5.4 HICCUPS

benXJ

Well-Known Member
Joined
Dec 5, 2005
Location
Raleigh NC
Got a 02 f150 with the 5.4. 175K miles. Runs great, no problems what so ever.

Except for one thing....

After getting up to operating temp (short trips, long trips, it doesn't matter) and cutting it off, if I try to crank it after it sits for 10-20 minutes, the engine turns over just like it should, strong and fast, but will not start up normally. I have to hold the key for a second or two longer in the 'crank' position and then it will catch and stumble for a split second and then run great. One time it would not catch, just sat there and cranked over for 3 seconds and would not catch. So I turned it off, let it sit a second, and then cranked fine. It only did that once, usually it just takes a second or two longer cranking and then fires up. No warning lights, no smoke, new fuel filter, up to date on all maintenance.

If I let it cool down an hour or so or longer, it cranks up great. It also fires up properly if I shut it down and then immediately crank it right back up.

I was doing some internet reading, and was informed to clean the Idle Air Control valve, which I have done twice with throttle body cleaner. It was dirty and needed a cleaning. Truck has never had an idle problem through.

Any hints?

Thanks
 
Sounds like my 01 right before the fuel pump went out.
 
Yeah it's easy. There is a test port on the fuel rail that looks like a tire valve stem. You will have to buy/borrow a test gauge. Should be around 40 psi almost instantly when you spin over the engine.
 
Run a tank of good gas through it. 93 octane or higher. If its like any engine I've owned in the last few years it hates the cheap garbage.
 
I have had the same problem with my '97 7.4 . Fuel pressure checks out as well as everything else. The hotter it is outside the worse it is. I thought about fuel vaporization. Does the 93 octane have a higher boiling point?
 
No, 93 octane is just harder to burn (it'll take more compression before it detonates).
 
GotWood said:
Sounds like my 01 right before the fuel pump went out.
Click to expand...

I'm with this guy. Twelve years on a pump is pretty good anymore. Fuel pumps always give you odd symptoms with no check engine lights because the pump is not monitored by anything, you only get an engine starved for fuel. Typically I can always hear the pump whine in a vehicle if I turn the key to "run" without going past it to "start". Can you hear the pump prime the fuel system if you roll the window down before turning the key to "start"?
 
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