Reg return and still dropping pressure?

wetnsloppy4x · Feb 26, 2012

:doh:

Strictly Diesel · Feb 26, 2012

da94broncodude said:
i built the regulated return myself based off a write up on tdg, basically i have lines coming from the back of the heads to an aeromotive regulator and it goes from there to the factory return housing and is tapped in, i dont have pics of mine but here is a similar setup (person i got the writeup from), he used a .125" thick by .5" o ring on the inside to keep the plunger closed, does that sound right? i havent done that yet but will if i need to

pump is stock hfcm

So the front lines are stock? Stock banjo bolts also?

If I'm reading this right, the original person used an o-ring behind the poppet to keep it from opening, but you didn't do that? If that's the case, the stock poppet is opening and causing your pressure issues and your regulator is nothing more than a fancy crossover line right now. You MUST prevent the stock regulator from opening or the aeromotive regulator won't do anything.

da94broncodude · Feb 26, 2012

Strictly Diesel said:
So the front lines are stock? Stock banjo bolts also?

If I'm reading this right, the original person used an o-ring behind the poppet to keep it from opening, but you didn't do that? If that's the case, the stock poppet is opening and causing your pressure issues and your regulator is nothing more than a fancy crossover line right now. You MUST prevent the stock regulator from opening or the aeromotive regulator won't do anything.

Front lines are stock but has 6.4 banjos, i blocked the factory regulator on fri night and it still does the same thing drops from 60psi to 20psi on a WOT run, didnt change anything from how it was before

Strictly Diesel · Feb 26, 2012

Under the stock regulator cover, at the top of the slot, there should be a small white plastic insert with a TINY hole in it. Is that still there, or was it removed?

I don't remember, but did you indicate whether you've recently changed the fuel filters (both of them) and whether they are Ford or Non-Ford?

da94broncodude · Feb 28, 2012

dennis, pretty sure the white insert is in there as i didnt remove it, fuel filters maybe have 2k on them? i change them every other oil change, and i change my oil every 5k

Strictly Diesel · Feb 28, 2012

Assuming nothing is plumbed wrong and no external leaks, the stock HFCM should be enough for 175s (also assuming the stock HFCM is working properly).

That said, if pressure isn't holding at the filter bowl (which is BEFORE all of the significant pressure drop of the filter and fuel rails/injectors), you've either got a problem with how you've blocked the stock regulator, got a missing air bleed orifice insert (the little white piece I asked about) or the HFCM you have isn't doing it's job. I would pull the regulator cover again, and make darn sure the stock regulator is blocked (how did you block it?). We actually redesigned our replacement regulator cover due to changes in the later fuel bowl castings causing similar problems, it was too hard to get the stock poppet to properly seal that big bottom port without the black rubber insert that the earlier bowls had. If you're trying to seal the factory regulator port with a poppet and some pressure on the back, it might not be enough, you might have to get creative with an o-ring on the bowl side of the poppet too.

Once you're positive you've got that factory regulator port blocked and that the white insert is still in place...if you still have pressure drop...try a different HFCM.

Just some thoughts...good luck.