'08 impreza turns over but wont start. Replaced battery twice, new. This morning same thing, cranks and feels like it's going to turn over but doesn't. Attached jumper cables, starts in a heartbeat. Drove it for a few minutes, no problem starting after that. This has happened the previous 4 mornings. It's my son's car and he's driving me crazy.
1Is the battery of the right capacity? I went to a battery shop where they tried to sell me a 20 amp-hour one for a lawn mower, when I needed a 70 ah one. But it's not just the capacity that varies, but the amperage it can deliver. When the engine is warm, you don't need as much battery power to start it.– Weather VaneNov 14, 2019 at 16:49
I had a battery store and mechanic replace the batteries so I would think they're correct. Thanks– Russ6261Nov 14, 2019 at 18:53
Exactly where are you connecting the jump leads to on the faulty car?– HandyHowieNov 14, 2019 at 22:41
This sounds like you have a power leak somewhere draining the battery as it sits overnight. This could be a simple as a map light being left on or a trunk light or something similar staying on due to a faulty switch.
The other cause of a power leak would be a short in a wire or component that isn't bad enough to blow its fuse but enough to drain the battery. I've had that happen with a stereo once, it could be many other things though.
Tracing the problem, first I would wait until dark and look for lights still on. Try pushing the glove compartment light switch in to see if it turns off, have someone sit in the trunk when you close the lid to see if the trunk light goes off as well.
Checking the lights takes minutes and no tools, confirming you have a battery leak and tracing the leak to the source requires a multimeter. You connect it inline with the battery's negative battery terminal and look for amps above 50Ma, a serious drain would be well above that. You have to wait for everything to turn off in a modern car though, it often takes up ti 30 minutes for all the electronics to turn off. I'm not going to go into more detail on this because there are several sites to help, for instance this one.
2I'm inclined to think there might be a parasitic drain as well - New Age Imprezas can be awful for this. Alarm, immobilizer and tracker (if fitted) are common culprits as well as what you mentioned Nov 14, 2019 at 17:20
1I think vehicle specific guidance like that is worth an answer on its own @motosubatsu.– GdDNov 14, 2019 at 17:27
That makes sense, I'll look for that tonight. Thanks, I appreciate the advice. BTW, this is my first time on this forum and thanks for the quick responses.– Russ6261Nov 14, 2019 at 18:57
We all know what it's like @Russ6261, I hope you get it resolved quickly!– GdDNov 14, 2019 at 20:38