Check fuel pressure <——————
Read Below about The two different fuel rails
You can turn the engine over and watch the flag turn in the cam synchronizer… this confirms the camshaft is turning (timing chain)
Valve seat issues can lead to low compression but that is not likely the cause here since it was running one day and not the next
There are 4 02 sensors on a 5.0
And you can plug 3’of them in wrong.. I would triple check that they are plugged in correctly, green is upstream sensor blue is downstream after that it’s kind of obvious which ones plug in the where. Make sure he didn’t torch through any big wires or pinch the main transmission 02 sensor harness on the spine of the trans
You are doing g a good job! I feel like if I was there we could have this sucker running in a few minutes.. but I’m loaded with spare 5.0 everything and tons of Knowledge about these rigs…how did we get this way? School of hard knocks… desperation to get my truck running lol you only have us and YouTube…
Check your work, the last place you worked it likely where the issue came from
You know this started when he chop cut welded on the exhaust… there Is a bunch of wiring down there and welding can do crazy things to wiring (especially if the key is on or battery still Hooked up) to make things worse this is a custom Rig that somebody else did the conversion on… not factory so a number of things could be contributing to the no start situation
Your injectors are black, not sure if they were painted or have always been black? Factory injectors for returnless 5.0 are white
Your old pcm could have been tuned.. as this is a v8 ranger. And now we are running a stock pcm.. who knows what those injectors are rated for or where they came from?
I can send you a complete fuel rail for a returnless system and a set of stock white injectors.. it would take me a few days to get parts together and ship.. you gotta pay me for shipping though so let’s see how the next round of testing goes
It’s got to be something simple so the best advice it stay focused on the simple
Air, fuel, ignition timing, and spark if all of those check out then it is compression
Check all wiring especially near where he was working
Check firing order and ignition wires carefully
FUEL RAILS
Your fuel rail is not correct. I know you dead ended the return line but there is one more
Difference between a return fuel rail and an returnless
On the return rail the thing the vacuum lines hooks to is the pressure regulator. The vacuum regulator is what regulates the 42
Psi at the back of the injectors and all un used fuel is sent back to the tank
On the returnless rail the vacuum Device is a pulse damper, there to soften any pressure spikes that happen inside the rail. On these systems the 64psi to the back of the injectors is regulated inside the fuel tank
I’m not sure how that is going to effect things but as long as you have 64 psi fuel tail pressure this sucker should start
So a pressure test of the fuel system check is needed, We at least need to rule it out
Check battery terminals and wiring especially on the ground side, I’ve seen a missed ground cause a no start a time or two on the 5.0
One of the main grounds feeds the engine down by the timing Cover