Oddball Oil pressure issue

[Rex_Kelway]

Hello all,

The Problem:

Rex has an aftermarket electronic oil pressure gauge.

Connect the sender to a tyre pump and the gauge reads exactly what the gauge on the pump reads, and swings at the proper rate.

Now install in in the motor and it reads 20psi at 6000rpm, where it should be 60psi and 0psi at warm idle. It also swings very slow.

The motor is from a front half with 63,000km and is in perfect stock condition. It also makes absolutely no noise or rattles and has taken three hard practice days with no dilemma's at the indicated 0psi oil pressure.

So basically Rex discounts the engine's oil system as the problem.


The Setup

The sender is in the stock location but as the thread is different it is spaced perhaps 25mm out with a brass adaptor.

Hardly rocket science...


Potential causes?

Rex has inserted a slender piece of wire into the block to check for blockages, which is unlikely.

The only other thing Rex can think of is the sender has a very, very small inlet, could this be preventing oil from actually filling the sender and acting properly on the diaphragm?

IE is the sender still full of air, which is dulling down the reading?


Any ideas, it just seems kinda wrong caning a car that tells you it has no oil pressure.


Cheers Lads

[gianttomato]

Air could possibly be dampening the peak level and the transient response.

Could Rex remove the sender and using a small needle and syringe fill the sender with oil?

[oldcorollas]

did Rex use any kind of sealant when installing the sender?
is the sender a 2 wire type? or a single wire type where it earths thru the body of the sender?

put jumper lead between body of sender (rub slightly to scratch surface) and ground and check gauge response then?
failing that, fill with oil, or install so sender is pointing down (gravity fill).

[Rex_Kelway]

'Tis a single wire jobbie. Thread tape was used but Rex has tested the resistance between the sender body and the negative terminal. Tis negligable if any.

He also tried the jumper earth, to no avail...

Syringe it is. Anyone know any Heroin fiends?

Or perhaps Rex could try opening the inlet hole up a little?

Thanks Lads,

Rex

[gianttomato]

Usually a pharmacy can help re syringes.

[YLD-16L]

Syringe it is. Anyone know any Heroin fiends?

Chemist, heroin users get 'FIT' packs free of charge. It should have a couple of swabs and a needle disposal container too.

Edit: GT beat me.

[oldcorollas]

local hospital might even give you small packets of sterilised water

\/\/ just going on a friends experience, perhaps it was a trial thing...

[gianttomato]

local hospital might even give you small packets of sterilised water

Very unlikely. Druggies generally TTFO.

[off-road]

I doubt air is the drama given that it works with compressed air from a pump.
Maybe if you leave it loose and crank the motor over you can see if oil actually comes out.
(This could also remove any air.)

[30psi 4agte]

I doubt air is the drama given that it works with compressed air from a pump.
Maybe if you leave it loose and crank the motor over you can see if oil actually comes out.
(This could also remove any air.)

Excellent point m8. When all else fails start with the basics. + rep

[TC1600]

Most workshops will have a mechanical oil pressure gauge thay use to diagnose oil pressure problems with, I'm sure for a small fee they could hook it up and that would tell you for sure if its an engine or gauge issue.