AZ-LBZ
10-18-2010, 11:38 PM
So I bought a 2007 classic with LBZ in Texas drive it home to Tucson drive up to lake Powell with empty trailer, pick up Bobcat and back hoe brings trailer wait to about 10k get right out side of flagstaff when my check engine light comes on and my truck begins to shoot a bunch of black smoke. Limp it all the way home buy clearing the code and take to dealer. Guys tells me that my number 3 and 7 injectors are leaking or i have a bad pump or both.
SO i have been reading around these boards about LBZ and it seems that there are several people that have had the P0087 code come on. The tech at the dealer hooked up there scanner and sad that when the LBZ is under 1k or 1200 RPM (i don't remember) that the computer is able to since how much power each cylinder is making based off of the crankshaft senser and compensates for full based off of this. Once you go over that rpm the computer shut that off and you get a fuel mixture based of you ecm tables. Well my truck was compensating for number 3 and 7 cylinders, leaning out the mixture when compared to the other six cylinders and as soon as you would go over 1k rpm the ecm would stop compensating and the engine would run ruff and lots of black smoke. The P0087 code only comes on when i am towing or the truck is real HOT. He managed to get the truck hot enough buy driving around town and them power braking the truck to put the engine under load then when the engine was hot enough and he reved it up to about 1k rpm shutting off the ecm compensation and dumping lots of fuel into 3 and 7 cylinders when the ecm would command 180k kpa(26000psi) and only get 140k kpa(20300psi) and WALA P0087! I find it pretty impressive that with two leaking injectors that it can still pull 140k kpa.
Pretty interesting and i thought i would share that with all of those who have had this problem. Have yet to replace the injectors because the dealer wanted $1600 to replace two injectors and $5K to replace all 8. I think i would attempt this endeavor on my own, i am pretty confident about this mans trouble shooting. i can replace all 8 injectors and the cp3 pump on my own and still not spend $5k.
SO i have been reading around these boards about LBZ and it seems that there are several people that have had the P0087 code come on. The tech at the dealer hooked up there scanner and sad that when the LBZ is under 1k or 1200 RPM (i don't remember) that the computer is able to since how much power each cylinder is making based off of the crankshaft senser and compensates for full based off of this. Once you go over that rpm the computer shut that off and you get a fuel mixture based of you ecm tables. Well my truck was compensating for number 3 and 7 cylinders, leaning out the mixture when compared to the other six cylinders and as soon as you would go over 1k rpm the ecm would stop compensating and the engine would run ruff and lots of black smoke. The P0087 code only comes on when i am towing or the truck is real HOT. He managed to get the truck hot enough buy driving around town and them power braking the truck to put the engine under load then when the engine was hot enough and he reved it up to about 1k rpm shutting off the ecm compensation and dumping lots of fuel into 3 and 7 cylinders when the ecm would command 180k kpa(26000psi) and only get 140k kpa(20300psi) and WALA P0087! I find it pretty impressive that with two leaking injectors that it can still pull 140k kpa.
Pretty interesting and i thought i would share that with all of those who have had this problem. Have yet to replace the injectors because the dealer wanted $1600 to replace two injectors and $5K to replace all 8. I think i would attempt this endeavor on my own, i am pretty confident about this mans trouble shooting. i can replace all 8 injectors and the cp3 pump on my own and still not spend $5k.