Ok pops car 70 GS 455 car is set per Larry's power timing thread and distributor was redone. Runs awesome at full throttle and idle etc. After a drive and it's warm when you go to start it up again it seems like it doesn't have enough spark and almost like timing is off. When cold no issues Edelbrock carb and intake Stock distributor with electronic conv. Also has crane coil. With key to on position 12.6 volts to coil While turning it over volts drop to 6.2 5.8 untill she fires up which takes a while. Same happens on alternator side untill fires up. Battery is in the trunk with a big ol thick cable to the front. I tell my pops it's gotta be the battery is weak any thought or opinions are appreciated thanks guys. Car has a new engine harness also
What is the voltage across the battery terminals when doing the same test you stated for the coil and alternator (assuming your battery is fully charged before the test)?
That is a huge voltage drop. Everything is suspect as far as cables and connections as well as the starter motor. The voltage should never drop below 9-10 volts when cranking, if everything is up to snuff.
When I converted to magnet pickup, I changed the coil also, and run a 12v wire, instead of the restricter wire, from the fuse box (radio?) and had the same problem.. When cranking the voldtage to the coil were 6,5v IIRC, so I took the coil wire, which got juice when the key is on, and used it as remote for an relay box with 12v direct from the battery.. Is that understandble?
I didn't check battery volts that day I'll try this weekend I was thinking about running a wire from the box straight to coil to test out too. I will try and do more testing this weekend We also pulled a spark plug wire and had a weak spark.
