Ranfurly

Just had an issue come up with the pressure the oil pressure gauge is showing.

Normally afer a cold start the gauge shows pressure near '5' after warming up it drops down to around 3 at low revs.

The other day after start up it started to flicker between 4 and 5 before the needle went past 5 and stayed there. The car seemed to run okay, after parking it and leaving for a few hours I restarted it and the gauge still showed a reading past the 5 mark.

I haven't been brave enough to drive her again. I'm hoping it is something to do with the pressure sensor that gives the reading??

Any thoughts?

Cheers

Mrmerlin

first thing is to check the connections at the sender you may have to remove them and clean the connections then run the car , if its pegging with the key on and the engine not running then you may need a new sender.
If it pegs when the engine is first started at idle, then after 15 mins comes down to 2 to 3 bar at idle then its working correctly

Ethre

Be careful with the connections on the sender - they are delicate. While they look like studs, they're actually small diameter tubing with a wire running through the center and then soldered onto the end. Its very easy to shear them off if you're not careful. Better to just work with the clip on connections.

Speaking from experience . . .

Mike Frye

You just described in perfect detail what a very observant person would see when an electrical circuit goes bad. The 'flicker' leads me to believe this is electrical and not related to the actual oil pressure.

Of course you need to track it down before running it, at least for very long, but I'm with Stan on this, it's probably the sender. If you have any oil leaking down there it might have isolated the wire or the circuit may be grounded along the wire somehow.

Another thing to do is clean all your grounds if you haven't recently. I don't know much about the OBs but there must be a ground for the engine wiring, the engine block, as well as the dash. Cleaning them all would eliminate that as a possibility.

Failing that, you could clean up the connections to the pod as well. Never hurts to make sure you've got clean connections everywhere and THEN start troubleshooting.

Ranfurly

Thanks guys. Funnily enough I had her in for a WOF a week or so ago and had to get a power steering hose fixed because it was leaking - maybe that has caused the fault?

She's going back in for the trans sump gasket, trans cooler libe and CV boot replacement. from your feedback I'm confident to drive her back to the mechanic - I don't trust myself playing with tricky bits of wiring. From your feedback I can at least point the shop in the right track.
Really appreciate the info.
Cheers
Richard

Mrmerlin

did you ever figure out the oil pressure issue?

FredR

Stan,

A good question. On mine I replaced the three wires, I replaced the sender, there was no 3 pin connector available for the sender wires so I had to jury rig connections using crimp conectors- one end crimped to the wire the other pushed over the sender pin. I also pulled the display unit, checked all the terminal rims for cleanliness [all very bright] abd when all ths was done I still saw the gauge peg full scale when the motor was switched off.

When operating the display generally works correctly but can be a bit twitchy at times.

If you or anyone else can figure this behaviour out all well and good. The only other thing I could think of was to put a heat shrink over the sender terminals but I doubt that would do anything.

Rgds

Fred

Brian'sIris

I found something 'interesting' last night while refurbishing my front engine wiring harness. My pressure sensor is the 2-wire version ('85 32v) with stud connectors. While checking resistance of the old wires, I found that one of the pressure sensor wires was upwards of 200 ohms! Oddly enough, the harness connector at the end of this wire (at the sensor) was constructed of 2 separate pieces, one being a female blade style crimped onto the wire, the other a short male blade + round lug. Clearly this extra connection was oxidized and providing resistance.

I wonder if the wiring harness was originally made like this and may be causing problems for others...? My oil pressure gauge seemed to work properly, but generally read about 1 bar when hot. Most folks see about 2 bar.

FredR

By now just about all the original harnesses are effectively toast or close to it.

Your 1 barg reading may be a false number due to issues - 1 barg is typically what is seen if you are using Witch's Pee for engine oil. Have you run 20W50 and seen this number?

Rgds

Fred

Brian'sIris

Yes, the old harnesses are likely the source of many issues.

Thanks for the tip on oil viscosity and pressure. I believe the PO put in 10W30 not long before I bought it. I drove it for awhile until starting intake refresh, timing belt, etc.

I decided to use 10W40 since my climate doesn't get that hot in summer (max. 20-25 deg. C. in Newfoundland, Canada) but haven't finished the work in order to start it up yet.

Cheers,
Brian

worf928

Yes. It was.

Brian'sIris

Good to know. Thank you!

I've completely replaced those wires and a couple others anyway...not that difficult once the old sheathing is cut off.

Mrmerlin

did replacing the wires in the harness fix the gauge pegged issue?

G.P.

I had similar issues with my oil gauge flickering intermittently, but not pegged.
After checking the wiring and cleaning connections all the way from the sender to the cluster, the flickering was still happening. I then changed the sender and have had no problems since.
Engine at idle pressure is ~3bar and above idle 5.

linderpat

Thread revival - my oil gauge was working just fine until recently. When the problem first started towards the end of the driving season last year, the gauge would not move from 0, then would activate and read correctly while driving (around 5 bar, then drop to around 3 at idle). Now it never activates - just stays at 0. Doesn't move at all. I checked the connections at the sender, and all is well there. Is this a symptom of a dead sender?