non-functioning knock sensor= what kind of drivability???

NYSpeed Automotive
1

Car is question is my '93 Taurus SHO in which I swapped the auto for a manual last year, and since then have had some drivability issues where the car feels like it is out of time and/or running on 5 cylinders, I copy/pasted this from another forum I posted this in…

In my seemingly endless battle with trying to track down an issue with my car I’m am now lead to the question of how would a non-functioning knock sensor affect the way the engine performs??? To those unaware, to sum it up I did the mtx swap on my '93. In doing so I made a small error of pinching the main engine wire harness between the head and the AC dryer on the firewall…this resulted in 4 exposed wires; one of them being to the knock sensor, this was the worst one. I patched up the harness and replaced the computer but the car ran the same. My next steps are to replace the harness and knock sensor once the weather warms up a bit here in NY…but between now and then I was curious about the knock sensor.

Not sure how related this may be but in the past before I knew of the wire issue I had never been able to perform the cylinder balance test that can be done after pulling codes…my thoughts were that if there was an issue in the harness or the sensor that this would make sense why it couldn’t do the test…thoughts???

2

in my nissan, a bad knock sensor retards the timing and adds fuel. made it slow and get shitty gas mileage. but im not sure whats gonna happen in the SHO

3

Not sure on that car to be honest, I know with 4th gen f-bodies people program them out, and don’t have problems.

4

[quote=“elgarvo616,post:2,topic:24767"”]

in my nissan, a bad knock sensor retards the timing and adds fuel. made it slow and get shitty gas mileage. but im not sure whats gonna happen in the SHO

[/quote]

That’s basically what it’s doing…feels out of time, definitely down on power/performance, rough idle, not so good gas mileage (average 20 when it should be 25ish), slow to rev…

5

[quote=“elgarvo616,post:2,topic:24767"”]

in my nissan, a bad knock sensor retards the timing and adds fuel. made it slow and get shitty gas mileage. but im not sure whats gonna happen in the SHO

[/quote]

word

6

I recall that with a GM you could test those by tapping on the block while running to see if it retarded. dont know if yamaha did the same. i can look it up on alldata tomorrow if ya want mike

7

find the resistance of the sensor in an FSM then put a resistor in place of it to see how it runs

8

[quote=“my240nissan,post:7,topic:24767"”]

find the resistance of the sensor in an FSM then put a resistor in place of it to see how it runs

[/quote]

+1
I did this on my Nissan and the car runs great now. Then, when you get a chance you can replace the sensor if it is faulty.

9

[quote=“my240nissan,post:7,topic:24767"”]

find the resistance of the sensor in an FSM then put a resistor in place of it to see how it runs

[/quote]

What is an FSM?

FWIW, I can replace the sensor ($30) and harness (free) in a matter of 2-3 hours…it’s really not a difficult job.

10

my old truck wouldnt even start when the knock sensor went bad.

11

Are you driving this or the Mustang now?

12

[quote=“LXTASY,post:9,topic:24767"”]

What is an FSM?
.

[/quote]

factory service manual

13

[quote=“TrueBlue,post:11,topic:24767"”]

Are you driving this or the Mustang now?

[/quote]

Haha…no, Mustang has been sleeping for a few months now. The car is still plenty drivable, in fact I’ve put on nearly 20,000 miles with it like this:(

FSM…makes sense:smash2: