Cleaned HFCM, now losing FP

[6speedsd]

Slightly changing the subject...

The regulator that came with my RR was just some off the shelf basic efi regulator. I started having issues with it sticking closed and spiking fuel pressure up over 100....I've mentioned this already I think. Anyways, I did a little air testing on it this afternoon, trying to figure out what the deal was with it. I sort of rigged together a way to shoot shop air to it, and with the adjustment screw out completely, it still spikes at over 100psi (roughly what I was putting into it). Nothing at all comes out of the return port. I get the same results with the spring completely taken OUT of the regulator. What the heck would cause one to do this? The air bleeds off out the valve I have at the head of the system where I introduced the air...nothing out the return on the regulator. I'm still scratching my head as to what would cause that. I'll link a video I took at the end. Sent that to the shop that sold me the kit to see what he has to say about it.

https://youtu.be/Pvb_H3748kM

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[6.0 Tech]

That may be your whole issue. Put a high quality regulator on it and see what happens. I would be worried about the injector o rings after having it spike over 100psi. Ive nheard that 70-75 is max th o rings can hold. But you'll never know with a bad.regulator on there that is not doing its job.

 

[6speedsd]

That one is not on the truck. That's my old one (original that came with the RR). Currently has an Aeromotive on it.


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[6.0 Tech]

Oh, ok. Well chit man i dunno. Maybe this one is failing now too :shrug:. I am lost though at this point. Only other thing i can think is injector o rings. The only things i can think that would cause a bouncy gauge, and massive pressure drop would be pump, regulator, filters, restriction, aeration, or o rings. Aeration and restrctiob have been pretty much eliminated, if i remember right you canged the fikters. You did use motorcraft right? 3 pumps is unlikely as you said. All thats left really are regulator and o rings. Unless some crap got by when you were cleaning and there is a restriction between the pump and the secondary filter. You could try blowing the lines out and see what happens.

 

[6speedsd]

Yep, always Motorcraft filters. And the supply line between the pump and upper filter is new...just made it last week. -6 line with quick connects on either end. I think I might cap off the RR lines coming off the back of the heads, put the factory regulator spring and return line back on, and run it without the reg return as part of the equation.


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[6.0 Tech]

Ok, sorry must've forgotten about reading that, youve tried so much on this tjing. Removing yhe regulated return sounds like a good plan. It should be slightly easier than pulling all 8 injectors and re oringing them. Let us know how that goes. Good luck buddy.

 

[6speedsd]

Absolutely. Trying to leave pulling injectors as a last resort. Just glad all this didn't happen during the summer when I need the truck every day. Right now, I'm in no rush...just tinker with it as I get time.


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[mandkole]

What an ordeal.. feel for ya and hard to be much help not being right there.

Yes, you confirmed its not the regulator. I still think its the supply fuel 'quality' (air) and it gets worse as the velocity from demand increases. A few more suggestions;

--make sure the bowl is real clean, remove the upper filter and run the truck. Perhaps there's an issue in the bowl that's creating air?
--If operation is unchanged, loop the supply line through a tee with a ball valve connected to a line on the 3rd leg to a bucket (to mimic injector consumption), then run the main line to the regulator and return it to tank, watching the gauge.? This will allow you to manage an injector flow but completely isolate the engine plumbing for the moment and confirm a steady gauge. Then, run pump on battery and watch the gauge for pulse or shake. If it does, its in your supply plumbing. If not, its in the engine somewhere.

Im kinda lost as well, but I still think were missing something with the return loop of the module and continue to come back to the first few posts which signaled the start of this issue. The coincidence of any other engine (or engine plumbing) issues that started exactly when you serviced the module is still hard to imagine.

 

[6speedsd]

Yeah I agree the coincidence of it all is really hard to believe. Thanks for the suggestions, and I'll give them a try at some point this week.

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