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But do this, strip the 88 motor down to the long block, build it back up using the 92 parts including the sensors, tap a hole if necessary for the nock (knock) sensor.
The 88 should have had a knock sensor as well. Should be located on top of the block in the back behind the lower intake. You should be able to use the sensor off your 92 and put it in place on the 88 block unless I am missunderstanding your situation.
the 88 does not have one at lease in the same location as the 92. i can't use the wiring off the 88 for the 92 cause it will not plug into the other half. Someone told me to weld a nut on the back of the block in the same location as the 92 and place the sensor there.
You might get a code for the knock sensor not found/out of range but it won't trip the CEL. All the knock sensor does is retard the timing if it detects a knock. It can't detect a knock if the sensor isn't connected.
I'm still confused by the fact that two engines with identical systems (damned near anyway) have such contrary wiring. 88's have knock sensors too. The only engine that didn't have one in the Bronco during those years was the 351. Not to mention EVERY piece of information I can dig up references a KS in the 5.0 (302). Of course it is possible that the 88 had the engine replaced (even if it was just the short block) with an older (pre-fuel injection) block. That would account for the lack of knock sensor and hole in which to mount it but truly be about the only way it would happen. I'd bet if you dig into the harness from the 88 you will find a LT./GREEN-BLACK wire and a BLACK-WHITE wire snipped off and taped up inside a wire loom somewhere near where the harness passes behind the engine near the firewall.
But then, like Andy said, it won't do anything but trigger a code 25 or code 225 depending upon whether your ECM gives two or three-digit codes. And even then, those two codes are only thrown during the KOER test. Which actually requires you smack the block during it so the computer can see a response from the KS.
This 88 motor is a 351 and my 92 was 302. so this is make some sence now. i will look through the 88's wiring for those two wires. this motor is stock to this 88 bronco. i know the guy very well and he was the org. owner of the 88.
This is all Great info and i really do appreciate everones help.
If the engine in the 88 is a 351 then you won't find those wires in the 88's harness. I think that is what had some of us confused. We were going under the assumption that you were swapping 302 for 302. The 351W never had a knock sensor.