would the wrong knock sensore set a check engine light. like a 305 knock in a 350motor?

 

I had a 305 knock sensor in my 350 for awhile, before it dawned on me that it was the wrong one.

I never had the check engine light come on because of it, but it ran like *** and took in gas at a rediculous rate.

 

It's possible. I had a knock sensor fault in my truck a few years ago. I bought a new sensor and the fault didn't go away. I took out the dash bulb and lived with it for a few years before deciding to find the problem.

Local parts store has the Alldata CD's. I went through the diagnostic procedures for my truck and said my knock sensor should have something like 100 ohms through it. The new one I bought was closer to 100,000 ohms. I went and bought another one and it was the same. We looked through the parts book and discovered that the 100,000 ohm sensor was the most common but there was also another uncommon one available. When I checked it, the ohms were 100 ohms. I put it in my truck and the knock sensor fault went away.

There was no way to physically tell them apart. Without knowing the tolerances, I would never have found out what the problem was.

This isn't saying that this is your fault but don't assume a part from another vehicle will work in yours.

 

The wrong knock sensor w/ the wrong MEMCAL will set a check engine light.

In the case of going from MAF to SD, you have to change knock sensors or you'll get a code. Measuring resistance on both sensors, you find one has much more resistance than the other.

So...like I said in your other thread, get the right sensor for your year and engine displacement. Buy a new one if necessary.