I blew my motor aobut 2 years ago replaced it and have yet to drive it more than 1-10 minutes. It has a serious fuel problem that comes and goes. I have replaced, cps, maf, fuel regualor, converter, tps, idle air, coil pack, temp sensor, air intake temp, switched computers mine runs another truck fine,egr valve is good, changed injectors, you named i have changed. My fuel pressure is sitting at about 68-69, vacuum seems to drop when it starts loading up. If i open up a vacuum to the intake from the booster it will lean it out and let it run and clear it up for a few minutes????????? HELP i am about to lay the match book to it.....

 

did you change the o2 sensors or the fuel pump? the o2 sensors might be key to this because they control the fuel misture

 

maybe a dumb question, but did you replace the plugs/wires when you replaced the coil ?

 

68 pounds of pressure is wayy too much
your fuel pressure relief valve is not working

 

Maybe not. FP spec for a 98~00 Ranger is

55 +/- 8 PSI FFV
64 +/- 8 PSI non-FFV

 

Can you give me some more info on the relief valve. yes i changed plugs, wires, almost everything but motor and harness that i knew could deal in fuel system, 02 sensors are working, short and long term fuel are reading rich like a vacuum leak but no leak

 

the fuel pressure relief valve should be at the back of the driver side fuel rail
( it feeds the fuel return to the tank )

it should be controlled by a vacuum line with electrical connector

check to see if there is any vacuum from that line

 

98+ Rangers do not have a return line or a fuel pressure regulator on the rail. The regulator is in the fuel tank and the system is returnless.

 

hmm you are right

i just checked my truck-- it looks like the fuel pressure regulator is built into the fuel filter now

you may have debris that has clogged the return line from the fuel filter
thus preventing any excess pressure returning to the tank

i will call my mechanic tomorrow to clarify this

i still say that 67-68 psi fuel pressure is wayyy too high
but i will find out tomorrow

 

The spec for my 2003 is 64 +/- 8PSI (56~72 PSI) and it runs at 69~70 PSI consistently.
The 98+ Ranger fuel pressure regulator is inside the fuel tank, not inside the fuel filter.

 

then can you explain why there is 2 lines going into the filter from the fuel tank

and only 1 line coming out of the filter leading to the engine

 

The high pressure pump sends fuel out on one line to the filter. The second line goes back from the filter to the tank where fuel is bled off by the regulator to maintain constant pressure in the third line that goes forward to the fuel rail.

That is the Ranger setup for the years that have the the 3-port filter. In other Mechanical Returnless systems, the regulator may simply bleed the excess fuel directly from the main supply line from the pump before it leaves the tank. Those would typically have a 2-port filter instead.

 

you can buy my engine lol

 

i talked to my head mechanic

several of your injectors are jammed open

the usual cause is sub-standard fuel being used

looks like you are going to need new fuel injectors sorry!

and i was wrong 69 psi fuel pressure is normal

 

Another possibility is that the Fuel Pulse Damper on the fuel rail has a ruptured diaphragm. This is not too common but it does happen occasionally.

Questions:
Was the replacement engine from a 99 Ranger or some other year?
Was the engine donor a Flex Fuel Vehicle or not?