Another Oil Pressure Question

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Joined
Dec 7, 2004
Threads
70
Messages
370
Location
NW of Denver
Here is the problem- Last year I swapped my 3fe with another 3fe that I got from cruiser parts. Everything runs great except for the oil pressure gauge reads nothing. Of course we check the wiring, voltage etc as well as put a mechanical gauge on the motor to check the oil pressure. Reads fine. Put a new sender unit on the truck. Nothing changes. One option is to run an aftermarket gauge (not may first choice) on it or get a new gauge from cruiser parts. Got the cruiser parts gauge but I have not installed it.

Fast forward a year- I am farting around under the truck and I see the yellow oil pressure wire that had been left unhooked up and I hook it back it to the truck. Reads nothing. I go for a drive and I notice that it has moved south some. Start it up after lunch and it goes up to the lower third of the indication and drops back down as I start driving to almost nothing. Has been doing the same thing now for the last week

So is it working now or is it a bad gauge that was hooked up wrong with to begin with (I read from a search about them burning out or something if they are hooked up wrong)? I know that I should put the new one in, but I am lazy and I do not feel like taking apart my dash or is the old one working and I have no oil pressure. If that was the case I would see rise in the temp gauge as well- right?


Lastly when my fuel gauge reads empty the most I can put in it to top it off is 14 gallons. I am pretty sure that it is 20 or 25gallon tank??? Maybe I should just replace the whole cluster?
 
Did you attach the wire to the center post on the sending unit or the tab on the side, which is for a ground? If you hook the wire to the ground you'll fry your oil pressure gauge, which will then give you wonky readings.

Put in a good Autometer mechanical gauge. This'll be just as easy as replacing gauges in the cluster and may also be less costly. Plus you'll know exactly what the oil pressure is.
 
before you scrap the whole cluster, try polishing up a ground connection somewhere on the cluster and running a small wire to fresh sheetmetal screw on the body so that you know you have good ground. It can help a lot.
 
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