today my car went for a m.o.t and pasted with flying colours.but ive had a little problem as late the car keeps cutting out when hot or cold.so i had the ecu hooked up and full diagnostics test and it found 1 error code knock sensor is fooked.. what is a knock sensor what is it for and what does it do..i could google it but i thought one of you's might of had the same problem. my car Nissan Primera 2.0i 16v twincam GT
The ECU is always adjusting the timing so that the engine runs at peak performance and if the timing gets advanced too far the fuel will ignite before it's supposed to and will try to push the piston down when it's going up and will cause a "knock/ping" sound. Which if left alone will also end up fucking the engine up. It can be caused by too low of octane or overheating also, not just the engine timing. The sensor detects the "knocks" and tells the ECU to retard the timing so it doesn't fuck up the engine.
It's not really a killer and it's in a very fucking inaccessible place, so you might as well just let it be. Your MPG's might go down after you reset the ECU, but should return to mostly normal after a few short trips. It will make your shit run rich, and resetting the ECU constantly will make it worse. Try running it for 2 or 3 minutes at a time and shutting it off completely a few times to get the ECU back to normal. Might want to run some Seafoam to clean your shit while your ECU is learning how to burn fuel again... always seems to help mine. If you just want to do it yourself, buy a new sensor (offline, those things are fucking fragile) and I'll send you the Alldata shit for your car.
its not really hi rev's its more like low revs. are up and down..mainly when changing down down gears it cuts or leaving it running 3min's. the tech guy said it is the knock senor and won't cost alot to buy a new one but a bastard to fit.
<div class='quotetop'>CITA(FUZiON @ Mar 16 2009, 10:04 PM) <{POST_SNAPBACK}></div> here is no machine shop
hesitation at low RPMs has a couple of culprits, but yea, it sounds like your knock sensor's hosed or its wiring is frayed/shorting somewheres if the OBD gave you the trouble code. I'm surprised it wasn't accompanied by a check engine light though. The knock sensor itself is dirt cheap compared to what your mechanic is gonna charge you for diagnostic and replacement. Time to find a gay mechanic friend who'll work for favors... just to avoid a potential wild goose chase, i'd check the fuel line pressure first just cuz it's a whole lot easier to do.
<div class='quotetop'>QUOTE (fumanchu @ Mar 17 2009, 02:18 PM) <{POST_SNAPBACK}></div> yeah the Engine management light was on about 2 weeks ago.i put it down a oil change and it went off. and one of my mate's his job is diagnostic testing & rolling road so i only pay £10 insted of £60+ but when it comes down to fitting it that will cost abit.
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