Yo,
OK.
As far as the old harness ground, I do not see a seperate ground to frame, body, or other point. Each injector's ground to operate it is done individually in the PCM through the tan & wHite wires at each Injector.
How do you know it is a ground; does it have an oval terminal?
Try this Fuel Injector Test (5.0L Engine, 5.8L Engine) @
http://troubleshootmyvehicle.com/ford/4.9L-5.0L-5.8L/how-to-test-the-fuel-injectors-1
by Abraham Torres
Then;
Inspect the wiring harness to the injectors and at the PCM.
The injector is normally closed. It is operated by 12V VPWR from the EEC-IV Power Relay and the ground signal is controlled by the Powertrain Control Module (PCM). This is the Red wire to each connector.
Wiring diagrams:
http://www.revbase.com/BBBMotor/Wd/DownloadPdf?id=11304
Follow path to injectors (RED) from Ignition switch THROUGH EEC POWER RELAY THROUGH splices to each injector. It is labeled circuit 361 on page 2
Note: Do not apply battery voltage directly to the injector electrical connector terminals. The solenoid may be damaged internally in a matter of seconds. Try grounding the Tan and White wires @ the injectors.
If spark was present in all of the cylinders:
ignition control module is OK
PIP is OK.
coil is OK.
Here is the EEC IV PIN Connector Diagram
http://web.archive.org/web/20120115055623im_/http://www.oldfuelinjection.com/images/eec04.gif
And the PIN LEGEND
http://web.archive.org/web/20120118104425/http://www.oldfuelinjection.com/truckpinouts.html
Both by Ryan M
All resistance tests should be done with the ignition key in the off position. Having voltage going through the system can return a false reading of excessive resistance. Additionally, it is possible to have a ground that tests OK when the engine is cold, but not when the engine is hot. Heat increases resistance, so these tests should be performed on a warm engine when possible.
To test for an adequate ground circuit in the EFI system, use a Volt/Ohm meter to check the resistance of the
following circuits. Disconnect PCM Connector:
• To verify a proper ground to the PCM, check the resistance from pins 20, 40 and pin 60 DIRECTLY to the negative side of the battery. Of course, battery ground cables, connector, and grounds must be clean and tight.Resistance should be no greater than 0.2 ohms.
•Replace faulty wiring between computer and battery if not.