Late yesterday one of my friends, Bob "the welder" - handy man to have as a friend, knocked on my door and said "help, my car won't start". He has a wee mk1 '07 plate Honda Jazz, one of 4 MK1 Jazz's which I run into from time to time. So I grabbed my multimeter and off we went into the next street where he lives. As we walked he told me they'd just been out doing the weekly shop. When they returned he turned the engine off while they took the shopping into the house and while his Mrs put the shopping away he came back out to move the car into his garage but it wouldn't start.
I asked him to try starting it and it behaved like a classic flat battery demo. a slow grind over compression on one cylinder and then the solenoid started chattering. Ok, let's see what the battery volts is. Oh, 12.5 approx. I would have thought it should kick over on that? Loose terminals? No, all nice and tight but I slackened them anyway and gave them a good "twist" before retightening them. Then I put the meter across the battery terminals again - directly on the posts because I want to monitor the battery without having to "worry" about poor connections at the terminals and 12.5 volts are still there. Keeping the probes on the posts I got him to operate the starter and, shock horror, the volts slump back to 5.8 volts!
So what's going on? I suspect there's an internal cell or connector problem. Whatever it is it's not going to be easily "fixable" so new battery needed. However let's just check if the alternator is charging. So I nipped back home and loaded my very large (ex diesel) 12 volt battery onto my sack barrow and slung my jump leads over my shoulder, to the amusement of the neighbours, trundled it up the street and round the corner. Actually they don't mind me doing this sort of thing as, over the years, most of them have benefited from me being able to help them with their cars.
One thing worth knowing about Hondas is that if you are mucking about with their batteries in any way, especially if there is to be an interruption to the electrical supply, you must not have the ignition key in the ignition switch barrel otherwise the communication between the key and the car's immobilizer can be corrupted and that would mean an expensive visit to the dealer to reprogram it all. So, having checked Bob has the key in his pocket I connect up the jump battery. This is "old tech" on this vehicle so you could connect directly battery to battery but I know this battery has been stressed by our attempts to start the car so it's likely there may have been gassing and I don't want any explosions so I connect pos to pos on both batteries then neg on the slave battery to engine block on the Jazz. For those who don't know, if you do it this way and get a spark as you make the last connection to the engine block then that spark isn't going to have the opportunity to ignite the gasses being given off by the stressed battery - as it might if you connect to the neg terminal on the battery. It's also good practice to let the batteries equalize for a few minutes after making this connection before trying the starter.
Ok, a few minutes have passed so I put the meter probes back on the Jazz's battery and am not surprised to see 12.7 volts (same as my big slave) Then I get Bob to sit in the car and start it up. The starter spins vigorously and she bursts into life! Looking at the multimeter and it's showing 14.7 volts. Lovely jubbly, just what you would expect to see from a healthy alternator.
So the car needs a new battery without doubt. I offered to go with him down to Halfords where we could use my trade card to get him a wee extra discount (maybe not so wee as if you buy actual Halfords branded goods the discounts are quite healthy). But, for some reason known only to him, he says he wants to get it from the wee garage that does his servicing. That's fine, makes no difference to me and I want to stay friends with him, so I don't push the point, but I think he'll probably pay more.
So I was actually feeling quite pleased (smile) with myself over this. This morning he arrived on the door step - his mechanic can "do" the battery right away if he can take the car to him right now, so can I jump it again for him? Absolutely, in fact he's caught me with my mucky gsrdening clothes on because I'm sorting a fence post which got snapped off in the gales, so it's just a quick nip up the street with the battery, connect the leads and Brrrum, he's ready to go. So I'm now coiling up my jump leads and he gets ready to depart. But oh dear, as he selects gear - the car has a CVT gearbox - there is a dry sort of "scrunching" noise and as he starts to move off there is a strange, not very loud, grindy rubbing noise which disappears as soon as the car starts rolling. That doesn't sound good! (so that's the grumpy bit) Think I'll just keep my head down though as I doubt if there's anything I could do about it!