I am still waiting for a knock sensor to arrive and want to prove it is the knock sensor which is causing the hesitation/missing, so if i just unplug the sensor would this be ok?

Would the check engine light be on perminantly with the knock sensor disconnected?

Any info appreciated.

KR

Dave

 

at a guess i would say the cel light will stay on all the time and you probably would not be able to prove the sensor is causing your hesitation/misfire as engine will not run correctly with it disconnected so you are probably best wait for the new one to arrive

 

Cheers for the reply, I did wonder that maybe it would go into full det defence mode and retard the ignition loads.

Just annoying i want to know for sure this is the problem !!

Dave

 

Can't see why knock sensor could cause missing. If knock sensor is giving false signals, you would see no boost and end up using rich maps but not going to be missing (my guess) , but I could very well be wrong though just can't see the link right this moment

 

From talking to the bloke doing my mapping last week I'd expect it to fall back to a compensator map and run rich too, but you never know.

 

Well its not so much missing as having short bursts of less power, sometimes completely and other times intermitantly.

I understand that if the knock sensor "detects" detonation it reports this to the ecu and the igniton is retarded?

Its not a good old hard cut missfire.

Dave

 

And i'm getting a error 22 on the ecu.

DAve

 

Without knowing which which year the car is it could do anything earlier cars would probably do diddly squat to throwing up CEL lights etc, and I would doubt it would be what is causing your running problems.

NOT all Imprezas are the same. Like not all users are telepathic in knowing what car you drive

 

View my Scooby 93 WRX

Dave

 

Sorry bud i dont understand what you are saying ?

Dave

 

Well, you will get a CEL light and code 22 with it diconnected. Shouldn't harm normal running though.

But seeing your already getting code 22, its not going to make much difference

 

it wont make any difference to the error code, but what i want to know is will it run correctly? if it does then i will be sure its the sensor sending faulty info to the ecu.

Dave

 

Well, the ECU will apply assumed values. That is the to say the engine will run, and generally drive ok. And normal driving would be pretty much unaffected. If your getting CEL with it connected, the ECU is ignoring the sensor readings anyway.

There is a risk you may experince detonation or loss of performance on full boost.

So don't thrash it

 

I think i'll just wait till i get a replacement and try that, think its going to be the safest option.

Dave

 

All sorted now,

To confirm the knock sensor WAS causing the running problems, the "missing" must have been the ecu retarding the ignition when recieving erronous signals from the dodgy knock sensor!

All is fine now and is running very well

Dave