2002 F150 5.4 long crank time to start

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My '02 F150 with the 5.4 just recently started taking longer to start. It used to take about 1 second of cranking to start, it now takes about 4-5. It all started after I disconnected the battery when checking and adding water to it. I know it is not related to that, but just a weird coincidence.

If I turn the key on and wait 3-4 seconds, it starts immediately. It runs and idles fine, no black smoke on startup, no codes, drives just fine, no difference with engine hot or cold. Everything I read was leading to 4 things, fuel pressure regulator, leaking fuel injector, bad check valve or dying fuel pump. I figured I would start with the easiest and most likely culprit and replaced the pressure regulator. No change after replacement (I know, don't throw money at it till I have done the correct tests). So that leaves leaky injector (least likely I think), bad check valve (most likely) or bad pump (kind of likely). I did replace the fuel filter about 10,000 miles ago, so I don't think that is it.

I finally got a hold of a fuel pressure tester (AutoZone rents them, but forgot my wallet when I was by one, they let me use it in the parking lot).
It was at 10 PSI when I hooked it up (truck was off for about 15 minutes).
Turn the key on, still at 10 PSI, but after waiting 3-4 seconds (with it still at 10 PSI) it starts right up, pressure goes up to 34 or so for a second then levels off around 29. I know that is in spec (28-40 PSI is normal from what I have read), but at the low end. I disconnect the vacuum line to the pressure regulator with the engine running and it goes up to almost 40, so I know the regulator is good (duh, I just replaced it).

I turn the engine off, pressure drops from 29 to 20 in about 15 seconds, then seems to stay there for a few minutes and then very slowly drops down to 10. And it is back to where it started.
I forgot to check if pressure would build up with 2-3 key cycles.

So how can I differentiate between fuel injector, check valve or actual pump problem? I guess it really does not matter if it is the pump or check valve, both require dropping the tank to change, although there are pump replacement kits out there for around $60 vs the $170-250 for an entire quality pump assembly (but have not seen a check valve replacement). Seems I read about turning the key to on, clamping off the fuel lines and watching the pressure. If it drops, it is a leaking injector, if it stays, it is the check valve. I know I could pull the plugs and see if they are wet, but anyone that has the 2v modular motor knows what a pain that is.

If it is just a bad check valve, I can live with that and will let it be, just turn the key on for a few seconds before it starts. If it is a fuel pump issue or fuel injector, I really need to get it taken care of.

Any ideas or comments?
 
I know someone that had ignition problems with their F150. The ignition coil was changed, helped temporarily. Ended up being the Flywheel, had to be refinished or he got a new one, I dont remember. However, his vehicle was making horrendous sounds at startup when it was determined the flywheel had to be changed.

You say you're confident the battery situation is a coincidence. I will assume, then, that you have checked the voltage of the battery under load.

Probably did not help much but just some thoughts.
 
Pull the fuel rail with injectors intact. If one leaks with the key on but not cranking that's your culprit.

If you haven't noticed drive ability issues or fuel smell in the oil it's most likely the check valve on the pump allowing the pressure to bleed off.
 
Heh heh 'zactly what the 528e does. I think its a whacked sensor. It has 3 separate electrical gremlins. It doesn't like to sit. I put less than 150 miles on it last yr.
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Originally Posted By: cb_13
Pull the fuel rail with injectors intact. If one leaks with the key on but not cranking that's your culprit.

If you haven't noticed drive ability issues or fuel smell in the oil it's most likely the check valve on the pump allowing the pressure to bleed off.

I thought about doing that, but there is nothing holding the injectors in the fuel rail if it is disconnected, it would just shoot the injector(s) out when the system is pressurized.

lucas, the battery checks fine, and it would not account for the actual low fuel pressure reading.
 
Sounds like the check valve in the fuel pump. My truck does the same thing but the fuel tank looks like the deck of the Titanic ...rust city. I live with it
 
Sounds like you have two good methods you already described. How flexible is the fuel line? Can it be securely clamped off without damaging it? If so, this sounds like an easy test.
I know pulling plugs can be surprisingly difficult in some of these things. But if you had a leaking injector, I'd think that would be an easy tell by looking at the plugs. I like changing plugs. I use copper and change them every 30k. It gives a good read on the motor.
Keep us posted. I'd be interested to know what you find.
 
Leaking check valve is 95% certainty on that vehicle. Leaky injector could cause a few seconds of miss in the effected cylinder. Cycle your key to see if pressure builds accordingly. Fuel pump ck valves were almost always the cause of long crank times with leaky regulators being a very distant second place. Leaky injector maybe encountered once/twice in 11 years at Ford. Doesn't mean it can't happen.

Sounds counter intuitive but we would sometime disconnect the vac from the pressure regulator to spike the pressure, then shut the engine off. Sometimes the extra line pressure would seat the ck ball and confirm the diagnosis.

Neighbor roped me into helping replace a fuel pump on his old Toy Hi-Lux. Makes me miss the Fords.
 
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Well, after replacing the fuel pressure regulator and the fuel pump assembly, it is still doing it.

I guess it is a leaky injector. Not leaking enough to flood the engine (not getting any smoke at startup, no raw fuel smell, no drive-ability issues), but leaking enough to let the pressure drop pretty quickly. That is the only thing I can think of now that it could be.
Any other ideas before I pull out the injectors (and need to figure out how to test them).

Part of me is frustrated that I wasted money on replacing those parts, but with 180,000+ miles on it and being 15 years old, figured I will count that as just some preventative maintenance costs.
 
Well, after A fuel pump, fuel pressure regulator, fuel filter, crank sensor, cam sensor, changing relays and checking all fuses as well as an hour banging my head on the wall , brought it to my mechanic.
He did some testing and found the PCM was the issue, so after replacing that, it is fine now (actually replaced it twice, replacement one worked for about 30 minutes the quit).
 
Glad it's sorted out. With 180,000 on the truck, "it owes you nothing." ie, that's great and hopefully this repair will keep it solid for a while longer.
 
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