Hey everyone,

So I recently rebuilt my R50 head due to a split cylinder 4 exhaust valve that was causing a cylinder 4 misfire. I did all new gaskets, intake and exhaust valves, valve seals, thermostat, timing chain and gears, time chain tensioner, plugs, wires, and injector o-rings. I took my time and bled the cooling system until bubble free coolant was coming from the two larger bleeders and the 8mm bolt down by the throttle body. Car runs fine not throwing any codes and not overheating. Got to my home tonight after about a 30 minute drive and found out I forgot something at the store, went to go out and get it to realize the car won’t start. Doesn’t crank and barely makes a clicking noise when the key turns. Battery tested good and all the lights and radio turn on when the key is turn the accessory position. Anyone ever have a similar issue? Super confused. Will try restarting in the morning as it is currently dumping buckets of rain right now.

 

I know you report the battery was tested and found good but the symptoms suggests a bad battery. But I can't just come out and say replace the battery.

But the charging system, alternator, also comes under suspicion. It is important to confirm at engine start the alternator is supplying sufficient power to besides supply the electrical needs of the engine/car to recharge the battery. And my limited experience -- with another brand of car -- is while the alternator can work just fine after a cold start and for some time after in (my case) after about 30 minutes the alternator output was dropping.

Check the battery connections/cables. Check at the battery but also at their other ends. Be sure all ground straps are present and in good condition.

Old school trouble shooting with an engine manifesting the behavior you describe was to tap on the starter motor. If this worked the starter solenoid/motor was usually condemned.