knock sensor

[Lyndon S.]

On the 1989 L 98 engine where is the knock sensor located ?

[Joe L.]

Re: knock sensor

On the 1989 L 98 engine where is the knock sensor located ?

Lyndon-----


As far as I can tell, it's located on the right side of the block on the upper rear.

[Edward J.]

Re: knock sensor

to add to Joe's post Under the exhaust manifold.

[Lyndon S.]

Re: knock sensor

Thanks, how does one tell if one is bad or going out? Even when I run high octane gas I get a pinging from the engine it is ever so slight but it annoys me. It has had a tune up with new wires cap rotor and plugs. The plugs are not what came in the car they are AC platimun ones. Would that make it ping with those plugs?

[Jim T.]

Re: knock sensor

The knock sensor on my 1985 and both knock sensors on my 1996 are screwed into the block drain plug locations. I remove sensors to drain the blocks with coolant changes.

[Edward J.]

Re: knock sensor

Lyndon, the are easy to test, just warm up engine to operating temp and take a timing light and watch the timing while tapping the engine manifold with a wrench you should see it retard the timing. I rarely see problems with the sensor its self, What generally happen to them is the electrical connector is plastic and the heat will cause the connector the fall apart, and the vibration will cause a poor connection. And when this happens it will set a code for the knock sensor. Are you sure the base timing is correct? there is a single tan/black tracer single wire that generally has to be disconnected to set timing, again the engine should be warmed up to temp. Spark Plugs will not cause a ping. Have you check the computer for trouble codes? Code 32 (EGR problem) will give a ping if the EGR valve is not operating. timing to far advanced is another, Or just plain old injector problems, which are a big problem when the engine is running lean because of lack of enough fuel, Sometimes the computer will set a code 44 Lean condition.

[Lyndon S.]

Re: knock sensor

Base timing is set to fact specs EGR is new, but when the car is at idle those injectors are real loud ticking.

[Joe L.]

Re: knock sensor

The knock sensor on my 1985 and both knock sensors on my 1996 are screwed into the block drain plug locations. I remove sensors to drain the blocks with coolant changes.

Jim------


Most C4 are as you describe but not 1989.

[Edward J.]

Re: knock sensor

Lyndon, why did you replace the valve? trouble code? was it a Delco or GM part?

[Lyndon S.]

Re: knock sensor

It was a AC delco did it when I replaced a cracked head on the engine.

[Joe L.]

Re: knock sensor

It was a AC delco did it when I replaced a cracked head on the engine.

Lyndon-----


Not a bad idea to replace. EGR valves can carbon-up and stick open, causing poor idle. Also, these things run real hot and, consequently, the diaphragm can fail rendering the valve inoperative. That usually won't cause operational problems but it will set and code and cause you to fail an emissions inspection if your area requires it.

The replacement valve should have been GM #17113456 (or one if its predecessor part numbers), aka Delco #214-5535.