buzz test results...looking for input

[DieselSVT]

I borrowed someones snap on scanner to try and figure out an intermittent miss/hesitation/breaking up at 1400-1600 RPM when warmed up. It almost sounds like a lazy injector. It will seem to make the noise or break up when letting off the foot pedal at that same RPM range.

I performed a Cylinder Contribution Test a few times now over the course of a few weeks and I still come up with a pass result. I performed a buzz test today and got the P1298 code so I searched and found that the code comes up alot when performing the buzz test and I wasn't the only one.

I waited an hour or so and went out and turned the key on and did the buzz test again. This time NO BUZZ just the tach moving 8 times and the P1298 came up again. I started the truck real quick and shut if off I performed the test a few more times and it buzzed and spit out the IDM fault again.

I then performed the KOEO test and got the P1298 IDM fault again. I think I'm going to swap out the passenger UVCHarness (I have one on hand) as I did the drivers side a few months back when I was fooled by grey CPS to change #8 injector.

So far I've swapped foot pedals, swapped over to the black CPS. Cleaned the strainers in the tank and put a solid fuel line to the pump, changed #8 injector and drivers harness, added a 5.6K resistor to the ICP. Each step has made the truck run better overall. Any input is appreciated I think I'll change the passenger UVCH and then try to find someone with an IDM to swap.

What do you think? Thanks in advance.

[SButler83]

I have had similar issues with the P1298 on an injector buzz test. It only will show up on a buzz test. The truck seems to run OK, however gets only 16 MPG on 33" tires, My other truck not exhibiting the condition gets 20 MPG. At the time I found the code, I found that my driver's side wiring harness had a short on the #4 glow plug so I changed that UVC setup on that side, put it back together and the glow plug issue was gone but not the P1298. Did you ever swap out the other side harness and have any luck. I have been researching as well and found that on some IDM's ford had issues with them, specifically with production codes OEO5 and OEO26.

Keep me posted and I will do the same for you. My truck doing this is a 2003 (10/2002) F350 7.3L Crew cab Auto 4x4.

Differences in my scenario are that I don't think I've been getting the hesitation, and I have never not had my injectors buzz for the test. I believe on that truck I have had the #8 injector come back low on the power balance test.

[97Fordrunner]

Did the Under Valve Cover Harness do the trick? Also check your wiring harness on top of the motor as they are prone to loosing the wiring insulation after awhile(not sure why just have seen a few) Also where the harness plugs into the valve cover is a problem area, look for melted wires or plug. If it ends up being the IDM check with Auto Computer Exchange out of Florida, I got one from them a month ago and am very happy, was $$$ less than the $750 from Ford