I have an 89 5.0 EFI and the knock sensor is bad. The part is discontinued. I have read through post and am trying everything to get a replacement to no avail. Without the knock sensor the truck will not advance the timing causing low power. I was wondering has anyone changed the distributor to a mechanical advance for this? And if so will the check engine light come on? I would like to get a knock sensor p/n E3AZ-12A699-A but this seems impossible. So I want to change to a mechanical advance distributor.

Scott

 

rockauto has them. for the 302
AIRTEX / WELLS 5S2211

 

That doesn't make sense. The knock sensor is piezoelectric. It puts out voltage when knock occurs. The ecu reads the voltage and retards timing to eliminate knock. If your sensor isn't working it won't send voltage so the ecu will advance the timing regardless of detonation. Simply put it will work fine but if you get a knock you may damage the motor. If your not getting any advance you may have another issue.

 

Thank you for your response. I just looked at rockauto and can't pull that part number up I think these knock sensors are discontinued

 

That sounds correct what you're saying although what I have been researching is that also the knock sensor will allow the ECU to advance the timing until until it pings then slightly retard the timing. The timing is currently set at 10° BTC and the truck runs okay but if I advance the timing manually the truck runs great. Problem is it won't start correctly with timing too far advanced.

 

The sensor doesn't allow it to advance. It only retards. How would it allow anything if it doesn't send a signal? By the way have you tested the sensor? The reason they are rare is because they don't fail often.

 

From the research that I've done the knock sensor just like all other sensors Feed information to the ECU. The ECU then uses this information to advance the timing until the knock sensor sends a signal of pinging, then slightly retarding the timing until the detonation stops, thus keeping the engine at its highest possible timing advance keeping power and efficiency up. As far as the sensor I had a knock sensor not detected on the KOER code and when I investigated the knock sensor it was broke in two.

 

OK I see your issue now. The sensor doesn't really control the timing but because the computer determined it wasn't even there it went into safety mode. You might try just unplugging it. I have been searching for that sensor and I can't find one anywhere so you might as well do some testing. Might try searching used parts or junkyards.

 

Thanks for your efforts! I have been searching everywhere, parts houses, junk yards, to no avail. I finally found two sensors, I think the last on the earth, out of Canada. $275 + shipping ouch! The things we do for our loved ones. Anyway I purchased one and hope that it does the trick and will allow the ECU to get out of safe mode and go to work! If not I guess I am going to replace the distributor with a mechanical advance. I have to go out of town for a month and will have to wait to see but will post results, good or bad, once I get it done.

 

I would resist doing a mechanical advance if at all possible. You loose a lot of advantage of the computer. I am pretty sure its going to give you an error as well. I'm thinking it might effect the fuel delivery. $200+ is a lot of cash for a $30 part. I gotta find someone to start making these things. I could make a fortune.