Overboost question

[dpetersen]

Gday guys!
Quick Overboost related question.
Iv had my egr recently blocked and Dawes and needle valve installed. Boost is set to 18 psi. Everything seems to be running pretty good now apart from one slight Overboost issue. I usually sit around 105 km/h and the car runs fine but when iv got to get that little bit more out of the car, usually to overtake a road train or caravan the engine light comes on due to over boost. I try to get a bit of a run up and gradually increase speed before overtaking but it's not always that easy. It happened the other day just as I'd pulled out to overtake a road train (was not a pleasant experience), anyway I'm guessing it's due to the turbo spool up being to quick? To fix this is it just a matter of winding the needle valve in slightly?
Thanks guys, car is a 3ltr series 3 wagon manual.

[BigRAWesty]

I'd say it's possibly the spool up rate more than over boost..
Does it spike at all??

[threedogs]

I would probably reset the max boost back a
touch to say 16 and go go from there

[Daveyboyjunior]

I had this limp mode reaction every time I gave the truck a squirt for an overtake too.
I was running at 18psi max also at the time.
I did as TD suggested above but eased it just down to 17psi max and haven't had the issue since.
Little adjustments at a time is the way to go with the Dawes setup.

[threedogs]

dpetersen Forgot to mention to dis-connect the battery to re-set the ECU

[dpetersen]

Thanks guys, will disconnect the battery first before I start adjusting it. Hopefully shouldn't need too much adjusting to get it right.

[Hodge]

Hello mate.
Is yours a CRD ? And are you getting any codes ? (providing you have the means to read codes)
If it is. I had the IDENTICAL symptoms to yours. And after a long time tinkering with needle 'n dawes, it was still doing it regardless, every time I punched the car to overtake.

To cut a long story short. Mine ended up begin the rail relief valve. I was getting codes P0087 & P0192.
In a nutshell when you gun it, it doesnt matter what boost you're running, the fuel pressure in the rail becomes too much for the valve and it triggers a limp mode.
Might pay to check this.

My original thread on this:
http://www.nissanpatrol.com.au/forums/showthread.php?32851-Fuel-pressure-problems

Instructions on how to swap one:
http://www.patrol4x4.com/forum/3-litre-zd30-crd-engine-82/instructional-fuel-rail-relief-valve-swap-212418/

Instructions how to check one:
http://www.nissanpatrol.com.au/forums/attachment.php?attachmentid=69087&stc=1

[mudski]

Gday guys!
Quick Overboost related question.
Iv had my egr recently blocked and Dawes and needle valve installed. Boost is set to 18 psi. Everything seems to be running pretty good now apart from one slight Overboost issue. I usually sit around 105 km/h and the car runs fine but when iv got to get that little bit more out of the car, usually to overtake a road train or caravan the engine light comes on due to over boost. I try to get a bit of a run up and gradually increase speed before overtaking but it's not always that easy. It happened the other day just as I'd pulled out to overtake a road train (was not a pleasant experience), anyway I'm guessing it's due to the turbo spool up being to quick? To fix this is it just a matter of winding the needle valve in slightly?
Thanks guys, car is a 3ltr series 3 wagon manual.

Is it just the engine light coming on or is it going into limp aswell? If its just the light then I would be too concerned about it. These motors will happily run at 25psi mate. The overboost light is just another annoyance of the ZD30.

[dpetersen]

Thanks mudski and hodge. Mine is a direct injection. It's just the engine light coming on. 99% of the time it's fine, it's only when I put the right foot down a little too hard that it comes on. Iv got a day off on Monday so il give it a go then

[dpetersen]

So I disconnected the battery over the weekend and hooked it back up today. So far so good! Went for a drive a gave it a bit of a squirt and no engine lights! Thanks for the help guys! Hopefully shouldn't need to adjust anything.

[mudski]

You wont need to adjust a thing. If its just the light, don't be concerned. The light would come on on mine, but only when I hit around 28psi, lol. It was more of an annoyance than anything. Your certainly not hurting anything that for sure.

[foggs]

Had my ECU remapped yesterday, I better go give it some hell and do a proper test before I hit any major trips. thanks