Hi, newbee looking for help, I have a 98 Ranger with a Explorer 5.0 in it and a M5OD behind it. I have been fighting this problem for a year, I have a intermitent engine surge it typically happens right after or while I am climbing a hill. All of a sudden out of nowhere it will start surging, Here is what I have done, Read the codes, nothing I don't expect there, blocked off the egr, changed TP sensor, changed mass air, changed cam sensor ,disabled evap just in case it isn't venting properly, changed coil packs, check all the vacuum circuits, funny thing is it will disappear within a day usually and be gone for a long time, I even tried unhooking the battery thinking maybe the ecu doesn't like the fact there isn't an aod in it,the other thing is it never has happened during the summer, I am at a total loose here I need a new set of eyes and there really isn't anyone around my area that can or wants to help because of the engine swap....thanks for any ideas you can come up with,,,Neil
One thing occurs to me and I don't know if this is your problem or not. The automatic transmission portion of the PCM calibration is allowed to take charge of the ignition timing during shifts to smooth them. I guess it's conceivable that the surging could be happening when the PCM commands a timing change and tries to command a gear change that never happens, then returns to engine control then tries again and again. It might be that it gets into a loop where it chases its tail when you back out of the throttle slightly as it crests the top of the hill. Just an off-the wall thought.
You could get a flash tuner like Special Forces or SCT along with a custom tune to reflash the PCM yourself. I believe that you could also send the PCM out to have it reflashed: try asking mlw20lu about this option. I think he was planning to go this route for his V8 swap.
The fuel pressure regulator used depends on the year of the Explorer engine.
Return Fuel: 96~98 Explorer had a vacuum controlled, rail mounted regulator that gives about 30~40 PSI variable. This system needs a fuel supply line and a return line back to the tank.
Returnless Fuel: 99~01 Explorer used a single fuel line (supply) and an in-tank regulator that gives a constant rail pressure of around 65 PSI. Your 98 Ranger also used this type of system from the factory.
yea this one has the rail mounted regulator and I had to use the fuel lines from the explorer donor I had. I think I am going to replace it just cause I can't think of anything else besides reflashing the ecu. I wanna do that also....