Search the Community

I just replaced my VP and although it starts much better, there is still the 5-8 seconds of cranking to get her going.... I have read that the fuel pump should not be running while cranking, but I'm pretty darned sure mine is...I don't want to hurt this VP. Should my FASS150 turn off while cranking and then pump once it fires up????I'm jealous of Mike's video where his truck fires in just 3-rotations....

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

My truck is having a hard time starting. When idling the pump pressure 14. When going 70 it is 11. When trying to start it is 0. I now get the p0216 code and 1693 companion code. It is possible low pressure set off the codes so let's hope that is the case. The codes came a few days after the hard starting started. I have a new oem lift pump. 730k miles.

Hey fellas,I'm new in town here but I love this forum so far!!! I'm having issues with my 01 5 speed starting after it has ran for a while. The vp is only about 5 months old and the raptor 100 and the power puck went on when the vp did. It always starts perfect cold and it runs great all the time. I hasn't not started yet but it will turn over several times before it starts after it's warm. I had some water in the fuel issues a few days ago and I thought this may have caused it. I drained the separator and it straightened up for a couple of days and now it's back to the same old trick. I plan on checking the water separator again but the weather has been nasty here for a couple of days. It also has a brand new fuel filter on it. I'm praying this vp is not failing because I can't afford another one nor do I want to buy another one right now!!! Any ideas would be greatly appreciated!!!

after a long and arduous battle, my vp44 has been replaced and seems to be running like a top....good fuel pressure and such....but after letting it sit for about a month, I now have to crank it pretty hard to get it to start, almost feels like it has air in the lines however I have torqued, checked and re-re-double-quadruple-checked all the lines and they are all holding fuel....?? my second question, just after I replaced my vp the first time with a used pump, that failed shortly there after, my 47re started having issues shifting out of first!! I thought it may have been a clog in the valve body, it sat for a while, but a good ****** of the valve body with brake clean and a filter and fluid replacement gave no change, I tried the speed sensor at the rear of the trany, also no luck when replacing that! it will shift fine through all gears once its out of first, but to get it out of first it needs to be at about 22-25 mph so I need a down hill run or I have to rev it to about 2700 rpm to get it to speed, then drop it to neutral and then back into gear, it will NOT shift out of first any other way.....?? please help, I am at a total loss with the trany and am pretty puzzled with the hard starts as well....I was thinking maybe apps?? it konked out today before I replaced the speed sensor when I dropped it into reverse and surged when I would shift into drive with a huge drop in rpms before returning to a normal idle but now seems to do fine, just the normal change in engine load when its put into gear.....thanks guys!!!!its a 2001 2500 about 160k miles all stock minus raptor lift pump

OK fellow Cummins fans, I've got a big problem that many days of web searching has not found an answer to.I recently replaced the VP$$ and added an Airdog 100. Now my truck will start fine when cold and runs great. The trouble comes when I try to start it when hot. The engine will fire immediately and idle for a couple of seconds then it stumbles and dies. I can re-fire it immediately with the same result. If I try to start it within 5 minutes of shutdown all is well. Beyond that it's a no go until the engine is cold again. Does this condition fall under the hot start banner? Would the LP cutoff relay mod help me? Idle PSI is about 17psi on my test gauge. I don't have an in cab gauge yet since i had to blow my gauge fund on repair parts. I did plumb in a needle valve in prep for a gauge. :thumbup2:I have checked all points along the fuel lines where there is a connection and found everything to be tight. All high pressure lines are tight with no visible signs of leaks. I also checked the return fitting at the back of the head which did have a loose connection but did not solve the problem. I checked for codes and found none. I did not have this problem before the VP died.I'm at a loss here! Any thoughts? :banghead:

OK I posted this on CF. Thanks Mike for the tip on the Overflow valve. I just finished reading your testing on it and then rechecked to see you mention that lol. Quote is what I posted over there: I did some testing according to the bluechip diesel VP44 diag page and came up with it being a fuel delivery problem. Like I said I only installed a DSV replaced the supply line to the filter, cleaned the prefilter and replaced the walbro with another one, and redid the regulator. The fuel lines used to weep fuel and would drip ocasionally. It no longer leaks but now the hard starting. Used to fire up right away. Not sure if its in the tank, or the new line or? I havent tested the overflow valve as I dont think that would cause this. Or would it? PICs and narration: 3/8 clear tubing between the filter housing and the vp Long enough to loop up under the wiper. This is the truck idling. Air is somewhere getting in the system.http://s12.photobucket.com/albums/a207/CrazyMoparGirl/Mobile%20Uploads/?action=view&current=0718111045.mp4 A quick run. Got on it and the air gets worse. How with an electric pump? After shutdown, the fuel draining back to the tank I hope. Nothing on the ground so its gotta back to the tank. The bubbles appear from the filter housing. Why I dont think the relief valve is stuck open.

Hi, just joined the forum and this is my first tread.A week ago replaced my vp44 and upgraded lift pump to airdog2-165, did everything myself and truck started right after bleeding. I've been driving the truck since i got it back running and have noticed that the truck now takes longer to start. I've been searching the internet and haven't found an aswer to my problem, finally found this forum and any help would be appreciated.

Everyone,Well my truck has done this for a little while, but thought I would ask and see what people say. The truck starts great in the morning everytime. It seems to mostly do the harder starter (when it has to crank a few more times to start) when the engine is warm. I'm going to start to watch and see if that is a rule with it or not. The VP is new for the second time on 7/23/2010 from Midwest Fuel Injection. The first one was replaced on 1/11/2010. Fuel pressure is good, no codes and the truck runs great otherwise with high 17s or 18s mpg on average. Any thoughts guys??:shrug:Also I should say it did this a few times after I put the new VP on, then I tighten the injector lines and it didn't seem to do it again. But recently I started doing it again. Doesn't always do it and it doesn't seem to matter if the truck is facing up or down hill...:ahhh:Thanks,Winslow

OK I've put a Timbo APPS on and a noise isolator. That took care of the check engine code, however, it is still turning over a while before it wants to fire. Sometimes I have to crank it 2 or 3 times for about 3-4 seconds each time before she fires. I don't have anymore codes going off. I'm thinking that it is losing its prime of fuel. Could the airdog 150 be causing this? Before the sensor went bad it was starting fine, suggestions??