Rough Idle R34 Rb25det Neo Engine

[ShadowKnyght]

Hello all,

Looking for some answers

I have noticed for the last few months that my car when at idle gets rather randomly rough - like it is miss firing... it will simply idle normally then the car will shudder.

Initially I thought it was simply related to a loose tube / or pipe that comes from the top of the engine (just to the left of the petrol cap and up a bit on the left side of the engine when the plastic cover is removed). When I fixed this the rough idle went away for a short period (as did my oil leak that Unley Nissan wanted to charge me $120 for various Diff and engine gaskets along with 8 hours worth of labour @ $110/h to fix!).

But it came back - seems once the engine has warmed up - but the outside temperature is cold - that the idle gets worse!

I have also noticed my car back firing a few times... so...

After speaking to random people at work, I have changed my oil and oil filter (needed to be done anyway - used Shell Ultra synthetic 5W-40W). Then I changed my spark plugs (Car has only done 74,000km and I discovered that I had NGK platinum plugs installed in the car - so probably did not really need to do this...)

I installed the NGK Iridium plugs (saved about $27) Motortraders have them for $17.60 inc or the platinum ones for $22 inc each.

Problem still seems to occur...

Which pissed me off as it took a long time to pull my engine apart to install the plugs - nothing like my old Celica... These NEO engines take a lot of work to pull apart!

I also have pretty high fuel consumption - my 60L tank gets me about 300 to 330km city driving and high 3's for freeway. I had thought this was more due to the cars weight mixed with it being turbo and AWD... but when your car uses more than a V8 you kind of get worried. 18.5L / 100k or around 6km / Ltr

Anyway - what do you guys suggest I try next?

O2 sensor?

Temperature sensor?

And where to buy and how to install?

Additional info - the car is bog standard - no PSI increases, nor any pod filter - but it does have a HKS super seqential BOV, and a large exhaust, along with a turbo gauge - no leaks...

So O2?

http://www.ngkspark.com.au/tech_index.htm?...nsors_index.htm

MotorTraders in SA are the official NGK distributors... so along with spark plugs I may be able to get an O2 cheap from them as well...

[ShadowKnyght]

Just checked out the NGK website - seems they only support up to the R33 for O2 sensors? is that correct?

i.e. part number OZA395-E2

Is this part compatible with the R34 NEO engine?

[ShadowKnyght]

Nobody?

Is there a thread some where covering this already - specifically for the R34 neo engines? I could not find it? Only for the R32 and R33 and a few people asking about the R34 but no specific answers... come on - there has to be a few people on here that know - the R34's have been around for 10 years now!!

Next question - could this be the Air flow meter that is causing this?

Either way - if anyone has an R34 and has changed the O2 sensor can you please tell me if the R33 O2 sensor fits and works?

i.e. part number OZA395-E2

[blind_elk]

"Petrol cap"? In the engine bay? You mean the oil filler cap?

Try having the injectors cleaned. Try cleaning the AAC valve. Check / replace the air filter panel. Check base ignition timing.

Is it auto or manual?

[ShadowKnyght]

hahaha oops yeah - oil cap was what I meant to type... and it wont let me edit the original post anymore )

Auto - triptronic plus the controls on the steering wheel.

Air filter panel is like new!

To clean the injectors and the AAC as well as having the timing checked I would need to take her to a mechanic. Which I very well might need to do.

Thanks for the suggestion (more things that might be wrong to add to the list... great )

May also need to work out how to check engine error codes on the R34 - seems easy enough on the R33...

But in the mean time - can anyone answer the O2 sensor question?

[Amec]

misfiring causes include:

- coilpacks

with the car idleing, pull a coil pack connector and if the idle changes, then you know that coilpack is ok. if the idle doesnt change then there is something wrong with either the coilpack or something injector related not right on that cylinder. do this for each cylinder.

can also be:

- failing ignitor module

- failing cam angle sensor

poor fuel economy can be caused by:

- dead knock sensor

- dead O2 sensor

- faulty engine coolant temp sensor

- bad injector(s)

[ShadowKnyght]

hmmm ok - with the R34 engine though - you have to pull half the engine apart to access the coil packs - so you suggest put it back together minus the cover plate over the plugs and then perform these tests... can this not itself damage the engine...?

So could a bad O2 sensor also cause rough idle - i.e. a random shudder at low revs - especially on a cold night when the car has warmed up?

Or would that be more likely one of the other parts you mention?

How likely is a "bad injector" to be able to be fixed by simply using a fuel addative when I next fill up to clean them?

