Short version, my 1997 OBS
7.3 truck has 202K miles on it. When I got the truck the stock Under Valve Cover Harness was a disaster. Melted, soaked in oil, broken wires, etc.
I replaced both sides with new Dorman valve cover gaskets and wiring pigtails in 2014
Only a few hundred miles later I learned about the upgrade from problematic OBS
UVCH (dual plugs, smaller pins) to the updated Superduty version.
The Superduty valve cover gaskets have larger pins for the GP power leads then the older OBS
New parts are FAR SUPERIOR to the Dorman pieces
Having a single hookup instead of two eliminates some wiring and connections.
Shopping around for OEM quality UVCH you will find it is not cheap to replace the wire pigtails (truck side), gaskets themselves and the under valve cover harness. Between $250-500!!!
I settled on Alliant wiring pigtails gaskets and wiring from Riff Raff.
They sent me
2ea Alliant pigtails part number Ap0016
2ea Navistar? Alliant Gaskets Ap0014 / F81Z6584AA
2ea Injector / Glow plug harness F81Z9D930AB
I researched the wiring portion of this swap and found the info I needed here on PSN courtesy of SBluke.
Pin 1,2,8,9 are glow plugs.
Pin 3,4,6,7 are injectors
Pin 5 common.
Pin 1,5 are glow plugs
Pin 2,4 are injectors
Pin 3 is common.
So let's make the sd
pin 1 the front pin.
Let's make the obs
front connector 1-5, front pin 1
Let's make the obs
back plug 6-10, front pin is 6.
So connect SD
pins 1,2,8,9 to obs
pin 3 to obs
pin 4 to obs
pin 5 to obs
pin 3 and 8
pin 6 to obs
pin 7 to obs
Hope this makes sense...
I took this a step further and created a simple chart (I'm a cad operator by trade so..... can't help it)
You can download the PDF file here:
Wire colors truck side may not be 100%. My 1997 harness is faded! and my eyes are getting older
Step one is to prepare your engine side & valve covers! CLEAN CLEAN CLEAN
Clean the new gaskets of any lint or grease, these gaskets are fit dry
Install the under cover harness into new gaskets, they click into place in several spots
Perform 50 cent mod here if you wish, I did not see the need, these gaskets fit tight
Next we cut out the Dorman / or stock pigtails ONE WIRE at a time
I started by stripping back factory pigtails to their junction at main engine harness.
You will see the 4 glow plug leads are joined upstream all in one union
Separate the GP leads from the remaining 3 wires per OBS
pigtail (6 wires total)
Save the factory bare wiring and foil tape, long enough to re - insulate your new pigtails
You can now match each wire up one at a time until all 10 wires from truck are hooked to all 9 leads at new SD
I chose to make all 9 solder joints at once, then heat shrink.
All leads were wrapped with factory bare wire / shielding wire and then foil.
Only the INJ and COMM leads need to be insulated.
Keep the GP power feeds separate (not shielded).
I then wrapped shielded injector bundle with a full 2 rows of electrical tape.
Next wrap GP power leads into same bundle
Finally whole pigtail gets plastic conduit to protect it, zip tie to keep everything tidy
Before, dorman pigtails from 2014 (don't try and save $$$ here, not worth it!)
Dorman removed, plastic melted, pins bent and loose in housing:
Wiring work / Finished product
I fired the truck up afterwards and shes running fantastic
I am very happy with the results, $$$ well spent