Oil pressure issues.....
Thread Starter
Drifting
Joined: Oct 2001
Posts: 1,351
Likes: 20
From: Back in San Diego Ca
Oil pressure issues.....
My oil pressure has been acting strange for about the past couple of weeks. At cruising on the freeway it some times fluctuates between 60 and 70 but most of the time it is stuck at 80. Then sometimes after I drive the car some what hard and then come to a stop, it drops to around 4 and the little red light comes on on the gauge. If I rev the engine it then starts going back up to about 45, where it has been at idle the past couple of weeks. Any ideas on what the problem might be?
Team Owner
Joined: Mar 2000
Posts: 83,383
Likes: 87
From: Boston, MA
Then sometimes after I drive the car some what hard and then come to a stop, it drops to around 4 and the little red light comes on on the gauge.
Drifting
Joined: Aug 2000
Posts: 1,521
Likes: 0
From: West Islip New York
Re: Oil pressure issues..... (OrangeC4)
Definitely check the level, but I'd also get a mechanical gauge on there to see whats going on. 4psi is ng and you really shouldn't have 45 at ide (warmed ?).
Could be sending unit or gauge but using another gauge as a reference will get you a lot of information. Have you changed oil weights or filters recently?
Could be sending unit or gauge but using another gauge as a reference will get you a lot of information. Have you changed oil weights or filters recently?
Drifting
Joined: Aug 2000
Posts: 1,521
Likes: 0
From: West Islip New York
Re: Oil pressure issues..... (scorp508)
If you got 55-60psi at idle (hot) with a stock pump and the mileage you've got on that engine, thats great. Guess you're pegging that thing at 3500rpm.
I typically see 20-25 hot at 800rpm on my 89 with 5w-30.
I typically see 20-25 hot at 800rpm on my 89 with 5w-30.
Team Owner
Joined: Mar 2000
Posts: 83,383
Likes: 87
From: Boston, MA
Guess you're pegging that thing at 3500rpm.
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Team Owner
Joined: Mar 2000
Posts: 83,383
Likes: 87
From: Boston, MA
Re: (OrangeC4)
Low pressure is fixed, but still have the issue of being stuck at 80.
Team Owner
Joined: Mar 2000
Posts: 83,383
Likes: 87
From: Boston, MA
Re: (OrangeC4)
Page 8A-82-14 in my '87 electrical diagnosis service manual supplement has a test for constant high pressure.
K: OIL PRESSURE DISPLAY INDICATES HIGH PRESSURE CONSTANTLY
Connect: Fused Jumper
At: Oil Pressure Sender Connector
Condition: Ignition Switch RUN
Jumper Between: (TAN) & Ground
Correct Result: Oil Display indicates 0 psi (0 kPa)
For Diagnosis Otherwise: See 1
Correct Result = Replace the Oil Pressure Sender
1 = Check TAN (31) wire for an open. If the TAN (31) wire is OK, replace the Instrument Cluster (see Section 8C)
Here is the test for the opposite.
J: OIL PRESSURE DISPLAY INDICATES LOW PRESSURE CONSTANTLY
Disconnect: Connector
At: Oil Pressure Sender
Condition: Ignition Switch RUN
Action: Disconnect Oil Pressure Sender Connector
Correct Result: Oil Pressure Display indicates 80 +/- 3 psi (550 +/- 30 kPa)
For Diagnosis Otherwise: See 1
Correct Result = If the result is correct, replace the Oil Pressure Sender
1 = Check TAN (31) wire to Instrument Panel for a short to ground. If the TAN (31) wire is OK, replace the Instrument Cluster (see Section 8C).
K: OIL PRESSURE DISPLAY INDICATES HIGH PRESSURE CONSTANTLY
Connect: Fused Jumper
At: Oil Pressure Sender Connector
Condition: Ignition Switch RUN
Jumper Between: (TAN) & Ground
Correct Result: Oil Display indicates 0 psi (0 kPa)
For Diagnosis Otherwise: See 1
Correct Result = Replace the Oil Pressure Sender
1 = Check TAN (31) wire for an open. If the TAN (31) wire is OK, replace the Instrument Cluster (see Section 8C)
Here is the test for the opposite.
J: OIL PRESSURE DISPLAY INDICATES LOW PRESSURE CONSTANTLY
Disconnect: Connector
At: Oil Pressure Sender
Condition: Ignition Switch RUN
Action: Disconnect Oil Pressure Sender Connector
Correct Result: Oil Pressure Display indicates 80 +/- 3 psi (550 +/- 30 kPa)
For Diagnosis Otherwise: See 1
Correct Result = If the result is correct, replace the Oil Pressure Sender
1 = Check TAN (31) wire to Instrument Panel for a short to ground. If the TAN (31) wire is OK, replace the Instrument Cluster (see Section 8C).
Team Owner
Joined: Mar 2000
Posts: 83,383
Likes: 87
From: Boston, MA
In short it means this. :)
Ground the tan wire coming out of the pressure sender. Turn the key to run, and the gauge should read 0 psi. If it does, replace the sender. If it doesn't, then you do 1. Now I am not positive if it means to do this while the tan wire is still connected to the sender or not. That I can not tell you as I am not positive.
As you can see from the LOW pressure test though, disconnecting the wire should bring up 80 psi +/- 3 psi on the gauge automatically.
I hope that helps somewhat.
Ground the tan wire coming out of the pressure sender. Turn the key to run, and the gauge should read 0 psi. If it does, replace the sender. If it doesn't, then you do 1. Now I am not positive if it means to do this while the tan wire is still connected to the sender or not. That I can not tell you as I am not positive.
As you can see from the LOW pressure test though, disconnecting the wire should bring up 80 psi +/- 3 psi on the gauge automatically.
I hope that helps somewhat.
Team Owner
Joined: Mar 2000
Posts: 83,383
Likes: 87
From: Boston, MA
I'll check the service manuals. Do you recall if your sensor has 3 wires scorp?
Team Owner
Joined: Apr 2001
Posts: 22,267
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From: Dallas TX
Re: (scorp508)
It's different then. Mine has more than just one wire coming out of it. Not sure why though. I bought a new one to try, and I would like to test the one on there currently before i put the new one i bought on.
Race Director
Joined: May 2001
Posts: 14,165
Likes: 9
Re: Oil pressure issues..... (OrangeC4)
A friend of mine bought a 95 Z-28 that had over 100k miles on it, the owner had badly mistreated it. When I drove it home for him I noticed that oil pressure would go up and then stick, it wouldn't go down until you shut the
car off. That night we changed his oil to Mobil 1 synth, 15 minutes later his gauge problem was fixed.
The old oil looked like crude, it was about as thick as syrup while warm. NASTY. We pulled a valve cover off and were scared, we put it right back. He's got spun bearings in his future. The motor looked just like yours Glock, and he's starting to have low idle oil pressure issues. He has it in his head that he'll just change the oil pump. I mean damn, if you're gonna take it that far apart at least do a budget or performance rebuild. He KNOWS how nasty the motor is.
car off. That night we changed his oil to Mobil 1 synth, 15 minutes later his gauge problem was fixed.
The old oil looked like crude, it was about as thick as syrup while warm. NASTY. We pulled a valve cover off and were scared, we put it right back. He's got spun bearings in his future. The motor looked just like yours Glock, and he's starting to have low idle oil pressure issues. He has it in his head that he'll just change the oil pump. I mean damn, if you're gonna take it that far apart at least do a budget or performance rebuild. He KNOWS how nasty the motor is.