Rb25det Doesn't Idle Properly

[Kujotk]

Hey i need some help with my series 2 r33,

Car drives well but when i'm doing little stop and starts and dodnt rev hard the car almost konks out and today at a roundabout it did turn off as i was rolling through it.

Its a manual, when i do a light acceleration to about 2000revs and then come to a stop and i either push the clutch in or put it to neutral the car goes way under the 500-600rpm idle to about 200rpm and then goes back to normal idle.

If the lights are on when this happens the lights dim.

I replaced a faulty pcv valve today that had a leak hopeing that was the solution but same thing happens.

When i rev it over 2000rpm and bring it back to idle the problem doesnt show...

any ideas????

is it a fuel issue?

Ignition issue?

throw around some ideas please

oh and i only use vortex 98 or Vpower fuels

thanks

[arbess]

v-power sucks imo but fuel choice wont be an issue.

my rb26 does this same thing. i am in the process of locating the problem. sounds like you have a vacuum leak to answer the idle variation. Loss in power around the round-about could be anything, so i wont rattle on to confuse you.

your lights are dimming because your alternator is slowing down and not providing the voltage/current required for the system, this is more a side affect (though could indicate low battery)

ignition is supposed to be more noticable throughout the rev range, so may not be this. Though what i read a lot is the coil pack in the 33's cracking on the outside.

Our cars are very sensitive to vacuum leaks, all it takes is a small hole for air to enter/escape and you get alternating idle.

In summary problems vary from car to car with the same symptoms, but for me that heads towards a vacuum leak. If you find your idle at stop is pretty consistent and not too much variation (lets say plus or minus 100rpm) then it might just be a small crack in a hose or seal of some sort.

good luck, i could be wrong all together

[Kujotk]

hahahah yeah i noticed vpower wasnt as good or maby thats just in my head....

battery is fine..... only got it 2 mnths ago and still got correct amount of acid in it and voltage is over 14volts so that shouldt be the issue...

i did find one leak in one of the hose seals but replaced it and same prob,,,, checked over all other hosses and seals and they look ok.....

any other sugestions from anyone???

also i been reading up that allot of cleaning might need to be done to things like air flow meter.... the thing that sists behind the plenum nect to the fire wall.... dont know what its called but has something to do with the idle that can benefit from a good cleaning..... "well thats what i read on this website somewhere anyway"????

[br3ndan]

You got blow off valve?

Aftermarket blow off valves will cause exactly what your talking about.

Nothing really you can do about it, unless u want to go back to the stock plumb back.

[teng]

I had the same problem everytime i stop and idling close to 500rpm. In the end it was the airflow sensor (AFM). Just needs a bit of contact cleaner and it idles at around 900~1000rpm now.

On other note, we only have Shell fuel here. Max RON is 97.

Edited July 8, 2008 by teng

[Kujotk]

standard bov, could the standard one get worn out and would it make this issue????

and what you mean clean the air flow meter???? do i clean the mesh or open it up???

[wht510]

standard bov, could the standard one get worn out and would it make this issue????

and what you mean clean the air flow meter???? do i clean the mesh or open it up???

Best thing to do is get some 'CRC' Air Flow Meter cleaner or carby cleaner. Basically it's a whole bunch of solvents which clean all the dirt/oil and other crap on your hot wire AFM. If that doesn't work, I'd replace the air flow meter. Same thing happened on my R32 RB20DET. The AFM died, and it wouldn't idle properly. No amount of cleaner would fix it. I had to replace it. After you have checked all the vacuum lines, get stuck into the AFM.

[arbess]

hahahah yeah i noticed vpower wasnt as good or maby thats just in my head....

battery is fine..... only got it 2 mnths ago and still got correct amount of acid in it and voltage is over 14volts so that shouldt be the issue...

i did find one leak in one of the hose seals but replaced it and same prob,,,, checked over all other hosses and seals and they look ok.....

any other sugestions from anyone???

also i been reading up that allot of cleaning might need to be done to things like air flow meter.... the thing that sists behind the plenum nect to the fire wall.... dont know what its called but has something to do with the idle that can benefit from a good cleaning..... "well thats what i read on this website somewhere anyway"????

