Time to appeal to others of a similar nature again, my problem is starting to annoy me, and defy logic.
I have a truck, with a super powerful 1703 straight 4, and low compression head, about 7:1.
During summer months, it starts on the button, and runs no problem at all. Just recently, it will not go without a jump. Off a booster, it goes straight away, and I tried it once with just a ten second charge, and away it went.
Yesterday, went for a spin, had to boost it, and drove to a mates, about 3 miles away. So it was nicely warmed up, I turned it off, wouldn't start. Jump started it, and away.
We got to where we were going, about 30 minutes away, and I left it running. Turned off. Waited a minute, and not enough oomph in battery. 5 minutes later, and she fired up, on first click.
Now I am starting to get annoyed with it, I can usually suss electrickery, but this has me scratching my head. Battery is new (ish) off a Transit, so 590 CCA. If it willl turn a 2.5 HC diesel, it should do an old fourpot. I have earths from battery to chassis, chassis to block, battery to block. All with good connections, and star washers under bolts to bite into connections.
New starter motor fitted Saturday.
The only thing I have not checked is a remote solenoid, the original was a push button starter which I did away with. Has anybody ever have one of those go high resistance, cutting volts to starter motor?
It all points to a knackered battery, but why should it not start, then start 5 minutes later?