Have a Cat 303e that starts very hard when cold out and only on the first start. Once warmed up it starts fine. Serial is hard to read, but appears to be 8A10303ECHHM01160. I have read a few posts about different mini excavators having this problem, but can't find much on the forum. Jump starting doesn't seem to make a difference except helps the battery hold up after multiple attempts. I haven't run tests on the glow plugs yet, but wondering where to start effective diag.
That should be your first step IMO. The glow plugs are manually activated. The following from the O&M Manual may be of interest - "Turn the engine start switch to the ON position. During cold weather, leave the engine start switch in the ON position for 10 seconds in order to preheat the glow plugs." Are you doing it this way.? All you need is the last 8, and HHM01160 is good, built April 2015.
Yes, we even try cycling the glow plugs a second time to be sure they are hot.
That doesn't mean that they are actually getting hot but OK, cross that off the list. I didn't know if you were aware that the glow plugs were manual. Do you have an electrical schematic.? That would help you in chasing the glow plug power circuits.
No, I have no schematic, If there is one I could view it would really help
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When you turn the key switch from OFF to ON and leave it there, does the glow plug warning light come on.?
Can you shoot a temp gun at any of the glow plugs?
No glow plug warning or code
Left the cat plugged into the block heater overnight, started right up I feel it should do that at 50 degrees outside
No power coming out of the control assembly in that case. Get checking......... The location of the Control As on the machine is shown on the electrical schematic. 1. Check for batt+ on wire 303-C43 BR when the key switch is moved from the OFF to the ON position. 2. Check for batt+ on wire 306-C24 GN when the key switch is moved from the ON to the START position. 3. Check for a good ground on C903-C11 BU. 4. Check for batt+ on wire 171-C6 GN (hot at all times). If there is no voltage check the 60A fuse shown just above it on the schematic.