How to check fuel pressure? How to Force Limp Mode?

[enigma9o7]

My 04 EB stalled and won't start again. It turns over but doesn't seem to fire, although it sputters a bit, never after I stop cranking. I've checked lotsa fuses/relays related to fuel/ignition and tested compression, no problems found.

Two things I want to try. First, how do I check fuel pressure easily? Or if not pressure (without buying something), just a way check to make sure it's at least flowing to injectors or whatever. I'm no mechanic but I can follow directions pretty well... maybe something I can disconnect and see fuel coming out?

Is there a way to force an engine failsafe mode? On my car, all I have to do is unplug the MAF sensor and then it forces a limp mode that'll at least run til I figure out what's wrong assuming fuel/compression/spark are ok.... I think it uses some rich fuel mix and ignores sensors and the ecu only does the bare minimum; does explorer have something similar?

 

[enigma9o7]

btw, is there something weird about our spark plug cylinders thread? When I tried to screw in a generic compression tester gauge I'd used years ago on a chevy, it wouldn't catch. When I looked down the hole with a light it looked to me the threads don't start right away or something. I dunno. The reason I wanted to test it was I wondered if timing chain had skipped or something. Anyways a buddy who's more familiar with engines than me thinks there's enough compression based on plugging the hole by hand and feeling how much it pushed, said it can't be that strong if timing was off so doesn't think it's that...

 

[WaterBrat]

If you have access to a bluetooth or wifi OBD scanner and use the forscan software, it can read fuel pressure in real time. On my 05 EB 4.6, I pulled the ABS fuse due to a bad sensor in front hub. This caused Limp mode.

 

[imp]

If you have access to a bluetooth or wifi OBD scanner and use the forscan software, it can read fuel pressure in real time. On my 05 EB 4.6, I pulled the ABS fuse due to a bad sensor in front hub. This caused Limp mode.

@WaterBrat
Which proves the ABS Module has the power to throw Limp Mode. Mine did; the main chip in the module died. Replaced with a used module, works, but ABS light permanently ON because the replacement module has the previous vehicle's VIN # in it. imp

 

[enigma9o7]

Thanks Waterbrat. I tried pulling a couple ABS fuses from under the hood, still won't start, so maybe fuel, I ordered this to try forscan:
https://www.amazon.com/Forscan-ELM327-Bluetooth-Scanner-Diagnostic/dp/B073VLQHMK

Chilton's says to relieve fuel pressure, start the engine and remove fuel pump relay. Since I can't start the engine, is there another way?

 

[WaterBrat]

If the engine cranks but does not fire, pulling the fuse and cranking it may work. Don't know for sure. Good luck with the scanner.

 

[Drewmcg]

I had to buy two fuel pressure contraptions on Amazon in order to get one setup that worked on my '02 4.0 SOHC. The schrader valve adapter is tricky on that motor. Not sure what setup the '05 V8 uses.

Sounds to me like it could be a failed fuel pump. How many miles on this truck?

You might try spraying some stater fluid in the intake while having someone turn over the engine. If it sounds like it wants to start, that might at least tell you its a fuel delivery problem. If it is, lots of folks will start with replacing the fuel filter (which is a b****ch), but I've never heard of a fuel filter clogging so badly out of the blue so as to create this problem . . . .

I removed rear and passenger front seat on my '02 and cut three-sided flap in the rear passenger floor to replace . my fuel pump w/o dropping the tank. Not too difficult. Recommend Delphi pump from Rockauto or Amazon. Good luck.

 

[enigma9o7]

~130k miles. I changed fuel filter last summer, so unlikely clogged. Got the scanner, going to try it right now, once I know if there's fuel pressure at the rails I'll at least know if I should be checking fuel things. I looked in chiltons, no access to fuel pump thru floor, have to drop tank to replace pump, argh, hope it's something easier than that, but will do whatever it takes, only other running vehicle I have is a motorhome and have being using it - literally - as a grocery getter.

 

[enigma9o7]

Fuel pressure seems ok. 280kPa before starting, 360 while turning the key, no DTC faults.

Forscan seems useful but I dunno what to check next. I guess spark related things.

 

[enigma9o7]

Continued: Help! 04 V8 EB won't start! Fuel/Spark/Compression & starter ok... any ideas?

 

[Drewmcg]

Check on Youtube and on this site for videos/instructions on how to cut a hole in the rear passenger floor to access the fuel pump if you need to.

How did you check the fuel pressure? Also, did you try starting with starter fluid in intake?