Weird Issue With My Stagea

[Scratch]

Hey all,

I noticed today morning when i parked the car, my idle was a bit high - this happened about once or two before but nothing since. On my drive home today from work, everything was fine and then my stagea started to lose acceleration pretty consistently. It happened at no particular RPM range, either on or off boost. She'll be going nicely and then it feels like i just took my foot off the accelerator, but i'm still pressing it! no squealing belts, choking or misfiring.

I'm wondering if AFM could be causing this? but i had it cleaned during my last service at xspeed and haven't really had this issue.

I have a greddy infometer plugged into the OBD port, i noticed the following the AF/C reading is showing 104% - 118% and when the drop happens it goes down to 97%. (a bit high but does anyone know if the greddy infometer 1's displayed this correctly?). I can also see voltages, but i dont know whats normal voltage for a AFM.

Don't think it could be the battery, as it didn't completely shutoff the engine. its an odd one! now i have to figure this out so i can drive to work tommorow.

does anyone have any ideas regarding the above?

thanks

[SHETLANDER]

I had the same thing happened to me last friday, i took the AFM off yesterday and cleaned it with contact cleaner and took it for a spin, seems to be a lot better.

[Scratch]

cheers for the reply shetlander, i cleaned out the AFM this morning with some contact cleaner - no protective mesh on the front and back of the AFM though, was your stag's AFM like this? parked the car and the idle was up around 1400RPM while in park. turned the engine off and back on again and it was normal (~650rpm)and didnt repeat.

however drove ok into work this morning no drop outs in acceleration, i monitored the voltages with my greddy infometer:

1.20volts (+/- 0.01v) with A/Cond off

1.31v(+/- 0.01v) with A/Cond on

peak voltage: 3.02v

ranged between 1.4-2.8v during driving.

Does anyone know if these voltages are within operational spec?

Also the infometer showed a diagnostic code of "1", but that doesnt relate to any codes that i know of. This could be a lost leader, as I dont know if the greddy infometer v1 can get the DTC fault codes from the stagea ECU. its currently set to Nissan-non obd, wont connect otherwise.

thanks

Edited May 10, 2011 by Scratch

[SHETLANDER]

my Stagea is the same year as yours, mine just had the mesh on the front (filter side)

[pipster11]

some ppl pull the mesh off cos they think it makes turbulance (i think)

your voltages sound about normal but your peak seems quite low (unless you didn't gun it)

[QWK32]

Vacuum leak. But because your car isn't running like crap? the air is being metered. The 2 things to check are the Idle Contol Valve, and the Cold Start Valve.

Both of these valves get gummed up with crap over time causing them to stick open and cause high idle.

Search for the DIY tutorial on this forum on how to clean your AAC idle control valve. The cold start valve isn't covered in that tutorial but it would be worth cleaning as well. On the S1 I believe it is located under the intake manifold.

[Scratch]

Ah! good point - didnt think about that. Looks like i'll be having a busy weekend

i'll give it a crack and see how i go.

Thanks to all for the tips, much appreciated!