Engine/Transmission (1998.5 - 2002) Changed out LP; very hard starting

[slowneasy]

This is the second LP I've installed on the ol' 99 and both times it's been a real bear to get started. I crack the banjo bolt on the VP44 that comes from the FF, turn the key and let the LP run several times but it's still a bear. Am I doing something wrong? Someone... help me fix the error of my ways!



Thanks!

 

[JR2]

Sounds like you got some air past the VP44, you need to bleed the injector lines where they go into the head. No big deal as long as you got it running.

 

[ChrisOlson]

I have a 99 as well and after 7 lift pump changes I have come to the conclusion for my truck I have to bleed the fuel filter first using the filter drain on the bottom of the filter first, then bleed the banjo into the vp44 several times, when the fuel pressure gauge reads a quick 15 plus pounds with the starter bump then i try to start and start it does with no problems but that is my truck hope this helps

chris

 

[slowneasy]

thanks for the replies.

Chris-

When you bleed the banjo on the VP44, do you tighten the banjo in between running the LP or do you leave it cracked the whole time? If you tighten the banjo each time between running the LP, at what point do you tighten it- while the LP is still running or after it has stopped?

Thanks!

 

[JCyrbok]

I alway retightened mine between running the LP cycles to keep air out. I would just leave a wrench on the bolt and as soon as it stopped I would tighten it.



I would also bleed air first out out of the FF housing like Chris does, then do the banjo at the VP. ONce I got good consistent stream of fuel out of Banjo at the VP for a couple of cycles I would bump the starter twice more to purge any air out of the VP, then fire truck up with out a problem. Usually would not even stumble at all with this method.



I think the most it ever took me was about ten cycles to get the air out and started after a LP change. My truck is a 2001 but I think that the method should work equally well on your '99.



I never had a bleed any injector lines this way. Basiscally if yo work from the rear most point that you can bleed air (FF) towards the front (VP) you will get the most air out.



Hope this helps,



J-

 

[Moose Truck]

Slowneasy, Is this the 1st time after you changed the LP, is it every cold strart or every time? If it's the 1st time, then I'd say that you need to rebleed the system. Bleed it at the VP44's inlet Banjop bolt. I'd guess that it's fixed now. If it's every cold start, I'd say it's an air leak in the fuel system, that lets in the air after you shut down. If it's every start I'd say the VP44 has been wounded and it is weak. See: http://www.acptee.com/dieselpp/pdfs/installation10-05/FASS-HPFP-150-1002.pdf



Here is A Qoute "6a. Hard Starts

A. Usually the FASS only encounters hard starts on the 1998. 5 – 2002 Dodge Cummins with the VP44 injection pump. If this occurs it is usually on a VP44 with high mileage, and/or a VP44 that has been subjected to around 5psi of fuel pressure or less. It is more likely to occur when the weather is

warmer/hot.



Explanation of Diaphragm: The diaphragm in the VP44 is designed to move about . 5mm with proper fuel pressure (about 7psi min. ). When the VP44 is subject to about 5psi or less the diaphragm can move up to 2mm, an increase

in movement of 4 times more than what it was designed to move. With this type of movement the diaphragm will eventually develop stress cracks thru out the body of the diaphragm. One job of this diaphragm is to separate low

fuel pressure and high fuel pressure in the housing of the VP44, when the cracks are present this separation does not occur. This will lead to hard starts even with a stock OEM lift pump!!

Here is a simple test:

Note: Not all failed pumps with broken diaphragms will start with low to no supply fuel. Sometimes the diaphragm is so broken that charging pressure is not able to build to a level that allows the pump to deliver fuel.

Try starting the vehicle without waiting for the fuel pump to cycle. Meaning when you turn the key to the on position immediately engage starter.

Or: Unplug the FASS pump or remove the fuse so the FASS pump does not operate. Note: If the engine operates without fuel pressure for a period of time the VP44 will be destroyed.



Understanding this condition, start the truck. If the truck starts shut it off immediately!!!! This test just indicated that the better/increased fuel pressure from the FASS pump is overriding the thinner diaphragm and/or cracked o’rings surrounding the diaphragm in the VP44. "





Hope this helps, Moose00