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How to test an oil pressure sending unit (Read 1506 times)
FDrex
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How to test an oil pressure sending unit
Dec 12th, 2012 at 4:31pm
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Hello Guys,

I was just wondering if anyone can tell me how to test an oil pressure sending unit with a load tester. My gauge is pegged at 5 and it does not move. Thanks!
  

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kfanazini
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Re: How to test an oil pressure sending unit
Reply #1 - Dec 12th, 2012 at 6:11pm
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I cannot help with the load tester, but has it always pegged at 5 or did this just start?

Some thoughts...

Its a two wire sending unit often the ground comes loose and it will show 5.

Did it do this after an oil change, if so what weight oil are you using?


[quote author=FDrex link=1355351462/0#0 date=1355347862]Hello Guys,

I was just wondering if anyone can tell me how to test an oil pressure sending unit with a load tester. My gauge is pegged at 5 and it does not move. Thanks![/quote]
  

1986 944 na
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FDrex
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Re: How to test an oil pressure sending unit
Reply #2 - Dec 12th, 2012 at 7:50pm
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No the oil pressure gauge stopped working correctly when my console gauge grounds fried. They fried from the defroster switch wires rubbing against dash metal. Those are all repaired now and when it is hooked up, it is still pegged at 5. I am wondering if a jolt of power fried the oil pressure sending unit if that is possible? The sender and gauge was working fine after a previous oil change and I am using Castrol 10w 30.
  

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Ohio_Tom
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Re: How to test an oil pressure sending unit
Reply #3 - Dec 13th, 2012 at 10:56am
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Pegged indicates an "open" circut.
Either the guage is bad, the wire broken, or the sending unit took a jolt and fried (yes they will do that).
To test the guage and wiring, take the lead off the sending unit and ground it. The guage should read "0".

To test the sending unit, measure Ohms from the terminal to ground. (engine off). Should be "0" or close to it.
  

Tom Simpson&&VW/Porsche freak.
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Dave W
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Re: How to test an oil pressure sending unit
Reply #4 - Dec 14th, 2012 at 2:09pm
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Time to run some SeaFoam in the oil.  A search will find instructions easily.

Unless you're running really thick oil like something over 40 W.
  

Dave - 84 NA, Black, running, smogged, titled, registered, and insured.  On the road!
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Grandpa#3
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Re: How to test an oil pressure sending unit
Reply #5 - Dec 15th, 2012 at 5:58am
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Dave, He is using Castrol 10w30 motor oil. The oil weight should not matter. We run 20w50 year round and FDrex only lives about 25 miles from me.

Cheers,
Larry   Smiley
  

Use Spell Check and you will always bee right.&&Half way between Perry and Hawkinsville, Georgia&&1985.5 944 n/a  Graphite Metallic, a work in progress. &&1992, 968 Horizon Blue Cab&&&&
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FDrex
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Re: How to test an oil pressure sending unit
Reply #6 - Dec 18th, 2012 at 1:06pm
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Hey guys, these are all very informative posts. I don't think the oil is going to be the issue in this case and I ran a seafoam treatment as soon as I got the car  Wink

Does anyone know where the ground is wired to from the sending unit? I have a feeling with the ground wires being fried from the previous issue I had that this may be the case. I will probably start from that, then test the unit itself, and if not that then perhaps the gauge.
  

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Dave W
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Re: How to test an oil pressure sending unit
Reply #7 - Dec 18th, 2012 at 7:17pm
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I think this is a 1 wire unit so the unit is the ground.  Check to see if someone put teflon tape on the threads.  That would mess with the ground.
  

Dave - 84 NA, Black, running, smogged, titled, registered, and insured.  On the road!
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