My 2004 Cat 3126e wont start

The problem is that you need to bleed the air past the filter... Once air is in the fuel delivery lines it will need to be bleed.

Only one filter in rear on passenger side. When I pressurized the tank I had the line at the bottom of the pump cracked. When fuel came out I tighten the line.

ATF is not engineered to serve as fuel... when combusted it will leave residuals...Never a substitute for diesel...

You will need to bleed the air out of the fuel system... Wolfe10 is the best source for how to do this..

JohnnyT

One fuel filter or two?

If fuel did not run out of the primary filter/water separator housing when you removed the filter it is likely that fuel siphoned all the way back to the tank.

If you have a secondary fuel filter (may be on the engine), does it have a Caterpillar manual primer pump? If so, that can be very easily used to fully prime the whole system.

If not secondary filter with primer pump, when you mildly pressurized the fuel tank, did someone crack open the bleed screw on the filter-- secondary filter if two filters in the system?

Your engine runs on diesel fuel. I am not sure why you filled the fuel filter with ATF!

The system must be pressurized to run. Cranking the engine forever probably will not do it. Try to find a service manual to tell you what to do, or find a mobile mechanic to fix it.