24 Valve 2nd Gen Dodge Cummins 98.5-02 Discussion of 24 Valve 5.9 Liter Dodge Cummins Diesels with VP44 Injection Pumps
Sponsored by Trailer Plus

Optimum Fuel Pressure

  #1  
Old 07-10-2012, 07:46 AM
EggosBrother's Avatar
Diesel Enthusiast
Thread Starter
Join Date: Jul 2011
Location: Nashport, Ohio
Posts: 150
Received 15 Likes on 11 Posts
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.
 
  #2  
Old 07-10-2012, 07:46 PM
dustys24valve's Avatar
Diesel Wrench
Join Date: Jun 2009
Location: Coventry RI
Posts: 724
Received 32 Likes on 31 Posts
Default

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.
 
  #3  
Old 07-11-2012, 08:08 AM
EggosBrother's Avatar
Diesel Enthusiast
Thread Starter
Join Date: Jul 2011
Location: Nashport, Ohio
Posts: 150
Received 15 Likes on 11 Posts
Default

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.
 
  #4  
Old 07-11-2012, 09:28 AM
empty wallet's Avatar
Diesel Wrench
Join Date: Jun 2011
Location: New England
Posts: 667
Received 118 Likes on 61 Posts
Default

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.
 
  #5  
Old 07-11-2012, 10:58 AM
EggosBrother's Avatar
Diesel Enthusiast
Thread Starter
Join Date: Jul 2011
Location: Nashport, Ohio
Posts: 150
Received 15 Likes on 11 Posts
Default

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; 07-11-2012 at 10:58 AM. Reason: Automerged Doublepost
  #6  
Old 07-12-2012, 06:00 AM
kman522's Avatar
Newbie
Join Date: Jul 2012
Posts: 6
Likes: 0
Received 0 Likes on 0 Posts
Default

At idle I am at 18psi, I lose about 3psi while cruising 70-something down the interstate.
 
  #7  
Old 07-12-2012, 07:07 AM
RAW's Avatar
RAW
RAW is offline
Administrator

iTrader: (1)
Join Date: Aug 2009
Location: Alberta
Posts: 6,218
Received 684 Likes on 549 Posts
Default

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.
 
  #8  
Old 07-12-2012, 01:31 PM
EggosBrother's Avatar
Diesel Enthusiast
Thread Starter
Join Date: Jul 2011
Location: Nashport, Ohio
Posts: 150
Received 15 Likes on 11 Posts
Default

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?
 
  #9  
Old 07-19-2012, 10:35 AM
EggosBrother's Avatar
Diesel Enthusiast
Thread Starter
Join Date: Jul 2011
Location: Nashport, Ohio
Posts: 150
Received 15 Likes on 11 Posts
Default

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?
 
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Dbleo351
Chevy/GMC 6.2L and 6.5L
19
11-20-2016 09:34 AM
ctjkelley
Chevy/GMC 6.2L and 6.5L
7
06-03-2015 06:01 AM
robbyS
5.9 Liter CR Dodge Cummins 03-07
3
04-16-2015 02:22 PM
moneypitk5
Chevy/GMC 6.2L and 6.5L
3
02-12-2015 11:01 AM
powerstroker13
94-98 7.3L Performance
0
10-30-2014 02:57 PM


Thread Tools
Search this Thread
Quick Reply: Optimum Fuel Pressure



All times are GMT -5. The time now is 07:15 PM.