HPFP Repair

[mcpcartier]

So APR says this is irreparable...

I can't imagine that is the case...anyone been down the road of having a HPFP repaired? If so who did it? Looking for some options.

[i3oricua]

If I remember correctly when I upgraded the internals on my pump I replaced those parts. Look on JHMs site and see.

https://jhmotorsports.com/shop/catal...h=21_62_65_255

[aluthman]

Buying a set of pump internals will fix it. Make sure everything is clean clean clean when you put it together and listen to the torque specs that come with the kit.

[vce1232000]

Id go with IE internals.

[ericw.]

I have IE internals in my pump right now. No problems at all.
With that, I think the JHM cap at the top of the spring is a bit simpler to understand and the design is less likely to pop off.

The IE cap at the end of the spring (the piece which touches your cam follower) has retaining clips. They have a small possibility of coming off if not perfectly seated.

[mcpcartier]

I'm leaning towards JHM only because Jake's been an avid supporter of the forum for as long as i can remember.

I'll do some digging tonight when I have some time to think it through. Want to have it all rebuilt this weekend (do the timing belt + other junk I've got stacked in the garage which is all due...high mileage).

Thanks for the input...much appreciated.

[ericw.]

Here's a little picture I drew for you. lol



If you press the cap in, compressing the spring but not the piston at the same time, these retaining clips can potentially slide out and get lost which leaves you with a HPFP brick. While this would never happen when the HPFP is installed, it's a risk when we're changing cam followers that requires a bit of care.

[Copen-cisco]

I can vouch for IE internals as well.

On your earlier pics it looked like one of the sensors were gone.. you will need that but I'm sure you already know.

[vce1232000]

Id IE piston design. Less likely to leak fuel into oil

[seal66]

john's hpfp. no issues with mine, over 60k miles almost and about 20k on full e85

[aluthman]

john's hpfp. no issues with mine, over 60k miles almost and about 20k on full e85

Stage 1 or stage 2?

[seal66]

Stage 1 or stage 2?

Stage 2

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[mcpcartier]

john's hpfp. no issues with mine, over 60k miles almost and about 20k on full e85

Remind me who John is.....I recall you and JR talking about him a while back.....but I seem to recall slow response and other challenges. I suspect his stuff is great but it would take me weeks/months to get parts and I'd like to have this done by Sunday.

[aluthman]

Remind me who John is.....I recall you and JR talking about him a while back.....but I seem to recall slow response and other challenges. I suspect his stuff is great but it would take me weeks/months to get parts and I'd like to have this done by Sunday.

John @ HPFPupgrade.com

I have their stage 1 pump and it has been problem free for over 50k miles.

[i3oricua]

I don't understand why APR won't fix it under warranty or replace it?

[vvenom800tt]

because apr sucks, theyll want you to rape yourself and buy a whole new pump so they can make more money off you

[vce1232000]

I don't understand why APR won't fix it under warranty or replace it?

Mite be out of the warranty period

[Theiceman]

What are the costs of these internals ?

[z_wrecker]

$325 on sale right now

What are the costs of these internals ?

[mcpcartier]

John @ HPFPupgrade.com

I have their stage 1 pump and it has been problem free for over 50k miles.

That rings a bell....thanks

[mcpcartier]

Here's a little picture I drew for you. lol



If you press the cap in, compressing the spring but not the piston at the same time, these retaining clips can potentially slide out and get lost which leaves you with a HPFP brick. While this would never happen when the HPFP is installed, it's a risk when we're changing cam followers that requires a bit of care.

Interesting...will compare designs and see if my laymen mind feels more comfortable with one over another.

[aluthman]

Here's a little picture I drew for you. lol



If you press the cap in, compressing the spring but not the piston at the same time, these retaining clips can potentially slide out and get lost which leaves you with a HPFP brick. While this would never happen when the HPFP is installed, it's a risk when we're changing cam followers that requires a bit of care.

This is the exact same style retainer that is holding all of your valvesprings in your head.

[ericw.]

This is the exact same style retainer that is holding all of your valvesprings in your head.

but you're not removing valve springs every other oil change i hope.

maybe it's just something that I noticed since I'm OCD with detail.. but because of the short length of the rubber hose on the HPFP, pulling/reassembling the pump without also accidentally pressing the side of the "hat"(?) on the edge of the cam lobe hole requires a bit of attention.

That was one benefit I saw to the JHM "hat" was that it's a closed cap and you cannot compress the edge of it without also compressing the piston.

[aluthman]

Banjo bolt here.

[seal66]

Remind me who John is.....I recall you and JR talking about him a while back.....but I seem to recall slow response and other challenges. I suspect his stuff is great but it would take me weeks/months to get parts and I'd like to have this done by Sunday.

