hello out there, I have 1969 d8h dozer . the issue with it is low fuel pressure.the tractor only had 20 to 22 psi at fuel throttle. I have changed the primary screen and filters,have removed and inspected fuel feed line from tank, its ok, fuel flows freely thru line and thru primary screen and steel line to the transfer pump.i have replaced the transfer pump with a brand new one, the new pump also came with a new fuel bypass valve. but no improvement in the fuel pressure.thought that mabee it could be the valve at the bottom of the hand primer so removed it and blocked it at the filter housing with a plate off of another cat that didn t have a primer. still the pressure is at 20 , my cat manual says it should be 32psi plus or minus 7 psi this dozer runs great except for this low power issue,all the cat service troubleshooting manuels say to start by making sure there is minimum of 25 psi. also I have unhooked the throttle linkage and pulled the governor lever by hand just to make sure its not a linkage problem. I'm stumped, any ideas would be greatly appreciated thanks
could it be the guage is bad ?
A check of my D8H Cat service manual indicates transfer pump relief valve should be set at 20 psi. You can stretch the spring some if desired but sounds like it's making spec to me. Your source of low power is elsewhere.
hello, thanks for the replys, ihave installed a new gauge on the after filter gallery on the filter housing, the gauge in the dash is a red green cat one. my sn is 46a21258 , the old manuals that I have do not cover this sn but do say 32 plus or minus 7, so does the manuel for the 8 ks, do you mind looking to see if your old service manual covers this sn. mabee I am chasing a problem that doesn't exist. thanks for the help
You need to be looking in the correct manual. Covers 46A10725 to 46A28136 D8K's are in fact 32 +/- 7 psi but the H's are lower pressure and typical of the earlier machines.
thanks old magnet , you are right about the fuel pressure , and I have ordered the correct manual , thanks again.