okay, got the codes...new need some help

[95USsubaru]

pulled a knock sensor malfunction (p0325) and an o2 sensor code (p0141)

now what do i do???? i read that if there's corrosion by the knock sensor to clear it out and check how tight the bolt was and stuff but any other info would be awesome. as for the o2 sensor.... i have no clue where to begin on that...

[jey]

as for the o2 sensor.... i have no clue where to begin on that...

Replace it

[95USsubaru]

okay i did that now the engine dies after start up. no rough idol and putter out its just high rev start and on the way down it just dies.

[green97gt]

did you forget to re hook up the quarter-ish sized line from the IAC to the plastic intake tubing? ive done that before, starts up, but with no foot on the gas, dies right quick...just a thought...

if all you did was replace the o2 sensor and now it doesnt stay running, its almost gotta be something got left unhooked.

as for the knock sensor code, i had that on one of mine, it was a "knock sensor circuit malfunction" i dont remember the exact code. i swapped sensors with a known good sensor, verified wiring was good, cleaned block mating surface, etc. i did everything i could think of to make it go away, it never did, i sold the car that way, wish i knew what it was, i kept thinking of the ECU

not saying thats what it is in YOUR case, i would try unbolting and cleaning the sensor mating surface, and wireing connector, should only be one wire. and if your really into it, check continuity on the wire from the ECU to the knock sensor, also check continuity from the head of the bolt that holds the knock sensor on the block to ground, if good, replace sensor and reset ECU, if that doesnt work, your in the same boat i was in a while back.

unfortunatly knock sensors cant REALLY be tested with a multimeter, you would need an Oscope.

knock sensors are pricey, but maybe you can find one from a junk yard? even if you have to solder in the wire, just make sure you get a good, solid connection.

[95USsubaru]

okay i checked all that. does anyone think it could possibly be the fuel pump??

[phi11]

can you hear the fuel pump when in the acc ignition position?

[95USsubaru]

no... but i also cant hear it on my other one...

[ouch1011]

there have been some instances where older engines will constantly set knock sensor codes. They do this because the engine computer occasionally tries to force the engine to ping and watches the knock sensor for a response. Older engines with lowish compression have lower cylinder pressures and are less prone to detonation. So if the pcm can't force the ping, it won't see a response from the knock sensor and will set a code. That isn't as common as the sensor just failing though. Replacing it usually fixes the problem.

As for the stalling problem now, odds are that it is due to something left disconnected.

[95USsubaru]

wasnt the fuel pump and everything is connected....WTF

[goodnight1985]

Try replacing the knock sensor as well. If the car is having trouble with the timing, it might be causing the shut off issue.

A lot of cars that throw codes for O2 sensors don't always need new sensors. There might be an underlying issue causing the computer to think it is having an issue with the O2s. Make sure you have no vacuum leaks and your MAF is operating properly. Check your plugs, the age of the plug wires, even the fuel filter.

Always check the basics first, then move forward into the more difficult stuff. You may find you can correct the issue with no cost because there is a leak.