Fuel Pressure Regulator question

[Greg Peters]

Hi Guys,

Finished my EFI install. Here's some background info to get you all up to speed.

345 w/ 727
1227747 w/ BCC ACSF (5.7 ECM)
19.5 vacuum at idle
350 injectors
E2182 fuel pump
All key-on voltage checks within spec
Running knock sensor and EGR
Rebuilt TBI including new FPR diaphram

I was reading very lean on the BLM table so I adjusted the fuel pressure to the max position (tab at top of slot). The gauge now reads 9 PSI and is steady throughout the RPM range. If I pinch the return line for half a second the gauge max's out at 15 PSI.

I'm thinking it might be a weak FPR spring? If you agree, any ideas on where to find a replacement or substitute?

I have attached two very short log files. For some reason one log had a rich error code right from the start and a lean error code part of the way through. This seems a little odd since the BLM's don't look that bad (to my uneducated eye). I reset the ECM and grabbed another short sample. I was taking a longer drive when my tuning laptop died, so I wasn't able to save the BLM. I'm going to add a power inverter so I can plug it in and get a longer sample (both log and BLM) tomorrow.

Thanks in advance for any feedback on the FPR situation or data log.

Greg

[Bill usn-1]

Where's the BLM?

Looks like the alt is a little high or your batt may be weak.

You need to back the idle screw off 1/2 turn.

If you ran the regulator up too far then it may have unscrewed off the end of the screw.

Either way you should pull it and reset it to about 12-13psi.

The 350 inj's at 12-13psi should be close.
I would hit a JY or ebay for a spring

[Greg Peters]

Hi Bill,

My computer died before I could save the BLM. I will post one tomorrow.

Thanks for the tip on the regulator. I don't think I unscrewed it all the way off the end, but I will pull it and check in the AM.

Battery is new. Should I replace the alternator given the high reading?

Thanks again.

Greg

[Bill usn-1]

If you have a stock alt then check the sense wire to make sure you aren't full charging all the time.
See Madelectrical.com

It looked like you were going to a commanded 128 meaning the ecm saw the afr out of spec and forced a BLM of 128. It makes you think the fuel is great when it's not.

[Greg Peters]

Hi All,

I replaced the FPR with a junk yard unit and still have 9 psi even after adjusting the FPR tab all the way to the top of the slot.

A couple of questions:

1) Is pinching the return hose and getting a spike in PSI (to over 15) a reliable test of the fuel pump?

2) I have 3/8 fuel line from the pump to the TBI, but kept a short section (approx. 2 feet) of new 5/16 line from the tank to the filter. Could this be the issue? I didn't think it would matter because the tank outlet is 5/16.

Thanks for any help or direction you can provide.

Greg

[Bill usn-1]

Are you sure the gauge is accurate?
Sounds like it's off.

Pinching the return verifys the pump is capable of higher pressures.

The hose won't hurt it.

[IH64Scout]

just aquiring parts for my swap and stumbled upon this post, now with the ford inline pump being higher pressure the TBI HAS a pressure regulator in it already? no need for an inline regulator? i'm not 100% so i figure i'll ask here instead of another thread, sorry if i jacked this one!

-Jon

[Greg Peters]

Hi IH64Scout,

No problem on the hijack. Yes, the TBI has a fuel pressure regulator built in. Check out the FAQ for a link on how to make it adjustable.

Greg

[Bill usn-1]

Originally Posted by IH64Scout

just aquiring parts for my swap and stumbled upon this post, now with the ford inline pump being higher pressure the TBI HAS a pressure regulator in it already? no need for an inline regulator? i'm not 100% so i figure i'll ask here instead of another thread, sorry if i jacked this one!

-Jon

Read ALL the FAQ's. hint: there's one for changing injectors and making the regulator adjustable!
Did you see a regulator listed in the parts required FAQ?

[IH64Scout]

Originally Posted by Bill usn-1

Read ALL the FAQ's. hint: there's one for changing injectors and making the regulator adjustable!
Did you see a regulator listed in the parts required FAQ?

i've read the FAQ a while back, i thought i read that but forget where it was and just did a quick search. i didn't see one listed. all the info in the FAQ is very helpful. yet all the reading makes my head spin! i will hopefully be getting my 392 back in a week or 2 and i'm going to start mocking up the TBI parts. i can't wait!

thanks!
-Jon