Would a damaged knock sensor cause timing to jump around with the EST connected? Car runs fine with it disconnected. I hit it and knocked the connector off when changing out my starter . Is there a way to test the knock sensor?

Thanks

 

I don't know if there is a way to check it but it can cause the timing to jump around a little. I had a similar problem with my camaro. I broke the connector and it wasent making a good connection and my timing would go crazy at times. bought a new connector and it fixed it. It ran nice and smoothe where before it would run rough at times. could really tell it at 1/2 to WOT.

 

It's a $30 part - just replace it.

 

Having the knock sensor disconnected causes the ESC to default to full knock retard. This will make your car run like a dog. Go with camaronewbie's advice and replace the sensor. The connector breaks easily so you may want to replace that as well.

 

Would it cause the idle and timing to jump around like crazy with the EST connected?

 

If the sensor is bad, or giving a false reading to the ESC, the ESC sends a signal to the ECM telling it to retard the timing up to 20* in order to prevent detonation. So yes, it could if the sensor is bad. With a bad sensor that's only giving intermittant false readings, I would hazzard a guess that you could see your timing jump around a bit. Not sure it would affect the idle that much though.

Also, make sure your knock sensor wire is routed away from your plug wires. You can get a false reading from any conducted energy from the plug wires. This happened to me when i bought over the valve cover wires as opposed to the stock under the manifold wires. Car kept throwing code 43. Rerouted the wire, code went away.

 

Changed knock sensor no change in behavior. Car has a new distributor and just wont idle correctly with the EST plugged in. No error codes being thrown except for the one when i disconnect the EST. Im thinking next step is to change wires and plugs. Anybody have any other suggestions as to the cause?

 

Just a thought, but double check your ECM fuse in the fuse box. I know that if I don't disconnect the battery when plugging/unplugging my ESC connector (it's a four wire connector on my 84) to set my timing, I will blow the fuse to the ECM causing it to run in limp mode. Not sure if this will help or not, but something to look out for anyway.

 

Definitely clear codes after setting timing. Aside from that, I've seen guys have this problem caused by a worn out distributor.

 

The distributor is new so i dont think that is it.

 

Turns out to be inline ECM fuse by the battery i had probably knocked the connector when changing out my battery. Must remember to check small things first.