HFCM Testing - Diesel Forum

Maui Stroker · 11-13-2009, 02:20 PM

Will ('06, 6.0 F250) HFCM deliver spec fuel flow to secondary filter housing/PCV if the primary (10 micron) filter is not installed in the HFCM?

I seem to recall reading somewhere that proper insertion of the primary filter into the HFCM housing is necessary to open an internal valve thus enabling flow. Or am I imagining this!

Thanks in advance

**teamroper60** · 11-13-2009, 02:37 PM

I recently took an HFCM apart. The only valve I saw in it was a flapper style, one-way check valve that appears to be there solely to prevent a vaccuum on the tank side from pulling the fuel out of the HFCM.....

OT · 11-13-2009, 02:54 PM

Welcome Maui

I think f.pump will work with/without f.f. Look hereHFCM Fuel pump Problem can occur if hfcm cap w/oring isnt screwed (not cross threaded) all the way on.

Maui Stroker · 11-13-2009, 04:46 PM

Thanks TR60 and OT - much appreciated. Almost like real time response - amazing forum here. Anyway, that's the feedback I was hoping for. I'm thinking I need a new HFCM at this point.

Still on the HFCM service/repair subject, have you used the OTC Tools (# 6760) cover remover? I can't link the live page but it's viewable at;

http://cache01.voyageurweb.com/otcto...cts/09-139.pdf

Seems like it might be worthwhile to better access the unit if I replace it with stock.

The obvious follow on thought pertains to upgraded fuel pump/primary filter systems. I've done some preliminary research and am thinking I might go this route. I'm going to do a proper pressure/flow rate test first though before I commit. Is the stock HFCM a weak link in the 06 F250? Is it a sensible candidate for a first upgrade (my truck is stock with almost 60k on her). I intend to keep this black beauty for life so am definitely thinking about reliability and ease of service. I'm not sure what effect non stock HFCM has on any emissions/power train warranty I may have left.

OT · 11-13-2009, 07:23 PM

M..you shudda got here sooner.

1st time I've seen #6760 but, looks like a handy tool to have. I just use socket etc & works ok for me. Try "6L upgrade/aftmkt" forum on changing fuel pump system. Good luck!

**teamroper60** · 11-13-2009, 10:33 PM

I have not seen the need for a tool like the one you linked to.. A 36mm socket (which also fits the oil filter cap) works on the HFCM cap and a 24mm socket works on the top filter cap. Both can be bought at Sears and many other tool places....

bismic · 11-13-2009, 10:50 PM

The Lisle tool is a WHOLE BUNCH cheaper than a 36 mm socket from Sears.

dieseldiesel · 11-20-2009, 07:36 PM

There is a valve on the end of the fuel pump that the filter element opens. Without a filter you will be unable to pull fuel into the pump.

**teamroper60** · 11-21-2009, 05:47 PM

Funny, I did not see a valve on the end of the pump........ Now I will have to back to the garage and look at the pump again.....

69cj · 11-21-2009, 06:48 PM

My opinion, if it means anything is to leave everything alone, stock, and put a pressure gauge on the secondary fuel cannister. Min. press. is 45 psi @ wot. If you don't have that and fuel ilters are good the the hfcm or fuel press. reg. are bad. Don't, again my opinion, subject your injectors to sub filtered fuel.