Check Engine Light
 

hi all from Scotland

looking for some advice on a fault code. Check engine light has been flashing on and off for a while now, its starting to iritate so i flashed the codes and only error that came up was

LAF Sensor (Lean Air Fuel) defective circuit or unplugged / defective sensor

now i would like to know where the sensor is located and also what conditions would cause the error to flash, the car has been running funny as its great one day and crap the next, when running crap the v-tech doesnt work either.

there was a leaking fuel line when the car went for its test but now there is a sometimes strong smell of fuel, also i have changed the oil & filter and also the plugs, could a faulty fuel filter and poss fuel leak drop the pressure and cause the car to run lean? or more like a faulty sensor?

any help would be great

thanks

Toby

RE: Check Engine Light
 

car and engine specs are in my sig

RE: Check Engine Light
 

Except you don't have a sig.... Anyway, i suspect your problem is in the oxygen sensor circuit (which is the one that tells the PCM if the A/F mix is lean or rich). THere are 2 O2 sensors in OBD II cars. One tells the PCM the A/F ratio and this is the one you are gonna be concerned with. First check if the O2 sensor is actually connected. If it is not connected, connect it. If it is connected, you have one of two possible problems. The first scenario is that there is a problem with the wiring. Trace the wires that go to the O2 sensor as far back as you can. If you see that they are broken or anything, then that is the problem. If you don't see any broken wires, you will need a scan tool that can output live data. You are going to want to first disconnect the sensor. This should give you a reading of 0v. Then you are going to want to jump the connector (i think you jump the power and signal wires) this will give you a reading of 5v. If you get 0 and 5v respectively, then either your O2 sensor is bad or yoru engine is actually running lean. What you can do for the O2 sensor is spray some carb cleaner into the throttle body and watch the O2 sensor voltage on the scan tool (2 man job). After you spray the carb cleaner the voltage should go higher. If it stays the same, then you most likely have a bad O2 sensor.

RE: Check Engine Light
 

hi thanks for the advice dunno why but my sig and avatar aint working

i know what u mean about the o2 sensor, when you say about it actually running lean could this be caused by a leaking fuel line and an old filteror would there be an underlying prob? there is def a fuel leak as there is a strong smell around the car at times.

funny thing is the MPG is fine but the performance is crap compared to what it used to be, would it damage the CAT if the car is running lean?

car details are as follows-

SILVER 3DR
1.5i VTEC VEi
1493cc 16v SOHC
EG43(Man) D15Z1(VTEC)