starting problem during the day
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Mountain Pass
Joined: Mar 2022
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Likes: 21
starting problem during the day
Good morning
I have a starting problem on my 1993 Ford F150 5.0.
the first start of the day and very good, then all day the start will take 5 to 6 seconds.
The fuel pressure is 37.7 psi with the ignition on and the engine off.
With the engine running I am at 31.9 psi and with the regulator vacuum disconnected I am at 40 psi.
I have a starting problem on my 1993 Ford F150 5.0.
the first start of the day and very good, then all day the start will take 5 to 6 seconds.
The fuel pressure is 37.7 psi with the ignition on and the engine off.
With the engine running I am at 31.9 psi and with the regulator vacuum disconnected I am at 40 psi.
Lead Driver
Joined: Oct 2016
Posts: 6,185
Likes: 633
From: Houston/Sugar Land
I show you should have 35-45 PSI at idle. If you are dual tank try the other. Single tank would indicate need a new FDM. Dual tank: check fuel pressure in the other tank. If good the other tank appears to need the FDM. If other tank is the same as the first test then I would consider a new fuel filter. No codes indicate something like the above.
Fleet Owner
Joined: Oct 2005
Posts: 20,786
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From: Kentucky
30 to 35 PSI at idle is what most folks report for V8 engines. 35-45 is what I would expect with the engine under load.
Lead Driver
Joined: Oct 2016
Posts: 6,185
Likes: 633
From: Houston/Sugar Land
My Haynes manual says engine running pressure should be 30-45 PSI. Engine off should be 35-45. Doesn't mean it is accurate but its what I have. FPR vacuum hose off should increase 5%-10%.
Lead Driver
Joined: Oct 2016
Posts: 6,185
Likes: 633
From: Houston/Sugar Land
That's why I would do what you say instead of the Haynes manual.
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Mountain Pass
Joined: Mar 2022
Posts: 247
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the rear tank was removed by the previous owner.
when it starts it doesn't start right away, like the fuel isn't coming right away.
the filter and new, the regulator and new, the PCM too. the new water temperature sensor and the entire ignition system and still the same problem.
When I turn it off and then lower the pressure via the ramp, just afterwards, it starts again immediately.
the problem happens after several minutes or hours of rest. even after 4 hours
when it starts it doesn't start right away, like the fuel isn't coming right away.
the filter and new, the regulator and new, the PCM too. the new water temperature sensor and the entire ignition system and still the same problem.
When I turn it off and then lower the pressure via the ramp, just afterwards, it starts again immediately.
the problem happens after several minutes or hours of rest. even after 4 hours
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Lead Driver
Joined: Oct 2016
Posts: 6,185
Likes: 633
From: Houston/Sugar Land
The only other thing I can think of, IS. Make sure you hear the fuel pump come on for a second or two before key goes to start. Try to keep fuel level above 1/4 tank as any lower causes the pump to work to hard and it will over heat.
Hotshot
Joined: Sep 2001
Posts: 11,958
Likes: 228
Pressing the gas all the way down is clear flood mode and prevents the injectors from firing when cranking.
My previous 95 5.0 would do that. It would start up fine first thing in the morning or after sitting all day. It would re-start fine after less than a few minutes. But after 10 minutes ore so it was hard to start and would chug and puff out black smoke like a diesel when it got running again. This would clear up in about a minute or two.
Turned out new injectors fixed it. It was flooding out after shut down. I had to figure it out myself because 2 shops and the Ford dealer couldn't figure it out. This was also back when the truck was only about 5 years old, so the Ford techs should have been able to diagnose it.
If you decide to go that route I would get a refurbished set or maybe order new from Summit or LMR but not from the parts stores etc, since those are probably not as good and far too expensive.
You can try to clean and refurbish them yourself for very little money,
My previous 95 5.0 would do that. It would start up fine first thing in the morning or after sitting all day. It would re-start fine after less than a few minutes. But after 10 minutes ore so it was hard to start and would chug and puff out black smoke like a diesel when it got running again. This would clear up in about a minute or two.
Turned out new injectors fixed it. It was flooding out after shut down. I had to figure it out myself because 2 shops and the Ford dealer couldn't figure it out. This was also back when the truck was only about 5 years old, so the Ford techs should have been able to diagnose it.
If you decide to go that route I would get a refurbished set or maybe order new from Summit or LMR but not from the parts stores etc, since those are probably not as good and far too expensive.
You can try to clean and refurbish them yourself for very little money,