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Specifications Here is a copy of the fuel system specifications from the Dodge Factory Service Manual. Fuel pressure Normal fuel pressure should float about 14-15 PSI running down the pavement. Should never fail below 10 PSI at all. Here is a colorized fuel pressure gauge to give you a clue of the fuel pressure span you want. You want the needle to stay in the green at all times. Yellow zone is a warning that you should check the fuel filter, lift pump performance, overflow valve, etc. This is undocumented maximum pressure is 20 PSI. Now take notice to the overflow valve is set for 14 PSI so excessive pumping of fuel does nothing for performance except create more heat for the fuel, which in turns reduces the cooling ability of the fuel and adds more stress to the lift pump. So a little extra fuel pressure is a good thing because it insures the VP44 stays cooled and lubricated properly. But excessive fuel pressure will heat the fuel and reduced the cooling ability of the fuel. Now always remember that the only lubrication the VP44 will see is the fuel itself so if you don't have enough fuel pressure it will cause damage to the VP44 injection pump. It's like the same as running the engine with low oil pressure it will continue to run but the damage to the engine will occur. Or in this case the VP44 which happens to be about $1,200 to replace. Pressure Drop Amount of fuel pressure drop between idle and wide open throttle. 2-3 PSI drop from idle to WOT is normal. But 5 PSI or more pressure drop from idle to WOT is pointing out a failed lift pump, plugged filter, and/or plumbing restrictions. 2-3 PSI Is NormalDropping more than 5 PSI is pointing towards a failed lift pump, plugged filter, or restrictive plumbing.Just to show you the difference in the stock plumbing which is 6mm ID plumbing and most performance pumps come with 1/2" ID plumbing. These pictures will give you a idea... First picture is a Big Line fitting over the top of the stock plumbing. Then the second picture compares the stock 6mm ID steel lines to a 1/2" ID Big Line hose. Here is a short video of stable fuel pressure from 55 MPH to 70 MPH at WOT. Cranking Pressure Test Here is a simple test on how to do the test for cranking fuel pressure. Pull the fuel pump relay in the PDC and then attempt to start the engine. Pay attention to the fuel pressure gauge during cranking. Be aware this test will trip a P1689 code and light the CHECK ENGINE light. Excessive cranking pressure can lead to difficult starting problems. Difficult Starting While Hot This problem is caused by a VP44 with a torn diaphram internally. This damage is typically caused from a VP44 that was operated at below 10 PSI for extended period of time. So technically you should replace the VP44 to repair the damage diaphram but most rig up a oil pressure switch or a starter delay relay. Here is my idea... This will cause the lift pump to remain off during the period of timing the starter is operating as soon as the key is released the lift pump will function normally and remain controlled by the ECM. Suggested Lift Pump Replacement You should replace the stock fuel system completely being that it cannot supply enough fuel for even stock requirements without causing damage to the VP44 injection or adding stress to the lift pump. The pumps I suggest are proven and come with a lifetime warranty. These pumps come with a full kit and replace everything from fuel tank to VP44. [*] AirDog 100, 150, or 165 [*]Raptor 100 or 150 [*]FASS 100 or 150 I don't suggest these pumps... Because they don't address the pump location, plumbing restrictions, or come with much of warranty. [*] Stock Carter or Carter Campaign Pump (4090046) [*]Holley Blue or Holley Black [*]FASS DDRP [*]AirTex