Or does one really have to remove each one and attempt to clean with CRC contact spray?

I am hoping it is just the O2 sensor but at this rate it appears I could replace a fair number of parts one by one before fixing the issue...

Also could a clogged fuel filter do this? (remember though that the shudder only occurs at low revs or simply is just not noticable when reving above 1200 RPM...

Still need to know from anyone who owns a R34 - does the R33 O2 sensor fit????

[Amec]

hmmm ok - with the R34 engine though - you have to pull half the engine apart to access the coil packs - so you suggest put it back together minus the cover plate over the plugs and then perform these tests... can this not itself damage the engine...?

no it will be fine to remove the cover plate and do the load balance test

So could a bad O2 sensor also cause rough idle - i.e. a random shudder at low revs - especially on a cold night when the car has warmed up?

possibly

Or would that be more likely one of the other parts you mention?

yes

How likely is a "bad injector" to be able to be fixed by simply using a fuel addative when I next fill up to clean them?

hard to say

Or does one really have to remove each one and attempt to clean with CRC contact spray?

would be far better to get them professionally ultrasonically cleaned and flow tested

I am hoping it is just the O2 sensor but at this rate it appears I could replace a fair number of parts one by one before fixing the issue...

Also could a clogged fuel filter do this? (remember though that the shudder only occurs at low revs or simply is just not noticable when reving above 1200 RPM...

unlikely but possible, cheap to replace so wouldnt hurt.

[ShadowKnyght]

Thanks again - Guess I need to start buying parts - or simply bite the bullet and take her in for a professional to take a look - especially as I can possibly claim a lot of this on insurance (problem did not exist prior to the car being stolen...)

Still - anyone on the part number for the R34 O2 sensor?

[ShadowKnyght]

Ok removed the original O2 sensor - very Sooty / carbon?

http://www.ngkntk.com.au/tech_index.htm?ht...nsors_index.htm

Excessive Carbon or Oil Deposits

Excessive carbon and oil deposits can damage the sensor. Carbon deposits can clog the sensor and effect its response time. The cause can be a rich mixture, exhaust air leaks or high oil consumption due to worn piston rings or valve seals.

mine was a different head obviously but still...

How does one regulate the "Richness" of the mix? i.e. if my car is running to rich?

Does this point towards another type of obvious failure...?

I have added a injector cleaning bottle to my fuel tank so hopefully that also helps...

So far though I still noticed the shudder exists...

I am hoping this will disappear as the ECU recalibrates but maybe I am being to hopeful...

I removed the battery terminal and put the lights on and my foot on the brake to speed up the discharge, this reset the trip computer so I assume it is also enough to reset the ECU? or do I need to do more?

BTW some basic info on the R34:

Original 02 Sensor was Marked:

LIC. BOSCH A24-A71 047 87280

New Sensor used (Has wrong connector so needed the BOSCH connector cut off and swapped using crimps as you can not solder to the stainless steel wires used on the BOSCH cable loom):

NGK / NTK OZA395-E2 $85.80

Spanner used to Remove the O2 sensor - 22mm

I first removed the Shield plate that the 02 sensor was cabled tied to (that holds the connector away from the heat of the engine) this gave me a tiny little bit more room to work. to do this you only have to remove 1 x 10m screw.

I had to use the spanner on an angle as there is not enough room between the firewall and the exhaust pipe, and the engine and some other box thing...

But anyway long story short - it came out ok - so no special tool required.

[Amec]

is the ECU showing any error codes?

[ShadowKnyght]

Not 100% sure how to get the error codes to display on an R34 / Stagea S2?

Everything I have read on these forums refers to the R32 and the R33. The R34 does not have the fuse box on the right and just below the steering wheel like the R33 so... not 100 on how to get into this mode... would be handy to know though if any one can point me in the right direction...

[ShadowKnyght]

hmmm car still back fires on occasion as well generally when changing into third...

again all these issues only happen once the car has warmed up, and tend to only occur under 1200RPM (although the other night in third I swear it was missfiring) - so I assume this could not be any of the following?

- Injectors

- Coils? (unless the crack only gets bad once warm?)

- failing ignitor module (unless these can be heat effected)

- failing cam angle sensor (unless these can be heat effected)

Not sure on this one?

- dead knock sensor

- faulty engine coolant temp sensor

- bad injector(s)

Unless I installed a bad O2 sensor or one of my crimps failed to connect properly I think I can now rule out the

- dead O2 sensor

Anyway - anyone know how to check the codes on an R34?

