JamesHigdon Posted October 12, 2011 Report Share Posted October 12, 2011 Just sold a '97 Chevrolet and the truck was sitting here in front of the shop running. We've been driving it for weeks with no issues and it had a fresh interstate battery. The customer tried to start to truck while it was already running and it died and wouldn't restart. I check the battery and it's showing 8.xx volts with like 50 CCA available. I put a new O'Riellys battery out of my truck in it and it starts right up and now it's showing low amperage output/bad diodes. I goosed the throttle a few times and the alternator appears to be charging well now but I am confused. Can trying to start a newer vehicle that's already running somehow short a battery or was this just a 1 in 100,000,000 random thing that the battery shorted out just then? James Link to comment Share on other sites More sharing options...
jwmbishop Posted October 12, 2011 Report Share Posted October 12, 2011 It is possible that the starter hung - and kept the bendix engaged (and thus the solenoid) drawing enough to short the battery. the 8.xxx volts is not enough to turn it so it could have just sat there in a loaded state until you disconnected the batt. Link to comment Share on other sites More sharing options...
lbeaver087 Posted October 12, 2011 Report Share Posted October 12, 2011 i had something like tht happen too me the truck would hav too b jumped in the mornin would run alday u let it sit too long would have too jump again it was the battery .but wat ur sayin i would have the altenator checked or just change it thy can check out ok but really b bad Link to comment Share on other sites More sharing options...
JamesHigdon Posted October 13, 2011 Author Report Share Posted October 13, 2011 It is possible that the starter hung - and kept the bendix engaged (and thus the solenoid) drawing enough to short the battery. the 8.xxx volts is not enough to turn it so it could have just sat there in a loaded state until you disconnected the batt. I'm trying to fathom what the chances are of hitting the key and the starter gear actually engaging perfectly enough into the flex-plate to spin and cause this. We where standing watching when he did it and there was no grinding sound, just running and then nothing. My electrical knowledge is good but mostly practical, I'd like to understand what happened here so I can tell the customer. Did the starter spinning from engaging the running engine actually send a voltage spike back into the system (by spinning the starter and using it as an electrical generator) or was it just a solid short to ground across the starter solenoid sending a ground back through the positive side of the starter into the battery? Link to comment Share on other sites More sharing options...
jwmbishop Posted October 13, 2011 Report Share Posted October 13, 2011 I'm not sure how to explain it either - when it happened to me on an olds 455, my ex wife hit the starter while I was standing in front - it clunked hard and died (no grinding) - but kept cranking with no start. The R wire thing - the ignition is fed from the solenoid during cranking (when sol is engaged) and I had no R connected. I had to cut the hot wire (which started glowing and melting insulation) to get it to stop. Brand new starter was misaligned causing the hang, and that battery had enough poop to keep it spinning. I think in your case it may have finished off the batt when it occured.... Link to comment Share on other sites More sharing options...
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