1st Gen R53 Cooper S Most liked posts in thread: Alternator might be dead.

I'll have to take a look at that connection.

I tried switching the "engine lightning bolt" relay with the "snow flake" one, just to test, but the car was still dead. So I tried hooking the charger directly to the battery. The car started right up with the 100amp start mode. The battery showed fully charged and the alternator put out 14volts.

After I got the car started I poked around the engine bay and heard a hissing noise and noticed that the vacuum line from the pcv valve was split. I fixed that, the car was off of the charger at this point. I then attempted a restart. The car started up just fine without assist. Then I shut it off and put the relays back in their original spots. It still worked.

Could a relay be dying and working intermittently? How would I test one (besides switching them around)? What kind of electrical reading should those give on a multimeter? Electricity is magic to me. I don't understand any of it beyond what the values and units should be for car batteries.

Possibly related: Over the past few months, I have been logging an electrical issue. The car would start up normal, then suddenly loose all electrical power and die. After turning the key off, the car started up normal as if nothing had happened but the trip was reset and the temps were back to ºF instead of ºC. This has happened 4 times already, random spacing.

 

So could it be the main relays in the engine bay fuse box? Those are only $14 a piece, it seems. It wouldn't hurt to replace the "lighting bolt engine" one.

The battery cables are tight and in good shape. I also hooked the battery charger to the engine terminals again with the car running and it read a full battery and 14.3 volts charge from the alternator. The positive terminal was tight and the cable looked good.

The car had started up this morning just fine, but I got a ride to work again. When I got back, the car started fine again. I've yet to drive it since this happened. I'll take it tomorrow if it starts, and I'll listen for the alternator whine.

It was also suggested that I check out the belt tensioner and get the car up to inspect the alternator cables from below, it seems that they can somehow chafe and not deliver full power.

Thanks for the help.

 

For more than a month it has been around 95ºF with a heat index near or just under 110ºF and something like 99% humidity. :crazy:

I got some engine codes today. One was because of the pcv valve vacuum hose that was split, and the other was something to do with vehicle speed calculation error.

P0500 - Vehicle Speed Sensor 'A' --- this one caused the tire "!" light to stay solid
P2270 - O2 Sensor Signal Stuck Lean (Bank 1 Sensor 2) --- this was just the "service engine soon" The light was on this morning, first time driving the car after fixing the vacuum leak. The light was gone when I left work and I drove right over the AutoZone across the parking lot.

 

My car seems ok for now. I'll call it mechanically sound and fit for regular use. If anything electrical goes bad again, I'll try a new battery.

Would a battery load test reveal anything? Is that what Autozone does when they hook up to a battery?

 

I had the start-my-car-then-all-power-fails issue again today. I have been keeping records of it, and had just forgotten the figures. Today was the 9th time.

"If anything goes bad, I'll try a new battery."

Well, I got a new battery from Autozone. 100% free. Seems Optima has a 3 year free replacement warranty. They put their tester to my battery (over the cable connections) and it came out bad.

Once the new one was in, the car was dead. Autozone buy tried to jump me with his Golf, but it didn't work. I had to get jumped by a guy's enormous diesel truck. The Autozone guy checked the battery beforehand and it read good. He also rechecked my old battery directly at the terminals and it read good as well.

The consensus is that some cable between the battery and the engine is bad, but that any looseness or resistance was overcome by the sheer ampage of this guy's diesel, something that the Golf couldn't provide.

Isn't there some kind of replaceable segment just off of the positive terminal?

I also figured out that this issue is connected to my tach reading 1,000 rpm too high a week or two ago (may have not reported it here). After this battery business, my tach was again reading 1k too high, but a gauge cluster reset (called an "ECU reset" on the sewing site) fixed it this time too.

My car ran great the rest of the day and started up somewhat better than usual at all my errands.

I still got to keep the free new battery, though.

 

That terminal seemed tight. I'll have to undo it, clean it, and confirm tightness.

I'll check the main engine ground where my oil catch can used to be. The nut there is badly corroded from something. (critically obvious things sometimes fail to surface from my crazy mind) Perhaps the nut was corroded due to the years in the oil catch can, but then oiled metal shouldn't rust, right? Might have to get a new nut and take a wire brush to that ground cable's contact plate. Come to think of it, the oil can seemed to drip rust... was steel wool inside a bad idea? I mean, that Alta foam crap didn't last a month.