Extra Diesel Filter..?

Which Mitsu do you have?
I have fitted a 2nd filter to my 96 paj, but the lift pump on the end of the injector pump has problems coping. Have fitted an electric pump near the tank to help.
Got fed up with dirty fuel and paying $35.00 plus for filters. Have put in a toyota LC filter that uses a R2590 cartridge. $12.00 ea. 15 micron, and the std filter is 12 micron. Seems to work OK and catch the worst.

As has been said some of the smaller engines with a rotary injection pump may have problems with the additional filter, the larger sixes seem to cope ok regardless of pump type (in line or rotary).
The best/cheapest additional filter to use is a CAV which are used by the majority of heavy vehicles and diesel powered equipment, freely available just about anywhere.
The actual filter unit with glass bowl sedimenter is available from Whitworths marine supplies ( www.whitworths.com.au I think) for $59.95 which is cheaper than most other places.
Replacement filter elements are made by various companies, CAV, Baldwin and Ryco to name a few, typically cost $5-$8 depending on quantity purchased and supplier.
The filter elements are also available in different micron sizes too.
Racor also make a good filter but filter elements are not as easily obtained and are nearly as expensive as the factory ones.

Another alternative is to fit a toilet roll style filter , probably little bit more expensive to fit but filters down to 1 micron