Its a little screw thing if thats what your on about, that plays with your idle. If your car is idling fine at rest then you shouldnt have to touch it.

Yes AFM's can disturb your cars operation, give that a good clean or test someone elses on your car.

BOV are a pain in the ass. Hard to tell if they are leaking without submitting it to some sort of pressure test, but they can lead to some severe idle problems and driving issues.

One thing I am doing in cleaning my injectors and replacing the seals. that could be another venture for you. I think, not confirmed, that I have lost vacuum through my seals. I'll let everyone know if i've fixed my problem by replacing the seals.

[Kujotk]

thanks guys this is helping heaps but please keep brainstorming other reasons coz im not a pro on rb25det engines and im worried some mechanic will rip me off blind.... more knowledge i have better chance i could fix it myself....

AFM sounds feesable, i'll swap it with a friends on saturday and let you know if that worked

cheers

[teng]

you don't have to open up the afm mesh, just point the contact cleaner at the inside thingy and spray it. let it dry and reconnect, then start your car.

[Kujotk]

thanks teng

[Psyrus]

Hey there I have the exact same issue with my DB25DET,

My quick fix has been to learn how to drop the clutch in second gear quickly, as that will jump start your car again. I'm not sure about the ramifications of doing this (about twice a week, when the stalling issue presents itself) engine wise, but I refuse to sit there at the roundabout/corner looking like an idiot who doesn't know how to drive a manual

People seem to point towards BOV or this vacuum issue, neither of which I know anything about [not very car savvy], so I'm going to take a friend who knows this-from-that and see what he thinks. I'll be pretty unhappy if it's a serious issue since I bought the car not two months ago, and have done <1000KM in it...

[Kujotk]

thanks psvrus

i'll be looking forward to what your friend has to say

[Kujotk]

.

[Kujotk]

i see that my car seems to idle a few hundred rpm lower than some r33's ive seen around.....

its a GTST and im idleing at 500-600rpm..... others i have seen around the place are about 800-900rpm..... could my idle prob just be as simple as turning the idle up????

can i have some stats of what your rb25det idles at???

anyone????

[teng]

Only way of turning the idle up on a RB25DET is by using an aftermarket ecu. That's the only way i know. Tried it on the apexi pfc before.

[Kujotk]

prob fixed today.... cleaned the AFM, put new spark plugs, cleaned the throttle body and raised the idle rpm up by 100rpm, cars like new now..... never driven it like this before.... goes awesome........ thanks for your help guys

[br3ndan]

My car idles at around 700 when warm.

With head lights on, it drops a bit to about 680.

how do i know exact figures? Gotta love Apexi RSM. LOL

900-1000 rpm is very high for idle. Unless its started cold, then its normal for it to idle at that rpm for a few mins.

[Kujotk]

hey brendan ive researched into the issue and nissan recommends the idle to be 700-800rpm when warm, the sticker under my bonnet from nissan and the manual from nissan both say it (i have a japanese friend who found it for me since i cannot read jap) so my idle was way too low to begin with at 500-600rpm..... yours is at the lower end of the recommended spectrum and should have no problems at that rpm, if the idle starts going down do what i did cleaned the AFM, put new spark plugs, cleaned the throttle body and raised the idle rpm up by 100rpm, but keep track of when you put the sparks in and when and how much you put the idle up..... if you put it up by 100rpm every month or 2 you have an underlying problem...

[Gabbo2047]

if ur problems happens again check ur AAC valve they get a little dirty and stick. its the housing that ur idle adjust screw is in. just strip it down and give it a clean and the problem sould go away and yo can lower ur idle to the recommended level.