beran earms

quick ? on my gauge. car off, needle down where it belongs, turn key to on position, needle pegs up , start the car and the needle stays pegged at 5. any ideas what to look for? thanks in advance
Justin

Adk46

Mine does the same peculiar thing, and I have the impression that this is common. It will come down to mid-position at idle once warmed up. Apparently, there is more to the circuit than a normal meter indicating current through a straightforward sending unit. Since I've read nothing here about genuine oil pressure issues, I'm satisfied to regard it as little more than an idiot light. I'm prepared to learn otherwise, though....

MainePorsche

And... what happens next as you drive ?
Sounds normal.
Let car get to operating temp and you should see gauge level out at idle.
Report back what you see.

https://rennlist.com/forums/928-foru...pressure+gauge

R.Pires

If it pegs up to 5 with the key on tne on position before starting the car and stays at 5 after the car warms up you probably have the wires reversed on the oil pressure sender.

GlenL

This. Or a short.

There are two wires to the oil pressure sender. One gets variable resistance to move the needle and one gets ON/OFF to set the "idiot" light. When reversed, the gauge pegs and the light never comes on. Does the light at the bottom of the pressure dial come ON when the key is turned ON but car is not started?

KenRudd

This information nugget is a keeper..

M. Requin

Or, as in my case, bad wires and a bad OP sender.

Alan

You really do get high (pegged) pressure at start-up at the gauge and as the oil warms it goes down. The gauge part is a normal style gauge - the oil pressures are simply higher than are common. There is a pressure bypass system that limits the max pressure to something above 5 bar (which is why it pegs for a while).

However that is not at all what is described here... here it hits 5 bar without the engine running - so a different effect, likely as others have described related to the sender/wiring.

Alan

davek9

deleted.. irrelevant post

MainePorsche

Read over that this morning. (Pre coffee)
Thought OP describing pegged at 5 bar on startup.
Likely sender wires reversed.
To the OP, it is an easy fix.

dr bob

Since the gauge pegs at 5 prior to engine start, yet still reads normally after start and as engine warms up, I would look first at the sender housing to make sure it's actually grounded. Sometimes a sender is removed, and the installer puts so much teflon thread tape on the threads that there is no longer a path to ground for both the switch and the variable resistance for the gauge.

The wiring is not reversed, else the gauge would not read correctly after engine warm-up.

I'd also check to see if the two wires are shorted together anywhere, such that the switch is grounding both the lamp and the gauge signals, although the current flow through the lamp itself would diddle with the gauge reading.

Clean the 14-pin connector with Deoxit or a brass-bristled brush.

Last but not least, the sender itself could have a fault. Senders are relatively inexpensive and easy to change. Take just the sender off if you can, without the spring and can it screws into. On installation, you have a 50% chance of getting the wires correct on the first try, and a 100% chance of getting them wrong. In my experience anyway...

vanster

Good advice
On cold morning start up the gauge pops up and then it settles in for about 15 mins. Reads like it should then just drops off. What is odd is that this only happens in the morning. Any other time it does not work at all. It's only been like this for the past 5 or 6000 miles. Now that I'm selling it I need to fix it. My guess it's the sender itself. Hate to rush into these things.

beran earms

Just checked in. A lot of help thanks. So I neglected to mention that the engine oil light does come on with key on, but goes out as soon as engine starts. And yes , the needle stays at 5 even after completely warmed up.
Thanks again,Justin

R.Pires

Hi,
So, with these exact symptoms I believe it's just the wires on the sender reversed, it happened to me once, but it's better wait for someone else to confirm!
Good luck!

outbackgeorgia

Dr. Bob, no mention by the OP of the gauge reading normally after startup, in fact, stays pegged. Sounds like wires reversed, a quick fix to try first. Could also be sender or wiring if reversing the wires doesn't work. The OP really did not say what happens after warmup.