turboaudi
New Member
hi i have a 6.5 sub that has a problem with controlling timing when i start it in the morning it will run quiet & very smokey it has no timing advance when it warms up it will run perfect sometimes for 60-80 miles when you shut it down for a few hours then restart it sometimes it will advance the timing so far it will almost stall then it will run normal for 500 feet then timing will advance again it may do this 8-10 times then settle down &run good when it does it the desired timing is normal but actual timing will go as high as 19 deg it rattles very loud also when it does this i have put a inj pump ,ecm ,set tdc offset& checked ecm to pump wiring when i use time set it goes to 2.5- 3.0 deg like it should my other truck is also starting to do this although not as bad i have a mastertech scan tool that has dealer software i am a gm tech also i started my own shop a few years ago i do alot of 6.5 work but have never run into this any ideas ? thanks dave