Chevrolet Forum - Chevy Enthusiasts Forums - in the 5.3L Vortec, wich knock sensor is #2?

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- - in the 5.3L Vortec, wich knock sensor is #2? (https://chevroletforum.com/forum/tahoe-suburban-25/5-3l-vortec-wich-knock-sensor-2-a-32924/)

I was going to say that if the engine was truly knocking, you would hear it. The sensors pick up a sonic (sound) wave and send a message to the computer to retard the timing and eliminate knock....a normal occurrence with an engine under load if the timing isn't adjusted. When the sensors are scanned and return an out of spec reading, the light is tripped.

I would venture a guess that if you are getting it from both sensors, you are probably seeing a problem with the wiring going to the sensors, or perhaps even water intrusion into the sensor cavities, followed by a short.

The bad news is the sensors are a pain in the a$$ to get to. You have to remove the intake manifold to access them, but once they are visible, they simply unthread from the top of the engine block.

My suggestion: take the manifold off and inspect the wiring. If it looks off, replace the wiring harness to the sensors. If not, invest in two new sensors and see if the codes disappear. You will be out a bit over $100, but much cheaper than a new truck or motor.

Regarding the slow shifting. I would seriously consider swapping out the trans fluid and filter before I spring for an overhaul. Often times, your fluid is old and dirty and the results are sluggish shifting.

Don't listen to the bull$hit folks that warn you to not replace the fluid in a transmission because it might fail. If you change it and it fails...that trans was on it's last legs and was about to fail anyway.

Quote:

Originally Posted by dh1 (Post 144453)

the one in the front, or the one in the rear? It is supposedly for bank #2, but neither of seems directed towards one side or the other.

I am about to take my manifold off and replace the sensor, and replace the intake gaskets and hoses. I really don't want to take all this junk off, then find out I replaced sensor #1.

I am tempted to buy two of them and replace them both, but for the cost of the sensor, I really don't want to be wasteful.

Thanks
DH1

2002 Suburban 1500 LS

The front knock sensor is number two. Rear is number one.

Quote:

Originally Posted by Aaronl888 (Post 310395)

The front knock sensor is number two. Rear is number one.

Sorry that was suppose to be the other way around. Front is one and rear is two.

Quote:

Originally Posted by dh1 (Post 152105)

I was going to say that if the engine was truly knocking, you would hear it. The sensors pick up a sonic (sound) wave and send a message to the computer to retard the timing and eliminate knock....a normal occurrence with an engine under load if the timing isn't adjusted. When the sensors are scanned and return an out of spec reading, the light is tripped.

I would venture a guess that if you are getting it from both
sens, you are probably seeing a problem with the wiring going to the sensors, or perhaps even water intrusion into the sensor cavities, followed by a short.

The bad news is the sensors are a pain in the a$$ to get to. You have to remove the intake manifold to access them, but once they are visible, they simply unthread from the top of the engine block.

My suggestion: take the manifold off and inspect the wiring. If it looks off, replace the wiring harness to the sensors. If not, invest in two new sensors and see if the codes disappear. You will be out a bit over $100, but much cheaper than a new truck or motor.

Regarding the slow shifting. I would seriously consider swapping out the trans fluid and filter before I spring for an overhaul. Often times, your fluid is old and dirty and the results are sluggish shifting.

Don't listen to the bull$hit folks that warn you to not replace the fluid in a transmission because it might fail. If you change it and it fails...that trans was on it's last legs and was about to fail anyway.

You do have a point there, if a vehicle is over 100,00 miles, its best to drain your transmission and place new gasket and fluid back in. NEVER FLUSH the transmission if you do, the forced flush will break apart pieces from the inside of your transmission and destroy your transmission completely.

Replace both knock sensors at the same time

Quote:

Originally Posted by dh1 (Post 144453)

My suggestion is replace both sensors at the same time. I've had a lot of experience with these knock sensors and if you replace only one you're going to have problems from the beginning of that and you're going to have to replace the other one shortly after so you might as well just replace them both at the same time.. best results.