Stock S14 SR running 10psi and only full 3" exhaust.
Under slight throttle the car runs stupid lean. Like 15.5-16s AFR. The car will build a bit of boost but wont move until it starts to reach the higher RPMs. When I push in the clutch the car sometimes wants to die/does die and tends to idle on the lower side. Did a boost leak test, couldn’t hear/see anything leaking. I don’t know what is causing this lean condition. Spark plugs look normal.
Any ideas? o2 sensor?
Check your fuel pressure. Getting a better flowing fuel pump and regulator will definately help. Could possibly be an O2 sensor, but I’d say check that last. A dirty maf could cause similar problems. and it would be a good idea to check the condition of the fuel filter and replace it if you haven’t already. Check the gaps on your plugs as well. Hope this helps
I have a walbro 190 fuel pump and brand new 300zx fuel filter. Gaps are fine.
are you using the stock maf? Are you sure its not a boost leak? If not i’d double check and pressure test it. May be a vacuum leak, but I’ not so confident on that one. the O2 sensor could be a culprite as well. Other than that, I can’t really think of anything else besides injectors, but I doubt it.
Ya stock maf. I pumped in about 10psi and sprayed everywhere and nothing bubbled and I couldn’t hear anything.
a bad or dirty maf or can cause you to run lean, same with a wideband o2 sensor. Maybe a leak in your intake piping? Make sure you dont have any leaks before the sensor. whatever it is, it should be before the turbo. Anything after should cause a rich afr. Being more technical, your ignition timing could be off or your tps sensor could be off or bad. I’d say leave the timing to the end. Check the condition of the o2 sensor, the maf, and the tps. If the wideband is too close to the end of the downpipe it will read lean. If all else fails, I wish you luck, cause im not sure what else it could be.
---------- Post added at 08:00 PM ---------- Previous post was at 07:49 PM ----------
oh wait, you say you are using a walbro 190 fuel pump? Seeing as how you’ve upped the boost to 10 psi, i think it would be better to go for a 255lph fuel pump. I dont think that fuel pump can handle anything more than stock on a SR motor.
How are you getting 10psi? did you do a “free boost” mod and use a different hose to the boost solenoid? Check your configuration on the boost T, and 2x clean the MAF sensor, not hard.