Hello, I need some help with a problem I came across when switching over everything from a bad engine to good one. The truck is a '93 F150 4X4 with a 302 automatic. I bought the truck with "blown" motor, the rest of the truck is fine. I have a couple of Mustangs and a extra 302 from a car to use in the truck. Only thing is, no boss in rear of block for Knock Sensor in replacement engine.

I searched this topic and it seems my options are either just not plug sensor back in and let connector dangle, or drill, tap, and install sensor in rear of block. This seems a little risky to me, and need someone to tell me I MUST do this before I will head in that direction.

So, any new thoughts on this topic, I would hope to just be able to not plug the sensor back in and be careful with timming, good gas, ect. Or is this just asking for check engine lights and other problems...???

Thanks in advance for any input, Justin

 

I had the same problam on an engine swap, already had the engine in the truck I just left the sensor pluged on and secured it with a hose clamp but I cant remember what I secured it to. I assumed a knock or ping would be detected thru the steel I dont know if it was working or not but I had no problams with it

 

If the knock sensor is plugged in you won't get a check engine light.

The knock sensor is bascially an electret contact microphone. It requires physical contact with the block in order to be useful. The circuitry behind the knock sensor (in the EEC) is a bandpass filter which takes the audio input from the knock sensor and strips off the high frequencies (harmonics) and the low frequencies (bass, rumble, rattles, and so on). It looks for a particular, narrow frequency range which indicates ping/knock/detonation. Then the EEC backs off the the timing as necessary to eliminate this condition.

There are a several factors that facilitate ping, knock and detonation and poor quality gasoline is only one.

Timing, load, being in the wrong gear and bogging the engine, extremely dirty air filters, lack of fuel pressure, low fuel flow, crud stuck on the valves, seats, chambers, pistons and any casting flash in the chamber, etc etc.

Me, I'd drill and tap the block in the factory spot and thread the knock sensor in. Thread it in dry and don't use RTV or other sealant as that reduces the audio signal transmitted through the block to the sensor.

It's okay to put RTV and other goo's under the collar of the sensor, just not on the threads.