Knock Sensor Q...

[mk3_dude]

Currently, my 7M is cranking but will not turn over to start.
Both of my Knock sensors are unplugged because the wires are crumpled to pieces.
Without these two knock sensors connected,
will this cause my car to not start?

 

[quake]

Currently, my 7M is cranking but will not turn over to start.
Both of my Knock sensors are unplugged because the wires are crumpled to pieces.
Without these two knock sensors connected,
will this cause my car to not start?

no

 

[shaeff]

no, it should start and run fine. you'll have no acceleration, code 52, and poor gas mileage, as when code 52 is registered in the ECU, timing is retarded, and fuel is added. if you're turbo, your car will hate boost.

 

[supraslo]

knock sensor wires are common to become brittle hence the reason why alot of dealerships replaced them for free back in the day, but even the replaced wires do not last forever. buy some shielded wire from radio shack and SOLDER at the ecu and knock sensor connector. this will eliminate knock sensor problems from bad wires. As far as the no start, start looking at something else.

 

[mk3_dude]

thanks guys.

 

[ABQMK2]

are you getting other codes beside the 52?

 

[survyor2]

Question: Do knock sensors have to be grounded?

I had code 52. I rewired both sensors with the coaxial cable. I still had code 52. I got a used knock sensor from a working car. I unplugged the front connector and plugged it into the "new" knock sensor. The sensor was just hanging out in space. I still got code 52. I repeated the step for the rear connector and still got code 52. I was trying to rule out which sensor is bad. Any ideas?

Dennis

 

[jetjock]

They don't have to be grounded but they do have to be in the engine. Even with good wiring you'll never get rid of the code with the sensors hanging loose.

 

[survyor2]

AH Thanks for the tip. I'll screw them in one at a time.