Knock Sensor

[SEREGA784]

When I replaced an engine in my 99 grand am, it had different knock sensor.
My original motor had one wire knock sensor and new one has two. I cannot use my old sensor because it is size #12 and whole is #8. On the other hand i cannot connect the new sensor to my single wire.
What is the best solution to this problem.

I was thinking two choices.
One. Find one wire sensor with the size of the hole. Do such exist?
Second. Connect one wire to existing wire, and other wire to ground (battery minus). But I do not know if it will work?

Can someone help me. Thank you.

[xeroinfinity]

What engine size ????

If its a, 4cyl , they can have either a one or two wire sensor.
Should be able to buy the one you need at any parts store.

[SEREGA784]

I know that I can buy. But one wire has has lager hole size then two wire. I was wondering are there are any one wire sensors with smaller size thread. Thank you.

----

Engine 2.4L 4Cyl.

[xeroinfinity]

Like I said above they used 2 different ones on the 99-01 2.4L.
Your best bet is to remove the sensor that you need(1 wire) and goto the parts store and get the new one with the right size thread.

OK heres the deal;
the one wire sensor has a 100k omh resister built inside it.
The two wire Knock sensor has the resister in the PCM.

So your original was the 1 wire w/resisiter,
and the new motor needs the 2 wire,
which would mean your PCM needs replaced.

Dont think the two wire will work with your PCM.

[SEREGA784]

Is there a difference between one wire knock sensors in different cars? Two make the sensor fit in smaller hole, I will need different one then it was specked out for the car.

[xeroinfinity]

I believe my post above explains it all.

You need a 1 wire sensor that has the reisiter built in and one that has the proper fitting to screw it in.

The motor you have now uses the 2 wire,
which to use that your PCM needs to have the reisiter built into the PCM.

So you might not be able to get it to work.
I'll see what else I can find out on this matter.

[SEREGA784]

I know that. Forget about two wire, I am not using that. My question was are there any difference between one wire sensors? There different one wire sensor out there, at least look different.

[xeroinfinity]

Ok I understand what your saying, one with one wire that came from something else that fits the hole in the motor you have in your car now.

The resisitance biult into the sensor is different from car to car and I dont even know the rsistance value of the one for your 2.4 .

I'll see if I can find it

[SEREGA784]

Does anyone knows where I can get more detailed info about the knock sensors. I checked the stores, they know almost nothing, and they don't have them in stock, so I can check. I'll be checking the dealer next week, their parts department, maybe they can help. But is there somewhere I can get this info myself? Thanks for all the help.

[crazy Jim]

huh?

[xeroinfinity]

SEREGA784, I dont think you can get more detailed then what I already have.
Maybe a GM tech manual

Best bet is to call a dealershit and talk to someone in the shop.
Tell them you swapped the engine and now you find out its the wrong motor, because it is !
Then ask them if you can make the Knock sensor work.

The only way I can think of is to get an insert the size of the hole on the block,
that will fit the sensor you need,
but that might throw off the Knock retard, and it might not run right either.


Good Luck!

Heres a PDF on knock sensors.

[redroan351]

Hey man, I know exactly what you're talking about. Someobody handed me a car with the same problem only half way put together for a 99 Malibu. I think the sett up is for a sunfire or something.
You might also find a place for an EGR valve but no connector for it in the harness. Course I got mine half way through so I don't know what it had before. But the EGR and PCV are attached to the side of the block on mine.
You could leave that thing unplugged and probably be okay. unless you had a knock. The problem is these cars always sound like they have a knock, and so are always over retarding the timing. A bad motor mount will trick it.
What he said will be fine though. Find a pipe fitting and stick it in there and then bolt the sensor into that.
I have a scan tool with live data and all, and I bolted mine to a random bolt whole I found and have monitered my driveability, and the fuel ratio, timing, and 02 sensor readings are perfect.
I say putting a knock sensor on these cars just proves that the tapping and knocking racket these things make is far from normal like the TSB's try to tell us.
good luck.

[xeroinfinity]

redroan351, I dont believe you are talking about the same thing.
If you had read above thiers 2 diferent 4 cyl's for the 99's, one pre 98' and one post made in 99 .

He had one type of engine and put in the other.
He just needs one to fit the hole, and still use the same 1 wire sensor, which...... I dont know if one even exists

But you are right that thier may be another hole that the smaller 1 wire KS will fit