In mine, I removed the in-tank FPR, ran and spiced the front half of the Expo doner's fuel return line to the Ranger's fuel return at the back of the original fuel filter. Did take a fair amount of reshaping to get the Expo's fuel return pipe to follow the Ranger's fuel supply and look right where the two flex hoses from the fuel rail plug in.
Used a fuel filter that matches the Expo doner.
Only tricky bit is at the back of the fuel filter. The Ranger filter's center pipe is the same as the Expo's fuel filter inlet, but on the Ranger, that pipe is the return from the filter.
The smaller line at the back of the filter is the supply. So, I used a pair of fuel system rated nylon hose couplings to swap the two lines.
So you created a return Hmmm if you are getting the right pressure that would lead me to believe the pressure regulation on the expo happens somewhere in the fuel rail? OR was it just feeding back enough fuel to bleed off all the additional?
OK I understand. Do I necessarily have to remove the ranger in tank FPR since it is a much higher pressure than the system needs? It would probably open wide up anyway being fuel is being returned?
That sounded lazy LOL I'll probably put a fuel pump in anyway since I have no idea if the original is still in there or not. I don't like heading into a project with too many un known areas.
Doner will be here on the 13th of June. He sent me pics of the motor compartment wow does it look similar to the rangers. I'm freakin excited. I'll start a build thread when I have 9 out of 10 ducks in a row.
So Ron, the injectors would have to be different to accept the higher fuel pressure, will the pulse width dished out by the 97 ECU give the appropriate fuel mixture if I ran the 2000ish fuel rail and injectors on the 97 motor with the 97 ECU? Just would hate to run lean and burn pistons or run rich and burn cats. If I use the cats LOL.
The PCM manages the fuel delivery based on the injector and fuel pressure.
Additionally, the return style expects a drop in fuel pressure during high vacuum events.
So, will the earlier PCM run the engine with later injectors and higher fuel pressure? Probably. Will it be 100%? Probably not.
If modding the system to a return style was a royal pain, it'd be a workable solution but given how easy the mod is, and the doner can supply most of the pieces, I personally think its better to stick with the hardware the PCM expects.
It would be fine to use the '97 computer with '99 returnless rail and injectors.
On first startup engine would probably run a bit Richer, not much though, thats cold start Open Loop and computer is using factory tables for air/fuel mix, pulse width, with old LTFT.
Once computer is in Closed Loop(engine warmed up) the computer uses O2 sensors to set pulse width, and it "learns" a newer Long Term Fuel Trim(LTFT).
New LTFT is then used in Open Loop on next cold start to compensate for long term changes to the system, i.e. dropping fuel pressure over the years, higher fuel pressure, lower compression from worn rings and valves, oil coming down intake valve stem, these all change the most efficient fuel mix over the years.
Correct fuel pressure and injector size are important, but system is fairly flexible.
But, all things considered, like the cost of rail and injectors plus you would probably need to change fuel line connection for 5.0l rail.
If you get all the parts from a donor then I would do that
Either direction technically works, choose which one fits the balance between work needed, parts available and money needed. Got it guys, thanks. It is always nice to have options.
That's probably why win's 02 was reading lower fuel pressure than he expected... the PCM had compensated for what the motor actually needed and was only giving it a certain amount of pressure. And it lines up with him getting the same pressure when he changed the regulator.