I have a 99 5.9 with a low pressure fuel pump not working. I changed out the pump today (160 bucks)with a new one but still no work. I ran out of time today to check voltage on the pump but I think it is a shoe in that it is not getting voltage during crank. I tried the bump engine but don't start, to hopefully get the low press pump to initiate but it will not. I did get the pump to work once a couple months ago and I think it happened when I drained the fuel filter through the bleed valve on the filter. Then went back to crank and the pump initiated. When I swapped out the pump today the filter was drained but it still did not initiate. All of that leading me to believe that it was a random initiate that once that it did work as it is supposed to.I can either mist the turbo and the truck will start up and run great.I know not to make this a habit or stand near when I start. Basically mist trubo, replace filter, go to cab start.I also just finished (this week) a 1500 lock n stitch repair on a 17 inch crack in the block.So, now I'm trying to keep monies spent at a low amount. Just from a day of working on this problem I can already see 3 things I could buy that would cost a grand that I don't have. Code reader, fuel pressure meter, fass fuel pump, dealer repair manual.If I could get some help here in working out this issue I'd appreciate it.The truck is still a pretty nice truck so I'd like to get a secure fix on it even if it is a solid work around.I have already read on this forum such things as possible air leaking in, possible bad diaphram in injection pump with others issues on the low pump not chiming in.My questions are:1. Is the low pump working to keep the engine running when I have it running? Or can the engine run at full pressure with out that pump once started? This could tell me that the pump is working but there is a prob with the pump on start up.2. If I find no voltage then where do I go from there. What fuses do I check? I checked the relays titled fuel.3. What pins do I short to read out the codes on the dash and where can I find the codes for this engine? There are codes stored but I'm trying to keep from buying a code reader for the fact that money is tight and I don't know what I'll need to buy next.4, Would there be an issue with Wiring a new wire to the low pump that would initiate when the truck is switched on? Sounds like a jury rig I know, but it is just a matter of getting the juice to components in my thoughts.

I just installed my gauge according to genos garage instructions using there universal fuel hose not much drive time yet but every thing seams to be working good i have 14 lbs pressure at idle 11 pounds cruising and 9 pounds wot.As of yet guage reading is steady no eratic movement.

A poll to help with quick look at vitals.

Hi there, I've searched Google, this forum, Cummins forum, and TDR without luck - if this is a dumb or repeat question I apologize in advance! The previous owner of my Dodge put the Autometer FP sender between the fuel filter and the line to the VP. The sender failed, I ordered a new one plus the snubber to prevent the premature wear on that part. Problem: the FP sender is angled such that the back butts up against the drain valve and the snubber definitely will not fit. I'm pretty scared of messing up the VP and don't want to tinker around without the advice/recommendations from more experienced folks! Can I rotate the sender/fitting so it doesn't stick out into the drain valve? Or is it fitting threaded such that this angle is necessary to achieve a tight seal? Thanks in advance!! -Tiffany

I have a 99 3500 mostly stock and im not to sure what this noise is or why its this loud when i turn the key on. It seems like something with the lift pump but it stays on for awhile and is very noticable in the cab then turns off. The trucks start fine and i have a crappy electric fuel pressure gauge and when it makes that noise its at atleast 25# and then i start it and it stays right around 24-25#. I have a few videos showing the noise and the gauge but none of the noise right when i turn the key forward without bumping. It sometimes comes on for a few seconds but lately has been coming on for the full 20- 25 second cycle without bumping the starter. Can you tell me if its supposed to be this loud and why it would cycle without bumping the starter only turning the key on. Also why the pressures so high? Heres the videos http://s1226.photobucket.com/albums/ee416/cumminsman7/

Can the main computer shut down the Bosch VP44 if there is a cooling problem or temp sensor error? I have been having cooling problems on hot days and under load. After flushing radiator, the engine ran normally for 5 minutes down the freeway and then suddenly stopped and wouldn't start. (as if it ran out of fuel) . Fuel pressure from lift pump is OK. Fuel to the injection pump inlet OK but nothing at the injectors. There was no missing, no smoke, no roughness, good 23 mpg, just before shutdown. Coolant temp was normal. It seems odd that the VP44 would fail after I was working on the coolant system. Is there an internal fuel shutoff solenoid inside the VP44? Any insight would be appreciated!

Ordered a fuel gauge today http://www.glowshiftdirect.com/search.aspx?find=GS-T11_30 Hope it works ok!

I have an autometer EGT in my 2000 and am going to add a edge juice with attitude which also requires a thermocouple. Instead of installing a separate T-couple is it advisable just to connect my edge to the existing thermocouple? I seem to remember that the leads are specific length and impedance so running 2 devices off the same thermocouple might not be a great idea... Anyone out there done this? Thanks, Chris