Has anyone replaced the KS or tested and found the ks out of spec without throwing a code in the computer?Any improvements in performance?

 

yeh, was out of spec and didnt store a code and cost like over a second in the 1/4 mile. if its out of spec try bypassing it with a 550k resistor. if your performance comes back either leave it that way or buy another knock sensor.

 

didnt get a CEL, but found symptoms of a bad sensor...

-sluggish low rpms...shi.tty gas mileage.

i just got it put in. acceleration is back; dont knwo about mileage yet

 

kinda sounds like my symptoms , let me know how it works out. did you do any tests on it(on or off the car), with an multimeter

 

MAXPOL you got to stop making so many threads about the same stuff...

 

where is the KS located at.... My car was in an accident after i got it fixed it ran fine for about 2 weeks then started running sluggish an givin really F***ed up gas milage..... an how hard is it to change?

 

just search, there are 10 threads about this on the first 2 pages. And read the FAQ, it's there for a damn reason...

 

Well, I replaced my knock sensor a few hours ago. I didn't have a code but ran horrible times at the track (I have pretty much every bolt on mod) the last time so I figured it was the KS.
After finally getting it in I went for a long drive.
I noticed that my CAI is much louder and my low end pulls much harder. Before, the car lagged up until about 4000-4500rpm. Feels much smoother and more powerful.
Can't wait to hit the track again and see what my car really runs.


-Tony

 

How off were your times?

 

Almost a full second

 

araffio. same thing here man. i dont feel anything when i push the car hard. its just barely gaining speed untill it gets to 4k rpm. could it be my ks too? 25k miles here. what is the best way to make sure that its bad!

 

lol it shouldnt be bad at 25k miles, but if u want to check look for a ghost code, if nothing, then i'd suspect something else is wrong

 

I didn't check for anything or test the KS. I just read so many posts about guys running a second too lsow in the quarter mile and then changing their knock sensor and that being the trick. I knew everything on my car was in perfect shape except i wasnt sure about the KS. I took a chance by replacing it and it worked out for me.

-Tony

 

ARAFFIO you will probably notice that after a week or 2 the performance will get slightly worse than it is now. I noticed that whenever I put in a different resistor,or even the bad KS, the car feels much stronger at first and then goes back to it's old ways. Now since you actually replaced it with a good KS the decrease should be barely noticeable if at all...

 

What mph do you get to on first gear right on 3krpm? With a normal foot, I'd be around at 17-18 mph. Anyone else?

 

I think that's all about the gearing in the tranny. Speed should be the same every time at any given RPM if I am not mistaken.


-Tony

 

Whether you're WOT or just half way down on the pedal the rpm and speed will be the same for the two. Of course adding mods will change that but the two will still have same numbers...

 

I can see it now, dozens of org members replacing perfectly good knock sensors.....

 

That's a possibility


-Tony

 

Yep, people believe that replacing the knock sensor is somehow the "holy grail" of restored power. Sluggish power till 4000rpms doesn't really sound like the knock sensor because the engine is more prone to knock in the higher rpms (4000+rpms), not lower rpms unless you're lugging the motor up a long hill is too high a gear. Poor gas mileage and sluggish performance below 4000rpms is most likely one or both of the front O2 sensors. From idle to 3800rpms, the O2 sensors regulate A/F ratios. Sometimes the O2 sensors will either fail entirely (throws a CEL) or as in my case, the sensors become slow to react (no code). The only way to check a slow reacting O2 sensor is with a mutlimeter. Both my 7 year old O2 sensors were reacting too slowly according to spec. Slow reacting or bad O2 sensors will cause the engine to run rich which makes for bad gas mileage and laggy performance.

Last year I got the knock sensor code. I checked the sensor with a multimeter and I confirmed the sensor was bad. I also inspected the knock sensor harness because that has been known to fail and cause knock sensor CELs.

Way to many people on this Org blindly replace good parts with no other reason than because of something they read in a post. Being able to use a multimeter ($20) and a Hayne's/Chilton's manual ($18) will allow you to truely see if any of your sensors are indeed faulty. It's not brain surgery. The misinformation on the Net is overwhelming. You need to make you're own informed decisions, not just what some other guy tells you because it worked for him.



Dave

 

Have you ever run your car before? Was it the same track? What were conditions like? How were your 60 foots? Hopefully you've considered all these factors before replacing a part that most likely wasn't the cause of your problems. Just by looking at your car and you're mods, it looks like you're hauling around quite a bit more weight than stock. The rims and all the stereo/TV stuff probably is making your car run high 15s to low 16s@85-87mph with high 2.3 to low 2.4 60 foots. Lots of weight and the autos poor gearing really hurt it's 0-40mph performance. The 1/4 mile is all about how hard you can get off the line.


Dave

 

Well here's my story:

Back in January and February I ran my max numerous times at the track with the intake/ypipe and a (suspected) knock sensor. I didn't know for sure because there was no cel. It felt really sluggish esspecially at the lower rpms and a downshift to 2nd from 40mph(4krpm) felt extremely torqueless. My best time was a 15.5 @ 88mph. My avg was a 15.7-15.8 with a 2.3-2.4 launch.

After changing my ks.......

It felt like a different car. Low range power was really strong and when I step on the gas in any gear it jumps without hesitating or lagging. So I headed to the track( this was around April) and my first run was a 15.0 @ 92!!! with my heavy 17" rims. My best time so far is a 14.762 @ 93.5mph with just i/y.

So just changing the ks took off .8 second from my 1/4 mile time.
-Paul

 

The way I saw it was the car has 84k miles on it, never replaced the KS before but have replaced everything else. It was more of a test. The $90 spent on the sensor wasn't a big deal, it's just $90. The fact that the sensor is brand new puts my mind at ease, even if it does nothing for the car. I like having new stuff, just the way I am.

You made a very valid point above and you are most likely correct about the track times. LOL. Except I dont have heavy stereo stuff....everything else was pretty much right on.

I am buying some 11lb Millenia wheels with Nitto drag radials to run with next time. I will also empty the trunk and back seat and convert the CAI to hybrid for the day. We'll see how it goes....5-speed in January will certainly help my times too, lol.

-Tony

 

I'm really surprised you would say this, Dave. I figured you if anybody would know engine timing is most advanced at low engine loads and at mid rpm for fuel economy reasons. See the Z32 timing map below. Even at high engine loads, timing advance peaks at the rpm where the torque reaches a maximum.

The effect of a faulty knock sensor is going to be felt most at the engine loads and rpm range that we drive in the most, i.e. low load, low-mid rpm.