Howdy gang. We just bought my son a 2002 Accord EX with the 3.0. We had to make some chassis repairs from a pothole impact. The car sat about a year before we bought it. Put it together, installed a new battery and gas, and it cranked right up. He drove it a few days. Then one morning it would not crank. The engine would spin slowly but not fast enough to crank. We made sure the battery was fully charged. We installed another starter (used, from a parts car) and it cranked right up. He drove it another couple of days, then it happened again. Turned over slowly but not fast enough to crank. We bought a new starter. It still turns over slowly. We changed the battery to a known good one and there was no change. We tried jumping from another car for added amps, no change. Cleaned both ends of the cables. We tried jumping the ground from the battery to the block in case that was bad, no change. No codes showing. I phoned a friend with a shop. He put it on a private mechanics forum and nobody could help.
We are at a loss. Does anyone have any suggestions? Thanks y'all.

 

Did you measure voltage drop? There are a few links online, could give you a good idea as to whether enough electricity is getting to the starter or not

 

I am going to check the voltage drop next. Someone messaged me and suggested that also.