on the temperature gauge on the dash.I also have a lifetime warranty on the sender and sensor.your sender hole look's smaller than mine.Their is a temperature gauge on Ebay for 25 bucks.Get a scrub pad and scrub the end of the sender.Clean it.Also as you see,I use all my vacuum hoses to my Weber.The reason for this is,when I put the Weber on,I left all the vacuum lines their and it runs perfect.If not broke,leave it alone.Works for me.Also if you look at your sender hole and mine,they are in different places.Your's in under the thermostat outlet bolt.Mine is more to the left of that bolt.

Edited May 18, 2023 by Thomas Perkins

[Messi720D]

59 minutes ago, Thomas Perkins said:

Look's like someone put that sender in that was not made for your 720.What year is your 720 and what size engine is it,Those senders are a one blade male sender.I looked everywhere and can't seem to see the one like you pulled out.Or that is another intake manifold.Here are mine from a 85 2.4 engine.The sensor has a new pig tail and the sender has a new female. blade connector.Both dry rotted long ago.I perty much replaced everything as you see on the date,but it ended up being a bad temperature gauge,one of the white wires melted away.What it was doing,was giving a real low reading on the temperature gauge on the dash.I also have a lifetime warranty on the sender and sensor.your sender hole look's smaller than mine.Their is a temperature gauge on Ebay for 25 bucks.Get a scrub pad and scrub the end of the sender.Clean it.Also as you see,I use all my vacuum hoses to my Weber.The reason for this is,when I put the Weber on,I left all the vacuum lines their and it runs perfect.If not broke,leave it alone.Works for me.Also if you look at your sender hole and mine,they are in different places.Your's in under the thermostat outlet bolt.Mine is more to the left of that bolt.

My truck is a 1984 720 2.4 4x4 i am the second owner previous owner didn't change much everything original for most part no major engine repairs so i was told, i do see the difference in location and size, at first i thought that the 1/8 npt sending unit was in a bushing adapter but no there there is non, and like i mentioned i ordered on online and thread was way to big

 

i ended finding this one from Napa P/N# TS6035 on specs it reads 39.5 ohms resistance @ 220 Deg F

i just don't know the resistance range on stock one and if this one will work 

[Thomas Perkins]

Wow,I just found one like your's...https://www.autozone.com/gauges-and-gauge-accessories/gauge-sender/p/equus-sender-electric-temperature-gauge-1-each/39179_0_0 Summit has them too.https://www.summitracing.com/parts/equ-9835?seid=srese1&gclid=Cj0KCQjwmZejBhC_ARIsAGhCqnd9YZzT37s5g7vz_Yf8Q8PPgRczPs-CAPC-EmV7fN32RjrvsL-XP2IaAsuFEALw_wcB Some more on Ebay.https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2334524.m570.l1313&_nkw=+NISSAN+720+TEMP+SENDER&_sacat=0&LH_TitleDesc=0&_osacat=0&_odkw=nissan+720+temp+sender&LH_PrefLoc=2

Edited May 19, 2023 by Thomas Perkins

[Messi720D]

2 hours ago, Thomas Perkins said:

Wow,I just found one like your's...https://www.autozone.com/gauges-and-gauge-accessories/gauge-sender/p/equus-sender-electric-temperature-gauge-1-each/39179_0_0 Summit has them too.https://www.summitracing.com/parts/equ-9835?seid=srese1&gclid=Cj0KCQjwmZejBhC_ARIsAGhCqnd9YZzT37s5g7vz_Yf8Q8PPgRczPs-CAPC-EmV7fN32RjrvsL-XP2IaAsuFEALw_wcB Some more on Ebay.https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2334524.m570.l1313&_nkw=+NISSAN+720+TEMP+SENDER&_sacat=0&LH_TitleDesc=0&_osacat=0&_odkw=nissan+720+temp+sender&LH_PrefLoc=2

Slapped on the one from Napa and this is the reading I get after letting it warm up for 10 mins and driving around the block for another 10 min drive with stop lights, seems a little low  😑 

[Messi720D]

Now that I know I'm getting a read on gauge maybe time to change thermostat could be that its stuck open I did see initial water flow in radiator when started with out cap because I was refilling coolant so that's my next step

[datzenmike]

There are ways to test a thermostat but when ever I have a cooling problem I just replace it. They don't last forever and all the bother to find out it's bad? Thermostat for the 720 is 180F. Spend at least $8 on a good brand name, don't cheap out. Over heating an aluminum head must be avoided at all costs and that $1.99 WallMart part just isn't going to cut it.