: Knock Sensor



beatz02
12-07-10, 05:23 AM
Is this easy to replace? If so, I'll do it myself. Where exactly is it?

Hopefully this will fix my fuel economy issue. I've already done a tune up, got a new air filter, and cleaned the MAF, but now I can smell gas, the check engine light is on, and I'm only getting 200 miles per tank (down from 300). I got the knock sensor code when I checked the computer. I thought maybe my mechanic did not tighten a spark plug correctly since it was having a hard time accelerating, but spark plugs, wires, and opti seem to be fine.

N0DIH
12-07-10, 08:15 AM
Easy, but messy, coolant dumps out when the Knock Sensor is removed... These were put in the block plug holes underneath. Make sure they didn't get disconnected, rare, but if someone was messing around, it can happen.

Often GM gets protective, if a knock sensor code is present, the PCM will automatically pull out max knock retard across the board.

http://i159.photobucket.com/albums/t142/mompower/Tom/PCMTuning/LT1MaxKnockRetard.png

So yes, it is significant timing to pull out.


Is this easy to replace? If so, I'll do it myself. Where exactly is it?

Hopefully this will fix my fuel economy issue. I've already done a tune up, got a new air filter, and cleaned the MAF, but now I can smell gas, the check engine light is on, and I'm only getting 200 miles per tank (down from 300). I got the knock sensor code when I checked the computer. I thought maybe my mechanic did not tighten a spark plug correctly since it was having a hard time accelerating, but spark plugs, wires, and opti seem to be fine.

beatz02
12-14-10, 02:18 AM
Thanks for that. I was looking for 2 of them since you used the plural, but I only saw one. I also found my factory service shop manual, which instructs to drain anti-freeze before installation. Crazy how that single part makes such a big difference in fuel economy and causes the engine to run smoother.

turbojimmy
12-14-10, 12:13 PM
Thanks for that. I was looking for 2 of them since you used the plural, but I only saw one. I also found my factory service shop manual, which instructs to drain anti-freeze before installation. Crazy how that single part makes such a big difference in fuel economy and causes the engine to run smoother.

The '96 (OBDII) has two knock sensors. You should only have one.

HUF
12-14-10, 10:14 PM
One can easily break the knock sensor, so one should be careful. To disconnect the connector, you should squeeze it and pull off. The socket is 22 mm. A common set of sockets does not have that size. It should be purchased separately.