I have a 1999 f-150 and am having a problem that I cannot pin down . After starting the truck and running it for 10 min or so I shut it off and it will not restart again for approx. 3-4 hrs . When you turn the key there is a clicking noise coming from behind the fuse panel . Also the truck will not start if temp outside rises above 80 degrees . Is there a replacable relay under there or is it the computer module ? Battery is new .

 

I would be advisable to get the codes scanned, then, post what came up.

It maybe a bad relay...but those are generally under the hood.

when it does start, does it run smooth or rough at first? does it belch heavier black or blue out the exhaust?

When started can you get in & drive normally?

Have you changed the fuel filter? the air filter? what has been done to correct this issue?

 

When I had the codes scanned after this first started it showed nothing . This is what is so frustrating - there is no pattern and either it starts or it doesn't . Runs perfect when it starts - one thing that it has done the entire time i've owned this truck (7 years) is the mileage on the dash has flashed off and on but was never a problem . If I turn it off and restart it right away (within 2-3 min.) it restarts fine but a couple of minites after that its done . It has gotten worse the last couple weeks . If you put your hand on top of the fuse box you can feel it tripping as well as hear it . Any time temp rises outside above 70 or so it won't start . It sure does appear to be a relay but I have no idea if there is a relay under the dash for the ignition or if there is a relay on the comp. module itself. also can I buy a used comp module that matches my truck and have it installed without reflashing it? Thank you so much for responding - I'm so frustrated but have a limited ammount of money to fix so I'm trying to pin this down (i'm disabled) so your advice is greatly needed .

 

Is this a v6 or v8 engine? manual or automatic tranny? If a V8 resides then which one? 4.6 or the 5.4?

OK the blank dash has been covered> see link>>https://www.ford-trucks.com/forums/1...lem-fixed.html

AS for the inconsistent starting....it maybe the ECM or the computer needs replacing...but I don't think that its the issue. personally i think the coolant temp sensor or the cylinder head temp sensor is giving false info to the ECM...there by making for the hard start. The reason being is that once the outside air temp is above 70-80* your saying that it wont start. or you have a vacuum leak.

If there is a vacuum leak the main culprit is the Elbow on the PCV line on rear of the intake. but that said vacuum leaks can be anywhere.

replacing the relays are not that expensive... hearing them or feeling them is OK... but are any of them feeling warm? I'd replace the one's that are getting warm.

DO you have any other "funky" things happening with the electronics...door locks locking and unlocking or windshield wipers going off by themselves?? does the symptoms improve with dry air ( when it hasn't rained for some time) and get worse when it has rained or heavy damp air?

not sure of your capabilities with your disability...but it just seems like some good ole fashioned maintenance is in order....most of which is not hard...just time comsuming

 

Put it in Neutral and try cranking is there a difference.

 

The relay you hear is the starter solenoid on the firewall in the engine compartment.
You likely have a worn out starter brushes that are hanging up off the commutator.
Consider changing both, inspect the battery cables and clean the battery posts.
If you don't do the whole job there may be other faults that will show later.
Good luck.

 

The tripping relay is coming from under the dash behind the fuse panel . It is a 5.4 v8 2-wheel drive with power windows and doors . I don't believe it is a vacuum leak because once it starts it runs great .

 

There may be a relay there you hear due to a low voltage condition but it has nothing to do with starting.
When you crank the motor the ignition switch cuts control power through the Neutral safety switch (the DTR switch on the transmission) back to the start solenoid.
The start solenoid cuts main battery through to power to the starter.
The starter has it's own second solenoid to throw the engagement gear out to the flywheel 'and' power the starter motor.
If the motor won't crank you have one or more issues in the above stated path.
Good luck.

 

..Im with Bluegrass....You have a bad starter

 

Sounds like a cable or starter. Mine did that one hot day and I crawled underneath to give her a gentle smack and the hot wire from the battery to the starter solenoid was just hanging loose. To get home I turned the key to run, crawled underneath and touched that wire to the starter lug and she fired up. That is kind of common to get corroded. Don't know if you are able, but maybe have someone check that main 12 volt red cable that runs from the battery to the solenoid on the starter.