My experience with my own 95 OBD-1 car is that I worked my butt off trying to elimate the low RPM, part throttle knocking that many on this board are experiencing. There are many things that could cause this but nothing worked except when I removed the LT4KM and put in the original LT1KM with no other changes, datamaster showed immediately that 99% of the knocking was gone and the engine ran much better and accepted more timing.

I have 1.6RR's, edelbrock shorties, forged and floating pistons, 10.8 to 1, ported heads, 52MM, stock cam, MSD coil, taylor wires, K&N, TBbypass, A4, Random tech cat, edelbrock cat back.

Simply put, the LT4KM was the root of my knocking problem (for whatever reason) and to assume that it is always working properly, avoiding a $35 simple test, or even free if you still have the original LT1KM to me is irresponsible as a tuner. Different things have worked for different people. I would start with the cheap and easy stuff, eliminate them as a cause, and progress to the more expensive/difficult items. The knock module replacement is simple and cheap.

It may work for you, but it did not work for me for some unknown reason. Just sharing my experience to those who are testing.

To say LT4KM always works better is a stretch...

 

Anyone, feel free to call me an idiot, but from what I have gathered in this post...

Knock detection (no matter how severe) will not throw a code 43. the only thing that will throw a code 43 is a bad sensor or circuit.

Knock detection will simply retard the timing. But, is there a certain level that the timing is retarded? Does it depend on how much knock is detected?

If the timing is retarded by the knock system, would it cause the engine to run rich?

 

Yes, DTC 43 is for an electrical problem in the knock sensor circuit, NOT for excessive knock.

The PCM retards the spark in proportion to the amount of knock detected. It starts to quickly pull timing (attack) at a programmed rate, and doesn't stop until there is no more knock. It then starts to reduce knock retard (decay) at a slow rate, and will return to timing table value if no knock returns. There is a limit programmed in the PCM for the maximum amount of knock retard that can be used. You can alter the attack and decay rates, and the maximum allowable knock retard via programming.

I can't think of any reason the engine would run rich because of knock retard.

 

It's just driving me crazy because the only code I'm getting is 43.

But it seems like there is another problem because sometimes all of a sudden the engine just starts bogging down, and if I hit the gas, it clears right up. When I'm at WOT, I don't notice it ever doing this. But when it does this, this is when the service engine light comes on.

I have already checked all the plug wires and they are all firing. I also just changed the plugs. I also checked the fuel pressure and it is right on.

What does it sound like is the problem here?

 

When you get your pcm tuned, does it matter which knock module you have in the pcm at the time of tune?

 

What knock module is in the PCM should not affect the programmer.

Since you feel the problem of rough running and the SES light are connected, why not just correct the knock sensor problem and see what happens.

 

Is it even feasable for the ses light caused by the knock sensor to cause a rough running problem?

 

The engine won't feel as "smooth" with DTC 43. The PCM is constantly pulling timing, so its going to feel "flat" and not make the power its capable of. I wouldn't describe that as "rough running".... but it could feel like a surge or a flat spot as the PCM is constantly adjusting the knock retard based on things like throttle position and MAP.

Fix the KS problem, then focus on the rough running. One thing at time.

 

That makes sense. I'll definitly go ahead address the knock sensor issue first. I was skepitcal about doing it before I got my new tune from ion, but now since all the other codes I was getting are gone, I guess it wouldn't be that big of a deal to address the issue at hand. It was just kind of overwhelming for a while with all the other issues I had.

 

One last time....

In no way, shape, or form can extremely excessive knock cause a code 43?

Since I have decided to just replace the knock sensor and circuit, where should I got to get it?