CPS adjustment with DRB scantool?
Posted: December 2nd, 2016, 3:18 pm
Hey guys, been meaning to do a write up for a while now, this site and the feedback has been a huge help and inspiration for a while now and with much research on here I have finally built my own 4.6 stroker and is currently running in my daily driver. I've only got about 3000 miles on it and from the first start its been running well.
However I have been consistently troubleshooting a misfire issue, it sometimes comes up for a specific cylinder misfire but usually with the random misfire code as well.
I am trying to get some more information about adjusting the cam position sensor with a DRB scanner. My understanding is that even setting the cam sensor on TDC, it can still be slightly off and that the DRB can zero it in or marry its setting with the computer and also the crank position sensor. I've talked to one jeep shop that had some experience with a few stroker installs and they said that they finally found that having it set at the dealer with the DRB got rid of the random cylinder misfire CELs
So I'm just trying to get a little feedback from anyone who was able to get to the bottom of this issue, I try to never go to the dealership unless its something absolutely out of my control. Ive found some sites that rent the DRB also. I know the next question will be the build of the stroker so with out going into too much detail ill just list the basics
2001 Cherokee
4.2 rods and crank
Sealed Power H802CP pistons
Block has been bored .030 over and decked .011
stock cam
0280155784 24lbs injectors
0331 tuby head and valve job done
I cant remember what part number the plugs were but I went with the next heat range cooler
I have tried swapping the coil rail with a known good rail (no difference)
also am running on 93 (tried 87 and it did not like it, probably from the larger quench)
Checked the fuel trims with a scanner LT trim is around +10%, ST trim usually around +2% (was much higher before going to the larger injectors)
However I have been consistently troubleshooting a misfire issue, it sometimes comes up for a specific cylinder misfire but usually with the random misfire code as well.
I am trying to get some more information about adjusting the cam position sensor with a DRB scanner. My understanding is that even setting the cam sensor on TDC, it can still be slightly off and that the DRB can zero it in or marry its setting with the computer and also the crank position sensor. I've talked to one jeep shop that had some experience with a few stroker installs and they said that they finally found that having it set at the dealer with the DRB got rid of the random cylinder misfire CELs
So I'm just trying to get a little feedback from anyone who was able to get to the bottom of this issue, I try to never go to the dealership unless its something absolutely out of my control. Ive found some sites that rent the DRB also. I know the next question will be the build of the stroker so with out going into too much detail ill just list the basics
2001 Cherokee
4.2 rods and crank
Sealed Power H802CP pistons
Block has been bored .030 over and decked .011
stock cam
0280155784 24lbs injectors
0331 tuby head and valve job done
I cant remember what part number the plugs were but I went with the next heat range cooler
I have tried swapping the coil rail with a known good rail (no difference)
also am running on 93 (tried 87 and it did not like it, probably from the larger quench)
Checked the fuel trims with a scanner LT trim is around +10%, ST trim usually around +2% (was much higher before going to the larger injectors)