long crank but does start

[heathv]

I have a 2005 F350 duelly with 65,000 miles. I just replaced all injectors and while I had it tore down that far I also replaced the dummy plugs, stand pipes and STC fitting. Now I have to crank it for 20-30 seconds before it starts, and I am getting a "low oil pressure" warning. Once started the truck runs smooth. I have taken the spring and that little cap out of the low pressure oil pump and inspected up in the hole and everything looked fine, still I get the LOP warning. I intend to replace the pressure switch tomorrow to see if that will take care of the LOP warning. Can anyone give me any sugestions as to the long cranking time?? I monitor the ICP on my Edge CTS while cranking and it starts building pressure slowly at first but when it passes around the 50psi point the pressure jumps quickly to 500-600 where it starts. It idles at around 800psi.

[southend]

Are you using motorcraft filter with matching cap?

Sent from my phone that somebody didn't help me get.

[ajgeo38]

could be air in the system???

[heathv]

Originally Posted by southend

Are you using motorcraft filter with matching cap?

Sent from my phone that somebody didn't help me get.

I do use motorcraft filters but I also have an FS2500 bypass filter using their cap to send oil to that filter. I've been using this setup since 2006 with no problems. Why would the cap make any difference???

[heathv]

Originally Posted by ajgeo38

could be air in the system???

If this is the problem, how do I purge the air out??

[southend]

With your setup, don't worry about the cap. Open up your oil filter, push down the oil filter drain valve, have someone crank it over, it should fill the resevoir quickly. It may be time to inspect the lpo pump.

Sent from my phone that somebody didn't help me get.

[dannyboy950]

Originally Posted by heathv

I do use motorcraft filters but I also have an FS2500 bypass filter using their cap to send oil to that filter. I've been using this setup since 2006 with no problems. Why would the cap make any difference???

To answer your question here while it doesn't really apply with your set up.

On a stock oil filter system it has been found that many aftermarket filters are
different than the motorcraft (longer in many cases).

Wix for example is about an inch longer than motocraft and comes with it's own high domed cap to accomodate that extra height.

The problem is when someone changes back to a motorcraft or other shorter filter and leaves the wix cap the filter no longer can push down and close off the filter drain valve. This can keep the filter from being able to fill up and supply enough oil to the HPOP resivoir which in tun causes the HPOP to run out of oil and loose pressure till its below operateing pressure. Causeing hard/no start conditions.

[heathv]

I purchased a new oil pressure switch and started to replace the old one only to find out that when I put everything after STC upgrade, I didn't plug it in securely. Needless to say, after connecting the switch that took care of my low oil pressure warning. Now if someone could help me with the long cranking.. After getting it started today, I took her out for spin. She ran great. Oil temp and coolant temp were 6 degrees apart. IPC pressure was between 600 - 800 psi, WOT 3500 - 3800 psi.
I'll continue reading trying to resolve the long cranking time but in the mean time I would really appreciate any help offered.