idle/misfire/backfire problem - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

aziankingz · 06-23-2008, 09:00 PM

My ka24e misfires badly and the idle drops up and down, as well as backfires like crazy. I replaced the MAF, coolant temp sensors, distributor, coil, rotor/cap, fuel filter and spark plugs/wires and the problem still occurs. At random times the idle would dip to 500rpm when i press the gas. Anyone know what this could be? I also get really bad mpg - about 13mpg city and 20mpg mixed.. could replacing the o2 sensor fix the idle problem as well as the bad mpg problem? i also have an exhaust leak from my cat..would that cause a bog in the idle when i try to accelerate?

Z U L8R · 06-23-2008, 09:04 PM

sounds like you have some vacuum leaks or possibly leaking injector grommet. a new 02 will improve gas mileage. you get any fuel odors when driving the car?

Dave

aziankingz · 06-23-2008, 09:09 PM

yeah theres a smell of gas at times.. my friend ran a diagnostic on the car and it came up with faulty o2 sensor, and it also kept reading my car running rich, then lean, rich, lean, rich, lean etc.. ill try and look for leaks when i have the patience

Z U L8R · 06-24-2008, 07:46 AM

cool. always start with things you know are a problem. you know your 02's a problem, they're onlly $30. if it fixes ur car , HELL YEAH. it probably won't fix it all but it's a start.

put in the new 02 and post the update. look for dampness around the injectors/intake manifold where they sit.

gl,
Dave

aziankingz · 07-06-2008, 11:47 AM

i tried to clean the aicv by spraying carb cleaner into the tube that connects to the intake and nothing changed.. my timing is good too.. it now tries to die every once in a while... the idle would drop from 800 down to 500 back up and just bounce around..then a few minutes later it would sound like a diesel with the idle dropping to 100-200..and dies. it starts back up the next try.. any ideas? i also smell some kind of burning smell..smells like the car is on fire..

06-23-2008, 09:00 PM	#1
aziankingz Nissanaholic! Join Date: Oct 2007 Location: NYC Age: 41 Posts: 1,735 Trader Rating: (28) Feedback Score: 28 reviews	idle/misfire/backfire problem My ka24e misfires badly and the idle drops up and down, as well as backfires like crazy. I replaced the MAF, coolant temp sensors, distributor, coil, rotor/cap, fuel filter and spark plugs/wires and the problem still occurs. At random times the idle would dip to 500rpm when i press the gas. Anyone know what this could be? I also get really bad mpg - about 13mpg city and 20mpg mixed.. could replacing the o2 sensor fix the idle problem as well as the bad mpg problem? i also have an exhaust leak from my cat..would that cause a bog in the idle when i try to accelerate?

06-23-2008, 09:04 PM	#2
Z U L8R Zilvia FREAK! Join Date: Jan 2007 Location: Georgia Age: 43 Posts: 1,194 Trader Rating: (0) Feedback Score: 0 reviews	sounds like you have some vacuum leaks or possibly leaking injector grommet. a new 02 will improve gas mileage. you get any fuel odors when driving the car? Dave __________________ RB25 280z GT30/76R 441hp/381tq 11.9@125

06-24-2008, 07:46 AM	#4
Z U L8R Zilvia FREAK! Join Date: Jan 2007 Location: Georgia Age: 43 Posts: 1,194 Trader Rating: (0) Feedback Score: 0 reviews	cool. always start with things you know are a problem. you know your 02's a problem, they're onlly $30. if it fixes ur car , HELL YEAH. it probably won't fix it all but it's a start. put in the new 02 and post the update. look for dampness around the injectors/intake manifold where they sit. gl, Dave __________________ RB25 280z GT30/76R 441hp/381tq 11.9@125

06-23-2008, 09:09 PM	#3
aziankingz Nissanaholic! Join Date: Oct 2007 Location: NYC Age: 41 Posts: 1,735 Trader Rating: (28) Feedback Score: 28 reviews	yeah theres a smell of gas at times.. my friend ran a diagnostic on the car and it came up with faulty o2 sensor, and it also kept reading my car running rich, then lean, rich, lean, rich, lean etc.. ill try and look for leaks when i have the patience

07-06-2008, 11:47 AM	#5
aziankingz Nissanaholic! Join Date: Oct 2007 Location: NYC Age: 41 Posts: 1,735 Trader Rating: (28) Feedback Score: 28 reviews	i tried to clean the aicv by spraying carb cleaner into the tube that connects to the intake and nothing changed.. my timing is good too.. it now tries to die every once in a while... the idle would drop from 800 down to 500 back up and just bounce around..then a few minutes later it would sound like a diesel with the idle dropping to 100-200..and dies. it starts back up the next try.. any ideas? i also smell some kind of burning smell..smells like the car is on fire..