This is an FYI.I just discovered that the 7.3 Powerstrokes have a known problem with the under valve cover wiring harness (UVHC). The connector for the injectors/glow plugs can come loose. This can result in the entire bank going out or just glow plug or injector. In my case, I had a glow plug code and then a few days later an injector went out. The newer harnesses are supposed to fix the problem. There's also a fix for the existing harnesses, but I think a replacement is a better option. Part of my harness broke as I was debugging the problem. It's possible it was my error in handling it, but I think it had turned very brittle and broke with very little force.Now I have the wiring harness for both sides on order.I would hate to have this happen when in the road for vacation or something. I'm no expert on this issue. It can be researched further on ford-trucks.com in the 7.3 Diesel section as well as other truck forums etc. I suspect that if you have a good shop you deal with they are well aware too....

Save yourself some money.Quarter mod

They do get brittle. Replaced on our old 7.3 also. Don't feel too bad.

camperfamily wrote:They do get brittle. Replaced on our old 7.3 also. Don't feel too bad.If that's the case I wouldn't do the quarter mod or the shims from Ford. It would be easy to crack the connector and never notice until it was tool late. If the connecter cracks, the quarter or shim won't help.

I have to say that the valve train in the video was super clean like everything was brand new for a 7 year old truck!! If you have both sides opened up like he said in the video, I am not sticking ground up quarters in my engine. I am replacing the harness.

justaboutretired wrote:....I am not sticking ground up quarters in my engine. I am replacing the harness.I agree, if that quarter ever becomes dislodged for whatever reason and gets into the valvetrain, the $0.25 fix won't be so cheap anymore....

Ford 7.3 Powerstroke Under Valve Cover Wiring Harness

13 Replies

nremtp143
Explorer
Jan 11, 2015
I've got a 7.3 that I've had since new in '01 and the harness separated at 195k miles. Started a little misfire,, but a cheap fix with the Ford products. I still love the 7.3 at 211k miles.
bucky
Explorer II
Jan 06, 2015
My 7.3 PSD was the best truck I ever had. Kept it 2 years. Should have kept it but made a profit so hey?
W4RLR
Explorer
Jan 06, 2015
Captain_Happy wrote:
And another great idea from the engineers at Ford. That's why I won't be buying one period.
The 7.3 PowerStroke engine was produced by International Truck and Engine (Navistar) Ditto with the 6.0 and 6.4 liter PowerStrokes. The 6.7 Scorpion diesel is built by Ford in Mexico. The PowerStrokes were built in Indianapolis, Indiana and Huntsville, Alabama.

The harnesses get brittle. When I had injector work done on my old 6.0 the mechanic insisted on replacing the harness on both banks. Cheap enough.
Lon-Str
Explorer
Jan 06, 2015
Had the "wedge" deal done to my 2000 7.3 in Smithers BC in 2010. Have been several thousand miles since with no problems, but am considering the replacement soon just for insurance. Broke down just south of Iskit on the Cassiar and would have been happy with a sweetgum peg at the time.
copeland343
Explorer
Jan 05, 2015
Engineers at Ford did not design or manufacture the engine. It is manufactured and designed by International. Also the shim or quarter fix is the approved repair.
LarryJM
Explorer II
Jan 05, 2015
Captain_Happy wrote:
And another great idea from the engineers at Ford. That's why I won't be buying one period.

And another totally clueless comment since FORD had absolutely nothing to do with this UVC design or manufacture.

Larry
hone_eagle
Explorer
Jan 05, 2015
Posted years ago, if the batteries are allowed to get too old ,the resulting very high amperage will heat up everything in the electrical system -all the wires ,glow plug harness ,starter and starter wires etc etc

replace batteries at 5 years , trying for 'just one more winter' is asking for big $$$$$ repairs.
Captain_Happy
Explorer
Jan 05, 2015
And another great idea from the engineers at Ford. That's why I won't be buying one period.
BurbMan
Explorer II
Jan 05, 2015
justaboutretired wrote:
....I am not sticking ground up quarters in my engine. I am replacing the harness.

I agree, if that quarter ever becomes dislodged for whatever reason and gets into the valvetrain, the $0.25 fix won't be so cheap anymore....
justaboutretire
Explorer
Jan 05, 2015
I have to say that the valve train in the video was super clean like everything was brand new for a 7 year old truck!! If you have both sides opened up like he said in the video, I am not sticking ground up quarters in my engine. I am replacing the harness.