Knock Senor Test with Multimeter
 

Do you trust the readings when testing the knock sensor? Or can the sensor test within specs and still be faulty sometimes? Anyone who knows about this testing procedure please help.

Anyone????????????

bump, I want to know also how to test it if possible....

it doesnt say in the stickys or TSB's?

Disconnect the harness, KS terminal 1 to GND should be 500Kohm to 620Kohm at 25 deg C (room temperature). Around page EC-198 in FSM.

The KS is a piezo-electric element, a piece of special ceramic between 2 electrodes. So it is pretty sturdy. The only failure should be detachment of the electrode.

Mine tested good and I replaced it anyway. Got one off ebay and the car turned back into a screamer. I think it just needs replacing after 100k or 8 years, LOL:doublethu

Although the Nissan FSM doesn't show it, the best way to look at a KS is still with a scope. Should see some sharp waveforms if the KS is working.

Please assist! Okay...I'll admit that I tried this during my hour lunch break. But, I was anxious. So I picked up my knock sensor and am having trouble getting the old one off. I have a Universal joint connected to a 12mm socket with a 9 in extension. So, getting to it is no problem. I need to know how tough is it to get off...and when accessing it from the driver side of the car do I loosen counter clockwise?

Any help is appreciated.

KS is regular thread (CCW=off) Mine was on pretty tight and I had to give it some elbow but when the nut cracked they came off easy. Read somewhere that the KS needs to be torqued on just right so that the KS has the right sensitivity. I just guessed and mines working fine. A great repair, highly recommended. Get your KS from ebay $75!

P.S. havent tried this but a piezzo should show a voltage on a DVM when tapped. Just like a crystal mic.

Okay...i am on hour 3 (total work time incl. trips to autozone to get correct tools). The ratchet, u joint, socket combo just won't stay on while applying torque. Am I supposed to remove the frickin' intake hoses....or that darn sensor which seems to be the ONLY thing in the way of sticking my whole arm in there?

Immediate help would be appreciated...because I will not stop. Also...I never fully let the car cool down....that is why I actually took a break to post. To let the engine cool.

All is well. Praise the girlfriend. She basically did it all. None of the recommended tools worked for us. You'll never believe what worked. I tied a plastic bag (twined it into rope and heated it with my garage lamp) to a close ended 12mm wrench and dropped it in the "V". When the wrench was on the the KS bolt only the open end of the wrench barely pertruded from under the intake. Girlfriend (small hands and arms) postioned it over the bolt closest to front of "V" for max leverage. Took 3/8'' extension and slide it into open end of wrench. Rested top part of extension on intake, balanced bottom in wrench and pulled. ONCE!...seconds later the KS was off. The whole setup took about 5 minutes. Trying to get this to work with 1/4'' swivel AND 3/8 swivel. 5 hours.


Got the new one and took it for a amazing test drive. My KS must of been bad since I got my mods. I'd really never seen what my mods can do. With bad KS I squeeked by with co-workers 05 WRX (I was in third gear).


Just thought I'd leave an update of my nightmare.

How did you conclude that it was the KS? Did you get a code?

Yes...two reputable places pulled my codes. And...I noticed that I would idle strangely. After a high rev the rpm's would hover around 1k-2k and then drop. NOW, it doesn't matter how hard or long I rev it drops back to idle speed. I noticed considerable pull.

I guess the original post was confusing, I know how to test the knock sensor.
Just wanted to know if people trusted the readings, or if they can still test good and be junk. Mine tested within specs just want to know if I can trust that.

I think the FSM test method should be reliable. But in actual operation, the ECU should be looking at the voltage KS puts out to determine whether to set a code or not. When ECU didn't see any voltage, then it goes to a table for ignition timing. That's when you will get reduced performance.

When pinging do occur, KS outputs a much larger voltage.

I didn't have any KS problem on my 4th gen but did have a pinging problem in my other car. It turns out to be carbon accumulated on the piston and the KS was working properly. In that case, there is actually an octane value setting in the ECU.

No prblems with the 96 I30 I just went through testing different sensors, coil packs, etc. Nothing was wrong, no codes, problems or anything just wanted to know the reliablility of the knock sensor with multimeter test. I thought I remebered reading a knock sensor can test good sometimes and actually be faulty.

