Emergency HELP Please F53 Fuel problems

[Gnarley]

WE are stranded in Grants Pass.

We broke down near the bottom of Sexton Pass on I5 on the Saturday of the Laborday Weekend. No Tow Trucks were available and we had to stay in the rig overnight 4 feet from the slow lane on a curve! We were towed at 11 AM Sunday morning back into Grants Pass and dropped at the Walmart and now safe. There are few tow rigs available in some areas and few shops or mobile techs or shops that can handle a large RV. This situation is exacerbated on long holiday weekends!

Vehicle: 1999 Holiday Rambler Vacationer F53 gas Triton v10, 1/3 tank of gas. Prior owner at some point installed a frame mounted aux fuel pump before and attached to the filter.

Conditions: Driving 55 MPH and pulling a dolly with a Hyundai Tucson on 9/5/2020 at about 2:30 PM and 99 degrees.

What happened? We don't yet know what failed. I crawled under and believed the aux pump failed and found a replacement. I installed it in the extreme heat, it did not fix the problem. It would start but did not continue running. FUEL or Pump in tank failure? We found a single mobile tech that was available, there were no other options. He showed up later Sunday and dropped the tank, the pump was non-op. We found one at a parts store and it was installed. It didn't seem to run any different. The tech questioned his install and dropped the tank again. Everything seemed as it should. Sunday he scanned and looked for codes and a few senors that were questionable were replaced as a precaution, and had no impact or change.

2 working pumps may have also overfuled the systems. We tried both and it runs really bad with the frame rail pump installed.

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

We drove with the engine cover off and had a fuel pressure gauge hooked up to the fuel rail and it had the correct pressures and the engine ran perfect! Up and down hills in town for about 30 minutes and no problems! You could watch the fuel pressure rise on the hills as should be expected. We put the engine cover on and went for a drive on I5. It immediately had a problem and under load lost pressure.

Everything was good with the engine cover off and with it on there was more heat and had an instant effect on drivability. SIDENOTE we only had about 1/3rd tank of gas, could a pump that's not fully submerged overheat and cause a loss of fuel pressure under load?

Due to the fires we are stuck. The 2 week trip we planned is canceled and now we are trying to get back home. We may have to abandon our RV and store it since we don't trust driving it home 400 miles away.

Does anyone have any helpful suggestions?

Please help

Thanks

[John_Joey]

Update ?

[Executive45]

Chum lee wrote:

IMO, you are dealing with a bunch of effing morons. I drive the same chassis as you. It DOES NOT NEED AN AUXILIARY FUEL PUMP. Any fault codes? This is a band-aid solution to fix a simple problem.

Chum lee

Pretty simple: In tank fuel pump goes bad. Rather than drop the tank and replace it,they bypass it and put on the aux fuel pump. Redneck fix, but effective....for a while anyway. That said, the OP posted on 9/5 and it's now a week later with no update, so I guess he either got it fixed or decided the heck with it and is hunkered down in a campground somewhere, fishing.....Dennis

[Chum_lee]

Gnarley wrote:
WE are stranded in Grants Pass.

We broke down near the bottom of Sexton Pass on I5 on the Saturday of the Laborday Weekend. No Tow Trucks were available and we had to stay in the rig overnight 4 feet from the slow lane on a curve! We were towed at 11 AM Sunday morning back into Grants Pass and dropped at the Walmart and now safe. There are few tow rigs available in some areas and few shops or mobile techs or shops that can handle a large RV. This situation is exacerbated on long holiday weekends!

Vehicle: 1999 Holiday Rambler Vacationer F53 gas Triton v10, 1/3 tank of gas. Prior owner at some point installed a frame mounted aux fuel pump before and attached to the filter.

Conditions: Driving 55 MPH and pulling a dolly with a Hyundai Tucson on 9/5/2020 at about 2:30 PM and 99 degrees.

What happened? We don't yet know what failed. I crawled under and believed the aux pump failed and found a replacement. I installed it in the extreme heat, it did not fix the problem. It would start but did not continue running. FUEL or Pump in tank failure? We found a single mobile tech that was available, there were no other options. He showed up later Sunday and dropped the tank, the pump was non-op. We found one at a parts store and it was installed. It didn't seem to run any different. The tech questioned his install and dropped the tank again. Everything seemed as it should. Sunday he scanned and looked for codes and a few senors that were questionable were replaced as a precaution, and had no impact or change.

2 working pumps may have also overfuled the systems. We tried both and it runs really bad with the frame rail pump installed.

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

We drove with the engine cover off and had a fuel pressure gauge hooked up to the fuel rail and it had the correct pressures and the engine ran perfect! Up and down hills in town for about 30 minutes and no problems! You could watch the fuel pressure rise on the hills as should be expected. We put the engine cover on and went for a drive on I5. It immediately had a problem and under load lost pressure.



Everything was good with the engine cover off and with it on there was more heat and had an instant effect on drivability. SIDENOTE we only had about 1/3rd tank of gas, could a pump that's not fully submerged overheat and cause a loss of fuel pressure under load?

Due to the fires we are stuck. The 2 week trip we planned is canceled and now we are trying to get back home. We may have to abandon our RV and store it since we don't trust driving it home 400 miles away.

Does anyone have any helpful suggestions?


Thanks

IMO, you are dealing with a bunch of effing morons. I drive the same chassis as you. It DOES NOT NEED AN AUXILIARY FUEL PUMP. Any fault codes? This is a band-aid solution to fix a simple problem.

Chum lee

[John_Joey]

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

[jy]

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.

[Dutch_12078]

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.

[carringb]

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.

[midnightsadie]

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

[theoldwizard1]

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 !

[theoldwizard1]

1995brave wrote:
Sounds like vapor lock. Check the IAC valve for sticking.

This does not compute !

[theoldwizard1]

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.

[carringb]

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.

[1995brave]

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

[Gnarley]

I'm concerned about adding even more gas to the tank in the event it could require coming down again.

There is nothing pinching any lines, vacuum or fuel, none are close to the cover. We also found a collapsed pressure line after the filter which connects to the fuel rail and bypassed it and it now has consistent pressures.

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.

The mobile mechanic suggested that the OEM Ford pump may be different from the aftermarket f53 pump that was called for. I don't believe that this was the case as it ran perfect with the engine cover off and only seems to be temperature related.

This is madness.