Boost levels at crusing speed

[mundlich69]

Hi All,
Just after your experiences and thoughts on how the boost should be behaving when travelling over 100kmph??
I've had a ultra gauge hooked up to the GU8 not long after the purchase and probably 3 months ago I noticed when cruising over 100kmph especially with cruise control engaged the boost level would rise from a consistent 12-13psi upto 17psi and fall away it was an iregualur occurance but something I kept an eye on and adjusted my driving to suit. I mentioned it to Nissan when it went for it's 10000k service and the found a faulty EGR valve which has since been replaced. Problem is it's doing more often now and has climbed upto 18psi on occasion. Took it back to Nissan and they spent a day on it could not find any issues, next step is they want it overnight so they can hook the computer up and take it for a run which is fair enough. I told them I'm getting all the upgrades installed this week (including new intercooler, exhaust and chip) so I see how it preforms when I get it back and if there's still an issue I'll bring it back.
Now firstly is there an issue (is the boost suppose to act this way) and secondly any recommendations???

[alfonso]

I dont have a boost gague but my 2012 dx ute makes a different sound when I get to cruising speed in 3rd fourth and fifth gears almost like the clutch is slipping usually around 2500 revs and when I let my foot off just a little. sounds like when you first start up and the oil hasn't stuck yet could this be boost also.

[paulyg]

How does it behave with out the cruise control on? I now with mine the boost does move up and down a lot more with cruise control on.
Could be the cruise control trying to maintain the set speed moving the throttle on and of.

[mundlich69]

It doe's the same thing with out cruise control on but not as bad and often??

[mudski]

Install a Dawes valve and block the egr and forget about those issues for ever.

I tapped that app

[kevin07]

check all your hose clamps but it does sound like an egr problem

[MEGOMONSTER]

My GU8 auto, EGR blocked chipped and zorst sits on flat roads at 100kph with cruise at a constant 10psi

[mundlich69]

I've checked all hoses and so did nissan all good there. I get the patrol back tomorrow so I'll see what differences all the mods have made to it.
Megamonster doe's your egr block have a 6mm hole or not??

[MEGOMONSTER]

Megamonster doe's your egr block have a 6mm hole or not??

It's MEGO MONSTER and I really couldn't tell, I just don't know, I don't even know where to look or what to look for.

[mudski]

These Nissan CRD's don't need the hole. For some reason. Just about every other CRD does though.

[threedogs]

Is your IC oily, at all.
Mine sits @ 10PSI doing 100 kph constantly

[mundlich69]

Threedogs - I checked the intercooler had a small amount of oil in it.
I now have the new intercooler and catch can installed as well as the 3" exhaust and it's still doing it but climbing up to 20 psi now??? One thing have noticed on my ultra gauge is when the engine load is around 56% - 58% is when the boost wants to heads north?? The chip goes in Tuesday so I'll see if that changes any thing otherwise back to Nissan I go!!!

[mudski]

If you block your EGR, your boost level may rise even more. Install a Dawes valve, at the least, and your problems will go for ever. Add a needle valve into the mix and you will have the power to make your CRD go even better.

[megatexture]

I thought the crd needed a 10mm hole in it Or it will throw error codes or limp mode.

[mudski]

I haven't come across one yet. Sold around 100 plates in the last five or so months and no reports yet. But having said that. There is a first time for everything. Being a CRD I am surprised really.

[Blacklotusdog]

Crd sometimes throw egr flow error code. Easily cleared with scangauge or similar and definitely does not go into limp mode.

[threedogs]

The ECU on the CRD is more tolerant of higher boost levels,
This Chip you mention is it after market and Nissan are fitting it,??
With the IC being oily it may mean its leaking, so my point being how can it hold boost.?

[mundlich69]

Three dogs its a tunit chip and not installed by nissan, but the chip has made no difference as the issue is still there. I have booked it back into Nissan and I reckon its due to engine load certain speeds as when I sit on 120 boost sits happy at 12psi, drop down in speed and either using accelerator or cruise control boost will climb up to 20psi at a certain % of engine load??

Sent from my AMID-9743G using Tapatalk 2

[threedogs]

Have you blocked the correct end of the EGR pipe ???
Disconnect your battery for 1/2 an hour

[mundlich69]

Disconnected the battery for hours and still the same. Took it back to Nissan again! Still no answer there still waiting to hear back from Nissan tech. In the meantime I've brought a Dawes valve at least I know that sort the issue once an for all!

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[june]

mine is the direct injected ZD30, before dawes and needle were fitted boost would do the same symptoms as yours. once fitted sits on 11 psi @ 100 clicks and stays there. don't know about common rail but fit dawes and needle as mudski suggested. [no more problems]

[mudski]

And block the EGR after the valves are fitted...

[schanmala]

more info here:

http://www.nissanpatrol.com.au/forums/showthread.php?19727-egr-block

CRDs do get the engine code randomly (depending on temp conditions?), just clear it with an ultragauge/scangauge. Or drill a hole but that kinda defeats the purpose.

Zorst and EGR block will raise ya boost

Chip, Dawes and Needle will fix it all.

[mundlich69]

Yeah the Nissan service manager suggest EGR block & workshop foreman suggested Dawes valve! I asked what about warranty and the answer was it mite effect it!

[mundlich69]

Schanmala I'm running and Ultra gauge (great bit of gear) and the reason I found the issue. Will hopefully finish off wiring up the Autron gauges tomorrow & fingers crossed the Dawes valve turns up by Friday cause only 10 days and it's up the Cape for 5 1/2 weeks