Got a 2003 ranger 4.0L 4x4 quit running would turn over but not start.Put a new fuel pump,filter and idle control sensor on it. Still wouldn't start.OBDII scanner shows no codes.Was trying it and it started run fine for about 2 days then wouldn't start again.Reset switch on passinger side firewall and still nothing.After it sits a day or two it will start.Anyone know of anything I am missing here.If you can help me I would greatly welcome anything.If need be I would be happy to call someone and talk with them.Thanks

 

Welcome to FTE.

Well it could b a number of things.

If the battery, it's cables & their connections are known to be in good shape, maybe the under hood power relays for the fuel pump & computer belong on your suspect list.

If all the dash warning lights are ON when you go to KOER, before cranking the engine, then the computers power relay is probably ok.
If you don't have warning lights lit during one of it's no start fits, then suspect the computers power relay.

Same for not hearing the fuel pump run for a couple of seconds, when you go to KOER, before cranking the engine.

Both of these power relays are located in the under hood power distribution box, located drivers side, up in the corner between the fender & firewall across from the brake master cylinder.

If you come to suspect one of the power relays, try swapping it with a known good, like relay, not needed to run the engine, say the A/C power relay & see what happens.

Or during one of these no start fits you could try "thumping" the suspect relay & see if it'll wake up & have the engine run!!!!

There are reports of the in cabin fuel pump inerta cut off switch becoming overly sensitive & tripping, but it seems you've already tried that.

If none of the above prove out, & you can't hear the fuel pump run for a couple of seconds to build pressure & shut off, try thumping the fuel pump atop the gas tank & see if it'll wake up & run the engine.

If you can hear the pump run, but the engine won't start, maybe suspect a clogged fuel filter, or a spark problem.

If you have a scantool, hook it up & scan for trouble codes.

A computer scan for "pending" trouble codes may be worth doing, as the problem may not have turned on a CEL yet.

If you don't have a code reader, or scantool, most autopars stores will scan the computer at no cost, if your having problems.
Post ALL of the code numbers found.

Do a fuel pressure & spark test, when it's in a no start fit.
You can safely do a spark test with a timing light & most autoparts stores have a fuel pressue test kit in their "Loan-A-Tool program, for a refundable deposit, if you don't have a fuel pressure gauge.

A whole bunch of trouble shooting thoughts for pondering, let us know what you find..

 

Have checked all relays and nothing showing bad.How would you check the in cabin fuel cutoff/reset switch.I think this may be the problem.It sit awhile then start abd run a day or two and then quit again.

 

Well you could disconnect the inertia switch & jumper the electrical connectors contacts & see if the fuel pump runs.

Or you could try thumping the inertia switch to cause it to trip, then reset it & see if it'll start.

Have you done a fuel pressure check when it's in one of it's no start fits????
If so post the pressure numbers.

Can you hear the fuel pump run for a couple of seconds when you go from Off to KOER, before cranking the engine????

If you have fuel pressure, then check for spark.

Do you have a check engine light lit???? If so, have the computer scanned at your favorite autoparts store & post ALL of the code numbers.

 

My 2005 stopped running on me several times. First time it was hauled into the dealership and the next day started for the mechanic. $800.00 later for a long haul and mechanical service with no cause found. After that bill with testing instructions from the mechanic and apology for not being able to fine a fault, I turned to the great members of FTE. Pawpaw is correct! Get a fuel gauge and when it acts up confirm if you have fuel pressure or not then you can go down the fuel or spark path. My issue ended up being an inertia switch which finally failed at 111000 miles. Each time it stopped I went through installing the gauge, cycle key, listen for pump, beat the bottom of the tank with my thermos, check the inertia switch, swap fuel pump relays until I got fuel and when it stopped all together installed ½ of a paper clip in the inertia switch plug and fuel pressure returned. Two things about this issue, best $800.00 I ever spent got me to FTE and forced me to learn about new trucks, second thing I don’t understand but the day it failed for the final time on the way out from work there was a paper clip laying there and something said pick it up your going to need it. Thanks FTE.

 

Good feedback & GREAT story on the paper clip!!!!
Because of FTE I now carry paperclips & spare relays, along with my spare fuses in the glove box!!!! lol

Way to hang in there & persevere on your problem.

Maybe consider dropping by & let the Dealers Servive Manager & Tech know how you fixed your problem, maybe they'ed refund some of the $800, seeing as how they missed the inertia switch on their trouble shoot.
As many vehicles as they service, they should know about the inertia switch, I believe there is a TSB out on them also.