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Checked power at the fuel inertia switch and no power coming in. From what I can tell on the schematics, the power runs from the fuel pump relay to the inertia switch to the fuel pump. The PCM tells the fuel pump relay when to turn on. I’m going to check the PCM pins and fuel pump relay tomorrow. Also going to replace my CPS for grins to see if it helps.
Getting to the PCM connector is easier through the driver side wheel well after you pull the liner out like you would to get access to the IDM.
It's probably been mentioned earlier in this thread but have you checked your grounds?
Good idea. Grounds can do some crazy things.
On a side thought. Would it be possible to disconnect the pump connector and power it directly from the battery? If it would run in this condition then maybe he could get it home and be able to do the trouble shooting at a more convenient and leisurely pace.
We/you are missing something... As Paul said, the WTS light is the issue waving the flag and the one you need to be searching for.
A new "good" PCM did not resolve the issue, so the issue is within a connector, splice or wire that provides power to the PCM and OBD plug.
Refresh our memory of what was going on after the last drive since you said "Was running perfect Last weekend, then to a no-start." Did you shut it off as you normally would, did it stutter a bit, did it die on it's own?
The GPR test that Paul recommended was just to verify power in the PCM power circuit, not identify the GPR as being faulty. The WTS light not on is independent of the GPR function, but not independent of the power circuit for the GPR. Something is not right...
Originally Posted by RacinJasonWV
On a side thought. Would it be possible to disconnect the pump connector and power it directly from the battery? If it would run in this condition then maybe he could get it home and be able to do the trouble shooting at a more convenient and leisurely pace.
Even if the fuel pump would run, the PCM is not working, so there would be no IDM or anything else that the PCM commands...
@ztodd377 Is it possible your WTS lamp bulb is burnt out and you are dealing with a different no-start issue? You can pull the instrument cluster in just a few minutes and check the bulb if you felt inclined to do so. A blown lamp bulb would NOT stop the OBD port from working, but something to consider as we are working through the process of elimination.
Even if the fuel pump would run, the PCM is not working, so there would be no IDM or anything else that the PCM commands....
Yeah that’s what I was afraid of. Didn’t know if the PCM wasn’t firing up at all or if it was just the fuel circuit. Thanks for the clarification.
It may be dangerous but what’s the thought on manually supplying power to the necessary circuit at the PCM?
Sorry guys this is just the way my mind works. If it were me I’d want to get it home somehow so I could work on it there.
Yeah that’s what I was afraid of. Didn’t know if the PCM wasn’t firing up at all or if it was just the fuel circuit. Thanks for the clarification.
It may be dangerous but what’s the thought on manually supplying power to the necessary circuit at the PCM?
Sorry guys this is just the way my mind works. If it were me I’d want to get it home somehow so I could work on it there.
No worries, this is the point we are at trying to help him out.
If it were me, I would not be supplying power to the PCM in any way other than what Ford designed it. There is a connector, wire or splice not quite right... Or, maybe it is the WTS lamp out and we are chasing a ghost by looking for the wrong no start issue.
Truck is a 2001. Work done recently, and it’s run great after, power steering system flush on June 29th, hutch mod with Racor install on June 12th, FRx install on May 6th, new fuel filter and Isspro fuel pressure gauge install on Apr 26th.
Last weekend the truck was running great. I shut it off like normal, no stutter or anything, and when I went to start it again, the engine would turn over rapidly but not fire up; no WTS light or GPR LED activation & no fuel pressure.
The WTS light could be burnt out potentially but I also have a GPR LED and is not coming on either telling me the GPR is not activating.
Items I’ve checked so far:
-Batteries are good
-Starter is good
-Engine turns over rapidly, but no start
-No fuel pressure
-No WTS light
-Pulled and tested every fuse under dash, all good
-Pulled and tested every fuse under hood, all good
-Fuse 22 (junction box batt feed) under hood has power coming in to it, and power out when checking wires from underneath power distribution box
-Fuse 19 (fuel pump motor, PCM) under hood has power coming in to it, and power out when checking wires from underneath power distribution box
-Fuse 24 (PCM power) under hood has power coming in to it, and power out when checking wires from underneath power distribution box
-PCM diode checks out good
-Bench tested relay 30 (PCM power) tested good for coil activation and continuity, and power out when checking wires from underneath power distribution box
-Disconnected fuel bowl heater plug, same symptoms
-Swapped PCM relay with blower motor relay and still same symptoms
-Good voltage at PCM pins 97 or 71 with key on
-Checked pin 24 of 42-pin connector for power with key on, its good
-Checked for voltage at PCM pin 55 (always hot) it’s good
-Checked PCM ground pins 25, 51, 77 & 103, all have continuity when measured with multimeter to an in cab ground
I’ll check the ground coming in to the GPR with the key on. Will go through and check grounds for good contact and continuity.
When I plug in the OBD dongle it gets power, but won’t talk to the PCM.
I’m at a spot where the PCM reset test guide Sous sent is telling me to disconnect the accelerator pedal connector but I can get it to pull free. Probably never been off in 20 years. I don’t want to break it. Any suggestions?
I’ll be damned. It wasn’t the accelerator pedal. I wasn’t getting a good reading between pins 90 & 91 of the PCM so I figured why bop swap in a new CPS (for giggles), the vref signal came up, GPR kicked on, WTS light is there, fuel pressure is there and the truck fired right up!
The no-start flow chart led me away from the CPS (but it’s still an awesome chart). I guess the moral to the story is, always check/replace the CPS before you start tearing fender liners out and ordering new PCM’s (which can go back now since the old PCM is functioning good).
gonna reassemble everything, then install the hydra, and see how it goes.
A huge thank you to all my FTE brothers out there! If you’re ever rolling through Tucson let’s grab a beer!
Last edited by ztodd377; Jul 11, 2020 at 12:35 PM.
Reason: It LIVES!!!
So, a failed CPS was stopping the 5v reference from transmitting data to the PCM which caused the PCM to act like it had failed by not lighting the WTS lamp?
