[SOLVED] More fuel issues!

Don't use oil to lube it. The HPFP gets quite hot and mixes with fuel pretty readily. Obviously, this can cause issues if the oil can't handle the heat loading while mixed with said fuel. Also, cleaning the spill valve is a supremely important part of cleaning the HPFP so you're going to have to do it again anyways since you *technically* didn't actually clean the whole thing.

If there's one thing I truly understand about this car/platform, it's the HPFP.
 
I read its best to take the spill valve off while attached to the car which is what im planning on doing, I bought a bottle of injector cleaner but its not redline, should i dump the bottle in there when the spill valve is out?
The issue seems to be low ITFP tho
 
chris' speed 3 said:
I read its best to take the spill valve off while attached to the car which is what im planning on doing
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Loosen it while it's on the car until you can take it off the rest of the way by hand. Leave it on there though, as it makes it easier to work with and ensures you don't lose the button and spring.

chris' speed 3 said:
I bought a bottle of injector cleaner but its not redline, should i dump the bottle in there when the spill valve is out?
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Uh, no. Get the Redline stuff (it will last a long time so it's worth it), and get that UOA or swap to an oil from the thread.

chris' speed 3 said:
The issue seems to be low ITFP tho
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What makes you say this?
 
Enki said:
Loosen it while it's on the car until you can take it off the rest of the way by hand. Leave it on there though, as it makes it easier to work with and ensures you don't lose the button and spring.


Uh, no. Get the Redline stuff (it will last a long time so it's worth it), and get that UOA or swap to an oil from the thread.


What makes you say this?
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Can I not take it off separate from the pump, I can't take the pump out again its cold asf outside I got to put it in my moms garage the last time but she's fed up of me being in there
I get 36psi koeo
 
Stock FPR is ~40 PSI and ramps to 60 at higher loads IIRC, so that sounds fine. You can't tell if your FPR or ITFP is shitting out at WOT without some way to directly measure the feed pressure, which ultimately doesn't matter that much since the HPFP is a positive displacement pump and will be happy with 6 PSI or 60 PSI going to it, as long as it keeps fed.
 
I don’t know good point, honestly if I can avoid taking the pump out of the car that’s be great because it’s snowing where I’m at and I gotta work outside now. The pumps in and it’s lubed and I inspected it there’s no damage.
The problem is there’s a whistle noise ever since I changed the fuel pressure sensor and my hpfp is low but afr seem to be okay if u checked my logs by any chance
 
Enki I’ll take my pump back out and clean it but I don’t see how that’s gna fix it.
can I use a generic fuel system cleaner for lubing it or does it need to be redline, I don’t have it locally I’d have to order online.

also I get the pump is a positive displacement pump but doesn’t Low side fuel pressure still matter, I’m assuming it fills up a chamber with fuel then gets compressed and shot into the fuel rail, if it’s not getting that chamber full enough wouldn’t that cause slightly lower fuel pressures? Just asking u you know way more abt this then me
 
The point of adding the redline to the HPFP after is more to displace and dilute the oil that will enter the pump. You can lube and prime with the lighter fluid that you use to clean it, but it won't last as long.

The HPFP fuel system is technically also a hydraulic system also, and since there's no return to the tank, fuel can really only flow one way without some kind of cavitation. While pressure might drop off under higher engine fuel requirements, as long as it's not zero you should be fine; again, the only way to know for sure if this is the issue is to put a gauge on the feed line to the HPFP and measure it directly (unless someone figures out how to measure this using other metrics in a verifiable and accurate way, which so far has not happened yet).
 
Enki said:
The point of adding the redline to the HPFP after is more to displace and dilute the oil that will enter the pump. You can lube and prime with the lighter fluid that you use to clean it, but it won't last as long.

The HPFP fuel system is technically also a hydraulic system also, and since there's no return to the tank, fuel can really only flow one way without some kind of cavitation. While pressure might drop off under higher engine fuel requirements, as long as it's not zero you should be fine; again, the only way to know for sure if this is the issue is to put a gauge on the feed line to the HPFP and measure it directly (unless someone figures out how to measure this using other metrics in a verifiable and accurate way, which so far has not happened yet).
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Okay got it but my question is can I use any fuel system cleaner as lube instead of redline?
 
Okay then ill give it a shot with the fuel system cleaner i got, so ur telling me my next steps should be crack the spill valve while its still on the car, then take the pump out, clean everything with naptha, clean spill valve, lube everything with the fuel system cleaner and then put the pump back in, fill the pump up with fuel system cleaner from the spill valve hole, tighten spill valve?
 
Alright Enki I just finished up with the hpfp, I took it all apart replaced every o-ring, the actual internals look good, the cam buckets has some light scratches on the sides.
I cleaned everything with the lighter fluid and lubed with the fuel system cleaner(was actually great stuff and felt much more confident in it then oil). Put it back on the car and filled the pump up w lube and tightened the spill valve.
It’s still making the same noise, someone on Reddit was having the exact same issue as me and he said the noise went away when he put his old FP sensor back in the car so I’m wondering if I just have a bad sensor
I’ll attach some pics
 

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