24 Valve 2nd Gen Dodge Cummins 98.5-02 Discussion of 24 Valve 5.9 Liter Dodge Cummins Diesels with VP44 Injection Pumps
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Optimum Fuel Pressure

Old Jul 10, 2012 | 07:46 AM
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Default Optimum Fuel Pressure

I know this is out there somewhere but i did a quick search and gave up. I finally bought the quick-lock tee to make my FP gauge functional. At start up i got straight to 13 psi, then at WOT or as close to WOT that i get, i drop between 11 & 12psi. Is this acceptable?

Also, changed my filter on Airdog for the first time, is it typical to have free flowing fuel when you are changing these? I unscrewed the B and got poured on until i put the new one back on.
 
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Old Jul 10, 2012 | 07:46 PM
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11 to 12 psi at WOT is more than acceptable. If you start running at 8psi or lower I'd start to worry. Did you take both the filter and water separator off. When i take the separator off the fuel free flowed on me too, i believe its normal.
 
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Old Jul 11, 2012 | 08:08 AM
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I did not take separator off all the way. but it was flowing when i loosened it up. so i tightened it back up before i did filter.

Got my clamps on last night for the fitting. no leaks, holding 11 psi.
 
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Old Jul 11, 2012 | 09:28 AM
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13 at idle wouldn't be acceptable in my truck. at that point you have nothing flowing out the return side of the vp which means it isn't being cooled as well as it should be. I think 18psi is the ideal pressure at idle.
 
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Old Jul 11, 2012 | 10:58 AM
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well i have found a small leak in my connection to my gauge. have to take it back apart tonight and see what is going on. I skimmed through the manual for my airdog but did not read in detail about how to adjust the pressure. do you know if that is fairly simple?

---AutoMerged DoublePost---

the manual says its preset at 15psi +/- 2, it also says to change the pressure, the spring needs changed out. I am wondering if i am losing pressure to my gauge due to the leak? I didnt install a needle valve, i was told the isspro's would be fine without. Also, i just hooked up both ends of FP tube to the fittings, i didnt bleed any air or add silicone as the directions said to do. Is that an issue? I have only dealt with FP gauges on the fuel rail on gas engines.
 

Last edited by EggosBrother; Jul 11, 2012 at 10:58 AM. Reason: Automerged Doublepost
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Old Jul 12, 2012 | 06:00 AM
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At idle I am at 18psi, I lose about 3psi while cruising 70-something down the interstate.
 
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Old Jul 12, 2012 | 07:07 AM
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I'd like to see higher pressures as well. See if you can bump it up to 20psi at idle.

The free flow fuel is normal. If the fuel level in the tank is higher then the filter manifold, gravity will keep the fuel flowing when the filter is removed. Siphoning.
 
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Old Jul 12, 2012 | 01:31 PM
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Yea the Siphon makes sense now that i think about it.

Other than ordering a new spring, do you know of any way to bump up the pressure on an airdog 100?
 
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Old Jul 19, 2012 | 10:35 AM
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ok so i took my pillar back apart and made sure the tube was seated and tightened with no leaks at the gauge. I checked the voltage and cleaned my power and ground connections. it jumped from 11-11.5 psi at idle to a shade over 12.

In the manual it says it is factory set at 15psi +/- 3psi. Did i just happen to get a -3psi setting? Is there any way to adjust the pressure other than buying the new spring or am i missing something that is making the gauge show a lower pressure?
 
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