Bozzy90210

Hi:
I recently had a Spec 3 clutch and aluminum flywheel installed. I have been having intermitent code 43(knock sensor) being tripped. The clutch is noisey as a function of design Im wondering of that could trigger the knock sensor? The check engine light seems to come on more when its cold and was triggered on a speed bump if thats relevant. The problem didnt appear before the clutch was changed.
Thanks Brian.

Aaron71771

You can tap on the exhaust manifold and fool the knock sensor, so it's possible to set it off with a lud cluth. Check to see if you have anything resting on the exhaust system from the resonator forward to see of there is anything that might be bumping on it.

comp

when are you getting it

R23HTC

Yes it can. I was getting some (very little) retard with the stock LT-1 knock module. I put in the LT-4 knock module and that fixed the problem.

Bozzy90210

The clutch noise is ever present. Tends to be more when its cold. At times it shuts right off(service engine light) at times it will stay on for 5-10 minutes. I cleared the code and it triggered in a few minutes.
I just pulled the knock sensor and noticed that the clip that hold the wire has a fresh break and the wire was hanging. From other posts this can be the issue as it can give a false signal when coming against exhaust manifold etc.
I did fill it up from a know good source of 94 gas and that didnt seem to matter. Apperently a sign that there is a problem with the sensor or wiring. I once went over a speed bump and it triggered the knock sensor.
Is it advisable to replace the LT1 with the LT4 sensor? I have a couple on the bench but dont want to install them if the LT4s are a better bet. Is there a downside to using the LT4s?

R23HTC

Okay, I'm no expert, but this is what I know.

The sensors (the part on the motor) are NOT interchangable. The knock module (the part in the computer) IS. The LT4's had the different module because of the LT4s stock roller rockers. GM found that they could cause a false knock so they modified the module so it would still sense true knock, but it wasn't as sensitive as the LT1's. I had it installed when I had all my work done on the motor. We determined that while my roller rockers didn't seem to cause false knock, the clutch was noticably causing false knock when it was out and the car was in neutral. Push it in and it would stop. I was getting a little in gear at lower RPMs and the LT4 module stopped it.

If you need more specific info you might see if you can get a hold of Chris@SpeedDemon, he did my motor. There's a link in my sig.

Bozzy90210

Thanks for the quick response. I went to do this a few days ago but with the site down im really reluctant to proceed with out the support on here.
Anyway. I've got LT1 sensors and Im half way there so Ill put them in and tied the wires down and see what happens. If thats not successful Ill try the LT4 ESC.
Thanks again

Bozzy90210

I replaced one of the knock sensors as i blew(?) the other one. Put the trouble light near it to see that it was going in square, the hook made contact between the sensor and the oil pan and bam big spark. Nice little arc mark on the sensor. Im assuming its fried as have no way to check it. Then i disconeected the battry. DOH!
Fixed the loose wire have a new sensor and took it for a brief spin and no codes.
One thing that hung me up was thinking that the sensor sat right down in the hole but it stands proud. So if someone is reading this dont think you gotta wind it down that hard.

R23HTC

Yeah, I've heard you don't want to over torque them. That'll cause them to go bad prematurely.