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96 vs 2000/01 Grand Am 2.4L knock sensor


rljt60
06-14-2005, 06:51 PM
I just replaced the 96 motor with a 2000 or 2001 2.4L motor. The '96 knock sensor bolts directly into the engine and is a single wire connector. I presume it uses the case as ground. The 2000/01 sensor is a two wire connector and totally different shape with a through-bolt of smaller diameter. Even if I was to find an adapter I could not re-use the 96 sensor as there is no room due to the different block shape and bars.

I bolted a terminal lug with wire to the block and connected the other end of the wire to the threads of the 96 sensor with a pipe clamp. And then I connected the sensor to the ECM using the original connector. I do have good continuity. The idea was to fool the ECM into thinking the sensor was installed. It didn't work naturally. After about a mile of driving I get the check engine light and it is code P0325 - knock sensor ckt malfunction. I clear it and it returns.

Can I take the 2000/01 two wire knock sensor and send one wire to block ground and hook the other wire up to the original one wire connector leading to the ECM? Or, do the two sensors operate differently with different AC voltage generation? The sensor has one white wire and one red wire and neither have continuity to the sensor case. If my idea is feasible, which of the two wires should go to ground?

And if my idea is not feasible, what do I do next? This is the last thing to fix before it gets detailed and back on the road.

Many thanks for your help on this project that was more than originally expected ....
Bill

97grandamld9
06-14-2005, 09:33 PM
I am not 100% sure, but i do know there are some differentces in the motors, for example the compresson on the 99+ motors are alittle lower (about 9:5.1 compared to 9:7.1 on the 98 and older motors) also there are low impedence injecters on one year, and high on another (cant remember right now) theres some other things. But anyways i would stear you towards www.quad4forums.com i know theres a guy over there that put an 99+ motor in his 96-98 grand am.

rljt60
06-15-2005, 08:21 AM
I am not 100% sure, but i do know there are some differentces in the motors, for example the compresson on the 99+ motors are alittle lower (about 9:5.1 compared to 9:7.1 on the 98 and older motors) also there are low impedence injecters on one year, and high on another (cant remember right now) theres some other things. But anyways i would stear you towards www.quad4forums.com i know theres a guy over there that put an 99+ motor in his 96-98 grand am.

Thanks for the referal. I just posted over there also. And I did see a note about having to tap out the newer block to accomodate the old sensor. And then weld a bolt on an older engine for the smaller 2000 sensor. The idea of tapping the block does not excite me. I am only trying to electrically fool the ECM into thinking the knock sensor is installed. We shall see if it is feasible.
As for the differences, yes, there are quite a few especially in the sensor issue. Although they may look the same the pin count is different so you have to be careful there and swap when necessary. Also the oil pans are different. The newer one does not have a oil level sensing unit.
Again, many thanks for the input. Bill

rljt60
06-29-2005, 04:11 PM
Thanks for the referal. I just posted over there also. And I did see a note about having to tap out the newer block to accomodate the old sensor. And then weld a bolt on an older engine for the smaller 2000 sensor. The idea of tapping the block does not excite me. I am only trying to electrically fool the ECM into thinking the knock sensor is installed. We shall see if it is feasible.
As for the differences, yes, there are quite a few especially in the sensor issue. Although they may look the same the pin count is different so you have to be careful there and swap when necessary. Also the oil pans are different. The newer one does not have a oil level sensing unit.
Again, many thanks for the input. Bill

The initial problem was I put a 2000 2.4L engine into a 96 vehicle. The knock sensor on the 2000 is a smaller bolt size going into the block than the 96 sensor and is a different configuration. The 2000 is a 2 wire sensor and the 96 is a one wire sensor going to the PCM.

The 96 sensor has an internal 100K ohm resistor going to the case and subsequent block ground. The 2000 sensor does not. Its 100K ohm resistor is internal to the PCM and that is why it is a two lead sensor. Naturally, the two are not interchangeable.

I tried fooling the 96 PCM into thinking the 2000 sensor was ok by installing the sendor after cutting one lead and attaching a 100K ohm resistor to the lead and taking it to block ground and hooking the other wire up to the 96 PCM. After about a 1/4 mile of driving the check engine light came on with a "sensor ckt malfuntion" code.

What DID work is this ... I took the 96 sensor and hand tightened a brass 1/4 x 1/8 FIP reducing coupling (Home Depot) onto the sensor. Although the threads are totally different it did grab and get tight. Then I cut the head off a M8x1.25x~30 bolt so when inserted into the coupling and against the sensor about 1/2" stuck out past the nipple. I removed the bolt and filled the nipple about half way with JB Weld and then reinserted the bolt cut side against the sensor. I let it set for 24 hours so it would fully cure. I screwed it into the block so the nipple went tight against the block and it worked. The sensor is feeding the PCM.

If you go into "member galleries" and do a search for "knock sensor" you will see the finished 'product' under rljt60.

Hope this helps someone,
Bill

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