Yes, it is common for it to test fine when cold, and then fail when the engine is hot.


BTW a universal socket works much better than a universal joint + socket

Hey guys i have learned from these forums to check the "check engine" CODES and i have a KS problem also. Is this very important to fix or should i just leave it and let the C.E. light stay on? I paid $3000 for this car 171,000 miles and it really runs good. Never have i owned a nissan so i'm kinda worried.

you'll be okay,
But you'd sh!t a brick if you knew how much power you were losing.

I have a scope at home so I would look at the KS output with the car running (haven't done so yet).

Hmm fastest car i ever owned.Had a camaro 170 HP which looked nice but SLOW. This car has 190 HP and it fells nearly 3 times as fast as my camaro.

I tested it with the engine still warm, guess I will do it again to be sure it is ok. No codes just want to get the most out of my I30. Thanks

Mine tested fine, but CEL continued after reset. I replaced it and all was well.

I'm not getting your point.

BTW I had an 86 IROC which was rated at 190 horsepower, but had an azzload of torque (Tuned Port Injection). That thing would stomp on my max.

But the quality of that car was sh!t compared o the max.


I'm guessing the Camaro you had was like a late 70s carbed version. Yes they were slow,

i finally got codes using the self diagnosis mode..got the knock sensor and evap purge but back OT how badly does a faulty knock sensor retard teh engines output?

it makes it hella retarded. I think you loose like 40whp from a bad ks...

there was a thread a while back about how the torque levels break the ks casing, can anyone confirm this?

40 whp :shock: that busts me down to like 130whp i think i might cry. ive had to drive with it like that for months now since my dad doesnt care about the nissan as along as it rolls and lights up. :bawling:

If I use 87 octane gas, will I still see a power gain from the new knock sensor or do I have to use 91 or 93 octane? Mine has been faulty for a while. High octane gas is so expensive that I may just leave the old KS in if I'll have to switch to premium gas with a new KS to get any hp benefit.

Using 87 will harm other components other than the knock sensor, not worth saving 2 dollars a tank when it might cost you hundreds in repairs.

I got the same codes 0304(KS) and 1008(evap),Does EVAP able to trigger KS code?Is the evap near the end of the car or under the trunk, driver side? Did you replace your evap or can you just clean it? TIA- 95 gxe 80k

i got the same codes as you

Assist Plz => Buying a knock sensor on ebay
 

Several have mentioned that they were able to purchase a knock sensor on ebay for $75 or so.

I am interested. The local parts store offered to sell me a Wells knock sensor for $139.

What brand of knock sensor did you buy on ebay? And is it as good as an OEM part?

Finally, any tips on how to pick one up on ebay -- e.g., where to look, what to watch out for, etc.??

Thanks.

3 ECU Codes - P0325 Knock Sensor, P0158 O2 Sensor, P0159 O2 Sensor
 

I borrowed a code reader from Autozone and was disturbed to pick up more than one code on my 99 Maxima (with 90K miles).

P0325 Knock Sensor

P0158 O2 Sensor Circuit High Volts Bank 2 Sensor 2

P0159 O2 Sensor CKT Slow Response Bank 2 Sensor 2

Given three codes where one could conceivably be triggering another, does anyone have suggestions regarding which one to fix first and/or whether it is likely that the codes are inter-related?

By the way, a fellow at the parts counter suggested that I first try a dose of Lucal Fuel Treatment.

Thanks.

NEW Nissan oem KS on Ebay right now for $68 He has 97 of them.

can the test ever fail a good knock sensor? also can the evap code trigger the ks code? my car doesnt really feel slow at all

I bought mine from hrspwr-281 for $68US. I compared it to the origanol and found no differences at all. The new KS works fine so i would recommend that seller.

I guess you didn't read the whole thread, yes a knock sensor can give a false positive reading cold then will be out of spec when hot. Test it hot and cold thats what I did as suggested before.

look under "nissan knock" and/or " maxima knock" to get the most results, many nissan/infiniti cars use this knock sensor. Test it hot/cold before you junk it to make sure it is bad.

There's only two faulty parts listed, a KS and an O2 sensor. Replace the O2, reset the CEL, and see if a KS code comes up.

I agree with pmohr get the 02 sensors fixed first, the KS code might be because of that.