A friend bought a business which came with a nice 1999 International daycab tractor. He hasn't been using it so he has been letting me borrow it to pull a lowboy for moving a D7. A couple of issues that I can't figure out: it uses diesel fuel out of the right tank only; I can't get it to draw from the left tank at all. I don't see a switch anywhere. Any ideas? Also, it seems to want to crank for 3 to 6 seconds before it will start, then it runs just fine after it starts. However, it seems to me it is weak compared to other trucks I have hauled the dozer with, and even compared to my 300 Cummins dump truck. The engine is a Cummins ISM, I have no idea how many HP. I can't find that info on the data plate. Also, there is a switch on the dash that is labeled "Diagonal" and it has on/off positions. What is that for? Other than the issues I have described, it is a wonderful truck and has less than 300,000 miles on it. I wish he would just sell it to me, although you can't beat the deal I have on it now.... until it breaks down or I put a dent in it.
I don't know for sure what fuel crossover setup you have, I think that will a valve to shuttle return fuel to each tank to equalize them, this valve could be stuck and all or most of the fuel is being returned to the left tank. It is located near the top center of the bellhousing. Look down in the tank to see if you have fuel returning to one tank and not the other, on a 99 I'm pretty sure that's what you have. ISM's generally have decent power check to make sure there are no fuel leaks on the suction hoses from either tank, that can cause this problem to.If the switch say's diag. it's a diagnostic switch you can use to access fault codes. Good Luck
I would agree with the crossover between the tanks might have a closed valve on one tank or a plugged line .
check the vent lines, if the vent is plugged it will only fill the tank with the return line
I have an International 9400 1995 model truck with 12.7 Detroit in it. Mine also developed the problem your having. My truck would overflow the passanger side tank letting expesive fuel rin out goin down the road,then would suck air in driver tank and die. I took all lines off at fuel pump then off at tank,put towel around fuel tank end of line. Using air blew back thru and a liitle trash came out, I didn't think it would have caused my problems though. Couple weeks later same thing again,this time I drained tanks and had a crossover line made to fit drain plugs in bottom of tanks. That has been 6 or 7 years ago and still working, but may quite tommorrow,but still don't know what caused troublr to start with,Good Luck.