Oil Pressure Dropping Rb26?!

[stagea_1998]

alright quick rundown of whats going on here on my 260RS stagea

1- as i pull up and my RPM drops it will dip to 600- 700 rpm for just a fraction of a second, as it does that the oil pressure gauge will shoot straight to zero for a few seconds then slowly rise back up

2- it will only do this on a hot engine, doesnt happen at all untill the car is up to temp

3- oil pressure light on dash also lights up (is there a separate sensor for the light and gauge?)

4- oil level is fine and ive checked for leaks, none

5- pressure will also drop if engine is warm and im sitting on the spot, rev it up to say 4000+ rpm and again on that drop to 600-700 rpm the oil pressure gauge will intantly drop to zero then slowly rise back up

any ideas guys??
cheers =]

[Ben C34]

The factory gauges are notoriously bad.

The fact your light come son in concerning as it's separate to the the gauge.

What grade oil are you running?

I would get something thicker in there asap and start planning pulling the engine out.

[stagea_1998]

Damn that's not something I wanted to hear lol

At the moment ive got some motul 10-40 in there

[Adrian P]

Both the factory gauge and warning light come from the same sender. And they are well known to be inaccurate and / or fail.

[stagea_1998]

Ohhh right so they actually are off the same sender?...well in a way that's good news

Hopefully that's all the issue is.... ill pop into nissan and grab a sender tomorrow

probably worth fitting an aftermarket gauge to keep an eye on things for future too if they're really that bad

[Ben C34]

Yes same sender.

Got confused.

Sorry to freak you out!

[stagea_1998]

Haha yea had me worrying about that rebuild $$$$$$$

All good man ...appreciate the input all the same

[Sinista32]

http://www.kudosmotorsports.com/catalog/genuine-nissan-oil-pressure-senser-genuine-nissan-nissan-300zx-z32-skyline-r31-jdm-r32-all-r33-all-r34-all-p-1220.html

This ^ is a very good price. I bought one recently which resolved a similar issue on a 32 4 door.

Normally $200+. God knows what Nissan will charge, so please post back their price too.

[GTRPSI]

Senders are known to fail, happened to us on our RB26, changed it and everything back to normal.

[stagea_1998]

Alright quick update

Thanks for the link sinista32

You're right on with the price $250 from nissan for that sender

But before forking out the cash for either I decided to pull my pressure gauge off the other car and see what's actually going on

The pressure definitely is dropping but not to zero like the factory gauge is saying

Its dropping to around 1kg/cm

Which at normal idle will sit at 2 kg/cm

And under acceleration raise to 6kg/cm

Anyone know if these figures seem normal? ??

Cheers

[Sinista32]

From the manual

[Ben C34]

From memory that seems fine.

I can't find it at the moment but reasonably sure the factory service manual says 1.5 at Idle.

Edit.

Beaten to it!

Edited June 17, 2014 by Ben C34

[stagea_1998]

Ohhh awesome looks the pressure figures are sitting well within reason

Suppose I should just get a new sender anyways but at least ive rolled out having to pull the motor out now

Thanks for the assist guys

[jjman]

seems like a win overall. But what is going on with this rev drop when you clutch-in? Otherwise what does it idle at generally?

[stagea_1998]

Yea its just a slight dip as I clutch in then its straight back to 800ish where it will usually sit

[niZmO_Man]

Maybe clean the AAC/IAC/whatever it's called?

Maybe the gauge drops because the idle drops that low (voltage starvation?).

[stagea_1998]

I had it off and gave it a clean 15000 kms ago id assume it'd still be in good nick

Not a fun job to get that one out either its buried deep in the depths of hell