12 valve crazy problem

kframdiesel

cummins fan
Joined
Oct 2, 2012
Messages
79
gotta 12 valve that the check engine came on once cecked the code with the key the crank sensor, checked it and the plug was loose, but since the light went out the truck is gettin bad mpg and loss a bit of my top end also cranks way more then it use to but runs fine and has power just not the same any ideas?
 
gotta 12 valve that the check engine came on once checked the code with the key the crank sensor, checked it and the plug was loose, but since the light went out the truck is getting bad mpg and loss a bit of my top end also cranks way more then it use to but runs fine and has power just not the same any ideas?

Do you have any mods do to your truck? Knowing what you have done to your truck would help with sorting out the problem. :doh:
 
bought it with a fuel plate thats all i know looked at the plate cause the cover was leakin oil there was a bolt loose and the plate wasnt in straight and the intake gasket was cracked
 
Make sure your fuel shutoff is working and not hanging up. Unhook it from the pump and drive it
 
Also check to make sure your not sucking air in the fuel lines anywhere, in particular on top of the fuel tank.

I know it sounds stupid but its stupid not to say it..... how's your fuel filter?
 
Check fuel pressure at the pump, and boost leaks.

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thanks guys

have fuel, changed the lift pump when i built the truck changed the filter again, clean fuel, no boost leaks i can find has plenty of power i can pull hills in od, however the top end is now 2500 to 2700 rpm after that it pops like its the governor topped out but was able to go 3000, do the governor springs fail?
 
Check your timing. Gov springs wont make a truck pop under load it just causes defuel
 
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