Let me start off by saying I have a '94 Camaro Z28 and I've been having a bad hesitation problem. I hooked up the scanner to the car and drove it around with it on and found out in about a 15 minute trip I got over 100 knocks detected. I always run 93 octane and I never heard the car knock or ping. So I thought maybe the knock sensor was going bad so I bought an LT1 knock module, but this went in the computer, is there an actual knock sensor on the engine that could possibly be going bad? I also forgot to mention that the car has no trouble codes when I scan it. Also the knock retard cuts the timing up to 15 degrees at some points, does this also seem a little excessive? Does anyone know what the knock retard should be at under regular circumstances? Thank you in advance for any help.

 

KR should be 0, unless you are getting real knock.

You mention getting a 'LT1 knock module' I hope you meant the LT4 knock module, as the computer already had the LT1 knock module.

A quick search of this forum will show that you are not alone, and there are many things that it can be attributed to. So I suggest you do a search before just throwing parts at it.

 

Yes, your 94 has a "knock sensor". It is on the bottom of the block, passenger side, and had a single wire connector on it. It basically screwed into the block drain hole. The sensor is a little piezo microphone that picks up all the noise from the engine. When the signal from the microphone is sent to the PCM, it goes through the "knock module", which is a simple filter on a chip, and filters out the noise that is not associated with knock, so in theory, only the knock signal reaches the PCM's processor.

There is an LT4 knock module that is a better filter, particularly with regard to the noise from the full roller rockers that were used in the LT4 engines. The module will help filter out false knock signals.

If you are getting up to 15deg of knock retard, you have a problem. You won't hear it "knock or ping".... that's the purpose of the knock retard... it eliminates the knock by pulling timing, before you can hear it. Have you tried some 100-octane unleaded, to see if that eliminates the knock? If it does, you have "real" knock, and have to find the source. If the 100-octane doesn't cure the retard problem, you likely have "false" knock, and need to find what mechanical item is causing the noise.

 

I meant LT4 knock module. I'll give the 100 octane a test, but 2 questions about that, I have a new cat on the car, will that hurt it? Also can I just use octane boost added to 93 octane? Thanks.

 

Octane boost doesn't really do much. Use 100-octane UNLEADED fuel. Only leaded fuel will damage the catalytic convertor(s).

 

Okay thanks for your help. I also was reading something else, the computer retards timing when the engine gets hot, and ever since I put an electric water pump on the car, it runs hotter. The gauge is over half way up all the time. What is the normal temp these cars should be running at?

 

Engine with a stock thermostat should run ~195° cruising.