[chook]

http://www.skylinesaustralia.com/forums/in...t&p=3569100

see link, bridge the 2 pins for a few seconds after turning on ign.

[RusH_]

Hey bud, any progress with the shuddering, it sounds very similar to the problem i have, when warmed it gives off a random shudder, i have tried replacing both the coil packs and plugs, to no avail, i took it to Dan (3lite 32) and we hooked up the lap top and went for a run, and he said that the car is running fine, (initially it was for a different problem which has turned out to be my tyres which were wearing unevenly due to needing an alignment etc..)

Anyway, with the laptop hooked up, i pulled into the driveway, it has a small slope and so im parked on the slope, and suddenly we notice this misfire like shudder occurring, quite strongly i might add but the laptop shows no problems, ecu had no error codes either, i rolled the car back onto the flat section and the feeling disappeared for the most part but still retained that gentle shudder here and there.

(this was all on a cold night, warmed up car)

So, all that said i think i have the same problem as you, and Dan had no idea what is going on with it, so im very interested to see what you come up with

Steve

[ShadowKnyght]

I changed the O2 sensor and had no real luck to start with - as well as ran some fuel injector cleaner through the car.

Nothing seemed to work - but then I asked my 4 year old son to sit in the drivers seat and Rev the car when Daddy says "now"...

Being 4... he kind of did not wait! Reved it like you wouldn't believe - black soot shot out the exhaust - the car has been almost perfect since!

I think my exhaust / or cat may have been blocked by soot possibly as a result of a bad fuel mixture - so the O2 sensor may have been a change that was really required...?

Either way car runs well now - I have only had 2 shudders since and 3 back fires Still no error codes BTW!

But I Plan to pull the exhaust off and clean her out - maybe do something with the cat as well...

Have not done this yet due to work commitments recently and the car going in for the Hyper Dolphin kit to be repaired and re-sprayed.

[RusH_]

lol, how strange, i think you need to reward your son though, heh

maybe when i get around to upgrading my exhaust it will solve my issue too

cheers bud

steve

[STLKHR]

I changed the O2 sensor and had no real luck to start with - as well as ran some fuel injector cleaner through the car.

Nothing seemed to work - but then I asked my 4 year old son to sit in the drivers seat and Rev the car when Daddy says "now"...

Being 4... he kind of did not wait! Reved it like you wouldn't believe - black soot shot out the exhaust - the car has been almost perfect since!

I think my exhaust / or cat may have been blocked by soot possibly as a result of a bad fuel mixture - so the O2 sensor may have been a change that was really required...?

Either way car runs well now - I have only had 2 shudders since and 3 back fires Still no error codes BTW!

But I Plan to pull the exhaust off and clean her out - maybe do something with the cat as well...

Have not done this yet due to work commitments recently and the car going in for the Hyper Dolphin kit to be repaired and re-sprayed.

SOUNDS LIKE YOU HAD A BLOCKED IJECTOR, ID SAY IT HAD NOTHING TO DO WITH EXHAUST, SINCE YOUR SON REVED IT HARD OUT THE INJECTORS WOULD OF BEEN AT 100% DUTY CYCLE (CONSTANT OPEN) WHICH COULD OF DISLODGED A BIT OF SHIT IN THE INJECTOR!!

REASON I SAY THIS IS AFTER READING YOUR PROBLEM I REMEMBERED DOING THE SAME TO MY CAR AND IT WORKED.

10 POINTS FOR YOUR LAD THOU... NICE

[V28VX37]

I just got myself an R34 GTT (RB25DET Neo), will post a proper introduction once I get it cleaned properly.

Sorry to dig up an old thread but it sounds like I may have a similar issue as ShadowKnyght, there is a slight shudder/miss on idle once the engine has warmed up.

A mechanic who inspected the car before I bought it said it might be just from being garaged for over a year and a good long drive down the freeway might help, haven't done that yet though.

Looking through the service history I know that it's had an injector & fuel system clean in 2008 and new NGK plugs put it. I 99% confident it still has original leads and coilpacks.

I did the old paperclip trick to read ECU codes and it came up with 34 (knock sensor) and no other codes.

I had a look under the inlet manifold near cylinder 2 (close to front of engine) and I am assuming the photo below is one of the knock sensors?

Is there any way of cleaning these things or do they need to be replaced?

Any advice on how to get to the other one (near cylinder 5), I couldn't find it from above even with a mirror?

Also, could it be just the wiring and not the sensor itself?

Thanks

[noahr31]

Quick answer is no

throw them in the bin (2 of them) and replace with new genuine items from nissan

they won't be cheap but they are very important in the running of your engine