Fuel System Randomly Primed

[C-WOODS-70]

I’m happy just to find out what this noise is. Opening the door primes the fuel system? Interesting. I haven’t had the car long, so hadn’t looked into source of noise. Mine did it once just walking past it in garage, fob was in house. Sometimes I’m surprised at what I learn from reading random threads that, at first, don’t seem to interest me.

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[Angrey]

The Fob may just be part of the equation. It may be cycling because it's getting source/signal to do so from another source (like the brake pedal position, the ignition switch, etc). My point was, someone smart that could identify all the "triggers" that prime the pump would be a good start. Then from there you could start to nail down why it cycles unexpectedly. My be the Fob thing. Might be a touchy sensor elsewhere. (kinda like how the windows get schizo and constantly jump up and down).

I will say this, it's not just a weird or inconvenient issue. If the car is cycling/priming the pumps intermittently (when it's not supposed to be) it's a threat to your battery reserve if you leave the car for long periods of time. Could possibly wear down the battery to the point of no crank.

 

[DRKHORS]

I believe this to be specific to certain (i.e. newer) model years. My 2015 never did this; however, my 2023 I have heard the pump priming for no apparent reason. I don't recall if I had my fob in my pocket, and there is a good chance it was on the battery tender. My 2015 stayed on the same battery tender and never did this. Normal...

 

[Proshop]

@LOL WUT OMG I think your right… the cars can smell us! I literally just walked up to the car (hood open and door closed) and the fuel primed itself . On a side note fighting fuel issues again ugh!

 

[LOL WUT]

@LOL WUT OMG I think your right… the cars can smell us! I literally just walked up to the car (hood open and door closed) and the fuel primed itself . On a side note fighting fuel issues again ugh!

LOL!

What fueling issues are you running into?

 

[Proshop]

LOL!

What fueling issues are you running into?

Fuel pressure dropping after car being hot.
Drove the car around all morning with the wife for errands fuel pressure was at its normal 48 psi or so depending on idle and driving. Got home and didn’t pull up enough in the drive way so started the car to move and fuel pressure dropped down to 39 and 40 and was running a little rough. Let the car sit for 45 mins and fuel pressure is fine but slowly drops down as the car gets warm (87 degrees in FL today). Pumps are running and have full voltage, no known vacuum leaks on hoses checked them all could possibly be a cracked intake manifold after boosting hard a few weeks ago or possibly the three pumps overheating the e85. Idle log sent to Wengerd to check fuel trims and anything else that could be funky and awaiting response. Sorry for the long winded post and hijacking of your thread. @Cory S any thoughts also?

 

[Cory S]

Fuel pressure dropping after car being hot.
Drove the car around all morning with the wife for errands fuel pressure was at its normal 48 psi or so depending on idle and driving. Got home and didn’t pull up enough in the drive way so started the car to move and fuel pressure dropped down to 39 and 40 and was running a little rough. Let the car sit for 45 mins and fuel pressure is fine but slowly drops down as the car gets warm (87 degrees in FL today). Pumps are running and have full voltage, no known vacuum leaks on hoses checked them all could possibly be a cracked intake manifold after boosting hard a few weeks ago or possibly the three pumps overheating the e85. Idle log sent to Wengerd to check fuel trims and anything else that could be funky and awaiting response. Sorry for the long winded post and hijacking of your thread. @Cory S any thoughts also?

Even with one pump running, base pressure should stay at set point. Interesting. This a Gen3 DI car? Are the pumps constant 12V operating setup or FPDM controlled? Ok. Saw the sig. Maybe a DI issue?

 

[jayhoogs]

I usually worry about random things with my car, but for some reason this has never really been one of them. I’ve always found it a bit weird, but just brushed it off as normal. My 2017 ecoboost did it, and my 2022 Mach 1 does it. At times it seems to be the fuel pump, at times other electrical noises, one I’m fairly certain has something to do with the transmission, but not sure. Even our sienna makes some weird noise every time it’s been off for like 60 or 90 minutes or something, and again apparently it’s a normal system check it does. Wouldn’t be worried about it imo.

