My 7.3 excursion (75,000 miles on odometer)has been recently Miss-firing.? Or stuttering. It's an occasional but steady problem. It might happen on acceleration or steady driving. For example going down a straight away between 45-50 mph and about 1500 rpm it all of a sudden starts misfiring. I give it gas and problem goes away. I took it to the Ford dealer who states that the computer does not show any problems and that I am OK. He changes fuel filter ($90) and computer testing ($80)and sends me on my way. I drive about 1500 miles, cross few state boundaries, (Midwest), different gas stations ... problem continues. I go back to the dealer... a mechanic drives my X and witnesses the problem. Again finds no mechanical problem, but claims that the cetane reading on the fuel that I have in tank is below acceptable standards. I can not beleive it (Does this mean that during the 1500 miles that I traveled all stations sold me low cetane rated diesel?) Service manager agrees to test fuel in my tank 4 times for free. He also suggests that I will from now on have to add cetane booster to my tank. (after he tests it) So that's where I am now.
Does anyone have similar problem. I can not swallow the story of bad diesel. Thanks
PS
Does any one know what agency (state or federal)controls the accuracy of instruments used to test the fuel?
There are a few things I would to. First I would take apart the fuel pressure regulator and clean it out. Look HERE to find out how. Then I would buy some Standadyn and treat the fuel with that. that will clean the system and raise the cetane of the fuel. Bad fuel can cause those symptoms, but to have them for 1500 miles from different stations is odd. Try that and see.
1996 PSD F-350 crew cab 4x4, AB CODE CALIFORNIA TRUCK, 5 speed,CON-O SMFW modified by Southbend Clutch, ORU Reverse Shackle kit, 4:10, u.s. gear chip, IDM MOD BY ME , down pipe, 4 inch straight pipe, boost and EGT gauges,PRO COMP A/T's 305-70's, Bilstein's, ditched the k&n filter for an open element Baldwin PA 2818, kenwood & polk audio sound system.
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2002 Excursion PSD 4x4 XLT Premium- TN BB 1.0 Turbo , 6.0 IC, 8 inch Sky Jacker lift, FOX shocks with remotes, 35-12.50R17 BFG Muds mounted on 17x10 Boyd Coddington Billet wheels, ORU Frozen rotors, custom hybrid intake, DVD/2 monitors, Billet grill, XM radio, DP Tuner PCM QLJ5/PMT1 combo, Edge Juice/Attitude for gauges.
I'd have my oil changed and see how it affects the problem.
Its my understanding the oil helps deliver the fuel through the injectors. A little air/foam in the oil can affect the fuel delivery and perhaps could be intermittant.
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My Daily Working Truck - 200,000 miles, 2001 X Wedgewood Blue, 4x2, Rancho 9000s, K & N Air Filter, Helwig anti-sway bars front and back, Weathertech catch-all rear mat, window vent shades, Molded mud flaps, Pioneer XM Radio, Escort 8500 Passport Radar Detector, Pioneer in-dash CD/FM/AM changer, SCMT (It Rocks!), Michelin LTX M/S 285/75 16 RD, Badged, Super Bright Back-up lights, Sylvania Silver Star Headlights, Thule roof rack system with Evolution Carrier Box, Extended Arm Rests
It sounds like the wiring harness under the valve cover is working its way loose. The wiring for each head (wiring to injectors and glow plugs) goes though a quick disconnect plug that is mounted under the valve cover, these connector do have a history of working their way loose and when this happens it periodically kills that side of the engine. It will get worse until the plug completely works its way loose and that side just dies. You can get a clip that mounts under the locking clip on the connector to keep them from working their way loose. Do a search for UVC under the 7.3 forum; be sure to click on the archived forum (second choice towards the bottom of the list).
good luck,
mark
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Under Valve Cover Harness Comes Disconnected, 98.5 and newer:
Egine serial numbers 0661894 and higher (98.5> E-van, 99> F-SuperDuty, 00> Excursion and F650/750) may have intermittent rough running, misfire or glow plug monitor concerns and/or trouble codes. This could be due to a loose connection between the UVC harness and valve cover gasket, resulting from a relaxed or distorted UVC harness connector lock. The connection between the UVC harness and gasket should be inspected, and if is found to be loose with no other damage (burnt terminals, melted connector shell), install locking clip P/N 2C3Z-14A163-AB. Retest to ensure that all symptoms have been resolved. Broadcast Message 3777
and
OASIS Broadcast Message #3777
1998-2003 VEHICLES EQUIPPED WITH A 7.3L ENGINE (AFTER SERIAL #0661894) - UNDER VALVE COVER (UVC) HARNESS RETAINER CLIP RELEASED FOR SERVICE
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. DO NOT REPLACE THE INJECTOR(S) IF THE CLIP REPAIRS THE CONDITION.
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