SC300 Hesitation, Idle Issues, Rich Exhaust Smell, etc....
#91
Lexus Champion
iTrader: (10)
did you pull it out already.. it just hit me, you could have a faulty fuel injector.
next time it is idling roughly, pull the injector clips one at a time and see if it clears up.
fits your symptoms and the cats getting hot most likely an injector sticking open and causing a misfire = false lean... or your cat is actually clogged. worth the test though, don't pull them all, just one at a time.
you can get a false lean when you have too much fuel because the fuel washes out the spark, and since no combustion happens all that fuel and air enters the exhaust, and since an o2 sensor reads unburnt oxygen, it reads 100% of the oxygen and shows lean, which is called a false lean because an o2 sensor is only accurate when combustion takes place, as in it reads left over oxygen assuming combustion took place, but when an injector sticks combustion will generally stop and start to hold things up then the ecu starts to pull fuel across the board and gets confused and starts to throw codes like maf etc...
Hopefully it will clear up when you pull the right one, cause it seems like you have replaced everything else. let us know how it goes.
next time it is idling roughly, pull the injector clips one at a time and see if it clears up.
fits your symptoms and the cats getting hot most likely an injector sticking open and causing a misfire = false lean... or your cat is actually clogged. worth the test though, don't pull them all, just one at a time.
you can get a false lean when you have too much fuel because the fuel washes out the spark, and since no combustion happens all that fuel and air enters the exhaust, and since an o2 sensor reads unburnt oxygen, it reads 100% of the oxygen and shows lean, which is called a false lean because an o2 sensor is only accurate when combustion takes place, as in it reads left over oxygen assuming combustion took place, but when an injector sticks combustion will generally stop and start to hold things up then the ecu starts to pull fuel across the board and gets confused and starts to throw codes like maf etc...
Hopefully it will clear up when you pull the right one, cause it seems like you have replaced everything else. let us know how it goes.
Last edited by Ali SC3; 10-15-13 at 02:04 PM.
#92
did you pull it out already.. it just hit me, you could have a faulty fuel injector.
next time it is idling roughly, pull the injector clips one at a time and see if it clears up.
fits your symptoms and the cats getting hot most likely an injector sticking open and causing a misfire = false lean... or your cat is actually clogged. worth the test though, don't pull them all, just one at a time.
you can get a false lean when you have too much fuel because the fuel washes out the spark, and since no combustion happens all that fuel and air enters the exhaust, and since an o2 sensor reads unburnt oxygen, it reads 100% of the oxygen and shows lean, which is called a false lean because an o2 sensor is only accurate when combustion takes place, as in it reads left over oxygen assuming combustion took place, but when an injector sticks combustion will generally stop and start to hold things up then the ecu starts to pull fuel across the board and gets confused and starts to throw codes like maf etc...
Hopefully it will clear up when you pull the right one, cause it seems like you have replaced everything else. let us know how it goes.
next time it is idling roughly, pull the injector clips one at a time and see if it clears up.
fits your symptoms and the cats getting hot most likely an injector sticking open and causing a misfire = false lean... or your cat is actually clogged. worth the test though, don't pull them all, just one at a time.
you can get a false lean when you have too much fuel because the fuel washes out the spark, and since no combustion happens all that fuel and air enters the exhaust, and since an o2 sensor reads unburnt oxygen, it reads 100% of the oxygen and shows lean, which is called a false lean because an o2 sensor is only accurate when combustion takes place, as in it reads left over oxygen assuming combustion took place, but when an injector sticks combustion will generally stop and start to hold things up then the ecu starts to pull fuel across the board and gets confused and starts to throw codes like maf etc...
Hopefully it will clear up when you pull the right one, cause it seems like you have replaced everything else. let us know how it goes.
Thanks for the response AliSC3
I am at the point of no return on the engine....Already have the wiring harness pulled out. All wiring harness connections are undone. Literally the only thing left for me to do is disconnect the fuel lines, clutch lines, motor mounts and trans mounts. I plan on having the motor out by next week.
#99
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WOW.. I'm having the same issue with my 93 sc300 sputtering threw the powerbands when i give it gas to go. Its been like this for 3 weeks on and off, like the other guy said its so intermitted. I've change the distrubtor, rotor buttom, spark plug wires, and fuel filter with no luck. I'm check the fuel injectors next just ali said
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