1993 FD single turbo

Lately my PFC is giving a knock reading (fake /noise) in the high 30s to low 40s.
The strangeness is that it happens only around 2000rpms in 2nd through 5th gear at low loads with mild acceleration.
I've reduced timing around 5 - 10 degrees with no affect.
When I try to shake the engine or exhaust, there is no apparent metallic hitting sounds.
??????????????????

 

Are you logging a wideband?

Are the ambient conditions much different to usual?

How old is the fuel?

I'd check engine/PPF/braces, you may have failed a clutch spring too. Shifter bushes still in good condition?

May be worth dropping gearbox oil and looking for any signs of bearings on the way out.

 

Chuck, check your knock sensor. Over time, the glue they use to isolate it breaks down and weird readings will show up. It’s easy to spot as it runs down the outside of the sensor.



~ GW

 

Weather is normal as it does it in the 50Fs and 80Fs.
Fuel is seasonal very fresh.
Trans oil only 10535 miles on it.
Have not checked under the car or the sensor yet. It is my second sensor as the first melted years ago but I did not record the date/mileage of that..