Like aluthman said john at HPFPupgrade.com

He used to be but I have been able to get ahold of him first call or email same day

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[jubegnx]

I'm running the IE internals also with the JHM big turbo kit no issues so far.

Main reason I chose it is because of the constant diameter piston.


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[Theiceman]

I guess if you are upgrading this is the way to go. I just wanted to repair my car so 230 for a brand new hitachi pump was the way to go vs 325 for parts.

[mcpcartier]

I don't understand why APR won't fix it under warranty or replace it?

Not sure....I'd like to get a new tappet (cap) for the end of the piston....I think the rest of the pump is in perfect condition. Their only reply was its "irreparable". I'll reach out to them again and see if they'll elaborate. Maybe the tappet is permanently attached to the piston during the assembly process and theoretically can't be replaced. If I could get that part I'd give it a go.

[mcpcartier]

Not sure....I'd like to get a new tappet (cap) for the end of the piston....I think the rest of the pump is in perfect condition. Their only reply was its "irreparable". I'll reach out to them again and see if they'll elaborate. Maybe the tappet is permanently attached to the piston during the assembly process and theoretically can't be replaced. If I could get that part I'd give it a go.

They did elaborate a little....

"When the button of the pump fails in that manner the internals can not be repaired at that point. This is the same damage that is apparent when cam follower failure occurs and unfortunately is catastrophic to the high pressure fuel pump."

I suspect this could be the case, but I don't think its always the case. I'm guessing my internals are fine...but maybe an off-center blow to the piston messes up the internals. The tolerances are very tight...

I really wish they'd disassemble, put in some new seals and cap and test it. I bet it would be fine. But they do not appear to be interested in providing that kind of service.

[Jake@JHM]

I am not familiar with what APR does in their HPFP upgrades so I cannot say for sure if our replacement kit will work. There is a good chance though.

[mcpcartier]

I am not familiar with what APR does in their HPFP upgrades so I cannot say for sure if our replacement kit will work. There is a good chance though.

APR has the larger piston so the JHM piston diameter is too small to work with the APR seals.

[Jake@JHM]

APR has the larger piston so the JHM piston diameter is too small to work with the APR seals.

We actually have a larger piston than APR. It's just our piston shaft reduces to OEM size to fit OEM seals.

[mcpcartier]

We actually have a larger piston than APR. It's just our piston shaft reduces to OEM size to fit OEM seals.

Good point....The APR piston is the same diameter for the majority of it's length. I think that diameter is larger than the OEM diameter which makes the seals the incorrect size. I'll measure it when I get back to the somewhere with calipers.

[Brillo]

The APR shaft/piston diameter is significantly larger than OEM which is why it is capable of pumping about 30% greater volume of fuel at the regulated pressure at high RPMs. This also explains why the higher volume HPFPs result in greater wear of the follower, and therefore need to be checked more often.

[vvenom800tt]

I think the accelerated wear is due more to a higher rate spring isnt it? IE, more pressure on the follower

[Brillo]

No, the spring back pressure is only a minor component of the contact stress between the follower and cam surface. Remember, the piston is pressurizing the fuel to about 1400 psi. That pressure divided by the piston/shaft cross section is about 130 to 140 pounds of force pushing back against the follower/cam. The spring probably adds only about and extra 20 to 30 pounds. If you increase the piston diameter by 30% to get more fuel volume, the fuel back pressure would increase by the same percent. You are now up to 176 pounds plus the spring pressure. That's a lot of force between the cam and follower and explains why they have a propensity to wear.

[yeoj112689]

All I know is to be careful when switching it out NOT NOT NOT NOT NOT NOT NOT to break the fuel pressure regulator valve on the top. Wanna guess how much that would cost to replace it.. IF YOU CAN EVEN FIND ONE! Pain in the ass.

Not that this happened..

[mcpcartier]

So I end up helicoiling the housing and it worked great.

Then Jake at JHM sold me a tappet that I threw on the pump.

Put it back in (with other new parts that were damaged) and all seems good. Did about 300 miles so far and the only thing I noticed is a boost leak (did timing belt/thermostat while it was apart). But fueling is awesome and averaged about 30 mpg commuting this week, better than before.










To make life easier to remove the pump in the future I'm going to replace the barbed low pressure fitting on the pump with a nipple (like the high pressure side) then get an elbow (threaded on one end, barb on the other...like the middle one in the pic below) so I don't need to slide that dang hose on and off every time I want to take the pump out.

Anyone know the thread spec's for the low pressure side? Once I know that I'll know what nipple to get and find the appropriate elbow.

[ericw.]

Nice work! glad it's back together and performing.

I think it's pretty rare that you need to remove that rubber hose. It's flexible enough that you can change cam follower with it still attached. I never removed mine except when I rebuilt the pump.

[mcpcartier]

Wasn't a boost leak...my Revo tune had lost it's settings....acquire came back with 0/0/0....reset to 6/2/9...back to normal.