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For some time now my oil pressure gauge has been acting strange. This is the symptom. Start the car gauge reads NORMAL, increase throttle gauge drops down as throttle is increased untill check gauge light is on, especially when cruising on highway @3,000 rpms. Let off throttle and check gauge light goes off gauge begins to read higher and higher pressure untill back to normal. At first I was concerned that my brand new engine had a bad oil pump , but I think I would have known by the way the gauge was reading so my guess is that the gauge is bad. Today I had to know for sure so I brought my car to the shop and me and my father hooked up a mechanical oil pressure gauge where the sender would go. Started up the car and at idle it read 60PSI "with engine hot" Reved up to about 3500-4000 Rpms and pressure goes up to 90 PSI. So my guess was right I have a bad oil gauge, so I hope this thread will help someone else in the future.
thank you :)
 

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Its the sender, common problem.

Check the tech articles, there is one that tells you which sender to buy to make it so your stock gauge will give actual readings rather than alwsy staying in one spot on Normal, it isn't hard to do and if you have to change the sender anyway you might as well do it. When I did it I also needed a little elbow fitting for clearance between the block and sender and you need a little wire to jump across a resistor.
 

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Do those numbers sound high to anyone else besides me?

I'll have to pull my manual out, but I thought at warm idle the 4.6L were only supposed to pull 10 to 20 lbs. I also thought I read somewhere that the 4.6L is designed to run on less oil pressure than "normal" engines. (Can someone check their manual for the exact pressures?)

I see in the Dr.’s photo it’s at 89 psi.

I've always heard that oil pressure should be 10 psi for every 1000 rpm. But that was "old school" so it may not hold true anymore.

Any clarification/thoughts? :thumbsup:

But thanks for those numbers anyway. I've been fighting a similar problem for a while now and I just haven't connected the gauge yet. (I had planned on it yesterday, but got too lazy after work. :D )

I seem to be eating sending units; four in the last year, 2 OEM “switch” type, and two “sending unit” types. And every time the symptom is a fluctuating gauge. :mad:

http://forums.tccoa.com/showthread.php?s=&threadid=39482

http://forums.tccoa.com/showthread.php?s=&threadid=34586

http://forums.tccoa.com/showthread.php?s=&threadid=5138
 

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Hey Lazania, I also have a problem with my oil gauge, but mine isnt reading at all and also my voltage gauge is very low.. I'll work on it today and see whats up...

Gotta question dude, when I start the car, the RPM is at 1100 and then after 3 minutes it will go all the way to 2100. I disconnected the IAC and the car didnt stalled, disconnected the TPS and still nothing.. Whats wrong with this thing man?? Its really getting to me and I really need my car. I thought that putting the exhaust one would at least calm a little the problem, but it didnt do squad... Help me out dude, I am out of ideas. I checked the cables and I thought I had switched them, but then I cheked them and swith them and nothing happened.. :(
 

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My voltmeter died once too! All I had to do to fix that was replace a fuse. So check your fuses and you might find your problem tx_cat.
 

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Ok, I did some checking. In the specifications section, my 94 OEM manual says the oil pressure should be:

138 – 310 kPa at 1500 rpm hot

138 kilopascal = 20.0152078 pound-force/square inch (PSI)
310 kilopascal = 44.9616988 pound-force/square inch (PSI)

So I guess the pressure range is 20 to 45 psi at 1500 rpm and at operating temp.

Sorry for the confusion. :leftright
 

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Discussion Starter #7
4 Cam Bird said:
Its the sender, common problem.

Check the tech articles, there is one that tells you which sender to buy to make it so your stock gauge will give actual readings rather than alwsy staying in one spot on Normal, it isn't hard to do and if you have to change the sender anyway you might as well do it. When I did it I also needed a little elbow fitting for clearance between the block and sender and you need a little wire to jump across a resistor.
[/QUOTE

Its the gauge, I already replaced the sender because I know they are notorious to go bad, Thanks for the help though :) . As far as the numbers go they are very good , about 60 at idle and 90 at WOT is perfect.

Shawn 40th is gonna give me a working gauge and Im pretty sure that will do it if not Im going to get a Autometer and leave it at that.
 

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94 Daily Driven 4.6L said:
Ok, I did some checking. In the specifications section, my 94 OEM manual says the oil pressure should be:

138 – 310 kPa at 1500 rpm hot

138 kilopascal = 20.0152078 pound-force/square inch (PSI)
310 kilopascal = 44.9616988 pound-force/square inch (PSI)

So I guess the pressure range is 20 to 45 psi at 1500 rpm and at operating temp.

Sorry for the confusion. :leftright
That doesnt make sense, thats way too low
 
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