I am getting up to 13.6 deg. of KR as shown by Datamaster. Would any of you be able to take a look at my datamaster file and possibly tell me what could be causing this? I wish I would have had the chance to scan the car before my LT's so I would know if that was the problem. I have the LT4 KM, but obviously it doesn't seem to be doing much.

 

It could be a number of things... I will list the most common problems here for you since I've recently battled with it.

It could be REAL knock. Even though you can't hear it, doesn't mean it's not there. So you need to eliminate that FIRST.

Try octane booster when low on gas to see if it gets rid of it.
Try a couple of gallons of 104 unleaded on 1/4 tank and see if that does the trick.
If you have LT1 Edit or tunercat, try pulling 5 or 10 degrees of timing (I assume this is happening at WOT), and check it again.
Watch your o2 readings, if they show lean watch your fuel pressure.
Try adding some fuel in PE mode to ensure that you're not leaning out.

If none of the above to the trick, see if you can swap LT4 knock modules with a buddy or something.

Then you should check to make sure:

1) plug wires aren't run too close to the knock sensor wire causing interference.
2) good connection on the sensor itself.
3) measure the sensor's resistance, it should be close to spec. (OBDII cars is 93k-107k ohms, but I know that OBDI cars are lower)
4) If you have headers, check the clearance between the headers and the frame/body. It might be bumping and causing it.
5) Verify you don't have an exhaust leak, this includes loose plugs.
6) Try a thicker oil (like 10w40 or something like that).
7) replace knock sensor (watch coolant mess) - make sure to torque properly.

That's about all that I can think of to check/try to cure it.

Most people with headers end up having to "turn it down" or "tune it out" to get rid of it.

13 degrees is WAY WAY high, and is what my car was doing when it had a bad sensor. I mention all the other stuff because it's not as messy as replacing the sensor is. Plus, most of that stuff is free/cheap and one good day's attention to check.

good luck!

 

Thanks you very much for the reply. Hopefully I can get this knock cleared up.

 

Be sure to keep us update on what happens. Your experience will go toward helping others.

 

Where is it that you all go to get 100 octane gas? Would it be alright to fill it up with 93 and then add some octane booster?

I normally run 87 octane, which may be part of the problem. I have put 93 in it before, but I didn't notice any change in the KR. Will I have to drive the car for a while with 93 in it before the KR would go down?

Thanks again for the help

 

87 for these cars is too low of an octane level. The manual recommends premium fuel (91, 93) because of the higher compression (10.4/1). Run your take pretty low then fill up with premium and drive for most of the tank and see if that clears it up.

 

You get 100 octane and up usually near racetracks. You can't pump it directly into your car in most cases, so you have to take an approved fuel container and pump it into it, then put it in the car. And sometimes you even have to do that off site.

Run the car down low on gas, put about 2 gallons of high octane (100-104) and then put 2 gallons of 93 in it. That should let you test. If you can't get the race gas, you can use xylene or toluene I believe, but I can't tell you how much to use or where to get that stuff.

If you're gonna use an octane booster, run the tank really low, put the octane booster in, and then add a few gallons of 93.