2002 5.4 - no start - at wit's end
 

2002 King Ranch supercrew 5.4 - 76K miles - had intermittent starting problems beginning in August - at that time, would start if I only turned key on/off 3-4 times to build fuel pressure.

After doing alot of searches for possible solutions and countless pages of advice printed, here's where I am at:

1. Replaced IAC back in August (didn't drive truck much Aug-Oct - would start on occasion if I turned key on/off - most of time, truck sat in driveway)

In past 3 weeks:
2. changed plugs (motorcraft) and aftermarket COPs (1st time change for both)
3. new fuel pump & filter
4. new fuel pressure regulator

When I try to start, it just cranks away as if no fuel. If I spray starting fluid in throttle body, truck starts up and purrs like a kitten - no problems.

EDIT: when I hook up fuel pressure gauge to rail, I get approx 36 psi when key turned. Maintains same pressure when running (after starting with starting fluid)

Check codes - none.
No flashing theft light at start-up
No dashes on odometer
Tried starting with gas pedal to floor and also 1/4 way down - on cold start, would just crank. However I was able to re-start engine with pedal 1/4 way down after engine warmed up (initially starting with starter fluid),

I would assume crank sensor is good since truck runs fine after starting. Likewise, fuel injectors getting signals from PCM. Since it runs, I also assume inertia switch is OK.

I'm at a complete loss at this point - it appears to be some type of start condition from the PCM not triggering injectors at start-up.???

Could it be a bad TPS?

I'm open to any/all suggestions at this point. I've disconnected neg battery with headlights on to drain - no effect. I've read about putting a jumper from positive battery terminal to disconnected neg cable and wait 30 min to clear PCM - any thoughts on whether that would help?

Thanks in advance... long term member here from when Rockpick was still a young lad.... :beers:

Isn't there a fuel reset button behind the passenger side kick panel? Also, have you checked fuses?

Just checked fuel reset and it's fine (since truck runs when started with starting fluid, fuel pump would be working anyways.... fuses look OK. (not sure which ones would prevent starting if truck runs)

Note I also temporarily switched the fuel pump relay with trailer tow relay - still no start.

I'm really at a loss.... will try replacing TPS this afternoon but any other suggestions would be greatly appreciated.

Replaced the TPS today.... no change.... cranks but no start... :help::help:

Sounds like maybe the gas mixture isn't rich enough when cold to start. There is a temp sensor that tells the computer to enrich the fuel. Maybe other things. I'm just waging here.

There's nothing wrong with the fuel system up to the rail based on your pressure reading.

At this point, I'd be looking at the power to the injectors and the injector (ground) signals from the PCM to see if there's an intermittent electrical fault.

Connect a voltmeter to the common (red?) power wire to the injectors and see if it stays hot during one of those failed cold starting attempts. If that passes, move on to one or more of the individual injector signals using either a test lamp or a set of noids.

Thanks for the suggestions - will try.....

Stopped by the dealer this afternoon to discuss bringing the truck in (North NJ).... they want $300 diagnostic charge up front.. (applied to repair if they do repair).... sort of got you by the short hairs either way... if above suggestions don't work, I'm probably going to wave the white flag & bring it in somewhere :surrender:....

given all the time I've spent researching/replacing parts I'm probably saving myself $3/hr.... :think: fun learning though...:D

I hope they can identify the problem. But an intermittent problem may not be found so easily.

300 bucks for a diagnostic is ridiculous.

Not if you're chasing an intermittent. Those things can be VERY time consuming, especially if it starts working and won't fail while the system is under examination.

Been there, done that, got the gray hairs.

Thanks for all the suggestions... I took it to a different dealer today...(more reasonable $125 diag charge)

Anxious to see what they come back with... Will update what they find.

Time to place your bets!! 🍻 What do you think it will be?

$125 is a lot more like it - probably 1 billable hour.

Any update, Mike? Hope it's working out....

Hey brad! And we thought these things would increase in value all those years ago!! Ha!

I now have a fairly good looking truck with rusted out rocker panels that doesn't start!! Fate can be cruel... (So can stubbornness as I'll never get rid of this thing!😄)

Still at dealer ... No word yet ... Not sure whether that is good or bad ... They know I'm not in a rush to get it back...

quick update - spoke with dealer - they are seeing fuel pressure drop and say everything is pointing to the fuel pump. I just put a new Delphi fuel pump assembly in 2 weeks ago..... gave them the OK to repair (est $866) ... just can't deal with this anymore with cold weather/holidays...

saga continues.... supposedly will be ready on Monday...