I tried the other day to change the knock sensor on my car myself and i got the intake manifold off and got all the way down to the second bypass water pipe and i could not get it off the get to the knock sensor, well in the process i accidently cut the knock sensors wire so now it is totally disconnected, before it was throwing a malfunction code p0325 but now its totally disconnected and not my car does not accelerate at all and shifting hard and i hear knocking in the motor, would me diconnecting it completlybe the reason why its running horrible? cause before it still sucked but not as bad as now! anything would help thanks guys

 

Yes, I agree that whoever decided to put the sensor their should be flogged. When mine went (2.5) I lost power and fuel milage went down. Hint, The new sensor does not have to go in the original location. That is probably the best place for it to hear knocking, but I left my original in place and found a hole with the same size threads nearby and installed the replacement there. My power and mileage came back and their has been no knocking on regular grade fuel, which 2.5s seem to like better anyway.

 

Did not that was possible richard.....where was the hole cause im down for trying anything right now rather than spend 500 to have someone fix it cause i cant get past one water bypass pipe...yea my power and gas mileage is all screwed up, i guess all the timing is all messed up right now...

 

Sorry I did not get back to you sooner, for some reason I am not being notified when I get a response to a thread. I have a friend who is a mechanic at a Mazda dealership up north and he is the one who told me that the sensor does not know which hole it is screwed into. The only drawback is that it could miss some very soft knock or ping that it would hear in the factory position. I have had no trouble. I will look tomorrow and try to get a picture if possible and get back to you. The mechanic also told me to run the 2.5 on a goodbrand (Chevron, Shell, Texaco, etc.) of regular gradegasoline to help avoid carbon build up in this engine, and once in a while let it wind itself up through the gears and a can of Techron every 6k miles could not hurt. This engine now has 120,000 miles and does not leak anything and when I change the oil every 4K it does not move on the dipstick. I wish my 1973 Camaro was that tight when new.

 

Correct me if I am wrong but, doesn't the Mazda Millenia 2.5L engine require premium fuel? In my area I use Shell or BP.
The Techron works really well.

 

My 2000 Millenia 2.5L check engine light with code PO325 has illuminated most of the time from about 40,000 miles until now at 66,000 miles (3 1/2 years). I was informed the knock sensor should be replaced. I use regular fuel always. The engine runs well with no knocking. There might be intermittent light hesitation on initial acceleration. Do you think it's necessary to change knock sensor for about $500? Thanks in advance for your comments.

 

If you have your Knock sensor replaced your fuel mileage will improve and your engine should be more responsive. It is my guess that a bad knock sensor fault causes the fuel map to run rich with the timing retarded.
As far as the 2.5 and regular fuel when first built Mazda did recommened premium fuel, but then some carbon build up problems beganthat do not occur with regular grade fuel. I suggest you do some more research on this, I think there is a TSB then decide for yourself if you want to run regular. As said mine seems happy with it for the last 25,000 miles I have owned it. Current mileage 127,000

 

Thanks for the feedback. My fuel economy isn't bad averaging about 23 MPG over a 1 year period including winter operation in the Detroit area and mostly city operation. Since it doesn't knock and fuel economy is OK, I expect to continue using regular grade gasoline even though premium is recommended. It's difficult to justify replacing the knock sensor under these circumstances. Thanks again for the information.

 

I promise to get some pics of the knock sensors new home on my 2.5. It did make a noticeable difference in power when you put your foot in it and mileage went up about 3-4 miles per gallon is stop n go driving.

 

Yeah, I had questions regarding which type of fuel to use also... But then one day it hit me like a ton of bricks. It says right on the inside of the fuel lid... "PREMIUM FUEL ONLY - SUPER UNIQUE." Answered my question... haha