low oil pressure zd30DI 2004

[davrol]

Recently installed my racetech oil pressure guage. Went in through a joiner onto a t piece above starter motor. Joiner onto one side of T & into block, otherside of the T into original sensor & aftermarket sensor pointing down towards the ground. It had a very minor leak at first so i have just pulled it all out and redone( with the right deep sockets this time ). I used loctite into blok and into t piece and teflon for both sensors. The original sensor was damaged so i reapalced it. The oil level has never been off the

I am getting 10 psi at idle warm even before resealing the sensors. Using penrite HPR15 50. The oil level is def correct. At the top end of indicator on dipstick. It has a proven t catch can as well.

I guess i am hopong that racetecfh gauges are known for there faults or something to do with catch can becuse that oil pressure difference between 10 & the recommended 21 seems big to me. @ 2000RPms it is about 60 and 4000 about 90 and factory low oil light does not come on. Could it be how i have installed the sensors ? Should i have put original sensor facing ground and aftermarket straight off?

Any info appreciated.

Cheers

Dave

Edited June 2, 2014 by davrol

[Rumcajs]

That does look low but I'd use calibrated master gauge to confirm actual oil pressure before I start to panic.

 

The Racetech gauge sensor I'd actually test that  by rigging it up to compressed air and with calibrated regulator I'd check the output.

So like put 10 psi pressure in and read what gauge reads and keep increasing the pressure to its max and confirm that it reads correctly.

 

I'd also check that all the wiring is correct and there are no bad connections/voltage drops/resistance etc.

 

Cheers

[davrol]

Thanks for the reply. I will check all of that

 

Do you know at what pressure the low oil light should come on?

 

Cheers

[Rumcajs]

I'm not sure but anything bellow 1 bar (~14 psi) should be a concern. Does your GU only has one pressure sensor? GU4 series is suppose to have two units. You can test the opening pressure of the sensor the same way I described earlier. It simply breaks contact to ground. I believe the thread size of the sensors is 1/8 NPT.

Cheers

[davrol]

Had another look underneath and it appears to be leaking still. This would surely affect pressure. How is you oil pressure gauge setup?

[davrol]

Rumcajs,

 

A little more information the I have found out today. As is said I had to replace the original sensor as it was broken. When I checked the Tridon website it lists the thread as 1/8 gas (BSP) this is on all oil pressure switches for patrol.

 

I know BSP & NPT are similar but as I am having issues I feel to rule it out I will need to get a 1/8 BSP male T with 1 x 1/8 BSP female for original sensor & 1/8 NPT for aftermarket sensor. These are available through speco.

 

Cheers

Dave

[Rumcajs]

Last time I checked the oil fittings on my 05 ZD30 for oil pressure sender the thread was 1/8 NPT.

 

Also on the RHS oil pressure sender is actually mounted on the "stand off" fitting/pipe which is attached to the block with banjo bolt.

 

I found when I was replacing the sender on mine  it too leaked and no matter what I tried I couldn't seal it but it was actually the banjo bolt which became slightly loose/disturbed when I was tightening the sender which was enough to start leaking oil albeit slowly over the sender which appeared as leaking from.

 

To gain access to that fitting I had to drop the starter motor, I replaced two copper washers for it too. What a pain that was to fix!

 

 

Anyway there is ample room on the LHS of the motor right  where the second oil switch is mounted next to oil filter under the turbo charger. That's where I'd mount the extra oil sender for the gauge with male Tee run fitting to accommodate both units.

 

That's where Nissan service people measure oil pressure with master gauge anyway even though it is classed as "low pressure side" according to Nissan as RHS next/above to starter motor is classed as high side.

 

See pics

Edited June 3, 2014 by Rumcajs

[davrol]

Thanks for your detailed reply.

 

Got home last night and degreased the crap out of that side of the block and dried. Ran the engine for a good 30 mins & drove around the block a couple of times and bugger me if I could see any oil. I was resided to the fact that it must have been residual oil left over from prior to the resealing of the oil pressure adaptor.

 

I then started to look at the gauge. As soon as I touched the sensor wire on back of the gauge it started jumping all over the place. Made sure it was connected correctly and still when I wiggle the wire it started to jump all over the place and sometimes it would start to flash at me like it could not see the sensor. I will do a little more troubleshooting tonight by removing all the wiring and inspecting but I am pretty sure the gauge is faulty. Another thing I picked up last night was when I let it idle up to operating temp it rests at 20PSI but as soon as I touch the throttle and give it a rev it goes up but then back down to 10PSI and stays there.

 

When I was packing up I glanced down the sensor wire to see if I could pick up any potential issues with the external wiring and I noticed a small drop of oil on top of bell housing which then ran down the crack between the bell housing and gearbox. After getting mirrors and inspecting the back of the block and not seeing anything, off with the IC. Wallah! 3 injector oil seals leaking. There were pools in each valley which was working it way to the back of block and dripping down onto bell housing.

 

I a going to get a mechanical gauge to test the pressure on passenger side so I know it is safe to drive but while I am at it do you think I could plumb the provent back in on that side as well ?

 

Thanks again.

 

Cheers

[Rumcajs]

I'm not sure what are you referring in regards to Provent but if it is the oil return from Provent you could so long the block still has the hole blanked off by the steel plate. This was removed on later ZD30 blocks (GU4) so I don't have that option.

 

So if you are the lucky one, all you really need is to remove the plate, drill appropriate hole in it, tap the thread, screw in the fitting and refit.

Than run the hose from Provent oil return via a check valve (needed because the return is above oil level) so you never need to worry about Provent oil draining.

 

Cheers

Edited June 4, 2014 by Rumcajs