boost problem ?

[fishnsurf]

hi all any ideas of what could be the problem..
have had my dawes and needle valve on patrol for few weeks now and a week or so ago finally got it adjusted (5psi@1500,11psi@2000,12psi@2500,14psi@2800,15psi@ 3000 and about 16@3500) all good so made sure all fittings tight then took tools out of patrol.....
yesterday about a week after final set up drove to a job got back into 4wd (15min later) took off and had very little boost Maybe 6psi@2800 checked all hoses all good valves still tight in correct positions, drove home slowly as egts up due to little boost...... checked hoses again all good no hissing coming from under bonnet... so adjusted dawes and needle and got boost back to close within above figures drove around block a few times all good then around last corner lost boost again 3-5psi@2500 went home and disconnected needle valve and reconnected vac solenoid back up adjusted dawes now have normal standard boost back (which is all over the place compared to needle valve)

checked needle valve connections all sealed tight with cyberbond pipe sealant with PTFE SH22
can there be a prob with needle valve its self looks like not much could go wrong with it...

sorry for so much info but wanted to get the whole story out
at first my mech thought it might be a diaphragm in acculator so it was his suggestion to take off needle valve after we cleaned the MAF (which was only cleaned 2 weeks ago)

any help would be great

thanks jason

[Ade]

Gday mate,

I dont know much about GU 3.0 but similar thing happened once to my TD42 and it was the waste gate actuator that came off loose from the waste gate lever..

Ade

[fishnsurf]

Update Just got back from a drive on hway and I am still having same problem as with needle valve so it's not that...
boost under load and accelerating Seems to drop away to 5 ish then come back and go again... I can feel and here revs increase when turbo comes on then here when it drops away again almost sounds like a bad flaring transmission ....

[paulyg]

Have you checked your turbo hoses and the intercooler? sound like boost is leaking somewhere.

[fishnsurf]

yes checked all hoses and IC........ its strange because one minute it seem to be ok then boost just drops off to 2-3 psi @ 3000 then next its holding 10psi@2000 could it be the MAF?

[paulyg]

It would be a good idea to check it, even if just to rule it out, i would allso disconnect your chip and try driveing with out it.

[fishnsurf]

Thanks paulyg was thinking of that but my tunit chip is hard wired..... but i think they said if i turn it to setting 1 that is would be at factory settings ... i wonder if there was a prob with chip if it would still be there because i am going through the chip For my factory setting

[paulyg]

If you set the chip to setting one and the boost is behaving differently to the way it has been i would be suspecting the chip, if no difference then you may be able to look elsewhere.

[fishnsurf]

Just got back from a drive i put the passanger window down and i can here the turbo makeing a strange noise when it is boosting (like a really tinny rattle sort of noise )then when i back my foot slightly rev stays the same boost drops to 1-2 psi and the noise stops, when i increase rev boost comes back up and so does the noise ...... Could it be the turbo is stuffed (if it is anybody have an idea of the cost for a new turbo) i hope not

edit 16th may..... (found the tinny rattle noise) i had an 2.75 exhaust fitted only a few day before all this problem started when they fitted my exhaust they happen to miss the only support bolt to the motor... great! so my whole exhaust has been hanging off the turbo for couple of weeks very professional..... the other supports and rubber mounts....

[boots]

Sorry fishnsurf it could be your turbo . Probably wait until the engine has cooled down and remove turbo inlet side hoses and inspect your impella and bearing float /play/spin to see if its died.

[fishnsurf]

yeah think it could be the turbo going to mech this morning to confirm.....bugger... if it is dead should i be putting a genuine back in or are there other non exp options, already over budget on mods.

does anyone have an idea about cost just so when mech gives me price i will know if its fair (dont know them that well)
or could i install it myself over the weekend

thanks

[grimace]

this sounds like what my truck has been doing appart from the turbo noise which i havn't noticed anyway i am going to nissan for an engine diagnosis hopfully they find what is wrong and i will let youse know how it goes, cheers....

[fishnsurf]

Well mech said not turbo thinks it might be the maf ... said was fluctuating on scan tool even at idle.... Sitting outside Nissan now they tell me maf not sold seperately 2005 onwards , comes with part of housing $1150 and none in country .WHAT THE, Just saw on nizzbits.com.au $330 sold seperately is this a good price??

