Hello, Ive searched the threads but haven't found my issue or remedy.
1998 F-550, 6.8 v10, automatic.
What I know: truck will run when primed. I used a gravity feed through vacuum line to move truck.
Number 10 injector energized at all time and will hydro-lock if ignition cycled too many times. injectors 1-9 have no pulse using noid light. Fuel pump prime when key activated is about 1/2 second, not the usual 2-3.
no codes stored. harness looks good. Truck was running good with no problems before sudden failure.
Question: can I plug and play ecm from v-10 97-98 van, excursion, f-series? will a 99+ ecm work in any way? anything else that could cause this symptom? what numbers are relevant to ecm swap?

thank you

 

Nash, Let me say I know absolutely nothing about your engine. I can tell you a few things though based upon the V8's and injectors in general. First, the injectors are always powered. They operate by being shorted to ground and that's when they spray the fuel. On the V8's, injectors 1 - 6 are all spliced at the same place going to the battery junction box. Injector 7 and 8 are spliced to the same wire but at a different place. This is shown in the wiring manual by being identified by a different splice number. The circuit for 7 and 8 also involves the MAF to read the amount of air going to the engine to be mixed with fuel. If you have power to 9 but not 10 along with 1 - 8 my first thought would be you have a short somewhere otherwise you wouldn't have power to 9 if it was something else. BUT, you may want to have the injectors checked also. Injectors short to ground but a short to power will ruin them. I hope this helps with a place to start. A power probe is a good tool for this because you can run an injector with one and also read the pulse width. You might look into a wiring manual for your truck also.

You also seem to have a fuel issue. Check your fuel pressure. No way should you have to run with a gravity feed for the fuel. Seems you may have multiple issues which wouldn't be uncommon with a 22 year old truck. A work truck at that.

EDIT: Can't say for your engine but with the V8's, 97 and 98 are different from the 99's through 03. I doubt you can swap them. At least easily.

 

Thanks River. To clarify, Im receiving supply voltage to all 10 injectors but the number 10 remains active and grounded during "key on" and "cranking" All injectors were removed and individually ohm checked, and bench tested for operation and spray pattern.
fuel pump and pressure itself is operational when powered directly.
Im suspecting the ecm as the culprit here. Im working on obtaining a wiring schematic.

 

Nash, sorry I got that wrong. Look at your crankshaft position sensor also. It controls the injectors.