Medium and Heavy Trucks
Have Truck Repair Questions? Ask an Expert
Hi my name is***** will be glad to try to help. Try running a separate line from the tank fill to the pump to see if it will run from there or run the return and supply from a bucket of fuel to check if the problem resolves indicating a suction side problem. Also check the fuel shutoff for power and proper operation from the ECM. Inspect the lines from the tank to pump for restrictions and leaks. Let me know
Check your fuel tank vent and your cap. The vent is likely restricted causing a vacuum in the tank. Also check your return line for restrictions and excessive return pressure indicating an injector problem. You can install a clear hose to monitor this. Let me know
Check the return for excessive pressure and for a plugged tank vent. I would also verify the overhead adjustments are correct as well and did not damage the new injectors.
Use a clear hose into a bucket to see if there is excessive return pressure, bubbles, etc in the return. Usually if the return is restricted it will cause an overspeed on the PT fuels systems.
Hi, Did you get this resolved?
Hi My name is***** will be glad to try to help. Check your fuel tank vent for being plugged creating a vacuum and also for any return line problems or excessive pressure from a possible mechanically failed injector. What year and model chassis is this?
Check the exhaust ports for wetness from unburned fuel and also take temps with a digital temp reader for a cold cylinder indicating a bad injector or injectors. LEt me know
Thanks for the info. It sounds like you have a mechanically failed injector. Try to cut out each cylinder one at a time. The one with little to no change is the problem cylinder or cylinders. LEt me know
With the engine running and a pinch bar or pry bar Hold/pry the injector rocker arm down to cut out that cylinder.
Yes it is possible... Zero lash is the clearance between the rocker arm and the injector push rod. The injector push rod moves down into the injector to inject your fuel. You need to hold it there by wedging the pinch bar across the top of the rocker arm and holding it down with some leverage. I have done it many times over the years on these and the older 855 series. If you do not want to do this your only other option is to pull all injectors and send them out for testing at a fuels shop.