i was looking at a bd axilary fuel pump for my 98 24 valve. i noticed that it didnt kick on untill it read oil pressure. i was wondering if the stock lift pump could pull through that pump if it was not running right away or how the system worked.

 

The pump is a vane type pump which will easily be bypassed. Personally I'd just get a parts store Carter, though. Same pump, just different fittings NPTF (conventional pipe fittings with nipples) and they cost about half as much.

I use a relay to take the load off the ecm, which runs both pumps in series, but have a second relay to kill the framerail pump using the starter wire to prevent hard starts. But a simple hobbs switch can be set up to do the same thing from the oil pressure.

 

Save your money. Chuck the oem rotary vane carters and get a raptor,airdog,fass.

 

Carter makes a good pump. Chrysler puts it in the stoopidest place possible other than mounting it on the exhaust manifold. Then controls it with a relay inside the PCM.

The Carter is a fine pump. Put it in a good place where it won't have to prime dry every startup, be exposed to engine heat and vibration. Then control it with a relay to take the load off of the pcm, and you are golden.

Or you can throw money at it. I'll note that high pressure often causes "hard starting" though. And FASS and Airdog are high pressure.

 

Well, sort of. They CAN be high pressure, and are frequently set that way by people who actually think 20+ psi fuel pressure is good for their VP44.

I may be taking your statement out of context though--if you meant that they're higher pressure than the Carter, then I'd certainly agree with you.

 

Its a fine pump as long as the tank is mounted higher. Even relocating to frame rail the pump is still higher than the
pick up @ bottom of the tank. It also is meant to push not pull. A georotor pump is so much better than a rotory vane.

 

Well, I guess you can't really practically mount it below the pickup, but if it's on the framerail, it's about as close as you can get. Carter's do self prime as demonstrated by the OE...

Btw, if you set your FASS or airdog to low pressure, what's the point? You won't get more flow through the fittings if you don't run higher pressure. That's why a dual pump setup has an advantage- you can kill one pump for easy starts, and have double the pressure once it's running. And since its a vane type pump, the fuel pushes right past the one not running. Obviously not so easy to push past a geroler type pump.

I just HAVE to say that a geroler is just another way to do it. High pressure hydraulic systems use both types to push into the *thousands* of psi.

In short IMO FASS and airdog are great pumps, but other parts store high quality pumps work fine, too.

 

you can get a weldon pump..they are about indestructable .

 

do you have a step by step guide or can you walk me through this process?

 

If your talking about setting up a relay....get a simple 12 volt relay from an auto parts store, with a base or socket. Use the factory lift pump leads to power the relay instead of the lift pump. Do this by connecting it to the coil leads on the relay. Then run a heavy red wire from the battery to one side of the switched portion of the relay, then more red wire on the other side of that relay to the + LP, then ground the other side of the lift pump.

It's really simple. I have a fuse in my red wire that's as close the the battery as I can get. Realy handy too when you want to crank the truck and not have it start. Just pull that fuse and the LP can't run.

 

Yeah, pretty simple. I used a replacement underhood relay. Just use female spade connectors.

I'll add though, that the main lead should have a fuse, and be careful how you hook it up. The power should go to the switched end, not the switch end. If you put it on the switch end, when it's off the other pole will be hot. Most parts store replacement relays have a diagram on the side of the relay. I might be using the wrong terminology, but look at the picture, you'll see what I mean.