My 02 F-150 XLT, 4.6, auto, wouldn't start when I was leaving work today.

The starter cranks without sounding weak, and it cranks for a long time, so I don't think it is the charging system.

It will crank but usually not do anything, just spin for as long as I hold the key. Sometimes if I turn the key off and on a few times, then hit the starter, it will act like it's going to start, get to about 300 rpm, and then die.

It has done this 3 times. First 2 weeks ago, then it started with no problems for 2 weeks. Tonight leaving work it took 5 tries and then it started and ran fine for the drive home. When I got home I shut it off and it wouldn't start again. I tried about a dozen times, went to dinner, and when I got back an hour later it started fine on the first try.

Any ideas what would cause this?

I know this description sucks. What else can I check when this happens again?

 

could be your IAC does it ever act funny at a stop light or only on cold start up?

 

Don't crank for than 4 seconds. The PCM shuts down the injectors.

Rule out a fuel problem first, - replace filter and run a pressure check, - make sure you check the regulator as well.

Here's what service has -

Symptom --------------------------- OASIS Number

Starting Concerns :

—Hard Start/Long Crank
—Erratic Start/Erratic Crank ------------- 602300


Perform the following preliminary checks:

1. Vacuum leaks.
2. Fuel quality (concerns such as proper octane, contamination,winter/summer blend).
3. Intake air system (tubes).
4. Air cleaner (restrictions).
5. Battery condition and starter current draw.

 

No problems at stop lights. It has done this twice when warm and once when cold, it isn't just a cold start problem.

Any pointers to how to check fuel pressure? I assume there is a shrader valve or similar hookup near the fuel rails. I think my gauge is for carburetor levels, I'll need a new one for FI.

What is the normal mileage for a fuel filter? I'm at 80k on the one the UAW guys put on back in 02.

Would it be worth it to borrow a code reader from a friend? Are there any codes to be read in this scenario?

 

Depends where your getting your gas, 80k is probably due for a change, it's a $10 part. I normally change mine out once a year just for preventive maintenance.

 

I think the book says every 15 or 16 thousand. Every third oil change for me (around 9,000) and it's always dirty.

 

At 80k you should have already changed it twice, and it's coming close to time again.

Every 30k.

 

Well it happened again today. I paid attention to what it did when it worked and when it didn't.

When it works I can hear a buzz when I turn the key to the second position (last click before the starter engages). I assume this is the fuel pump. When it doesn't work I don't hear this buzz.

Could the fuel pump fail intermittently? After not starting a few dozen times it started and ran fine while I drove home 5 miles. It idled smoothly at stop lights, accelerated smoothly, ran great. When I got home I shut it off and it wouldn't start again.

This feels electrical, like a bad switch or relay. Is there a switch or relay I should check? Any other diagnostics I can do instead of throwing parts at it?

I'm going to change the fuel filter this weekend no matter what, just because it's due. But I don't think that will fix this.

 

Sounds like a plug somewhere in line is loose, or has moisture in it or something, if I had to guess. The reason I am thinking moisture, is because if there is moisture in the plug, and when the water or whatever is freezing, it is breaking the connection. Does this happen at a certain temp range?

At any rate, I would check the plug to the fuel pump, which probably wont be fun.


-Matt

 

These are the symtoms of a faulty fuel pump. I has happened to me, intermittant starting, and a fuel pump change fixed it. How many miles on the truck?

 

Just 80k.

I finally picked up a Haynes book for this truck. Now I've got an idea how the pump is wired and I can eliminate the easy things. Of course now it starts fine.

I changed the filter. The pump noise is a different pitch now, so that old filter was having a negative impact on the fuel system. I'm going to clean the throttle body today because I know it needs it badly.

I hope it isn't the pump, but I'm leaning that direction.

 

Fill your info in, - top right corner, like most others do. That way we'll know what your driving without having to back track and verify. Makes it easier to help.

When it's acting up, check the relay. If the relay is bad, it will be warm to hot. They should not heat up at all, - never. That's a quick way to determine relay or pump.

Specially If your buzzing inside the cab. That sounds electrical, - unless your battery is failing.

 

The truck finally got to the point where it never starts and the fuel pump never makes a sound. It's been stuck for 2 days. Fortunately it decided to do this in my driveway parked right outside my shop.

Using the diagram in the Haynes manual and I traced the wiring for the fuel pump. The relay in the under hood fuse box clicks when the key is turned and it doesn't get hot. There is power going to the impact switch under the kick panel. I was able to take apart the fuel pump plug without dropping the tank. My multimeter shows the pump is getting voltage through the pink/black wire and ground through the black wire, it starts at 12v when you turn the key, drops a few volts about two seconds after that, and it goes back up when the starter is turning. From what I understand this is normal.

I've finally given in to the inevitable and I'm going to drop the fuel tank and change the pump. The tank is less than 1/8 full so it shouldn't be too hard to drop. I'm glad I didn't stop for gas on the way home!

 

The simple way to confirm a pump problem is just listening to it. You should hear the words- "I'm not working", when you turn the the key to run.

 

Why didn't you say so earlier? I'll go talk to it and see what it says. LOL.