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2G Oil pressure gauge Dropping

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4g63Sneaky

Probationary Member
23
0
Jan 3, 2026
san diego, California
1997 eclipse gst i had recently gotten a new gauge for the oil pressure and boost. when car is first started oil pressure seems fine and boost it’s like shaking. once car is warming up the boost stops shaking and oil pressure starts slowly going down all the way down 0. there’s oil in everything seems fine ruins a little rough on cold start after warms up everything is fine
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4g63Sneaky said:
1997 eclipse gst i had recently gotten a new gauge for the oil pressure and boost. when car is first started oil pressure seems fine and boost it’s like shaking. once car is warming up the boost stops shaking and oil pressure starts slowly going down all the way down 0. there’s oil in everything seems fine ruins a little rough on cold start after warms up everything is fine
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What brand gauge is that? Have you cleaned grounds lately?
 
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pauleyman said:
What brand gauge is that? Have you cleaned grounds lately?
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real cheap gauge off ebay it was just something to get by i bought the car in january and i wanted just to get it running before i throw money at it. the car has been sitting for years before i bought it i haven’t cleaned the grounds. would grounds cause the oil pressure to drop down to 0?
 
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4g63Sneaky said:
real cheap gauge off ebay it was just something to get by i bought the car in january and i wanted just to get it running before i throw money at it. the car has been sitting for years before i bought it i haven’t cleaned the grounds. would grounds cause the oil pressure to drop down to 0?
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Is it a mechanical or electric gauge? On electric gauges the body of the sender is the ground (ie it's grounded through the threads that go into the oil filter housing). If you used Teflon tape, that could cause a bad ground.
 
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4g63Sneaky said:
real cheap gauge off ebay it was just something to get by i bought the car in january and i wanted just to get it running before i throw money at it. the car has been sitting for years before i bought it i haven’t cleaned the grounds. would grounds cause the oil pressure to drop down to 0?
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Personally I would just suspect the gauge. That behavior is not normal.
 
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RamenPride said:
Is it a mechanical or electric gauge? On electric gauges the body of the sender is the ground (ie it's grounded through the threads that go into the oil filter housing). If you used Teflon tape, that could cause a bad ground.
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it is a electric gauge it doesn’t have teflon tape. the sending unit came with the gauge and for everything it was around 30 bucks.
 
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I'd say you get what you pay for. A sending unit alone is between $15 and $45. That means the gauge is less than $15, including the circuitry and bulbs and board and casing...

I'm with Paul. Start with a good quality gauge and sending unit. If it's still wonky, then begin diagnosing problems.
 
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You can disconnect the wire from the sender, turn ignition on, take that wire and ground it off. See how smooth that gauge needle moves.. but I'm with everyone else on this.... Never trust this super cheap eBay stuff.
 
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Vladimir said:
You can disconnect the wire from the sender, turn ignition on, take that wire and ground it off. See how smooth that gauge needle moves.. but I'm with everyone else on this.... Never trust this super cheap eBay stuff.
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so i don’t need to worry about it going down to 0 pressure cause it might be the gauge? i feel like it’s really smooth when it starts but once it gets warmed up it starts dropping down to that all the way down to 0psi
 
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It's a very big concern...oil pressure slowly dropping to zero can indicate worn/spun bearings. Worn oil pump, clogged pickup tube, restricted oil filter etc .. but you don't diagnose any of those things with a crappy $20 gauge and sending unit.... Go to auto zone or at least a harbor freight and rent or buy an oil pressure tester at the very least ..
 
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4g63Sneaky said:
1997 eclipse gst i had recently gotten a new gauge for the oil pressure and boost. when car is first started oil pressure seems fine and boost it’s like shaking. once car is warming up the boost stops shaking and oil pressure starts slowly going down all the way down 0. there’s oil in everything seems fine ruins a little rough on cold start after warms up everything is fine
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I don't know at where the gauge sensor is reading the oil pressure but maybe just the gauge sensor's accuracy, maybe it can't read well low side like below 10 psi or so.
If the number on the gauge was true, you should have seen the oil pressure warning light come on in dash if you still have it. In case if you have seen the warning light comes on in dash when the gauge is showing below 7 psi, there is a chance that you actually have oil pressure issue.
If you are worried, check the actual oil pressure with a good mechanical gauge, or at least just remove the oil filler cap while idling and while the gauge is showing very low pressure, and see if the rocker arm below the cap is jetting the oil strongly to cam lobe or nor. At least you can distinguish if the engine has the minimum oil pressure or not. In case if you don't see oil coming from the rocker arm or just seeping out, then don't start the engine anymore.
 
