The truck: stock 04 Colorado z71 2wd
Stock motor: l52 3.5l 5 cyl 143 k miles
The replacement: stock 08 llr 3.7 5cyl 13k miles (per seller)
Using 04 pcm flashed 07 stock tune with custom tune to adjust for maf scaling.
The rundown: using 04 pcm and harness, all 04 sensors, 04 fuel rail, 08 injectors, 08 injector harness, 04 ported throttle body, 07 exhaust reluctor/actuator.
What we know: stock 07 will drop in to an 04 and run on the 04 tune and sensors.
04 and 07 exhaust reluctor are 5x. 08 is 4x. 08 lacks an intake cam sensor. One was we added one to the head in the proper location.
mechanically this motor resembles an 07 perfectly.
Compression is over 155psi, all timing marks line up correctly at tdc, coils check good, all sensors have proper resistance, only obd2code is p0300 random misfire (also pending)
The symptoms: truck will fire and run but will misfire constantly. Rpm will hover around 600+ which is normal idle rpm. Metallic sound coming from valve cover thought to be the timing chain. Tensioner is set and functioning, exhaust reluctor positioned correctly.
Mechanically and electronically this motor should be perfect.
What else can I check or is there something I have missed?
Sunday, May 6th, 2012 AT 10:51 PM