[fishnsurf]

just tested MAF myself seems ok i think or is the 3.3v too low (me 1.9-3.3v@4000) post says should be 4.0v@4000

ZD30 Series 4
there should be a 6 pin connector Nothing, White, Black, Red, White and Black, terminal 1,2,3,4,5,&6
With the car idling, warmed up to normal operating temp AC off, in neutral no load test the following
The 3 (B) should be reading 0v (me 0v)
The 4 (R) should be reading between 1.5 to 1.9v at idle increasing to 4.0v when revving through to 4000rpm (me 1.9-3.3v@4000)
With the car stopped but the ignition 'on' disconnect the MAF plug and test
The 2 (W) should be reading the battery voltage (me all good )
If they read these you MAF is fuctioning

[grimace]

just an update, nissan reckon all is good is doing what it should and that all commonrails go different (no 2 are the same) fork me!

[fishnsurf]

is this good news for u grimace or do u still feel something is still amiss

well another update..... drove into cleveland nissan late today(not in patrol) as i was informed that 3.3v is too low @4000rpm for the MAF now these guys do sell the MAF separately,,, got home disconnected battery and installed MAF 1 hour later drove for 30min and pleased to say at this stage all feels back to normal i am so happy.... tomorrow i will re install dawes/needle (had set all back to factory settings to narrow things down).... will also test tomorrow with my boat on under load to be 100%

by the way had prices for MAF ranging from $268 $330 $378 $437 and one nissan dealer said only sold as a unit with section of air intake $1150

[boots]

Thats good news fishnsurf . happy that I got it wrong for you with diagnosis . any way you look at it those MAFS are not cheap .goodluck , keep us posted with the verdict .

[fishnsurf]

YIPPY did i say YIPPY yet sooooo happy

all back to normal

apparently the noise i could here coming from turbo in the dead of night was just the turbo its self

now i think back to the boost dropping away around 2500-3000rpm then holding 10psi@2000 was a similar thing watching the multi meter while testing the MAF at idle all tested good then as revs increased volts went up but from approx the 2500rpm volts seem to struggle and only reaching 3.3v@4000rpm not the 4v as it should ,,,,,,,,,,,,

dont know much about the MAF but have been told that the resisters if that is the correct name wear out over time (this one was 7 years 130k old) slowly reducing performance was also told by the same person that when they test the MAF they replace them when they stop reading above 3.6v@4000.

so maybe not just clean the MAF but check it as well (only takes a multi meter and 2 people 5mins) 1 person to rev the other to check multi

i just pierced the correct wires coming out of MAF connector then sealed with liq electrical tape

did i say YIPPY yet

[grimace]

well i think it is good news but am still quite suprised, nissan technition said it was one of the better ones he has driven and the boost coming on and off was just the ecu preventing boost spike. i have cleaned the maf but it might be worth having it tested and my local nissan dealer tryed to sell me the entire maf sensor unit at over a grand.

[fishnsurf]

yeah i dont understand how one nissan dealer sells it separately and the next thinks they only come with section of air intake

[threedogs]

Have you found the problem yet, my 04 3lt doing the same thing, Boots has suggested it maybe some thing to do with vacuum sensor, cheers

[fishnsurf]

Have you found the problem yet, my 04 3lt doing the same thing, Boots has suggested it maybe some thing to do with vacuum sensor, cheers

hey threedogs my problem ended up being the maf sensor and the and the tinny rattle noise was when my exhaust when it was fitted they forgot a bolt.... if u go back through the whole tread i also listed how i tested the maf as well... hope it helps.....

[threedogs]

Hi new MAF fitted, seems the 3 vacuum hoses going to vacuum solenoid need to be joined with a TEE and the solenoid blocked off. Trying that this morning. Ditto on the exhaust bolt, just had sports cat fitted and they forgot that bolt, easy fix but annoying. Will let you know how I go, cheers

[fishnsurf]

Hi new MAF fitted, seems the 3 vacuum hoses going to vacuum solenoid need to be joined with a TEE and the solenoid blocked off. Trying that this morning. Ditto on the exhaust bolt, just had sports cat fitted and they forgot that bolt, easy fix but annoying. Will let you know how I go, cheers

hi threedogs i am sure u have seen this info on the dawes setup here it is any way... http://www.chaz.yellowfoot.org/Manual%20Boost%20Controller.htm i am pretty sure u can only block the the soleniod when u fit a needle valve.. cheers hope u get it sorted