Engine/Transmission (1998.5 - 2002) WHICH HOBB SWITCH (fuel system)

[len70]

i need too know what part # for the hobb switch to turn on the fass fuel pump when oil preasure reaches 3 to 5 ibs. im play with an 01 24v ctd and it will not start unless you unplug the pump start it, then immediatly plug it back in.

thank you

Lenny

 

[SConklin]

That sounds like a problem more than it does a simple inconvenience... something's wrong there... VP44? FASS spring pressure? Do you mean fuel pressure, not oil pressure?

 

[Hohn]

I'm guessing your FP is too high? This would cause the condition you describe.



He's correct on oil pressure. He's trying to rig it up so the FASS won't kick in until the engine has produced X amount of oil pressure-- meaning it is started and running.



Not a bad idea.



You can go to NAPA and get a Hobbs for $30. The one I have is set for 15psi, but is adjustable higher or lower using a 5. 5mm allen wrench.



Napa P/N 701-1577



This ^^^ is a "normally open" switch that will turn something on (complete the circuit) when it sees pressure. normally closed is the opposite-- it BREAKS the circuit when it sees pressure.



This P/N should work well for your intended usage. These NAPA Hobbs switches are designed for use with air, oil, gas, and just about any hydrocarbon media--- BUT NOT WATER!



Justin

 

[wlowe]

I have an 8 psi pusher pump which gives me a total of 23 psi when running. I've had no starting problems so far. One way to avoid problems is to use a relay which powers the aftermarket pump and is triggered by the hot wire to the OEM pump. The computer only runs the OEM pump for a second when the key is on the "wait to start" light. By the time the light goes out pressure is down to almost zero.



Bill

 

[len70]

hobb switch

thanks Justin for the part #. i think its short term fix for know until a can get the money together to put a new vp 44 pump in. the new fass fuel systems have a stronger spring in them know according to the trouble shooting instuctions. it sounds like the fuel is blowing by the diaphram in the vp44 pump. i did hook up a 3 to 4 lb hobb switch to the ground side. it was working great for about two days and then the fass quit on me. i put the orginal ground from the fass system back to the batt and it works fine. now i'm back to where i have to pull the fuse from the fass wiring to start. i might just buy the $7. 50 sping to lower the fass preasure.

thanks Lenny