Starting on second try
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Junior User
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From: Central Iowa
Starting on second try
Hi, my 03' F-150 5.4 has an issue with starting up the first time on ocasion when cold. It's got 35K on it and I have a fuel filter for it that I've been meaning to replace and thought now would be a good time. I'm guessing perhaps crud in the filter may be blocking/slowing the fuel so its not priming the injectors properly causing it to need another crank.
Any thing else I should look at while I'm tearing into it?
An AIC issue shows constant starting and idle issues, don't it?
It idles fine except for a slight RPM variation every few seconds until the EGR opens up.
THANX
--jpn
Any thing else I should look at while I'm tearing into it?
An AIC issue shows constant starting and idle issues, don't it?
It idles fine except for a slight RPM variation every few seconds until the EGR opens up.
THANX
--jpn
Hotshot
Joined: Jan 2004
Posts: 19,768
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From: St Louis
The EGR valve should never open at idle. If it does, it will be causing problems.
Sticky IAC valves usually do cause starting and idling problems. However, it's not the only thing that will cause those issues.
Try cracking the throttle 1/4 way when starting. If it fires reliably, then the IAC is not responding properly. Very common on Fords although yours is a little early.
If that doesn't help, try cycling the key to RUN without starting, turn if off, then repeat. Wait 2 seconds before engaging the starter. If it fires reliably, you have low fuel pressure due to either leakdown, restricted fuel flow, or a weak pump. Replacing the filter would be a good start, much like chicken soup. It's good for you even if it doesn't fix what's wrong.
Steve
Sticky IAC valves usually do cause starting and idling problems. However, it's not the only thing that will cause those issues.
Try cracking the throttle 1/4 way when starting. If it fires reliably, then the IAC is not responding properly. Very common on Fords although yours is a little early.
If that doesn't help, try cycling the key to RUN without starting, turn if off, then repeat. Wait 2 seconds before engaging the starter. If it fires reliably, you have low fuel pressure due to either leakdown, restricted fuel flow, or a weak pump. Replacing the filter would be a good start, much like chicken soup. It's good for you even if it doesn't fix what's wrong.
Steve
Cargo Master
Joined: Dec 2004
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From: NE Texas
If it's leaking down, you have a stuck injector, a bad check valve or a bad fuel pump. You could, of course, simply have a fuel leak somewhere but if this is the case you would be smelling gas.
Good luck,
Doc
Good luck,
Doc
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Junior User
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From: Central Iowa
Can I press the "tire valve" on the fuel pressure test point to check the leak conditon?
Without looking at it again, pressing down on that after it sits overnight would result in a dry valve, wouldn't it , as opposed to it holding some pressure yet?
just a theory
THANX
Without looking at it again, pressing down on that after it sits overnight would result in a dry valve, wouldn't it , as opposed to it holding some pressure yet?
just a theory
THANX
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From: Central Iowa
"watch the fuel guage" ????
If you shut it off the guages die and if you turn the key to run it primes the injectors.
When/what would youiwatch for?
If you shut it off the guages die and if you turn the key to run it primes the injectors.
When/what would youiwatch for?
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From: Central Iowa
Well I replaced the fuel filter. Here's what I found.....
Ran the truck for a few minutes and parked it in the shop, shut er' down and hit the pressure valve on the passenger side fuel rail to relieve the pressure and to my suprise it was very weak for just being ran and didn't really squirt out, it just kind of blurped and over flowed.
So I swapped out the filter and let both the lines to/from the filter leak out a little before I put the new filter in to make sure there wasn't any crap in there. Replaced the filter and cycled key to on then off three or four times to prime it back up.
Checked the pressure valve again and fuel shot out like I would have expected it to the first time. Ran the truck for a few minutes and let it sit for a few minutes, like I did before I checked the pressure the first time, and it was still a full stream.
So I think the filter may have been plugged. I tapped the filter to see if any crud was coming out. There were no chunks but what was coming out was damn nears black.
My question is how did the truck even run with such low pressure?
I haven't noticed any performance issues all though I haven't pulled or hauled anything in it for awhile. it was just the mis starting that got me looking in to it.
Ran the truck for a few minutes and parked it in the shop, shut er' down and hit the pressure valve on the passenger side fuel rail to relieve the pressure and to my suprise it was very weak for just being ran and didn't really squirt out, it just kind of blurped and over flowed.
So I swapped out the filter and let both the lines to/from the filter leak out a little before I put the new filter in to make sure there wasn't any crap in there. Replaced the filter and cycled key to on then off three or four times to prime it back up.
Checked the pressure valve again and fuel shot out like I would have expected it to the first time. Ran the truck for a few minutes and let it sit for a few minutes, like I did before I checked the pressure the first time, and it was still a full stream.
So I think the filter may have been plugged. I tapped the filter to see if any crud was coming out. There were no chunks but what was coming out was damn nears black.
My question is how did the truck even run with such low pressure?
I haven't noticed any performance issues all though I haven't pulled or hauled anything in it for awhile. it was just the mis starting that got me looking in to it.
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Cargo Master
Joined: Dec 2004
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From: NE Texas
To begin with I should have written FUEL PRESSURE GAUGE, not FUEL GAUGE. Sorry 'bout that.
From your description, I am skeptical that you have it fixed. If the fuel filter were that plugged up, the thing would not run consistently at highway speed. Maybe I'm wrong, and if you're lucky I am wrong.
I still believe that you have something allowing the pressure to bleed off. If the problem persists, you will have to do a little testing with a fuel pressure gauge connected to the test port.
Good luck,
Doc
From your description, I am skeptical that you have it fixed. If the fuel filter were that plugged up, the thing would not run consistently at highway speed. Maybe I'm wrong, and if you're lucky I am wrong.
I still believe that you have something allowing the pressure to bleed off. If the problem persists, you will have to do a little testing with a fuel pressure gauge connected to the test port.
Good luck,
Doc
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Junior User
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From: Central Iowa
Could be. It only acts up a couple times a month and then the second try allways works.
If a good system is known to leak down over night, how would one test for leak down if it only does it after sitting over night?
Is there just one test port on the pass. side fuel rail or is there one before the rails?
THANXX
jpn
If a good system is known to leak down over night, how would one test for leak down if it only does it after sitting over night?
Is there just one test port on the pass. side fuel rail or is there one before the rails?
THANXX
jpn
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Joined: Jan 2004
Posts: 19,768
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From: St Louis
There is a single pressure test port in the system.
A slow (overtight) leakdown is not likely to cause significant problems.
Again, the pressure guage is the test tool to use in diagnosing fuel pressure problems.
Steve
A slow (overtight) leakdown is not likely to cause significant problems.
Again, the pressure guage is the test tool to use in diagnosing fuel pressure problems.
Steve
