Power loss problems on the ScibyLine.

[Sciby]

Hi guys,

As the subject says, the poor ScibyLine has been losing power lately, and it's rather annoying. Any suggestions would be most helpful.

* Car is mostly stock in terms of performance... has a cat-back Apex'i RS zorst and an Apex'i Power funnel filter, replacing a HKS super happy filter thingy.

* Changes made lately: Put new filter on and cleaned and de-meshed the AFM. Next lot was new plugs, new gearbox oil, new fuel filter (new filter was because of the power issues, thought it might have been the culprit, no such luck). ECU has been reset a couple of times, made no real changes/improvements.

* Symptoms: Idles rougher than normal, very thub-thub-thub as opposed to the usual smoothness. When accelerating from a stop, there seems to be a hole in the power, ie: the throttle at 50% gives the same acceleration as 30%, not as responsive. You have to give it a bootful to get past this hole and then the turbo will start boosting... although even when the turbo is boosting, it still doesn't have the same power as it used to. Another strange one is when coming to the lights to stop, I put it into neutral, clutch out, brakes on gently, just before it comes to a complete stop, rpm dips and the car phsycially shakes, almost like I've still got the clutch in and I'm engine-braking and letting it stall out...

NB: The clutch plate is dying, but I can usually tell when it's the cause of loss of forward motion.

I'm not going to put forth my ideas on what could be the problem, as I don't want to colour people's opinions and ideas... but any suggestions/tips, etc, would be excellent.

[d0p3y]

Sounds like something may be stopping it from breathing.. The filter is brand new and clean, so that rules out the filter being too dirty. something may be blocking the intake, perhaps, check the filter again. If it's not that, maybe it could be the fuel pump?

[51jay]

Have you run the onboard diagnostics, could be one or more faulty sensors.

have you got your big fmic on yet?? if so ,post a pic

[Sciby]

Hey old timer. nah, no FMIC yet... broke as, badly need a new clutch first... the stock one is like almost mirror finished.

K, ran diags before, normal tests claim "ok", but I ran the O2 sensor realtime... and it was flashing on (for "lean") every second, like: lean, rich, lean, rich, lean, rich... like it was undecided... I decided to deviate from the "Run at 2k rpm" run and revved it up through the rpms, and it was about 50/50 lean/rich... it makes me wonder if my o2 sensor is buggered, because even sitting there, I can take my foot off the noise pedal and it'll pop and fart, indicating to me that it's still running rich, as Nissan programmed it to do.

Any opinions on this?

[Sciby]

**bumpage**

[slip]

mate put the mesh back on your afm, its there for a reason. did you oil the filter? I think the 02 sensor doing that is normal, if it was always rich or always lean you'd have a problem. (note: i think)

[r32-25t]

it could have something to do with removing the screens

it changes the reading the afm gives to the ecu

so try putting the screens back and if that fixes it u will need

a mappable ecu (power fc or similar)

to remove the screens and have it run proparly

[Morgs]

It does sound like a buggered AFM

[MYGTST]

sounds like AFM but before you dump it try sparing it with carby cleaner its safe and it will get any gunk of the wire

the afm is a self cleaning unit but it still sometimes gets contaminated

removing the mesh makes no diff its there to stop lage particles entering the afm from either side

hope this helps

[Sciby]

Originally posted by slip

mate put the mesh back on your afm, its there for a reason.  did you oil the filter?  I think the 02 sensor doing that is normal, if it was always rich or always lean you'd have a problem.  (note: i think)

Er... a bit hard to put the mesh back on, it's been literally ripped out... only the rear one though, the front one is still there...just like quite a few others have done, with no issues... *shrugs*... filter is dry type... you would think that considering the whole thing about nissan programming the skylines to be on the rich side, it would constantly state rich, or at least, for most of the time.

Probably also should mention that I demeshed the afm because I thought it may help with the problems I've been experiencing (ie, I was having the problems before I did the mesh), although it doesn't seem that way... perhaps I'll borrow a full afm from someone and see what changes it makes.