Good Sam Club Open Roads Forum: Emergency HELP Please F53 Fuel problems
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 > Emergency HELP Please F53 Fuel problems

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1995brave

San Antonio, TX

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Posted: 09/09/20 01:27pm Link  |  Quote  |  Print  |  Notify Moderator

Sounds like vapor lock. Check the IAC valve for sticking. Also try loosing the gas cap and see if it runs better.

carringb

Corvallis, OR

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Posted: 09/09/20 02:28pm Link  |  Quote  |  Print  |  Notify Moderator

Gnarley wrote:


I can't imagine what may be causing the loss of pressure when it's hot and the engine controls sense the need for more pressure and you can see it drop on the guage.


That's what made me suspect a vacuum issue. The FPR is controlled solely by engine vacuum. When vacuum goes down, fuel pressure should go up. But if it's missing vacuum, the PCM will compensate via the O2 sensor, but it doesn't respond fast enough to to "un-compensate". Whenever I've run into this, I use a hand vacuum pump with a gauge, and verify fuel pressure is responding correctly to change in vacuum. Autozone should have both on hand to loan out for free. A collapsing vacuum line can also make cause similar problems.

Do you have any other symptoms of a mass vacuum leak? Does your A/C come out the vents rather than the dash?

A stuck EVAP solenoid can also cause weird symptoms, becuase it draws too much vacuum on the tank. This one is easy to diagnose.... Try driving with the gas cap cracked next time it has issues.


Bryan

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theoldwizard1

SE MI

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Posted: 09/09/20 03:50pm Link  |  Quote  |  Print  |  Notify Moderator

Gnarley wrote:

Tuesday morning after checking various connections and replacing a suspect damaged fuel pressure regulator we removed the frame rail secondary pump!


Gnarley wrote:

I can't imagine what may be causing the loss of pressure when it's hot and the engine controls sense the need for more pressure and you can see it drop on the gauge.


Based on your first statement, you have a "return fuel" system and the engine mounted, vacuum operated pressure controls the fuel pressure NOT the ECM. With no vacuum to the pressure regulator you should get maximum fuel pressure.

Remove the vacuum line at the regulator, plug it and then see what the fuel pressure does.

theoldwizard1

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Posted: 09/09/20 03:51pm Link  |  Quote  |  Print  |  Notify Moderator

1995brave wrote:

Sounds like vapor lock. Check the IAC valve for sticking.

This does not compute !

theoldwizard1

SE MI

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Posted: 09/09/20 03:57pm Link  |  Quote  |  Print  |  Notify Moderator

carringb wrote:

That's what made me suspect a vacuum issue. The FPR is controlled solely by engine vacuum. When vacuum goes down, fuel pressure should go up. But if it's missing vacuum, the PCM will compensate via the O2 sensor, but it doesn't respond fast enough to to "un-compensate". Whenever I've run into this, I use a hand vacuum pump with a gauge, and verify fuel pressure is responding correctly to change in vacuum. Autozone should have both on hand to loan out for free. A collapsing vacuum line can also make cause similar problems.


Ahhh ! You may have a soft spot that causes a hose to collapse trapping the engine vacuum (actually lack of vacuum) to the pressure regulator.

I had a problem like this with my EGR in my 1998 E-Series. The soft hose was far from the EVR, close to the vacuum reservoir and close to the exhaust. The hose was MUSH !

midnightsadie

ohio

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Posted: 09/09/20 04:42pm Link  |  Quote  |  Print  |  Notify Moderator

heat ? cover off ran good? sounds like vabor lock,, fuels getting to hot.

carringb

Corvallis, OR

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Posted: 09/09/20 05:12pm Link  |  Quote  |  Print  |  Notify Moderator

midnightsadie wrote:

heat ? cover off ran good? sounds like vabor lock,, fuels getting to hot.


You can't get vapor lock in a pressurize fuel system. It can only occur in the fuel pump pickup tube, and only when an old pump is running extremely hot.

Dutch_12078

Winters south, summers north

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Posted: 09/09/20 05:45pm Link  |  Quote  |  Print  |  Notify Moderator

The starting but not staying running issues sounds suspiciously like a mass air flow sensor issue. If the sensor got wet or picked up a spec of dirt, that's a typical symptom. Sometimes it dries out or the dirt gets dislodged and they run fine for years longer. The MAF sensor is located in the air cleaner housing and isn't difficult to change.


Dutch
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jy

south east mich.

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Posted: 09/10/20 08:28am Link  |  Quote  |  Print  |  Notify Moderator

When I had my 99 f53 mh I had a large vacumn line split and it caused all sorts of problem.It was located at the base of the throttle body amd started out going towards the front of the engine,It was about 5/8 id at one end,had about a 180 degree bend,was about 6 inches long and was 1/2 inch dia, at the other end.It was split at the tight bend.I had to get a hew one from Fords.


2016 wildwood bunkhouse,2018 f150 5.0.Camping with the grandkids now.

John&Joey

Summer-North,Winter-South

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Posted: 09/10/20 09:44am Link  |  Quote  |  Print  |  Notify Moderator

Those v10 MH were also know for a coil or two going bad. They got 10 of them.

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