I've acquired a second HFCM for a low cost and was debating on whether to install this inline with my existing HFCM. It seems I remember a post from sometime back about this, but can't find it. Has anyone done this before? How did you route the fuel lines and wiring? Thanks.

 

I guess my question is why would you want to add a second HFCM? What purpose would that serve?

IMHO, adding a second HFCM would be a nightmare. The HFCM puts out over 100 psi. I found that out recently when I installed the GDS FPR spring with a FP gauge installed in the filter housing drain port. I was told buy FTE site guys that would blow the FI O rings even though GDS says that Navastar fuel system engineers have stated to them that the 6.0 fuel system is designed for 120 psi max operating pressure. The GDS spring raises the fuel pressure to around 105 psi.

AIRDOG makes sevseral inline assist and stand alone fuel pumps for the 6.0. However, the purpose of the AD is not to increase fuel flow but to remove any air from the fuel caused by tank sloshing and the HFCM. This produces more efficient FI spray patterns. If you want to learn more about AD, go to their site.

I elected to install the AD2 with an adjustable FPR that replaced the HFCM. I now run my fuel pressure at 70 psi. That is 25 psi above the standard 45 psi HFCM FI delivery pressure and 10 psi below the Ford recommended max fuel pressure.

DSMMH

 

I added a second HFCM. I had huge pressure drops at WOT. A single HFCM cannot keep up with aggressive tuning. Installing it wasn't anything close to a nightmare.

I started by making up a bracket to mount the 2nd pump on the frame rail, towards the rear. Then I dropped the tank and made a new rigid fuel pick up tube and plumbed to the new pump. A single 3/8" supply line is all any stock injectored truck will need. I used short pieces of flex fuel line at connections to hard line I bent up between the tank, new pump, and original pump. The return line nipples on the new pump can be capped off.

There's no need to remove any of the stock fuel lines. Disconnect the factory tank supply line at the original pump, and a piece of 3/8 will fit perfect to connect your new fuel line, and a clamp will hold it tight. If you ever have a problem with your new line, you can go back to a stock configuration in a minute.

For power, I have an unfused circuit from the PS battery to a relay for the new pumps source. I tapped the factory pump circuit to close the coil. Super simple.

I've had this set-up running for over a year. No problems whatsoever, and FP stays solid under aggressive conditions.

If you're serious about the install, I'll post some pics later this evening.

 

Im very interested in some pics if oyu have the time. something I have not seen done.

 

Here's few for ya cheezit..

Bracket made from scrap. Drilled to fit some exiting holes in frame rail.



New pickup mounted into stock tank cap. Gotta get a little creative with the brass. The parts I found tighten down and seal the grommet. A short piece of hose goes from barb to new hard line at rear.



Rear HFCM plumbed. The return fuel fittings have better caps now.



Looking from front to rear at both pumps. You can see the new 3/8 hard line fits in the stock retainers with the factory lines. I made a cap for the original supply line from a nipple cut off an old HFCM cover, filled with some round stock and secured with poly glue(the round stock, not the nipple). The modified nipple clicks in and seals perfectly. If the original supply line is left open, it will drain fuel when the tank is full.




When it come time for filter changes, I only buy one kit. The new filter goes in the forward pump.The filter removed from forward pump gets moved to rear pump, and old rear filter discarded. The used front filters that get moved have always looked great(still white) compared to the rear filters that get thrown away.

Also FWIW, pressure is controlled with an ITP R/R up top...

 

so if I see this correctly you just bypassed the oem supply line from the thank to oem pump. how did you block off the original supply line from the sending unit. the only thing im not getting.
looks to me like you really didnt need to mod the sending unit could have just used a 3/8 line from that to the added pump then in to thesupply of the oem unit.
also as far as suppling voltage could you have just tied in the fp ckt and used it to run both pumps? the ckt runs off a fused realy already.

very interesting as find a good fuel pump is not hard to do. I wonder if this would really solve the volume problem as pressure is not really the issue


O and nice train horns!

 

tried for the reps for the pics but it wont let me bahhhh.

 

Yes. Bypassed, and still intact if needed.

I edited my previous post and added that detail. Nipple cut from an old HFCM cover.

The OEM supply nipple at the tank has a tiny little hole in it for fuel to flow through. I had the tank dropped and didn't want to have to drop it again wondering if that little orifice was a restriction. 44 gal tanks are a PITA. The pick up was easy enough to make.

The horns were installed before I did this mod. When I did the horns I ran an 8ga from the battery fused at 40A. I tapped that wire for the 20A fused air compressor circuit. I ran the large wire because I knew I'd be adding something in the future. I don't need a bunch of little supply wires all coming from the batt. I tapped the same 8ga and fused the new fuel pump at 20A. I got a new pigtail with the new pump to make the pump connections easy. I'd do it like this again to keep the second pump electrically isolated from the original. That's just me.

It solved the volume problem for me. No more <20psi runs. I haven't lost an injector since(C94's), and last year they got hit pretty hard.

Thanks.

 

very cool and I can say I learnd something new today... Thank you for the lesson. Now I have more to ponder. I had a simular thought but was thinking 7.3L pump wich has no filter. and good volume

 

Thanks William!! I like the setup and will probably attempt this in the next few weeks. How long did the install take you? I have most of the parts available already, but may need to shop around for parts for a new pick up. So, you left the original supply line connected to the tank and in the factory clips, but just plugged it at the oem hfcm end, is that correct? Also, seems like getting the proper bends for the supply to the new HFCM might be difficult without the tank in place- any tips on that?

Oh yeah, rep added.

 

Fantastic post - many thanks!!