I cant figure out whats causing my knock retard. I'm 99% it's false. I just put in new header gaskets (no exhaust leaks), and it has a new knock sensor, and I have an LT4 KM. Sometimes I'll be cruising on the highway in 6th gear, and all the sudden I'll be getting 12+ degrees of KR according to my scanmaster. And when I start getting KR, if I floor it in any gear, it starts slowly going down. But its getting to the point where I'm always getting knock retard. Coulda bad knock module or bad PCM cause this? And I'm not getting any SES lights. And yesterday on the way to dennys, it started missing for a few seconds at low rpms. And it runs 1000x better when it doesn't get any knock retard, it starts running like **** when i start getting retard, it's alot less responsive, ect... And my MAP, MAF, and IAT read normal when all this happens... My long term BLM's are at the low 140's, and sometimes maxed out at 160 at idle if that helps.

 

This is just an idea, but one that may be overlooked. Did you torque your knock sensor or just bolt it in? If it is too tight you may get false knock.

Take care,
Colin

 

Are you getting any codes on the ScanMaster?

 

Like Injuneer said, If you dont have any codes then I say turn the thing off.

 

I have an obd2, so I don't get any codes. My check engine light isn't on though.

 

I tightened the hell out of it, I couldn't find the torque spec.

 

What does having an OBD-II PCM have to do with getting codes? There are quite a few "codes" in OBD-II. Not all codes turn on the SES light. If you can put a scanner on it and read the knock retard, that same scanner should be able to pull the trouble codes.

 

The exhaust noise inside the headers will turn it on. The LT4 KM has NEVER worked for me at any time. Rockers,header noise, and any other noise it isn't tuned for will trigger it.
Put your KR on a switch with one side on the resistor and ya can turn it off and turn it back on if ya want or just do the resistor mod if ya are sure it's false knock.

 

Scanmasters only pull codes off OBD1 cars.

 

I really don't want to have to disable the knock sensor if I don't have to. Are there any other options?

 

There are two disable it or let it pull timing.

 

Does anyone know what the torque spec is? I found a thread that said 14ft lbs, but I want to confirm this. I know I torqued the hell out of it with a 1/2 drive wrence, so its probably at 75+ ft lbs...

 

I made a little vid of a WOT run showing my scanmaster with my camera phone so its bad quality, but you can read the scanmaster. I tried loosening the KS and tightening it to 14ft lbs and that didn't do anything. I reset the computer too, and didn't get any knock retard for the first 5 minutes of driving it, then it started again so that didnt help. It ran the best it's ever run right after i reset the computer tough. The 02's go real lean on this run, Any ideas whats causing it? And this is when it's not getting alot of KR, it can be up to 15 degrees like i said...
http://s15.yousendit.com/d.aspx?id=3...W3J5SVM2FNVJ73

 

I have same problem on my 96z28.Have lt1 scanmaster also.I haven't changed out knock sensor yet was going to do that.I also am planning quite a bit of mods in next year or two ,installation of my CC306,1.6 pro mags,want to get some longtubes and LE2 heads.I think read a couple guys had some luck with new lifters,planning on installed some of those when do the heads.
Another solution should be to get tunercat lt1 or similar programming would think you can tune knock down or right out with that.I had to use a similar technique in my 92 talon turbo.It would get knock off idle terrible for no apparent reason and changed out knock sensor ,fuel system ,etc.etc with no luck finally got false knock programmed out in a chip.
I will likely go with some programming solution in my car.I also have lt4 KM.Heard of a few duds of those might be good to try another or the stock km.
I do also seem to have some lifter or valve train noise so maybe that is doing it in mine and if so then like I said should be able to get rid of it with new lifters,rockers,pushrods ,etc.
I do wonder if the lt1 scanmaster has a bug or something in it.I should hook up my autotap and log the car and compare the knock readings but car runs ok without the knock of course and gets doggy when it starts showing up.Can get counts pretty high and tuning with my maf translator don't seem to help that much either.I haven't tried a trick of running like race gas or you can use 30% or so xylene or toluene to see if its octane related maybe due to excessive carbon or something like that.
Just some ideas for you.Turning it off might be ok option for track and possibly daily use.If you run premium not very likely engine will get hurt by knock on a non forced induction car.Wouldn't be doing it with a turbo or supercharger though.

 

I agree with 1racerdude, the LT4 knock module is worthless--never helped me after my head/cam/header swap. I spent at least a month logging the car with datamaster, showed zero codes and saw 12 degrees during all different driving conditions. Best advise would be 1) If you haven't all ready, get under the car and see if your exhaust is hitting anywhere (ie K-member or over the axle). 2) Find out where you can get some race fuel (think 108 or 110). Run the car down close to empty and put 5 gallons in. If your scanner still picks up KR than you can be assured it's false. 3) Program the sensor out--that's what I ended up doing.....