Engine/Transmission (1994 - 1998) Air Dog and Overflow Valve

[MM800]

Just installed both (New). With the engine off and key in run position I can hear the overflow valve screaming (sounds like a mosquito). Does this sound right? I understand that the pump runs continueously (sp). Is this gong to weaken my overflow valve prematurely?



Thanks

Jeremy

 

[ATaylor]

The Overflow

Hi,



I also have a Airdog 150 and have been trying to figure out how to properly shim the overflow for more pressure. I have a 40 psi spring in the Airdog and would like that pressure to be held at the overflow to keep 40 psi in the injection pump. I hooked up a regulator to a piece of aluminum that is threaded for the overflow valve to make a tester. I'm having the same issues. The overflow valve is leaking slightly at any pressure, and really opens at 20 psi (mine sounds like small fog horn with air going through it instead of fuel). I thought the stock overflow valve was supposed to hold back 30 psi. I guess I will try a new valve.



Where did you get your new Overflow valve? I was quoted over $220 from Cummins. I know that TST has them for much less expensive, but are they good valves?



Here are some pictures of the overflow valve tester.



Archie

 

[MM800]

I got mine from PDR, I thin it was $60. 00 Ya this thing with the overflow valve scares me. How long till it fails? The spring has got to be working over time. Have u talked to air dog? I have another valve (old) maybe I should try and shim it?

 

[PRohr]

I have been toying with just gutting the OFV and putting a regulator made for EFI applications on the return line. Get one that is compatible with alcohol (Viton Seals) and it will be fine with diesel. You can pick them up for under $150... . They usually have a range of 20-70psi.....

 

[ATaylor]

Phil,



Since the FASS and the Airdog are internally regulated (30 or 40 psi depending on the spring), would putting on the external regulator in place of the overflow valve create problems since there would be two regulators fighting each other? I guess you could fine tune the external regulator so that it is holding back fuel just to the point that the regulator in the FASS or Airdog is opening. What do you think?



Archie

 

[PRohr]

Not really... . it's no different than the OFV only the external regulator is adjustable..... well the OFV is if you shim or stretch the spring.