Knock sensors, compatability

[zorcy]

I put this in the wrong forum. Hope this is a better choice.

Some earlier designs have the knock sensors inside the engine, under the intake manifold. This is a great spot for listening to the knock of the heads, but bad for access.

I have seen some that are mounted outside, with a bolt thru the center. This allows for easier access for repairs.

I have heard they pick up different frequencies then the older type. This may have been needed in order to put them someplace else. They have 2 leads instead of one and ground.

Here is the question: Are the compatible? It seems it would be so much easier to simply get the external sensor, bolt it on, ground out one lead and tap the other into the wire harness.

You would have to take things into consideration, such as noise, heat and proximity to the head for optimal sensitivity. But this sounds like it should work.

[Jason.MZW20]

Short answer: no.

Unfortunately, the newer knock sensors are not compatible with older ECUs. They are a better design, and offer a wide range of frequencies that can be tuned in the ECU of each engine, but they won't work for our ECUs.

The newer knock sensors are non-resonant, while the older piezoelectric ones are resonant. Big difference when it comes to the ECU.

[zorcy]

Thanks Jason,
Its a shame there is no bolt on doughnut like that we can use externally. I see people using the GM sensor, could there be another make that will work?

I will be pulling the plugs this weekend and testing which one is bad and good, then jumping it at the intake manifold. This will last for a while, then I will have to build a bracket and buy a new one..... Then I will use the jumpered connector and run it to the dog bone.

[zorcy]

I have seen GM knock sensors used externally. What year and model do we use? I tried to do a continuity test on the sensors from the plug on the engine and from the ECM. It had no resistance. I used a long wire and tested the circuit from the engine plug to the ECM plug, both banks were good. Both bank sensor read the same, but I am only getting one error code, 55.

I jumped the wires at the ECM and still get the same code. Do I have to cut one wire to keep from getting a bad signal from the other sensor?