Running 4EFTE Engine without Knock Sensor

[Ashrafi]

As the title say, has anyone run his engine without the knock sensor, how has the engine cope? ECU cope? has timing been retarded? does the engine runs like crap ?
all post are welcomed.

 

[Skalabala]

Ran it without knock sensor with a stand alone and it was mental
I experience is that one should not remove sensors when using a stock ecu, they tend to go into limp mode etc.

 

[dac69er]

will run ok, but that about it. not entirel sure if it retards the timing, but i would have thought so.

my power fc only used the knock sensor for indication only so it doesnt adjust anythig if it senses knock so in theory i could do without it!

 

[Ashrafi]

i am planning to keep the know sensor on my engine and try to modify its return frequency to the STD ecu with a 10k pot and sees if it retards the timimg when on full boost.

 

[dac69er]

if you want to retard the timing just adjust the distributor. i wouldnt bother messing with the knock sensor signal. what are you trying to achieve? you wont alter the freuqency with a pot alone!!!!!

 

[Ashrafi]

am not trying to retard timing but to keep it stable as i think the knock sensor is picking noise from the engine bay and retarding the timing from the ECU. and the result is lack of power and the car holds back but am not having any check engine light.

 

[dac69er]

if you have no fault codes relating to the knock sensor, then its not the knock sensor causing your problem.

if you have a noise problem then i would look into the shielding around the knock sensor cable. ensure it is grounded correctly at one end only. also make sure your ecu has a good ground.

have you tested the knock sensor signal to know that you are getting any excessive noise or spikes from it?

 

[Ashrafi]

what you mean if its grounded at one end, the knoc sensor has only one wire on it that goes to the ecu right? so where can it be grounded?

 

[dac69er]

it has a braided shield to reduce electrical noise. if you have issues that sound like noise problems then making sure the shield is grounded correcly would be a good start.

i would imagine the ecu has some sort of smoothing circuit for the signal coming back from the knock sensor anyway.

 

[Ashrafi]

need to check the insulator then, but as far as i know, inside a knock sensor there is like a piezzo type vibrator (like in tweeters), its creates a signal when it captures vibration and send the signal to the ecu, it is like a one way signal receiver.

 

[dac69er]

need to check the insulator then, but as far as i know, inside a knock sensor there is like a piezzo type vibrator (like in tweeters), its creates a signal when it captures vibration and send the signal to the ecu, it is like a one way signal receiver.

its like a microphone. it is still sending a small signal to the ecu and the shielding is there to try and reduce interferance from anthing else electrical.

 

[Ashrafi]

when i remove the knock sensor plug and do a self diag test no fault code apprears, is this normal?

 

[dac69er]

start the car and rev it to over 3k rpm for a few seconds and your engine light will come on. if you do a test you will get a knock sensor related code.

 

[Ashrafi]

will test it tonigh and let you know bro, but i remember when i removed the knock sensor plug and put the engine in diag test mode, i it has not throw the code 52.

 

[dac69er]

it wont see a problem until you rev over 3k rpm with it disconnected

 

[Ashrafi]

hya, av test it yesterday as you told me, i disconnected it and rev wide over 3k rpm and no light came on, i even did a diag test with it disconnected and no fault code came on even when on diag mode and rev over 3k rpm. this is really eating my heads.

 

[turbo head]

i had a similar problem before with my timing been retarded. are you just persuming its the knock sensor or are you sure ?

 

[dac69er]

hya, av test it yesterday as you told me, i disconnected it and rev wide over 3k rpm and no light came on, i even did a diag test with it disconnected and no fault code came on even when on diag mode and rev over 3k rpm. this is really eating my heads.

How long did you keep the revs over 3k rpm? You have to hold it there for a few seconds, not just rev too it. It proves nothing anyway, it will bring the light on, won't show if the knock sensor is at fault. Without measuring the signal back from the knock sensor your just pissing in the wind.

Have you been to a rolling road to see if your timing is indeed being retarded by something?

 

[Ashrafi]

man what have you done to remediate for the timing being retarded? i am not sure if its the knock sensor , but trying to figure out where the problem really is..

 

[Ashrafi]

bro, i did rev it to 3 k rpm for a few secs and no light came on. also i did pull it on the rolling road as you said , you see the boost upping and the car feels like someone is holding it back with a rope, it wont go anywhere. this problem is really pissing me off as you said.