Fuel/Oil gauges

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MiniPigg

MiniPigg

10 Year 15 Year 20 Year
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Jan 2, 2005
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278
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2,065
Location
CouleeDamWA, BoiseID
The Water Temp and Voltage gauges work fine. The Fuel and Oil Pressure gauges do not. The needles never move. I can see maybe one not working due to a failed sender or a cut wire, but two seems odd. I was thinking maybe something to do with the gauge cluster?
 
I have the inverse issue--I don't have confidence in the water temperature gauges at all. I'm contemplating adding aftermarket pod oil pressure, oil temperature and water temperature gauges to both my 70's. I've been trying to decide which ones to use. I'm even playing with the idea of using a little arduino and touchscreen. It's not like these sensors are rocket science.

1570250484954.png

This one, for example is less than 30 bucks and it states "Output: 0.5V – 4.5V linear voltage output. 0 psi outputs 0.5V, 50 psi outputs 2.5V, 100 psi outputs 4.5V" That's not hard to convert and I've been meaning to play around with those little 25 buck computers for a while. I don't like the cheap gauges on amazon very much--they all seem to have brand names prominently displayed.

The current arduino boards have 6 analog inputs. And this little display is less than 20 bucks.
1570251676054.png

This seems to me to be about the right size for three measurements, perhaps with bar graph.

I love my old cruisers but mostly they don't have OBD2, and even those that do, I don't really like relying on OBD2. I've looked and I've not found any reasonably priced engine monitors. There probably a lot of pitfalls and delay in trying to roll ones own as it were, but I think I'm at probably going to give it a try. If it turns out to be easy maybe I will add transmission temperature, etc.

I should add that I've had a real miserable time trying to get the original factory gauges working. I'm deeply suspicious of all of them and some plainly are non-functional. There are so many variations on instrument panels that it is really hard to buy a replacement. I've kind of given up.
 
On my bj74 there is an electrical connector for fuel sender at the rear in the middle Above the bumper. If you disconnect it then cross connect the wires coming from the tail light area you should see the gauge on Full.
My fuel gauge drops out from time to time and the oil gauge is out always.
I took the dash apart and lightly sanded each connector for the gauge cluster. The ribbon of conductors on the floppy printed circuit looked very clean to me. After clean and reassembly I went several weeks before the fuel gauge went out again. It came back after a few hours.
 
When I purchased my '93 PZJ75 the fuel gauge was always stuck at 2/3. I checked the connector on the passenger side behind the seat and cleaned all the connections and then went in search of the fuel sending unit connector which was tucked up above a cross brace. I measured resistance on the fuel sending unit and checked for voltage coming in from the electrical system. No problems with voltage or resistance; the problem was very dirty pin connections due to living in the tropics. My fuel gauge has been working properly since.
 
With the oil pressure gauge, the general rule is if the needle sits down a fair way past zero, the guage is the problem. If not its the pressure sensor
 
John Young said:
There are so many variations on instrument panels that it is really hard to buy a replacement. I've kind of given up.
Click to expand...


Usually parts have the part number on them somewhere.
 
roscoFJ73 said:
Usually parts have the part number on them somewhere.
Click to expand...
Well sure, but when you are pawing through scrap yards sometimes it is not that easy. Most of what I see is for later vehicles from AUS. I just really want to get some accurate readings of temperatures and pressures. I'm going to start a new thread on getting a better handle on this and something I'd like to try.
 
John Young said:
I have the inverse issue--I don't have confidence in the water temperature gauges at all. I'm contemplating adding aftermarket pod oil pressure, oil temperature and water temperature gauges to both my 70's. I've been trying to decide which ones to use. I'm even playing with the idea of using a little arduino and touchscreen. It's not like these sensors are rocket science.

View attachment 2099197
This one, for example is less than 30 bucks and it states "Output: 0.5V – 4.5V linear voltage output. 0 psi outputs 0.5V, 50 psi outputs 2.5V, 100 psi outputs 4.5V" That's not hard to convert and I've been meaning to play around with those little 25 buck computers for a while. I don't like the cheap gauges on amazon very much--they all seem to have brand names prominently displayed.

The current arduino boards have 6 analog inputs. And this little display is less than 20 bucks.
View attachment 2099205
This seems to me to be about the right size for three measurements, perhaps with bar graph.

I love my old cruisers but mostly they don't have OBD2, and even those that do, I don't really like relying on OBD2. I've looked and I've not found any reasonably priced engine monitors. There probably a lot of pitfalls and delay in trying to roll ones own as it were, but I think I'm at probably going to give it a try. If it turns out to be easy maybe I will add transmission temperature, etc.

I should add that I've had a real miserable time trying to get the original factory gauges working. I'm deeply suspicious of all of them and some plainly are non-functional. There are so many variations on instrument panels that it is really hard to buy a replacement. I've kind of given up.
Click to expand...

@saltycoconuts is working on an arduino setup as well. I’m wanting to do something like that.
 
John Young said:
Well sure, but when you are pawing through scrap yards sometimes it is not that easy. Most of what I see is for later vehicles from AUS. I just really want to get some accurate readings of temperatures and pressures. I'm going to start a new thread on getting a better handle on this and something I'd like to try.
Click to expand...

I wouldn't mind having the ability to search thru scrap yards for parts to use on my PZJ75; its just not available here in the PI.
 
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