hi, my timing is retarding on boost so need to check if my ACT sensor and Knock sensor is working correctly. what do i do to check them? want to make sure its not one of these before i replace the ecu.

Thanks

 

Only way to know for sure is try a known working one or a brand new one in their place.

 

are act sensors not just a ntc though? so surely if i put a multimeter on both connectors then heat up the sensor a biti should see a resistance?

 

Yes but you nee to know what it's suposed read at certain temps to be able to know if it's correct or not.

 

My knock sensor was actually causing alot of havok . The rolling read out looked like it was drawn on a etcha-sketch!! One way to tell that its playing up.

 

act sensor is an easy one to test, should be around 65-70k ohms at 5 degrees, about 2500 at 90 degrees or there abouts, same as coolant sensor.

 

my rolling road printout wasnt that bad really,

cheers xr2wishy will check tomo when im at work.

anyone know how to check a knock sensor? if not i might aswell just buy one. where from and how much? cheers

 

Any one know what happens if you unplug the sensor? does it just stop reading ie no knock, or does the ecu just retard the ignition (for safety).....

If you can just unlug it, i would give that ago so long as you have some det cans whilst setting the car up.

 

apparently if you just unplug it the ecu doesnt get a signal at all and wont run properly

 

Maybe put a multimeter across the knock sensor to see if you can short the connector some how to fool the ecu into thinking it has a sensor? Tbh i haven't ever had any problems with knock sensors so haven't taken the time to learn how operate. Know the basics just don't know how many outputs the sensor has etc.

Rob,

 

You can leave it plugged in but unscrew it and cable tie it to a rubber hose or somehting in the engine that wont vibrate. The car will run great if it is the knock sensor playing up.

 

That's easy to do as well lol