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Rogue
nissan gu patrol
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Discussion Starter · #1 ·
Background:
I've been having issues with really poor fuel economy (17L/100km) in my 2007 ZD30CRD ute and I've tried a few things to fix including new fuel injector, swapping ECU and TPS for a later model one (2009), improving intake system (HPDiesel airbox lid and intercooler) and general service items. Nothing has dramatically improved my economy, I've only picked up 1L/100km improvement, but that said my EGTs are down massively (from 500-700*C to 250-400*C). So I'm just trying something else. I haven't yet done a run with the new rail relief valve, but some report to have gains by doing it.

I have also called UFI to confirm this MIGHT be an opportunity to find the fault, they cannot definitively say and I'm not getting any fault codes which they tell me does happen.

Items needed
> 1 x ZD30CRD fuel rail pressure relief valve - Bosch Part no: 1 110 010 018 - UFI sell these ZD30CRD Pressure Relief Valve| eBay
> Flat head screwdriver
> 10mm socket and wrench
> 12mm socket and wrench
> 17mm spanner (I used a combination spanner, the longer the handle the better)

Time and complexity
15mins and a medium complexity job due to ability to ensure valve is installed correctly.

Procedure
1) Remove engine cover and intercooler. You can leave the intercooler rails on.

2) Unclip the main engine wiring loom from its support brackets and the following sensors



3 x sensor connectors and one loom support clip


and push the loom out the way


Note: I did not remove the fuel feed line to the common rail as that part is a non-reuseable item adds another $70+ to job.

3) Using a 17mm spanner, remove the pressure relief valve on the front of the commonrail. I found this required a lot of force. This spanner angle gave the most leverage.


Once screwed out so the O'ring is clear of it's spot or you can't get the ring spanner on the bolt head, use your fingers to remove.




New and Old



4) Reverse the procedure to put it back together. When installing the valve I rubbed some clean diesel over the new O'ring to ensure it was lubricated to prevent it pinching.

When doing up the valve, I put as much force as physically possible onto the spanner to do it up, then gave the spanner a slight few taps with a soft faced mallet to ensure maximum torque onto the valve.

End result
I have not noticed any driveability improvements, but have noticed on my Ultragauge that cruising at 60km/h my engine load has gone from 68% to 50%. I will do some fuel comparison over the coming two weeks to compare.
 

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Nissan Patrol GU
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Interesting. Ever since I put in blank valve in when I brought chip it. I didn't like it, decided to put the normal one back in, and never been the same since.. Might get one myself next paid and fit it on.

Cheers
 

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nissan patrol
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Is it just an illusion or does the used one have a slightly bigger tapered hole in the centre? Hopefully you have a good result from this.

Sent from my GT-I9505 using Tapatalk
 

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Rogue
nissan gu patrol
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Discussion Starter · #4 ·
Good point, I can't really compare now, but I just wiped the diesel off it then and it looks the same.
 

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nissan
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I have my fingers crossed that this new pressure valve will yield good economy results
 

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Rogue
nissan gu patrol
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Discussion Starter · #6 ·

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Heyhey,

Have you had any issues with rail pressure codes before you put the new relief valve in? I've had a few low rail pressure codes after putting the boot in and the occasional kangaroo hop as well. I've thought about replacing the relief valve to see if that helps... Not to mention my woeful economy!

Cheers,
Drew.

Sent from my GT-I9305T using Tapatalk 2
 

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Rogue
nissan gu patrol
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20,229 Posts
Discussion Starter · #8 ·
No codes for me and certainly no hopping. Maybe you do have an issue. I'm not sure mine was even a problem, just going through a process of elimination.
 

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Good write up, as a side note, don't forget to be clean around any area when opening a common rail fuel system. Also don't check for leaks with a finger.

The biggest problem we see with these pressure relief valve is that they bypass rail pressure to the return low when they shouldn't, generally causing hard start issues.

Andy
 

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129 Posts
ive got the Chip it, fuel rail block and ive had no issues with it
 

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Rogue
nissan gu patrol
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20,229 Posts
Discussion Starter · #11 ·
Just filled up the main tank today. Done about 100km on the main since the new valve went in, got 16.2L/100km which is one of the best I've done to date, but I won't attribute it to the valve swap just yet. We'll just use that as a reference point. That was a main tanks worth of driving around town not exceeding 80km/h and lots of stop start and hard acceleration (as that is just how I drive).
 

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nissan gu
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Heyhey, do you have a scan gauge ?

If so have you got the fuel rail pressure (xgauge) programmed into it?

What rail pressure at hwy speed are you getting, let's say 2500RPM under load.....?

Interested to compare yours against mine, I'm getting 21,900 PSI

Edit. I now see you have ultra-gauge, does this have rail pressure?

Thanks
 

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Rogue
nissan gu patrol
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20,229 Posts
Discussion Starter · #14 ·
Heyhey, do you have a scan gauge ?

If so have you got the fuel rail pressure (xgauge) programmed into it?

What rail pressure at hwy speed are you getting, let's say 2500RPM under load.....?

Interested to compare yours against mine, I'm getting 21,900 PSI

Edit. I now see you have ultra-gauge, does this have rail pressure?

Thanks
Yeah it has rail pressure. I'm too under the influence to take it for a drive to check. But I'll do it tomorrow.
 

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Rogue
nissan gu patrol
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20,229 Posts
Discussion Starter · #15 ·
At about 70km/h doing 2100rpm in 4th with 4.3 diffs, 33" tyres; 21psi boost, 11282psi fuel rail, 44% engine load, 27g/s through the MAF, 350*C EGT. That was once it was warmed up too (87*C engine temp).
 

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Rogue
nissan gu patrol
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20,229 Posts
Discussion Starter · #17 ·
How?
 

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Heyhey,

Have you had any issues with rail pressure codes before you put the new relief valve in? I've had a few low rail pressure codes after putting the boot in and the occasional kangaroo hop as well. I've thought about replacing the relief valve to see if that helps... Not to mention my woeful economy!

Cheers,
Drew.

Sent from my GT-I9305T using Tapatalk 2
Mine has been hard to start and getting worse over the last couple of months. Threw a p0089 code the other day. MTQ have diagnosed a badly leaking pressure relief valve. Being replaced in the morning.
 
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Mine has been hard to start and getting worse over the last couple of months. Threw a p0089 code the other day. MTQ have diagnosed a badly leaking pressure relief valve. Being replaced in the morning.
Thanks for that info. Think I might get mine changed next service. I pulled out to overtake the other day and it shut down on me. Had to manoeuvre back in front of 5 cars to get to the side of the road so I could get it started again. No engine light but p0089 code came up.
It's getting dangerous now.

Sent from my GT-I9305T using Tapatalk 2
 
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