I was just starting to learn something when....the freakin thread was closed. This is in regards to a Geno's filter lid replacement cap. If the port measures pre filter fuel then how does the fuel get to it? I don't get it.

 

My 05 plastic filter assy cap had clips that held the filter in place. Not so with the Geno cap. It doesn't push down hard against the filter. When I change my filter I have to bleed out air to my F/P sender. It's a added choir that goes with the pretty chrome cap -----RJ

 

Darn, looks like I will probably return it then unless I just want the billett look. I think I will just plumb my big line I have feeding the CP3 for my sender instead. Thanks for the info.

 

It comes with a allen plug screw installed. Post filter I hear is desireable. Makes sense to me. I'm accustom now to the pressure numbers associated with a clean filter and WOT readings so I can gather when my filter is getting tired. It is real pretty chrome----------RJ

 

I'll explain it as I understand it. I don't have one of these lids so I am speaking of how it would work if it was a stock lid. If I get it wrong, someone correct me.

Point #1: With fuel filters the fuel flows from the outside of the filter through the filter to the inside. The Cummins filter does this.

Point #2. The line that goes to the injection pump (CP3/VP44) comes from the center of the filter.

Point #3. The hole for the pressure tap in the Geno lid is in the center of the filter lid.

SO: one would think that it would take the pressure from the center of the filter and thus the pressure reading would be post filter.

BUT: that is wrong because the Cummins filter is closed in at the top. It is like this so that when the fuel restriction of the filter gets high the extra pressure pushes down on the filter helping it seal better. The pressure that is on top of the filter is the pre filter pressure, thus the hole in the Gabe lid measures pre filter pressure.

Does that make sense ? (It fooled me too. I forgot the top of the filter was closed in.)

BTW: I am going to drill and tap my stock plastic filter lid to receive a 1/8" NPT gauge mounted right on the filter lid. I'll do it this weekend.

 

So you're saying that you get post filter numbers from the sender mounted in the cap in the 1/8 NPT port?

 

No, The pre filtered fuel completly surounds the fuel filter except for the bottom base. The bottom base of the fuel filter slides on to the output port of the filter assy. The cap only gets exposed to prefiltered fuel. I ran a hydralic line from my cap center tap to the sender on my firewall. Hope this makes it clear as mud. My f/p guage is pre-filter pressure with Geno's cap------ RJ

 

Ok thanks. I'll probably use the cap for asthetics I guess. I'm going to use AN fittings and tee the supply hose to the CP3 from the filter housing.

 

You could also get a tapped banjo and pull the pressure right at the CP3 inlet

 

Or buy a tee and 3 hoseclamps and tee into the rubber fuel line between the liftpump and CP3. No vibrations, no tapped bolts or holes.

 

Like Ramtuff said. I just did the T in the supply line yesterday. No vibration, gauge needle is very still. Kept the stock hose and clamps in case I wver want to remove the F/P stuff for whatever reason.

 

Hope this picture helps clarify the way fuel flows through these things. This one here is a 2nd gen housing but I believe its similar to the 3rd gen. Here fule comes in the inlet, goes through the fuel heater, the through the filter down and out through the center post.

 

Wow, thanks for the picture and the clarification. That helps a lot.

I would have gone with a banjo but I went with a big line kit so the fuel line has been replaced from the tank to the filter and the filter to the CP3 with no more metric banjo. I'm going to tee in to the feed line to the CP3 with barbed AN fittings. I don't like hose clamps.

Thanks for all of the info guys.

 

That is basicaly what I have now. Only because of the FASS fittings @ the CP3. I never had any pulsing or vibration with the tapped banjo I was and am still using a needle valve, only opened about 1/8-1/4 of a turn.