High Oil Pressure

[kris450]

Hoping to get a little advice of possible chaps.

Just finished refitting my rebuilt engine from V8D. All went smoothly it seems except that when running for the first time I have insanely high oil pressure. As in its reading off the top of the scale.

Engine sounds good with no obvious issues.

I’d rather not carry on the cam running in process of course until this is sorted.

Could this be a faulty oil pressure sender ? It wasn’t changed during the rebuild. Any other obvious causes for it ? All wiring/earths are good and checked.


Edit: Now on further inspection it seems as if the gauge is reading about 10psi without the engine running but the ignition on !!

Edited by kris450 on Saturday 14th May 15:52

[kris450]

bobfather said:

Is it a new pressure sender? If so it could be ranged for a different gauge, sender and gauge need to be matched

No, its the same as before which never showed any issues. It was on the car for almost a year without the car being run though before the oil was drained and the engine sent for the rebuild. Sure I read somewhere that the oil can damage the diaphragm in the sender but not 100% sure.

[kris450]

QBee said:

If yours is the same as mine (99 car) the sender has a single wire , the earthing is via where it is screwed into the block.
I have no idea why a bad earth should cause a false high reading, but my first thought is to earth the body of the sender to the block separately.

Doh ! Stupid me, I should have mentioned it isn't the original sender. Its one of the Isspro senders with the 2 terminals, one to the gauge and the other a ground/earth.

It was working perfectly before the strip down (even if that was a while ago) which is why I'm hoping it just needs replacing. Just trying to see if anyone has some other obvious ideas I'm missing.

[kris450]

Zener said:

Get a mechanical set on the motor and finish breaking in the cam whislt moitoring OP I doubt you have an OP issue frankly , a cheap kit like this will confirm and useful for the tool box anyways , for example Ebay item number 265679304198

I've literally just come back in from the garage from doing this !! Pressure instantly rose to 60psi and stayed there solidly, dropping to around 55psi once the oil was up to temp. Still stunned I managed to order a gauge set on a Sunday morning and have it delivered by 9pm that evening !! Guess Amazon can have its uses sometimes.

Massive relief !

New sender has been ordered

[kris450]

I'm pretty sure its a short somewhere in the wiring annoyingly.

Its definitely not a post for a warning lamp or a second gauge, its purely an earth. Tried swapping wires around, running with just one wire on either terminal with the sender earthing through the block. Still same results.

Last thing I want to do is now unwrap all the loom to look for the issue

[kris450]

So to update and bring this to a close as such.

Managed to find the original tvr sender the car had when I bought it. Fitted it and everything worked correctly. Guessing I've either bought the wrong sender (almost certain on this after further research) or its a duff new one.

Happy days and glad I've found the issue.

Ps not sure if this is allowed, but if anyone is in need of an Isspro sender, R8917-03, pm me as its clearly not compatible with my later car.