HPFP Parts Question

[sloth8871]

So I am experiencing the hard start issue with my car where it takes 2-3 attempts and pumping the pedal to get the car to start after it been driven a bit then left to sit. Stage 3 SRM Turbos APR Tune, had new plugs done a month ago and still same thing. My indy shop wants to do the HPFPs next and I have a question about replacement parts.

the direct replacement for the S6 appears to be
079127025aj


which is a Hitachi HPP0023. This is out of stock everywhere and is $1000 ea roughly for OEM, can be found if in stock for around $300-400, but again not in stock anywhere right now.

There is also the Hitachi HPP0017, which as far as I can tell is either the same or an upgrade, google says its for the RS models so higher flow maybe... this is in stock everywhere for like $300 and the only physical difference I think I see is that the mounting holes are rotated a little bit, like 15 degrees or so instead of slightly slanted like the HPP0023.



Does any one know if these are interchangeable and will work? ... IN LINE UPDATE, I think now that I am taking a closer look they are not cross compatible , the HPP0023 has an extra threaded hole on the under side, noted in the pictured above. and the HPP0017 does not have that extra hole....

side note, I found a pair of the HPP0023 on aliexpress for $320 total, but I'm having a hard time trusting those will work lol.

[SuperCiv]

About to go through the same exact process with the HPFP due to the same hard start issue. Car also feels slightly...sluggish? I don't know if the pumps are cross compatible with the RS7 but I'll be stealing any research you post to save some time if they are.

[joeyjazesmith]

I was considering this, (dont have this issue, just wanted to upgrade) but i heard its best to do the fuel line upgrade to help with better flow into all the cylinders. Didnt look into it tho to verify and had to postpone

[Frost_GST]

ECS Tuning has a HPFP rebuild kit for like $130 that would be a good alternative to replacing the pumps since it's the seals around the pushrod that fail and cause the issues you are having.

https://www.ecstuning.com/b-tgk-moto...-hpfp-k01~tgk/

[Burkeomatic]

Yep, I ordered my seals from TGK, but it's great we have that option now. You've probably got fuel in your oil too. Is your oil level going up?

Also, always do these when you put bigger HPFP plungers in, or anytime you service them. It's pretty simple, you just need to buy the little socket adapter thingy to screw them off.

[sloth8871]

Yep, I ordered my seals from TGK, but it's great we have that option now. You've probably got fuel in your oil too. Is your oil level going up?

Also, always do these when you put bigger HPFP plungers in, or anytime you service them. It's pretty simple, you just need to buy the little socket adapter thingy to screw them off.

I looked at both of these, I am already stage 3 with no plans on going to E85 or anything so not sure that the upgraded plungers would do anything for me and also they cost as much as 2 Hitachi fuel pumps lol so I was kind of hesitant to pull the trigger on those. Would I actually get anything out of those?

Also for the rebuild kit interesting that it's just the seal basically, the spring or nothing else gets worn and needs replacement?

[Audibellybutton]

get the hitachi from rock auto its cheap, arrives fast and is literally the same as oem. Ive been running these for countless miles (I forgot how long but it has been years)

[sloth8871]

get the hitachi from rock auto its cheap, arrives fast and is literally the same as oem. Ive been running these for countless miles (I forgot how long but it has been years)

Unfortunately these have been out of stock for a while everywhere. Keeping my eyes open though.

I went and look over the weekend the extra hole is used on the s6 platform anyways and I also read that they feed fuel in series so I am guessing thats what the extra holes are for.

[Burkeomatic]

No access to E85 huh? Bummer.

Yeah, not sure if you need the plungers if you aren't running E. You could always try the seals and see if that fixes your problem. It will cost less than $200 to try it including buying the tool. Looks like those plungers went up in price. I forget what brand I used, either the autotechs or the 034 ones. But yeah, swapping the seals isn't hard at all if you have the tool. You could upgrade your fuel lines for a couple hundred more, but there's the noise no one tells you about.

[sloth8871]

No access to E85 huh? Bummer.

Yeah, not sure if you need the plungers if you aren't running E. You could always try the seals and see if that fixes your problem. It will cost less than $200 to try it including buying the tool. Looks like those plungers went up in price. I forget what brand I used, either the autotechs or the 034 ones. But yeah, swapping the seals isn't hard at all if you have the tool. You could upgrade your fuel lines for a couple hundred more, but there's the noise no one tells you about.

Haha I am sure I can get E85 in Austin but I don't want to mess with all of that. I daily the car and I am not doing anything crazy and am happy with the reliability and not going out of my way for gas. Plus at Stage 3 I would need to do all of the fueling upgrades and I am not super inclined to be dumping a bunch of more money into a 10+ year old car anymore... I actually ordered those fuel lines the other day figuring the dedicated lines would help with the issue and just be a slightly better overall setup than stock, what noise are you referring to with these?

[Burkeomatic]

Haha I am sure I can get E85 in Austin but I don't want to mess with all of that. I daily the car and I am not doing anything crazy and am happy with the reliability and not going out of my way for gas. Plus at Stage 3 I would need to do all of the fueling upgrades and I am not super inclined to be dumping a bunch of more money into a 10+ year old car anymore... I actually ordered those fuel lines the other day figuring the dedicated lines would help with the issue and just be a slightly better overall setup than stock, what noise are you referring to with these?

Oh you're APR, I missed that. The fuel lines make a vibrating sound around 2k rpm give or take a little unless you insulate them and tie them down well.

Like I said, no one tells you.

[Frost_GST]

From my understanding, the only parts that really wear/fail are the seals around the pushrod and the cam followers (both are included in the rebuild kit). When the seal fails around the pushrod, it allows fuel to leak around the seal and into the crankcase. This causes the hard start/no start because of the drop in high line pressure. Also the extra hole on the pumps you are referring to on our HPFP is used as a low pressure feed line on the passenger side pump and then on the driver side pump it is where the low side fuel pressure sensor is located.