Electric problem?
#1
11-07-2018, 11:38 AM
Electric problem?
2003 Ford F-150 4.2 was running rough and mis fire cylinder 3. Code 303. When it rained or really humid. It rained for almost a month here Now it cranks but won't start. The first day I tried every hour to start for about 4 hours. Then it started once and runs fine after it started. Killed it and started right back up. Went out an hour later and now it won't start again and hasn't started since. Changed the coil pack still no start. Now I'm trying to figure this out with out spending a ton of money on parts trying to figure it out. Thanks
#2
11-08-2018, 05:58 PM
Just wondering,, How are the plugs.. I changed mine and put some sea foam in the carb.. spray.... a can in the fuel and it starts and runs like a champ now..
#4
11-09-2018, 01:41 PM
Plugs and wires or good. Fuses relays all good. Inertia switch not tripped. It has something to do with the rain/humidity if it was dry it ran like a champ. Something is getting wet and now it finely took a crap. Move to Corpus Christi where it's wet and humid all the time so I think it finely ruined the part that's bad. Just trying to think what part to check next. This model does not have the Fuel Pump Control Module
#6
11-09-2018, 02:32 PM
Something you might check,
The PCM should be located under the hood on the driver's side firewall. Remove EACH plug one at a time , look for any moisture or corrosion on the plug pins and plug. If any is found just spray some WD40 on both plug and pins allow to dry and reinstall. Sometimes water runs down the firewall and can raise some heck with the electrical connections there.
The PCM should be located under the hood on the driver's side firewall. Remove EACH plug one at a time , look for any moisture or corrosion on the plug pins and plug. If any is found just spray some WD40 on both plug and pins allow to dry and reinstall. Sometimes water runs down the firewall and can raise some heck with the electrical connections there.
#7
11-09-2018, 04:57 PM
Yes that's what I was thinking. I pulled the pcm out already and checked it. I did not see any water damage on it. It appears that ford puts a thin layer of silicone on the board to protect it. I checked the plug on it for corrosion on it and it looked fine. The pcm on my truck is on the passenger side. Easy to get in and out. plus one thing I look up said if the pcm is bad the error code would not reset when I unplugged the battery to reset it. It did reset the code. So I'm now thinking to check all the wiring harnesses that run under the truck to the fuel tank to make sure there are no breaks or grounding out on the frame. Then after that the crankshaft sensor or the camshaft sensor. And thanks for the input and help.
#9
11-10-2018, 04:12 AM
Suppose we start from the beginning and get some answers.
Do you hear the fuel pump run for the usual 2 seconds when you first turn the key on?
If yes we go to something else , if no we go in a different direction , need to know this before moving on.
Can you remove one of the spark plugs and see of it is wet or dry?
If wet, it could mean fuel is getting in there , but no spark .
If dry , then we go to the fuel supply system.
The proper procedure gets a little lengthy and if we knew which direction to go based on what you found that would save a lot of time and work.
Do you hear the fuel pump run for the usual 2 seconds when you first turn the key on?
If yes we go to something else , if no we go in a different direction , need to know this before moving on.
Can you remove one of the spark plugs and see of it is wet or dry?
If wet, it could mean fuel is getting in there , but no spark .
If dry , then we go to the fuel supply system.
The proper procedure gets a little lengthy and if we knew which direction to go based on what you found that would save a lot of time and work.
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