when cold #2#7 injectors weak. have changed under valve cover harnesses.doing buzz test 2 and 7 sound weak. once warm cyl contribution test shows no problems. i checked connections to harnesses and at the idm. 129k miles on truck. is it possible i have some bad injectors. the parts guy told me he rarely sells these injectors thanks keith

 

Yes it is perfectly conceivable to have the o-rings go bad @130k. I would say it is a little premature but it is possible. Did the wire harness you replaced look bad? The reason parts houses rarely sell stock PSD injectors is you can buy hopped up aftermarket ones cheaper then stock. And new stock ones and about the same $$$ as rebuilt stock ones. How has your fuel filter looked? does it have a lot of black crumbs like stuff in it, this could be signs of o-rings going bad.

 

harness didnt have any rubbed spots on wires but the connectors seemed to have lost their tension.i will look for black specs in fuel filter bottom. the truck dosent start great and as it warms up the cyls seem to get stronger but dosent smoke at all. if the o rings were goin bad wouldnt it dilute the engine oil or does high pressure just bleed off into return. thanks keith

 

found some black material in filter housing gonna order a set of o rings

 

As far as oil dilution it depends on what o-ring has gone bad. Does the oil smell of diesel? You could also send a oil sample to a oil analysis lab.

 

You said these injectors sound weak, o-rings won't change that. The only o-rings you can service are external to the moving parts. The original UVC harnesses could lose retention and can be replaced with new design, or repaired using the add-on clips available at the dealer.

 

do you have the part numbers for the harnesses or the clips as i feel it is a connection issue

 

Some 1998-2003 Econoline, Super Duty, F650/7550 & Excursion With 7.3l (eng Ser #0661894) May Run Rough Or Miss During Hard Acceleration Due To A Poor Connection At The Junction Of The Injector/glow Plug Harness & The Valve Cover Gasket. If Any Cylinder Is Identified By A Cylinder Contribution Test Or Is Suspected Due To Injector Performance Analyzer, Remove Valve Cover Gasket & Inspect The Connection Between The Uvc Harness & The Valve Cover Gasket. The Locking Device For The Uvc May Become Relaxed & Allow The Connection To Fail. A Retainer 2c3z-14a163-ab Is Available To Install In The Locking Mechanism, Securing The Connection. If The Connection Is Not Secure, Install The Clip & Re-evaluate The Engine's Performance.

 

i replaced valve cover gaskets when i did the under cover harnesses. does this clip go on outboard side of valve cover harness. when doing cyl contribution test when engine is cold(not the way the test is supposed to be done acording to snap on} i get a couple cyls at fault this is when the engine will idle roughly also. once the engine is warmed up i get no faults and engine runs fine.

 

is this a possibility?