muderxtreme
05-13-2012, 05:36
hello everyone, ive been cruising the site for awhile but never posted anything so here goes. truck details are in my signature. ive posted this problem on another forum before and a thanks to great white for helping but i figure it wouldn't hurt to post this problem to a new crowd to see what advice i can get. A couple months back i replaced headgaskets and timing set, after reassembly the truck ran fine. i got a good deal on a db2 pump so i attempted to do a swap from my ds4 but later figured out that the db2 was bad so i put the ds4 back in. i didnt have a scanner at the time so i just put the ip back in the same position i had it before. It started right up and ran fine for a day or so till i came out from the store and started it. It was idleing fine in the parking lot till i put it in gear. the truck idled way down and started jerking and had no throttle response. i swapped pmds in the parking lot, checked that lift pump was working, and did a good once over on everything to make sure i hadnt forgotten to plug something up. i ended up getting it home 4 hours later by unplugging the optical sensor and limping it home at 25mph and having to restart it several times. i have since purchased the gmtd scan from engh motors and adjusted the timing and did a tdco learn. the only codes im getting are 91-98 cylinder balance faults.
the truck will start and idle fine then go into running rough. From viewing the data on my laptop, I've observed that whenever the truck is running good and accepting throttle the fuel rate is between 7 and 9mm2. the timing reads about 4* desired and 4*actual. Whenever the truck starts running rough and wont accept throttle the fuel rate between 20 and 25 and timing is about 7* desired and 7* actual with a tdco of -.75.
i started diagnosing by rechecking my work with the timing set, making sure all gears were lined up and no key ways were sheared. then moved on to checking sensors and wiring, ive checked the entire ip harness and the pmd extension harness as well. i also found the the optical sensor has a hole in the bottom of it and the plug that appears to have been covering the hole was rattling around inside the sensor. great white suggested unplugging the coolant temp sensor on the water crossover and the timing went to 16* and idled up to 1k rpm. it seemed to run a little better and accepted throttle. Ive read alot online and it seems that all of this may be symptoms of a warn rotor head in the pump but i want to make sure before i drop $600 on another pump. I figure if the rotor head was worn out then it would run like crap consistently instead of running fine for a couple minutes then going south.
I also noticed that the transmission turbine speed sensor output isnt consistent. it will read out about 800rpm at idle then drop to 50 for half a second then back to ~800.
thanks
i just remembered i posted a video about a week ago on youtube. i have done a relearn so the tdco is different but the symptoms are still the same.
http://www.youtube.com/watch?v=AEiw2k4yYNE
the truck will start and idle fine then go into running rough. From viewing the data on my laptop, I've observed that whenever the truck is running good and accepting throttle the fuel rate is between 7 and 9mm2. the timing reads about 4* desired and 4*actual. Whenever the truck starts running rough and wont accept throttle the fuel rate between 20 and 25 and timing is about 7* desired and 7* actual with a tdco of -.75.
i started diagnosing by rechecking my work with the timing set, making sure all gears were lined up and no key ways were sheared. then moved on to checking sensors and wiring, ive checked the entire ip harness and the pmd extension harness as well. i also found the the optical sensor has a hole in the bottom of it and the plug that appears to have been covering the hole was rattling around inside the sensor. great white suggested unplugging the coolant temp sensor on the water crossover and the timing went to 16* and idled up to 1k rpm. it seemed to run a little better and accepted throttle. Ive read alot online and it seems that all of this may be symptoms of a warn rotor head in the pump but i want to make sure before i drop $600 on another pump. I figure if the rotor head was worn out then it would run like crap consistently instead of running fine for a couple minutes then going south.
I also noticed that the transmission turbine speed sensor output isnt consistent. it will read out about 800rpm at idle then drop to 50 for half a second then back to ~800.
thanks
i just remembered i posted a video about a week ago on youtube. i have done a relearn so the tdco is different but the symptoms are still the same.
http://www.youtube.com/watch?v=AEiw2k4yYNE