Lean idle when warm, checked basics - Page 3 - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

di-devol · 04-03-2012, 02:49 PM

Well, the car runs fantastic, good afr's after first start. Good afr's in boost, good afr's cruise.

This seems to be an intermittent problem.

So here we go:
On a cold start car runs rich(normal) 20 vac. Once warm occasionally, vac goes to 12-15 and runs so lean that the wideband maxes out full lean. Car "lopes" like a V-8.
Car occasionally run lean on VERY light throttle/Tip-in as well.
The thing that is getting me is would the car even run this lean? Idle is stable at 850rpms. Doesn't die, even running a un-reticulated BOV(runs rich when opened of course).

No vac leaks
No boost leaks(checked @30psi)
No exhaust leaks
02 sensor good
Maf is good
Injectors are brand new(and good)
CTS good
TPS good
Timing @15
Fuel pressure stock with nismo fpr

JWT tune
Sard 850's
GT2871r
Z32 maf
9:1 cp
Tomei 256 PonCams

Help if you can, the only thing that COULD be it I think is my MAF placement.
Could be a little too close:

04-03-2012, 02:49 PM	#1
di-devol Zilvia FREAK! Join Date: Jun 2010 Location: Woodinville Age: 43 Posts: 1,412 Trader Rating: (5) Feedback Score: 5 reviews	Lean idle when warm, checked basics Well, the car runs fantastic, good afr's after first start. Good afr's in boost, good afr's cruise. This seems to be an intermittent problem. So here we go: On a cold start car runs rich(normal) 20 vac. Once warm occasionally, vac goes to 12-15 and runs so lean that the wideband maxes out full lean. Car "lopes" like a V-8. Car occasionally run lean on VERY light throttle/Tip-in as well. The thing that is getting me is would the car even run this lean? Idle is stable at 850rpms. Doesn't die, even running a un-reticulated BOV(runs rich when opened of course). No vac leaks No boost leaks(checked @30psi) No exhaust leaks 02 sensor good Maf is good Injectors are brand new(and good) CTS good TPS good Timing @15 Fuel pressure stock with nismo fpr JWT tune Sard 850's GT2871r Z32 maf 9:1 cp Tomei 256 PonCams Help if you can, the only thing that COULD be it I think is my MAF placement. Could be a little too close: