Phantom KNock Sensor - grounded

[1gawddsm]

I dont know if people ever do this but here is what i did. I was getting crazy "phantom" knock all the time at part throttle at all rpms. so i tuned my car as best as i could using o2s and the knock sensor at WOT. since the knock sensor is grounded through its contact with the block i simply unscrewed the knock sensor, stripped the end of a length of wire and wrapped it around the threads on the knock sensor, then wrapped it with electrical tape to keep the wire in place, then i connected the other end of that wire to my negative battery terminal (any ground connection will do).
if you simply unscrew the knock sensor you get a engine check light since the knock sensor is not being grounded and you get a default knock of 9 ( if i remeber correctly) at any throttle position. so now with the knock sensor grounded, i get no knock ever, ive been running my car like this for a few months now and it is better than ever, so if i am getting any knock i dont know about it doesnt seem to be a problem. i just tune with O2s and EGT...i need to get on a dyno with a wide band.
anyway just thought some of you would like to know this since a lot of people have "phantom" knock.

 

[Enigma_Man]

That is a very foolhardy thing to do.

If your leg is broken, and you unplug the pain sensor, that doesn't make your leg not broken.. Get it? You need the sensor, and if you have a phantom knock problem, there are ways to fix it, and it is indicating that something else is wrong, and needs to be fixed.

Now, in actuality, you'd probably be okay 99% of the time, but that one time you get a bad run of gas from the station that's 80 octane instead of 94, you're gonna blow it up man. I'm sure you could run months, even years without issues. These engines are built strong, and can withstand a little bit of knock, and unplugging the sensor will make it so the car won't retract timing, but you're flirting with danger man.

-Jesse

 

[1gawddsm]

i think you missed the part where i said i tuned the car as best i could at WOT with the knock sensor in. so it was not getting any knock at WOT. the only time i got knock was ALL THE TIME at anything but WOT. so my ecu was pulling timing to account for the 45 counts of phantom knock making the car completely undriveable as is bucked all over the road. I have read hundreds of posts about people not ever being able to cure a case of phantom knock in DSMs. Phantom knock caused by some mechanical noise does not mean there is something "wrong" like you said. it just means something is creating a noise on the same frequency that detonation in a cylinder creates. ive been pounding my car to the ground with 160K+ miles on it at 19psi on a 16g and no knock sensor for months, because I TUNED THE CAR AT WOT before i took the knock sensor out. so you see lad, it was not "foolhardy" (whatever the f8ck that means ,maybe you meant fool-heartedly) in fact, it was the perfect way to cure phantom knock.

 

[1gawddsm]

oh and if it does ever blow, who cares? itll just be time to get rid of this old stock block.

 

[1gawddsm]

and damn who ever heard of a pump having the wrong gas in it?

 

[LaserRST]

Ive had bad gas in my car B4. I go to shell more regularly now cuz of it. Enigma does have a point. Timing retard is important on forced induction, cuz it is so environment-sensitive. Gas is only a small portion of it. Its there to help reduce wear and tear, removing a sensor is never a good thing, improving one will always be better. If you have an injector that is slightly clogged you may never notice till that one hard run. Even NA hondas run it for a fool proof design... boy they never saw you comin...

 

[MNGSX]

It's probably a loose old block making all kinds of racket.

Its probably knock.... ROD KNOCK...


You can try running the knock sensor in not so deep. Over tightening causes things to get too sensitive.

I'd still run one. I'd just try to make it so it can't hear the non knock noises.

Maybe keep the ground wire on it but attatch it with ring terminal that slips over the threads.

Then you can wrap the sensor threads in something like teflon tape. Wrap it enough that it starts to get tight early... part way in as you thread it in. It will be less sensitive but still function when a knock is louder than the phantom noises. Better than nothing.

 

[1gawddsm]

you guys are missing the point, maybe none of you have had a bad case of phantom knock. i have already read and tried and thought of everything possible to keep the knock sensor in place. but NOTHING fixed it. this was the solution. you dont need a knock sensor, there are other safety measures to keep a motor from blowing. such as, i utilize my pocketlogger and my afc and EGTs to make sure im getting a nice A/F ratio thats not gonna make my motor blow up.

 

[LaserRST]

Alrighty... ground wire electrical tape. Id say make a tech article about it likely it will help some one down the road.... or prove our point, either way information is always the key to a better lifestyle.

 

[98TsiAWD]

Put a washer between it, supposedly that gets rid of phantom knock. the main cause is noisy lifters. I see you have a 1g, do you have the revised lifters?

 

[hose101772]

Hmmm.I was getting knock counts while cruising so i loosened my knock sensor thinking it must be picking up mechanical noise.I tuned my car with o2 and egt.Kept it extra rich to be safe and a week later blew half of the #4 sealing ring out the back of the deck/head.Egts went down to 1300-1400f at wot-looked good-it ran great but there is a reason for the knock sensor-about a $4k reason,in my case anyway.

