Which part doesn't make sense?

The part where the LT4 KM can cause more excessive false knock counts than the LT1 KM? I've tested, have you? If you're really a big disbeliever I could even test again and send you the data for your own eyes. Maybe you'd like to hear from other people with the same experience? I have

I'm assuming you run an LT4 KM? Did it solve your false knock problem?

The second part of my post makes total sense. Don't waste your money or time installing an LT4 KM unless you have a false knock problem. If you do have a false knock problem, the LT4 KM is not guaranteed to fix it.

 

anyone know a cheaper place than Summit or GMParts Direct to buy one? The dealers Ive called want 65.00....and I need this in kind of a hurry. let me know

 

ok heres the thing ON PAPER what you say makes NO sense...

Replacing a Sensitive KM with a LESS sensitive KM (LT4) should not cause problems...I dont see how it could cause more knock...Unless you were previously getting REAL knock


like I said, I just dont see how it makes sense

 

I bought one for $25 shipped off the boards...do some searching

 

As always, Dal or Jason.

 

It's not about sensitivity but frequencies. The KM is only a filter. A knock system based on audio detection isn't the best method but it was cheap and easy to implement so GM used it. The knock sensor creates electrical frequencies that are sent to the KM. The KM's job is to filter all the "normal" noise but let any frequencies that are potential knock frequencies through to register as knock counts. The LT1 and LT4 knock modules let different frequencies through. If you've got an engine that makes the wrong frequencies, an LT4 KM may not filter them whereas the LT1 did, and vice versa. It's entirely possible you could even use a module that would work too well and filter knock frequencies as well. Each KM is taylored to a specific engine's sound characteristics, and once you change that all bets are off.

One thing to note, I am OBD1. The OBD1 and OBD2 applications each have their own knock module (and of course the LT4 KM is OBD2). There may be a problem with compatibility. I didn't care to research it (not sure if it's a simple RLC circuit or what) since testing showed the LT4 KM simply didn't work correctly for my car.

The knock sensors used were also different between OBD1 and OBD2 so I wouldn't be surprised at all if the LT4 KM used in an OBD1 application filters the completely wrong frequencies.

Unfortunately too many people throw parts on a car simply because so and so said it works. I wouldn't be surprised AT ALL if a lot of people threw LT4 KM's on their car "just because", didn't know if they even had a false knock problem to begin with, and are now running around with retarded timing and they aren't even aware of it.

That's why my advice is to check for a false knock problem first. Eliminate the possibilty of real knock. Check for mechanical problems. If all that fails test an LT4 KM (I don't recall if the b-body and y-body OBD1 and OBD2 KM's are all different P/N's but might as well try them too). If all else fails and you don't want to lose the offending parts, disable the knock system.

I hope now my statements are a little more clear

 

Can a dyno find out if you have false knock? Or what about a GM mechanic? Do they have ways of testing for knock? I imagine that they probably do.

 

Yes you could take it to a GM mechanic to have it scanned. It might be cheaper to buy a scanner though. I don't know any prices or which scanner to buy. I use my laptop with datamaster. Some way to scan your car is one of the best tools you can have.

Z

 

Nah, im sure the guy that does the work that i cant do (family friend) at the dealership by me can scan her for me for probably nothing. Gotta bring it to him soon anyway to get new gears... ditchin the 2.73's for some 3.42's or 3.73's (havent decided). Id like to know since i see so many people running this thing. and since i have 1.6 rr and a cam now, i wouldnt doubt it if i am getting false knock.

 

How do you distiguish between real nock and false knock? I understand how they are differnet, but now do you test for them? Is race gas the only way? My car pulls 10-12 degrees at WOT.. I have the mods in my signature.. can't see how that could be real knock..