Poppet valve

gnxtc2 · Jan 2, 2016

What's the best way to diagnosis a bad/stuck poppet valve? Should I pull the valve covers and watch the oil coming out of the spouts?

When I first start the truck, the idle is smooth as glass. Once up to operating temp, the idle gets all choppy. If I get on the truck (highway entrance ramp), the IPR gets up to 65%, ICP +3000 psi at which time it trips the CEL, code 1211. I believe I have a high pressure oil leak.

Already swapped HPOP and IPR, same issue. Injector o-rings were already replaced. Ran CCT and buzz test with AE, all pass.

No issues starting hot or cold.

Billy T.
[email protected]

elrodalexander73 · Jan 2, 2016

I would remove them and have Tim or a reputable builder test them on a flow bench for poppet valve leaks.. You'd need to be able to cut out test and try to run the engine up into the rpms to while stopping oil flow to that injector to see if you have a possible leak, but it's not a dead accurate way of saying "that's it" when you could have several causing this problem. When they test the injector they can monitor how much oil it uses to produce CC's per time in the beaker, vs you trying to monitor a scan tool on two basic numbers, ICP and IPR cycle duty..

NC714 · Jan 2, 2016

I had a stuck poppet valve on one of my injectors. It would start cold, then once up to temp ran really rough. Would not start at all hot. I think you are on the right track by pulling the valve covers and inspecting the injectors while running to diagnose poppet valve issues. Mine was stuck OPEN and very obvious, oil pouring out the oil deflection spout constantly. Also while your under there check the oil rail drain plugs for leaks, too.