 

[1gawddsm]

Originally posted by hose101772
Hmmm.I was getting knock counts while cruising so i loosened my knock sensor thinking it must be picking up mechanical noise.I tuned my car with o2 and egt.Kept it extra rich to be safe and a week later blew half of the #4 sealing ring out the back of the deck/head.Egts went down to 1300-1400f at wot-looked good-it ran great but there is a reason for the knock sensor-about a $4k reason,in my case anyway.

well you should have tuned it at WOT with the knock sensor still in to make sure you werent getting knock at WOT. the knock sensor still works properly at WOT and mechanical knock plays no roll at WOT. i took the sensor out after i tuned it with it in. i now monitor the status with egts, o2s, timing, etc. i have been running like this for over 3 months at 19psi on a 16g. so obviously something was wrong with your setup. sorry you blew your shit up tho.

 

[1gawddsm]

Originally posted by 98TsiAWD
Put a washer between it, supposedly that gets rid of phantom knock. the main cause is noisy lifters. I see you have a 1g, do you have the revised lifters?

I already stated that every idea like "loosen the knock sensor" and "put a washer in it" and "change your knock sensor" and "clean your lifters" were all tried and they all FAILED. and just so you know it wasnt the lifters, i placed the knock sensor in 3 different possible locations that it can screw in on the block, and it had less knock when it was screwed in to the highest point right unerneath the head. it heard more mechanical knock placed lower on the block. how you like them apples ?

 

[98TsiAWD]

Pull yoru oilpan and check your rod clearances.

 

[JET]

Just cause you tuned it once at WOT doesn't mean it is going to stay like that, otherwise the car wouldn't come with a knock sensor! Changes in temperature, gas, altitude, etc will change the tune of a car. You just got rid of the one way your car has to change the tune. The knock sensor is a vital part of a FI car. Did you ever try a different knock sensor?

I do not like the way the knock sensor is attached on a DSM. I am running the AEM EMS, so I see the true voltage output. I had mine torqued to 10 ft/lbs like the manual says at got basically no output. I had to go down to 4 ft/lbs until I got a reading like it was supposed to! If someone had just put that in their car they would crank up the boost and lean it out until they got knock, but it would be WAY beyond a normal knock count and kill their engine in a short time.

 

[LaserRST]

Originally posted by JET
Just cause you tuned it once at WOT doesn't mean it is going to stay like that, otherwise the car wouldn't come with a knock sensor! Changes in temperature, gas, altitude, etc will change the tune of a car. You just got rid of the one way your car has to change the tune. The knock sensor is a vital part of a FI car. Did you ever try a different knock sensor?

I do not like the way the knock sensor is attached on a DSM. I am running the AEM EMS, so I see the true voltage output. I had mine torqued to 10 ft/lbs like the manual says at got basically no output. I had to go down to 4 ft/lbs until I got a reading like it was supposed to! If someone had just put that in their car they would crank up the boost and lean it out until they got knock, but it would be WAY beyond a normal knock count and kill their engine in a short time.

Good info... cant wait to play with my EMS!!

 

[Enigma_Man]

Originally posted by 1gawddsm
i think you missed the part where i said i tuned the car as best i could at WOT with the knock sensor in. ive been pounding my car to the ground with 160K+ miles on it at 19psi on a 16g and no knock sensor for months, because I TUNED THE CAR AT WOT before i took the knock sensor out. so you see lad, it was not "foolhardy" (whatever the f8ck that means ,maybe you meant fool-heartedly) in fact, it was the perfect way to cure phantom knock.

No, I didn't miss the part where you said you tuned for WOT at first. I've heard stories from guys that work at gas stations where the managers have the pump trucks just dump 87 into the 94 tank, because the tanker didn't have any 94 in it. I've experienced a couple bad "batches" of gas myself (for whatever reason, gas that's been sitting, or shoddy managerial staff) that lead to real-knock, even though I run at a mild 13 psi, and I can turn it up to 15 normally. And also, like I said, you'll probably be fine, but I'm just warning you that you're flirting with danger by unplugging it. I'm trying to help you, so don't act defensively, it's not a personal thing man (btw, the word is foolhardy, not fool-heartedly, see www.m-w.com for a lookup)

There's many things that can cause phantom knock also, and it _is_ 100% fixable. How are your engine mounts? Some have had those go bad, and noticed a stop in their phantom knock when replacing them. The lifters (actually HLAs) may not be quieted just by cleaning them, it's hit-or-miss. There is a revised set you can order that fixed the design flaw with the originals that causes the ticking sound. I have a bad case of phantom knock myself, it'll peg at 42 or 43 on the highway, and I'll get a couple degrees retard on the ignition, so I know what it feels like, and how frustrating it is. But again, it is a fairly important sensor, and while you may get by just fine, then again you may not.

If you don't care about potential (notice I've never said that you are definitely going to do damage, I'm just warning you of what may occur) damage to your block, like you said, then it's obviously no big deal, but please don't go insulting people, especially ones that are just suggesting that you might run into problems in the future. Double especially when you correct them on grammar without consulting a dictionary first

-Jesse

(really everybody, don't get defensive if you post something, and get criticism, especially if it's constructive, we're all car nuts, and for the most part, every single person on here is here to try and help if they can)

 

[1gawddsm]

jesse
thanks for the corrections. wasnt trying to take it the wrong way. i know its a risk, but its a risk ill take at this point, i have faith in my tuning abilities. and as far as the bad gas thing goes, ill take my chances there too. im also not scared of blowing anything, cuz then its just time for a fresh built motor from slowboy...and hopefully the head will get damaged too when it goes so i have a reason to get a fully built head as well. anyway, thanks for tell me whats what on that foolhardy thing, i guess in my head i was thinking of foolhardily, which is a synonym for foolhadry, but in my head it was spelled like foolheartedly...like foolish in the heart..dunno guess my head was making shit up =) anyway thanks again and sorry i was pissy

 

[pneumo]

Here's some more helpfull info you should know; EGT's are meaningless without a knock sensor.

EGT's go up with knock because the timing gets pulled, which means the gas gets burned later, and combustion is still occuring as the exhaust valve opens, sending flames out the exhaust port and onto the EGT probe. The actual temperature difference of combustion between a rich and lean AF ratio is quite small.

Your last line of defense, the A/F ratio, is regarded as the poorest way to tune.

Part throttle knock is not nessesarily Phantom knock, sometimes it's real knock that happens at part throttle. The best way to tell if it's real knock is to pull the plugs and check them for small white specks. Also check the piston tops for uneven coloring, such as brown, black, and/or silver.

"there's never been a problem made worse by knowing too much about it."

 

[MNGSX]

Another thing you can do is insulate the threads of the sensor. Maybe with the T tape.

For this you don't want the block to be the ground.

Use a ring terminal on it but wire a potentiometer between the sensor and ground. You can adjust the resistance so that it is like a volume control for the knock sensor.

 

[hose101772]

BTW-I had just filled up when motor went(4 miles later).Made it a week on other tank and yes i did check my plugs twice during that week(for detonation) to make sure.That is the point i was trying to make.I am not disputing your tuning ability was simply letting you know I tried the knock sensor trick and paid heavily for it.All because of wrongly labeled gasoline,had i still had knock sensor properly installed it would have picked up on the knock and pulled timing.Looking at 1st post I see i didnt make my issue with bypassing knock sensor clear so now I am.1g-good luck,as for anyone else I would not suggest disabling knock sensor.

cheap fixes can equal expensive repairs.

 

[1gawddsm]

Originally posted by hose101772
BTW-I had just filled up when motor went(4 miles later).Made it a week on other tank and yes i did check my plugs twice during that week(for detonation) to make sure.That is the point i was trying to make.I am not disputing your tuning ability was simply letting you know I tried the knock sensor trick and paid heavily for it.All because of wrongly labeled gasoline,had i still had knock sensor properly installed it would have picked up on the knock and pulled timing.Looking at 1st post I see i didnt make my issue with bypassing knock sensor clear so now I am.1g-good luck,as for anyone else I would not suggest disabling knock sensor.

cheap fixes can equal expensive repairs.

Yeah i hear you man, but all Im saying is, how did you determine you got a lower octane gas than you thought>? did you take the gas in your tank to a lab and have them test the octane rating? or did you just not know what the hell happened and someone suggested it might have been a 'bad batch of gas' ? How did you figure out it was the gas that made you go boom ??????

 

[kpt4321]

EGT's are not useless without a knock sensor, they will just be more indicitive of the actual A/F ratio rather than timing retard. Keep in mind that without a knock sensor, the EGT will change less, so your "danger zones" are different.

Jesse is right. He rules.

Just because the car was tuned to no knock, does not mean that it will be that way forever. Unless you get perfect gas all the time (something not likely to happen, and that you cannot control), check for boost leaks every morning, have perfect boost control, never add any mods, etc, etc.... you could have circumstances changing, and you could get knock.

Phantom knock always has a cause, and thus always has a fix. It's a pretty simple system, something has to be wrong for it to mess up.


....Kyle T.

 

[1gawddsm]

Oh and my father worked for MObil for 13 years and has a 148 Mensa IQ and his thoughts (and I concur) are that if any gas station ever did what you claim they did they would be commiting fraud and would be sued by every customer whos friggin motor detonated from it ! go figure....

 

[1gawddsm]

If anything HOse i think you were high or drunk or just not paying attention and filled your car up with the wrong gas all by yourself.