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Edward, ASE Certified Technician
Category: Ford
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Experience:  ASE certified. Auto Transmission rebuilder for Ford Motor Co. from 91 to 2000
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Ford F150 Pickup 4x2: after installing a new battery, new fuel

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after installing a new battery, new fuel pump & new spark plugs, my 2005 f150 does not start when it rains, other than that on a dry day it runs fine. help please.
Hello and thanks for your question. My name is XXXXX XXXXX I will do all I can to help.

Just so I'm clear, When this problem happens, You hit the key, and the engine just cranks correct? And doesn't start? or you hit the key and the engine doesn't even turn over?
Customer: replied 4 years ago.

it will start and immediately shut off

Alright, I understand. How many ignition keys do you have for this truck by chance? do you have 2 keys and does both keys result in this problem?
Customer: replied 4 years ago.

only I key


OK, Alright, There is a few things that can cause this, and to narrow it down, Next time it's raining and it doesn't start, Take these steps to try and narrow it down.

1. Get in the truck and just turn the key to the ON position, do not try to start.

2. Make sure the Check Engine Light comes on. It should come on everytime you cut the key ON. If it does not turn on, then I would suspect the PCM relay not powering up the system.

3. Also, Make sure the Anti-Theft light does not flash with key ON. It should come on and go out after a few seconds. If it flashes with Key ON Engine OFF, Then that would be a sign the Anti-theft system is not recognizing the ign. key. In that case, you may need another transceiver to read the ign. key, or another key itself.

4. In my opinion it may be a good idea to go ahead and replace the PCM and Fuel Pump relays. As these relays are pretty cheap, and usually it's one of them that causes this problem. But check those other things and see if you can correlate it not starting with either the check engine light not coming on at all, or the anti-theft light flashing with key on engine off. And that will narrow it down.

Edward and other Ford Specialists are ready to help you
If the check engine light comes on while driving, or if it stays on after the engine is running, Then definitely have the engine scanned. it could be a mass air flow sensor or crank sensor setting a code, that may be a factor in this problem.
Customer: replied 4 years ago.

when I turn the key it goes 'rrrrrrr rrrrr rrrrr' after awhile it will start, then just shut off

Alright, Does the engine crank normally? or does it crank really slow, like the battery isn't charged? (I know you replaced the battery, but alternator may not be charging it) Do you see a battery light on in the dash when driving? or a check engine light on?
Customer: replied 4 years ago.

Why only when it rains---maybe I just need a big umbrella.(lol)


LOLOL. That is really odd, but moisture and humidity sometimes do affect things. Check those things I mentioned. Especially make sure the check engine light comes on everytime the you turn the key ON.

If you don't see the light, and it doesn't start, then replace the PCM relay first. These intermittant rainy only type issues are sometimes difficult to pinpoint. What you might want to do, (or have a technician do) is put a spark tester, and a fuel pressure gauge on the engine and soak it then spray it down good with a garden hose to simulate the rain. Then with the diagnostic equipment on it. Make sure it has fuel pressure and spark. That's one way to narrow it down.
Customer: replied 4 years ago.

I need to wait to try these suggestions as the truck is still in the shop & it is closed today. I hope one of these work.

I believe you'll find your problem there Sandra, but they need to get a spark tester and fuel pressure gauge on the truck and soak it with a garden hose to try and narrow it down. I would tell them that. as if they check it dry and it's cranking everytime they'll never find it.
Customer: replied 4 years ago.

Ok I guess that's it on my end. Thanks for your help


absolutely, thank you and have a great weekend!

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