Had the opportunity to speak with the fuel distributor for Sunoco up here in the Northern NY area. I asked him what the filtration specs are for the filters at the pump and was told that they are 10 micron. He also said that they are changed out monthly or when the retailer notices a volume drop. He wasn't very informed on CR engines or the fuel filtration requirements. He sad they run a fairly large fleet and don't have any issues with the fuel. When I pressed further, he got his head mechanic on a conference call with me. I learned that all the trucks they run are mechanical injection, not CR. The mech and I had a 5-6 minute confab about fuel filtration and CR. Bottom line is the fuel is supposed to be 10 um at the pump.

 

I just replaced my fuel filter today with a Donaldson 550785 that is spec'd out at 10 micron. Don't know where the 2 micron units come from. Also that is what is specified by the Cummins book the truck dealer had. Noticed now that the fuel pressure is a little lower by about 2lbs but it never goes to zero even during hard acceleration. The old one was alittle dark but not real dirty. Must be good fuel up here in this part of Canada

 

I assume you are talking about the factory fuel filter mounted on the firewall. If so, the specs were revised to minimum 7 micron. Here is a link to the TSB on that issue.

http://dodgeram.info/tsb/2006/14-007-06.htm

If not, sorry to have wasted your time.

 

Truth be know there is only one filter that should be in the factory fuel canister, and that's the Baldwin PF7977. Rated at 2 micron nominal, 5 micron absolute.

MikeyB

 

Try this thread: https://www.dieseltruckresource.com/...d.php?t=286145

It will give you some additional info.