Chevy Impala SS Forum banner

1 - 14 of 14 Posts

·
Registered
Joined
·
24 Posts
Discussion Starter #1
Greetings everyone, so as soon as I turn the car on the engine oil pressure guage spikes up to High and never moves until I turn the car off and goes down to about 3/4 on the gauge. I have swapped out the pressure switch and get the same results, any ideas? It's been like this the 2 months I have owned the car, everything seems to run as it should so I was thinking this is possibly a bad ground or something.

Stock LT1 engine, Intake and headers
 

·
Registered
Joined
·
892 Posts
The sensor switch grounds through the engine block. No pressure gauge reads low, engine running (switch off) gauge reads 3/4.


The sensor needs metal to metal contact with the block. Did you use Teflon tape or pipe sealant on the sensor switch?



If you unplug the oil sensor switch and ground the sensor wire the gauge should read low.


as soon as I turn the car on the engine oil pressure guage spikes up to High and never moves until I turn the car off
Any chance this car was converted to a gauge sensor for real pressure readings? The gauge pining on High indicates your oil gauge resistor is damaged or has been removed by the PO to convert the car to a true gauge system.
 

·
Registered
Joined
·
24 Posts
Discussion Starter #3
Not sure about anything being removed, the PO definitely didn't as he wasn't too mechanically inclined but the owner before him maybe. Tomorrow I will try grounding the plug to see if the gauge goes back to low. The sensor came with something on the threads, liquid Teflon I'm assuming
 

·
Registered
Joined
·
5,231 Posts
Sounds like you have an SS with 9C1 caprice oil pressure sender.
The SS guage will always peg high unless you cut out the resistor behind the glove box.

Nab
 

·
Registered
Joined
·
24 Posts
Discussion Starter #7
I have a 95 and the sensor that was on the car and what I replaced it with is the "short" sensor. When I did a part search the longer sensor is what kept coming up however. Not sure if that could be the issue or not, I assumed the longer sensor was used when it was located on the bottom of the LT1 (where you had enough room to get to it with a wrench) rather then on the back of the motor behind the intake manifold.
 

·
Registered
Joined
·
10,907 Posts
The short sensor is an on/off switch. The long one is a variable sensor. If you have the short one, the gauge is working properly (it shows that you have pressure, but not how much). If you did not have a ground at the sensor, the gauge would not function.

The Teflon tape only fills the gaps to seal the joint, but the metal parts still make contact.
 

·
Premium Member
Joined
·
4,515 Posts
To touch on what is obvious to most of us but possibly not the OP.

IF stock,
Your 95 reads 0 ignition on , engine not running

Anything more than a couple -few pounds when running, the gauge will go to 3/4 and stay there whether you have 9 pounds or 99 pounds .

Testing a 94-95 Civi Caprice or Impala wiring and cluster,

If you disconnect the tan wire from the sender, with ignition on, the gauge should go to 3/4
Ground the tan wire, the gauge should go to zero.
If it does that, you need the "on -off" type switch the car cam with

If your gauge goes right off the end of high when the tan wire is disconnected, then the previous owner did the gauge mod and clipped the resistor out of the circuit. ( or your have a 9C1 dressed up ;) )

If it does this, you need to use a transducer ,like the SEO cars used, rather than the production civilian car ON-OFF sender switch

Note, the other sender back there with an orange and gray wires is the fuel pump switch
 

·
Registered
Joined
·
24 Posts
Discussion Starter #10
Something else that has happened twice now that could be related is when I launch the car (which is almost never) the low oil light comes on and the car looses all power for a spilt second then the CEL comes on and doesn't go away until I shut the car off. Oil is not low in the car, I know the oil in the pan gets thrown to the back of the pan when accelerating hard but there has to be something else going on to cause this?
 

·
Registered
Joined
·
24 Posts
Discussion Starter #12
CEL = pull the stored code and see what the car is trying to tell you
Just tried to pull the code, used a paper clip to jump the A and B ports on the obd1 but instead of the CEL flashing any codes (was waiting for at least the 12 code) the CEL just stayed off and the cooling fans kicked on. Remove clip and light comes on fans go off. Any advice?
 

·
Premium Member
Joined
·
909 Posts
Just tried to pull the code, used a paper clip to jump the A and B ports on the obd1 but instead of the CEL flashing any codes (was waiting for at least the 12 code) the CEL just stayed off and the cooling fans kicked on. Remove clip and light comes on fans go off. Any advice?
Neither of my 95's would work with the paper clip. I had to buy a cable and read the codes via a computer.
 

·
Registered
Joined
·
10,907 Posts
Only the 91-93s did the flashing light. 94-96 must use a reader.
 
1 - 14 of 14 Posts
Top