Hi guys, just joined up as it looks like there's a wealth of information here.  Been having a real hair puller with my latest project.  I've built a TBI small block for a swap into my Jeep Wrangler.  The engine is presently on a test stand and I fired it for the first time a few days ago.  I've been having constant trouble getting it to run right.  Everything on the engine is either new or rebuilt with the exception of the ECM which came out of a running vehicle.  The wiring harness and prom were built for me especially for this application by Affordable TBI (whose tech help by the way leaves much to be desired).

I constantly get a code 43 (knock sensor) and I can't figure why.  Sensor is new, wiring is new, even when I disconnect the sensor altogether shouldn't it run fine till the engine warms up?  When I put the timing light on it is constantly ranging.  As much as 5 to 10 degrees at 2000 rpm.

This morning I thought to check the voltage at the sensor lead.  I got zero voltage....shouldn't there be 5 volts?  Could my ESC be faulty (also new) or the new knock sensor or could it be the ECM itself?

Thanks in advance for your help.  

The knock sensor puts out voltage and sends it to the pcm. The more it detects knock the more voltage it puts out. It can retard the timing up to 10deg. Any kind of vibration or poor ign. timing will activate it. I know headers have been a problem with setting them off.