18 High Pressure Fuel Pump Operation

Video 18 of 51 in the Maximum Productivity Diagnostics for New Technology program: • Maximum Productivity D...
* Next: Fuel Volume Control • 19 Fuel Volume Control
* Previous: High Pressure Pump Description • 17 High Pressure Pump ...
* View our entire library: / @deadondiagnostics5502
COURSE MANUAL (20 MB): deadondiagnostics.s3.amazonaw...

[@edusson]

Awesome explanation. Thank you!

[@justiceifeanyi5420]

Is the high pressure pump saving as the injection nozzle

[@heylookitsherbie]

Is this a positive displacement pump?

[@lounsburyjud]

Can you think of circumstance that the hpfp would deliver too much pressure?

[@edusson]

Sorry, actually just had a curiosity question... Somehow on 1:54 you say that de-energized opens the fuel inlet. That would then actually create the max pressure on the HP circuit, isn't it? But in my GTI, they actually recommend disconnecting the voltage/control signal to the solenoid and running the car for 10 seconds before working on that part of the car (so that the pressure is low, for instance to remove the HPFP...). I.e., no voltage >> close inlet, isn't it? Am I understanding something wrong?

[@kasimirwulf1936]

How the solenoid works can be different for each manufacturer. What he is saying when the power to the solenoid is off the valve is open. I find that this is probably the most likely configuration.

[@dean-gm1lg]

Some fuel metering valves are open with no power and some are closed with no power you can usuely tell which is which by the way the electrical connector is fitted to the unit vertical fitting is usuely open when ignition off and an horizontal fitting is usuely shut with ignition off

[@nefgarza6419]

@@kasimirwulf1936 that makes perfect sense, so failed safe will create high pressure instead low pressure to prevent lean out in the combustion chamber

[@infinitewisdom4557]

Something 'wong' here!

[@jimbrown563]

Incorrect explanation ........
The job of the Solenoid is only to
hold the Spring-Loaded Inlet-Check-Valve in the Open Position.
As the Piston moves up in its Bore, the Fuel will be pushed
BACKWARDS through the open Inlet-Check-Valve until the
the exact moment when the Solenoid is turned-OFF,
which then allows the automatic Inlet-Check-Valve to Close,
which "traps" a certain percentage of Fuel above the Piston.
Only this limited quantity of "trapped" Fuel will be
pumped in to the Fuel-Rail.
If the Solenoid remains "On" continuously,
the HPFP will NOT generate any pressure,
or pump ANY Fuel, Period.
In this case, the only Fuel-Pressure in the Rails will be
coming from the "In-Tank" Fuel-Pump,
which is also controlled by the Computer,
and may generate as much as ~85-psi of pressure
on demand from the Computer.
The HPFP simply adds to this "Base" Pressure
when the Engine-Demand requires it.
The Engine will Idle,
and produce very limited Power,
without the HPFP producing any additional Pressure.
If the Pressure-Regulating-Solenoid fails on the HPFP,
the Fuel-Pressure will go as high as
the Safety-Bypass-Valve will allow,
which varies between different Pump-Models,
and could be as high as ~3,200-psi., and possibly higher.
.
.
.

[@ajsellas2771]

A bit confused by that though, how would the hpfp create pressure (in the case of a failed regulator) , if a hpfp does not create pressure without a pressure regulator (you said that)

[@jimbrown563]

@@ajsellas2771
No , You must have misread my post .......
If the Pressure-Regulator-Solenoid Fails,
the High-Pressure-Fuel-Pump will create it's
maximum possible Pressure.
I never stated that .....
"" does not create pressure without
a Pressure-Regulator""
Please read again.
""If the Solenoid remains "On" continuously,
the HPFP will NOT generate any pressure,
or pump ANY Fuel, Period.""
"On" means the Pressure-Regulator-Solenoid is
receiving power at that particular moment.
"On" holds the Inlet-Valve "OPEN",
so that the trapped Fuel can flow BACKWARDS
out of the High-Pressure-Pump.
.
.
.

[@ajsellas2771]

@@jimbrown563 ohhhhh ok i get it now

[@teluguvideomemetemplates1528]

there are two types of these right? one open type and other closed type .. means one opens when solenoid is activel other closes when solenoid is active

[@jimbrown563]

@@teluguvideomemetemplates1528
There are so many different Pump designs that I can't state
for a fact that no Pump operates differently.
But in my opinion, this is the best and most practical method
of controlling a HPFP.
Therefore,
it's highly unlikely that a Pump would be designed to
operate in the opposite manner.