Fuel filter restriction 6NZ

stock motor? if so that is good.

 

no stock at all, like said before the entire fuel system has been replace with everything upgraded, plus 600 hp ecm program, manifold, turbo, cam shaft and a set of flow balanced injectors.

but before all this improvements it was about the same.

 

I change mine in the fall and the spring. It climbs to 7 or so on initial start up in the cold weather when its getting close to replacement time. I've been doing it this way for ten years now. I do carry a spare in case it gets plugged on the road. Same goes for the engine mounted fuel filter. I have a pressure gauge to moniter that also.

 

No Cat's here with fuel restriction gauges but 8 is what I recall as a go/no go in trouble shooting low power. Below 8 go on to something else. 8 or above replace filter and retest.
To my understanding the primary filter is more or less a water separator/bird catcher. The secondary filter really does the filtering for the high pressure system.
The only ones with screens here are off road but they run 30-60 hours per week. The screens are usually cleaned out annually unless a fair amount of water is in the secondary at 250 hours. That almost never happens and never had a power problem with one.
The C15's with twin spin ons are changed at every twentyfive thousand mile service, no problems with two cats at on time. Some non-cat secondaries frequently did not make the interval.
A little bit on filters, off the top of my head so no stakes to the heart please, The FleetGuard FS1212 is for an N14 one filter system. May be confused with the 1000 but both are the same size and have the same mic. ,around 18, just the N14 filter has a tube going a third of the down from the threads. The point being that is a fine filter for the complete system. Wix makes CarQuest and the numbers are the same, for Napa drop the first number. The first number designates it use: 2 coolant, 3 fuel, 4 air, 5 oil. The one on the engine 1R-0749, LF2749, 33674 etc. I thank about 5mic. The one on the frame 256-8753, 33353, bf970, p1104, etc. is about 10 mic. TO MUCH ON FILTERS STOP! OK.
The point of using a gauge to change a filter at the end of its useful life span. That could be five miles after buying some bad fuel or 50,000 miles. The filter costs $8.00?
The primary filters job is to catch water, protect the supply pump, and to keep the secondary from catching everything extending its life.
The secondary filters job is to protect all the delicate injection parts with clearances, which on new engines, are similar to the federal deficit, beyond my comprehension.
These new fuel system components are very expensive! If you are not running equipment to be sold at the end of it's warranty stop running fuel filters to the end of the recommended intervals or maximum allowable restriction. Filters on these cats are really inexpensive and a little extra like coal does will save you a lot of money in my opinion. The Cummings filter is finer and physically larger maybe lasting as long and filtering better.
mtoo made me feel bad but I was watching for answers from the Cat guys that appear to have left. I do not own a Cat, just keep some up with out very good directives.