Marine

Is that bypass valve the copper deal above the pump?

Erska

Uhm. I didnt find any writings on it, only letter T wich means that's the tank neck side.

Mopar1973man

Yes there is a big problem with using copper tubing. The vibration of the engine and truck with eventiual crack the tube either creating a air leak or a fuel leak in either case in not good...

DL1221

I know this is off subject a bit, but I’ve been using 1/8 copper tubing to run oil and fuel pressure gauges for years, never had a crack problem. I always end up kinking, or crushing with the ferule, the plastic tubing that comes with the gauges. I use high pressure rubber fuel line from the banjo bolt to the fender, to isolate engine flex and vibration, then run copper tubing to the gauge inside the cab.

Mopar1973man

Ah... At least your smart and use a flexable ruber hose to get to the firewall. I've heard of a few that direct connected with copper and had some serious problems later with air and fuel leaks...

The only problem I've had with nylon tubing is the tube gets melted by hot parts or you kink it while stuffing in the dash. Other than that mine has been trouble free so far...

2500CTD

I cant say for sure, but i'm thinking its a check valve to prevent the fuel system from draining back into the tank when the truck is off. Its not really a bypass valve per say as to more of a controlled leak that returns back to the tank, thus reducing FP to a more managable level.

Erska

Aww...

Sorry guys, I didnt understand the question at first time.

It is sort of a by-pass valve, it regulates the fuel pressure, in my case, it keeps 14-15psi pressure constantly.

That lift pump is so much powerfull than the original and instructions said that it gives only 20% of it's full power because the by-pass valve, and that way it's has better longevity than the others.

You can hear the fuel when it flows back to the fill neck&tank when you open the tank cap.

Edit: I just installed big line kit from fuel filter to vp44 and fuel pressure dropped to 14.5psi.

GrampZ

UPDATE!! UPDATE!!

Dang! New info on the dual pump setup! As I reported at the start of this thread, the pressure was running NEAR the top of my 15 psi Westach electric fuel gauge. Since it didn't peg the needle, I assumed(yeah right!) it was giving me an accurate reading.
I just kept having a nagging feeling about it and finally double checked it with a mechanical gauge. HOLY COW!!! it was really running at about 26 psi @ idle!!!
Apparently the sending unit is maxxed out or out of calibration. Now I don't know what to do. Is that too high a pressure? Am I going to hurt something or can I carry on as is? Should I think about a different setup? ARGH!!!
Guess at least I'd better get the 0~30 gauge and sending unit....

GrampZ

Mopar1973man

You need to jump up to a mechanical gauge for one... DiPricol's are inexpensive... Also take notice that the gauge is marked in half pound intervals and also its a 0-30 PSI gauge...



26 PSI isn't to crazy yet I've seen a few that high... But I wouldn't go any highier...

dingoo

get the vulcan kit you wont be sorry. 14 at idle and about 11 or 12 heavy on the throttle

caleb

GrampZ im also in the same boat, after reading you original article and having a brand new campaign pump fail in just a matter of weeks I decided to add a pusher pump down on the frame.

my weapon of choice was the pro-comp "black" flows 140GPH @ 9PSI with no regulator its the same as the Holley pump, just without the sticker.
Install was fairly straight forward, however the truck being a shortbed didnt leave much room to mount it. I placed it just behind the frame crossmember wired in a relay that is triggered by the factory LP hooked it all up, jumped in started it, bam 26PSI Lowest recorded by the attitude is 15....

Only downside that I have seen so far is that it is harder to start I have to crank it a little longer. I think people running the FASS had/have this same issue. Trying to design a timed relay so that the pump wont kick on till after the truck is running. any ideas??

Mopar1973man

Hook up a oil pressure switch to hold the power off till oil pressure is seen at the pressure sender. This is a common practice to keep the pump(s) from over pressurizing the system too fast...

caleb

how do I plumb this in? just by adding a T over below the oil filter where the oil pressure sending unit already is?

Another ? could I just use the sending unit that comes with the campaign pump and the little wiring harness pigtail as well?

Mopar1973man

Use the oil filter housing... There should be a plug in the top of it. (1/8 NPT)

As for using the sender that comes with the campaign pump... I'm not sure the switch will with stand the amperage or the high oil pressure without damage.

Also the contacts at backwards. Its ON without presure and OFF when there is more than 3.5 PSI of pressure. This could be fixed with a relay and some extra wiring.

Remember that switch is used for telling the computer if you have low fuel pressure. So I don't know if it will withstand 80+ PSI of pressure anyways...

I would go out to a parts store and ask of a oil pressure sender that comes ON at 5-10 PSI... And hook it up on the oil filter housing... Then wire your power through it... To your pump...

427AC

My two cents. I am running the BD setup with AN6 fittings from the filter housing to the Vp44. I get 21PSI at idle and hold about 17PSI at cruise with 12PSI at WOT, Level four on the Jucie. Does this mean the lift pump could be weak?