 

[Proshop]

Even with one pump running, base pressure should stay at set point. Interesting. This a Gen3 DI car? Are the pumps constant 12V operating setup or FPDM controlled? Ok. Saw the sig. Maybe a DI issue?

Yes gen 3 car with DI, triple pumps running all the time (need a Hobbs switch for the third), dual regulators one before fuel system static and one after vacuum/boost based. Googled and actually did see possibility of DI issue but also saw boiling fuel can be an issue also.

 

[Cory S]

Yes gen 3 car with DI, triple pumps running all the time (need a Hobbs switch for the third), dual regulators one before fuel system static and one after vacuum/boost based. Googled and actually did see possibility of DI issue but also saw boiling fuel can be an issue also.

So all three are running full time??? If so, on hot days, with a heat soaked engine bay and fuel rails, you’ll probably experience intermittent vapor lock from fuel reaching boiling point. 3 turbine vane pumps running full time circulating fuel from back to front and back will do that. Sometimes even 2 pumps will after super long run time in temps above 90°+ and in traffic, sitting in the sun etc.

 

[Proshop]

So all three are running full time??? If so, on hot days, with a heat soaked engine bay and fuel rails, you’ll probably experience intermittent vapor lock from fuel reaching boiling point. 3 turbine vane pumps running full time circulating fuel from back to front and back will do that. Sometimes even 2 pumps will after super long run time in temps above 90°+ and in traffic, sitting in the sun etc.

That’s kind of what I was thinking also after researching the symptoms. I was hoping it was a manifold issue so I could swindle the wife into a better one but I’ll deal with the issue at hand for now and fix it.

 

[Cory S]

That’s kind of what I was thinking also after researching the symptoms. I was hoping it was a manifold issue so I could swindle the wife into a better one but I’ll deal with the issue at hand for now and fix it.

Keep your manifold. Nothing 1/2psi more won’t take care of….

 

[LOL WUT]

All good @Proshop hijack away, there’s good info here for others in the future! What are you monitoring the FP dip via? I notice that on my FP regulator it’s constant at its set base pressure at idle both cold and hot. Are you seeing the base pressure drop at regulator gauge or on a dash mounted FP gauge?

I know on my NGauge my FP is up and down constantly at idle and not held at a constant PSI. I assumed this was the norm? I haven’t made note of how low my FP goes on the NGauge at idle but I’ll check it out next time I’m in the car.

 

[Proshop]

All good @Proshop hijack away, there’s good info here for others in the future! What are you monitoring the FP dip via? I notice that on my FP regulator it’s constant at its set base pressure at idle both cold and hot. Are you seeing the base pressure drop at regulator gauge or on a dash mounted FP gauge?

I know on my NGauge my FP is up and down constantly at idle and not held at a constant PSI. I assumed this was the norm? I haven’t made note of how low my FP goes on the NGauge at idle but I’ll check it out next time I’m in the car.

I have a an AEM fuel pressure gauge in the dash that i monitor it with. Regulators are set at 60 for the static and 48 for the return obviously it rises 1 to 1 depending on boost. Normally my pressure stays at the 48 rising depending on driving… but today when super hot the gauge dropped to 38, the static regulator was close to 60 but not stopped at 60 like normal nor was the boost referenced regulator as it was slowly dropping and erratically moving. I’ve had good luck with this system since it being installed since early March but I think the heat of the day and the three TI 285 pumps be on constantly just caused the fuel to heat up to much along with other components like Cory mentioned. Tomorrow I will get the car good and hot again and see if I can replicate it and also drive it to see if driving helps cool things down vs just sitting idling in the driveway.

 

[LOL WUT]

@Proshop thanks for the details. Perhaps the only bad thing about living in FL is boiling your E85 occasionally..

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