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DSMPT said:
I don't know at where the gauge sensor is reading the oil pressure but maybe just the gauge sensor's accuracy, maybe it can't read well low side like below 10 psi or so.
If the number on the gauge was true, you should have seen the oil pressure warning light come on in dash if you still have it. In case if you have seen the warning light comes on in dash when the gauge is showing below 7 psi, there is a chance that you actually have oil pressure issue.
If you are worried, check the actual oil pressure with a good mechanical gauge, or at least just remove the oil filler cap while idling and while the gauge is showing very low pressure, and see if the rocker arm below the cap is jetting the oil strongly to cam lobe or nor. At least you can distinguish if the engine has the minimum oil pressure or not. In case if you don't see oil coming from the rocker arm or just seeping out, then don't start the engine anymore.
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i bought a oil pressure sensor everything seemed fine then it dropped to 5psi as i was removing the oil cap i felt blow back once i removed it the car shut off. to worried to try and start it again all i know from the car is that it had engine work down a couple years ago none of the engine components were in the car it was just help up by a engine and transmission mounts. i had a mechanic with me and he went through the spark plug holes with a camera and everything looked new no wear and tear just brand new. so i bought it in january and started putting all the components and everything back in place that’s all the information i can get the guy never sent me a list of the parts or anything
 
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Install a REAL oil pressure gage, a mechanical one. I run them in all of my cars and have never ever ever had an issue other than a pack rat chewing a nylon line that made it leak. Mechanical gauge, as was mentioned, will tell you the true reading of it. I stopped driving my GSX because the low pressure light started flickering at hot idle so I wouldn't ruin a good 6 bolt but its electric not mechanical so it may be my sensor also but I'm playing it safe since that car doesn't have any oil pressure guage in it except the dash stuff. Be careful and make sure it is truly low and if so, do not drive it. Save it.
Marty
 
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RamenPride said:
It's probably just your gauge. You can get something like this to see what your actual oil pressure is at idle, or just buy a better gauge.

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i did buy that and i was checking it and it was still dropping down it got to 5 and then it died on me
 
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1990TSIAWDTALON said:
Install a REAL oil pressure gage, a mechanical one. I run them in all of my cars and have never ever ever had an issue other than a pack rat chewing a nylon line that made it leak. Mechanical gauge, as was mentioned, will tell you the true reading of it. I stopped driving my GSX because the low pressure light started flickering at hot idle so I wouldn't ruin a good 6 bolt but its electric not mechanical so it may be my sensor also but I'm playing it safe since that car doesn't have any oil pressure guage in it except the dash stuff. Be careful and make sure it is truly low and if so, do not drive it. Save it.
Marty
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i did buy the mechanical gauge i tested not to long ago and it was still dropping down to 0 it got to 5psi and shut off
 
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It is dying because it has friction between the bearings and the crank. It is time to dig A LOT deeper. Don't hurt your motor.
 
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1990TSIAWDTALON said:
It is dying because it has friction between the bearings and the crank. It is time to dig A LOT deeper. Don't hurt your motor.
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what would be the next step? i’m not a mechanic i work on car here and there but never pulled a motor or anything like i said guy that sold it to me said he had work done to it
 
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Drain the oil and look for flakes. Cut open the oil filter and look between the ribs. Your bearings are probably spun or completely worn. Could be other issues.Drop the pan if you want to. But I'm not sure how mechanically inclined you are. Start with the oil and filter first.

You never mentioned in the post that you measured the pressure with a mechanical gauge before
 
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Vladimir said:
Drain the oil and look for flakes. Cut open the oil filter and look between the ribs. Your bearings are probably spun or completely worn. Could be other issues.Drop the pan if you want to. But I'm not sure how mechanically inclined you are. Start with the oil and filter first.

You never mentioned in the post that you measured the pressure with a mechanical gauge before
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i’ve done a couple stuff but i’ve never like dived in to the internals of a engine. and i bought a mechanical gauge about 5 hours ago so i had done the testing and everything
 
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Ok. Since you verified the pressure is low, park her to prevent further damage. Start diagnosing from easiest first. Check the oil for flakes, shaving, glitter etc..
 
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