So to start off I have a brand new battery, brand new alternator, brand new battery terminals, fuel pump is only a year old new from AB and the crankshaft position sensor was replaced in 2013 (15k ago). Autozone tested the battery alternator and starter voltages and everything came back as good. Battery and alternator voltage is on my voltmeter are exactly where they should be.

The issue is I turn the key it struggles like it's not going to start, like it barely has any power at all, and then always ends up turning over in the end.

Kinda puzzled, my next step is to trace the ground wire to the starter and try to clean it. I blew a coolant line when they were brittle during the winter and maybe that's why the connection is bad now? Randomly had codes p0307 and srs light randomly. Codes cleared on their own and may be completely unrelated but they happened around the same time.

Ideas?

 

clean every starter connection you can get your hands on.
p307 is a misfire on number 7, might want to check the plug and wire

 

I had that problem and it ended up my main ground cable wasn't connected to the block. Dumb *** mechanic didn't reconnect it so the block was only grounded through the strap.

Also, how many CCAs is your battery?

 

Where is that main ground? I've had a bmw where that cable snapped before. That would explain a ton....

Also my battery is die hard platinum, highest CCA I could find, 850cca rated. I kept it on a battery tender all winter and it was just replaced in November under warranty for this issue.

 

P0307 went away awhile ago after 2 appearances and hasn't come back in weeks yet but srs came back today, I assume these issues are related. Power isn't great lately, grounding might be off as that would explain alot.

 

several grounds on a DII the ones that get left off a lot at the one that run from the head to the fire wall, often does not get hooked up after HG