4.0 Mountaineer won't start | Ford Explorer - Ford Ranger Forums - Serious Explorations
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4.0 Mountaineer won't start


Well-Known Member
September 15, 2012
Reaction score
City, State
Charlottesville, VA
Year, Model & Trim Level
2002 Mercury Mountaineer
I have been having issues lately with my Mounty not starting. I'll turn the key and it will crank, but won't start. I'll take the key out and put it back in and it will start and run. It recently started just cranking but not starting. It would start with a jump, so I replace my battery yesterday. It started and ran fine last night and this morning, but this afternoon when I went to start it, it started but sputtered and then died. I tried starting again and it would sputter and keep cranking. I tried hooking a jump pack up to it but it did not start. My thoughts are the fuel pump is or has gone out. I am going to check to see if there is spark, but I can't think of anything else it may be other than a fuel pump.

Spark plugs were replaced last year when I did timing chains
Fuel filter was done last summer.
It has just under half a tank of gas.
No CEL prior to not starting, and it goes out when cranking and when the engine sputters.

Any input? I'm at a loss right now.

Borrow (free) a fuel pressure tester from your local auto parts store. Hook it up where the blue Schroeder valve cap is on the front of the fuel rail (drive side). (NB: these kits are often cheap crap and don't always work reliably; make sure yours is working before relying on it.)

Have a helper crank it over and see what the fuel pressure reads. Should be around 63 psi for an '02. If not, or if the needle fluctuates, could be a fuel pump.

Before replacing the fuel pump (expensive) you may want to replace the fuel pump relay, which sits in the fuse box near the battery in the engine compartment. Cheap part; what the hay?

If you decide its the fuel pump and want to DIY, consider cutting three-sided square hole in the rear passenger floor right over where the fuel pump sits below. Search for threads on this. Its easy to remove the front driver and rear seats and to fold the carpet/backing back. Buy a Delphi pump off of ebay for 1/3 or 1/4 the cost of other options (Delphi's have reportedly been more reliable than some other pumps, e.g., Airtex-Wells). I patched the hole with some an aluminum plate and self-sealing membrane from Lowes (or Home Depot).

Glad I didn't have to drop the tank. While you're opened up the floor, check to see if you can spot any bad wiring or EGR tubes on top of the tank in the same vicinity.

I don't know how hard it is to drop the tank, but it don't look like fun (especially w/o lift). Good luck.