Hey guys! I'm back, here on PC after a long time. I've been busy with work and moving. It's good to be back! My good ole trusty Prius is still running good, change the oil every month (3000-5000 miles) and still drinks oil and a little over half a qt ever 1000 miles.. No big deal. Well over the last 20,000 miles I started to notice this off rattle, noise when accelerating mid throttle mostly when up hill. I thought it may have been the timing chain after changing the water pump, spark plugs and using all sorts of fuel additives, but no change. After time it's only gotten worse, my works buys my fuel (regular 87) but one day I brought my self a tank of super premium, and hey!!! It sounded great, quiet, powerful, I loved driving again! My question is.. Is this because of a worn timing chain making the knock sensor do this, is this because of carbon in the engine? What should I know? What do you think. I really need to fix this. My work buys me regular fuel and I would like to keep it that way! Thank you so much guys! Sorry about the long post, had to give some background☺
could be carbon build up. you'd need a borescope to look into the combustion chambers to verify. if the knock sensor was bad it should set a code.
True! Another question, is there any in between (working like new, and not working at all) for Knock sensors? I know all the Toyota products I've had experience with won't throw a code till the part is completely failed or the problem is very bad. Thanks for your reply!
From Toyota manual: “A flat type knock sensor (non–resonant type) has the structure that can detect vibration in a wider band of the frequency from about 6 kHz to 15 kHz...” “P0325 Knock sensor signal level remains at low for more than 10 seconds P0327 Output voltage of the knock sensor is 0.5 V or less P0328 Output voltage of the knock sensor is 4.5 V or more” “TYPICAL ENABLING CONDITIONS The monitor will run whenever the following DTCs are not present Battery voltage 10.5 V or more Idle OFF Time after engine start 5 seconds or more Engine coolant temperature 60C (140F) or more Intake air amount per revolution 0.3 g/rev or more” So as long as engine warms up to more than 60c/140F (which it will unless you have faulty thermostat) and you have no other faults codes that would affect you do get code for non-working knock sensor.
I suppose it is possible for the sensor to be failing and not quite bad enough to throw a code. if the sensor isn't too expensive or difficult to get to, it might be worth trying a new one. but if there is excessive carbon build up, that would be treating the symptom, not the cause.
Thinking I should try and replace the knock sensor, it doesn't seem to expensive. Is this a difficult job? Does anyone know where it's located?
I haven't done the job on the Prius, but from the Toyota parts diagram it looks like it's near the top of the engine block, right in the front center behind the the intake manifold and throttle body and that means some work. Once it's exposed, it's just a 10 or 12 mm nut and a harness connector.
Great! I'll check it out once I get back from utah, I've taken off the air cleaner box assembly before so I can take it off again and see if I can get a good look where it is. Appreciate your reply
I have the symptoms where the knocking/pinging occurs only under moderate load/acceleration. Does not occur under light or heavy acceleration. Anybody fix those symptoms with a knock sensor replacement? This forum thread: Easy Knock Sensor Replacement | PriusChat covers an "easy" method to replace the knock sensor. Anybody out there think that will work for a 2006?
