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High Fuel trim at idle about 18% or so , Continues to rise as rpm rises, no driving issues. Fuel pressure at the rail is 60 Psi , the intake is inspected and clear , the mass airflow was cleaned, exhaust manifold inspected for leaks , new purge valve was used to fix p0455 , evap was smoked so no leaks on the evap side, throttle body is clean, high fuel trim when driving around road. MAP sensor reads proper pressure with engine on and not in idle, MAF reads about 3 g/s in idle. Unsure where to check . thinking MAF might be faulty or injector possibly. Thanks for the help!
The grams per second should be around 1 g/s per liter, at idle. Since your engine is 2.4 liters, we'd expect roughly 2.4 g/s at idle. So your maf is reporting slightly higher so we'd expect a slightly negative fuel trim at idle, definitely not the 18% positive trim at idle, so I would move away from a bad maf by that reading alone.
With the car cold and key on, engine off, what does your o2 sensor report in millivolts on your scan tool (upstream and downstream)? What happens when you start the car and it gets up to temperature? If the upstream stays lean (below 450mV) and the downstream reports rich (above 450 mV), then suspect a faulty upstream sensor. Can you make the upstream go rich by doing a wide open throttle acceleration in first gear? Or by spraying something flammable into the intake? Don't contaminate the maf sensor, shoot it up the purge line vacuum supply or breather hose on air intake, or remove the air intake hose altogether and spray then.
I was doing some runs with the wide open throttle but i did not look at the down stream sensor , i think it may have been staying pretty rich through out though, the upstream was constantly fluctuating from .1 to .7 v, also with car cold and reading the 02 sensors they should be reading close to eachother? and if not then upstream sensor would be faulty?
ysiguus wrote: With the car cold and engine on not running both 02 sensors read .45 volts.
That's good. How long does it take for this voltage to start dropping low and start oscillating up and down, from the time you start the engine? The oxygen sensor is basically an open circuit when it's cold so when it starts to heats up at start up from the heater circuit, it will begin to drop low in voltage and then produce its own voltage fairly quickly with a helping hand from the o2 heater. Exhaust heat helps too of course. But this heater will help the car enter closed loop faster. We want to see both of the upstream and downstream, cold reading voltage of .45 volts, drop low fairly quickly at the same time. This will confirm the heater circuit is fully functional and doing their job.
At idle what is the Short Term Fuel Trim and the Long Term Fuel Trim values and are you in closed loop? What are these values when you're at a steady cruising speed? At idle we want to see the short term fuel trim hovering close to 0, which would indicate the car is in fuel control, and the car has adapted to this lean condition by adding additional fuel (which is what the long term fuel trim value would indicate).
Is engine coolant temperature and intake air temperature reading okay? Does this have an EGR valve that could be leaking? Might as well do an injector balance test if everything checks out.
At idle the LTFT is at about 17 %, the short term varies close to 0, at rpm 2500 the LTFT is 25% and also cruising down the road the LTFT is at 25% , the intake temp reads well as does the coolant temp sensor. There is No EGR
ysiguus wrote: I was doing some runs with the wide open throttle but i did not look at the down stream sensor , i think it may have been staying pretty rich through out though, the upstream was constantly fluctuating from .1 to .7 v
That's a good catalytic converter when downstream stays steady
Focusing on the upstream, does it stay rich at wide open throttle? ScannerDanner calls this the fuel delivery test. Go wide open throttle in first gear and watch the upstream o2 and make sure it stays high (like 800 mV - 1000 mV) during the duration of the wide open throttle run. Car will go open loop, dumping fuel into cylinders, the o2s must stay rich.
Check your PCV valve maybe that's stuck open. The air's still metered but it goes through breather hose, into crankcase, then into the wide open pcv valve and into the intake manifold and into the cylinders. I don't know how to specifically check the one that's one you car but maybe give it a shake lol?
its just a lil orifice, and it is not plugged, already checked on mitchell its not on the valve cover , it is a part of it but its not anything more then a small hole which is not plugged atm and i thought i fixed it by fixing that hose with a hairline split, alas this is why i am here it is not that easy.
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