Loss of charge and other electrical problems

[Cobra Clutch]

Okaay...

Got some problems with the ol VS yet again.

First wanted to say thanks to all the people that help around here. I've had so many problems with the car over the last year, every bit of time I get off work I seem to be working on it. And seeing as its a long weekend I knew something would happen! Like clockwork it did!
Anyway, much appreciation.

The problem/s:

(VSII V6 Dual Fuel)

I thought the starter was on the way out, because it was taking a while to crank over lately. I only realised last weekend when I didn't drive it for a few days that it was flat and has been losing charge. I have had this problem in the past, but it was that thin wire on the alt, which I replaced by a big fat sucker and haven't had a problem until now.
Anyway, it starts straight away with full charge, so starters prob fine.

I didn't have time to work on during the week, so I have been disconnecting the battery at work, because I was afraid it would be flat when I went to go home and just connected it again before I left.
Worked fine, but I went out the other night and did the same thing. When I plugged the battery back in, it started, but the electrics went haywire. All the lights looked half-powered and the windscreen wipers started going (very slowly) and the blinkers and other things. My wife was like 'this is like that horror movie Christine!' ha ha

Anyway I had a look and barely started it again, with the same result. I thought I would just limp it home, but then it sounded like it was going to stall out, and BANG, everything went back to full power. Weird.

None of that happened again. So now I am back to where I was, but now there is an added: when I start it there is a short cranking, grinding sound in the engine straight after it starts, kinda like I'm still cranking it over, but not quite, and I guess its still taking a bit of charge.

I thought it might be the alt because I replaced the tensioner arm a couple of weeks ago and had to pull it out like 4 times to get the hose seal properly, so I might have damaged it or something. I assume it has been happening since that day. I replaced the back part of the alt (the switch??) last year, so it shouldn't be that. I checked the wiring to it and it seems fine and batt is less than a year old.

Sorry for the massive post, this one has me scratching me head
Any help would be great.

I kinda hope its the alt, cause I know I can replace it in 5 minutes, ha ha. But might not be the case.

 

[hako]

I'd be checking the big fat wire that goes under the nut at the back of the alternator - it can appear OK but be buggered internally...look for signs of the insulation burning, also try bending/moving where it connects. Check your earth to engine lead...also both battery terminals must be tight and clean. Good luck.

 

[Cobra Clutch]

I took the wiring off the nut and had a good look the other day, but I think its alright.

 

[The1]

sounds like a faulty cell in the battery not giving charge all the time, does happen.

Other than that it's time to break out the multimeter and check for current being drawn when everything is off.

Also check with the engine running and see if the voltage is higher to the battery compared to when it's off.

 

[Cobra Clutch]

I think the batt is okay, because when I unplugged it, it had plenty of charge. Its only when I leave it plugged in for a while, it slowly loses charge.

 

[slayer208]

I've got a bad cell in the battery in my VS. Seems to gradually lose charge, but over a week or so. Hooked it up to my diagnostic hand held scanner, and my program was coming up with low voltage errors on sensors and alike. SO if your battery isn't in tip top condition, your engine won't run right for a start. I would start there, and then check your wiring. You know a hand held diagnostic scanner and a laptop would be really hand for ya'. I've found it to be an in-valuable tool when working with my VS. You can get em' on ebay from $100-$160.

Also, are you suspecting the starter motor to be on its way out? coz that's what it sounds like to me. Either that or it's loose on the bellhousing. I had a vk commodore with a stuffed starter motor and it used to make a harsh metal noise as you described. Half the problem was it wasn't bolted up tight enough due to stripped threads in the bellhousing, the other half of the problem is that it was stuffed and really didn't want to crank over too well.

Check your battery condition first before going anywhere, and work from there. Might also pay to clean up your battery connectors and terminals if they look dirty or whatever.

Cheers!

 

[The1]

youl need a multimeter then to check how much current is being drawn from the battery in a off state, then start pulling fuses to narrow down the item flattening your batt.

 

[Cobra Clutch]

But would a bad cell cause all that crazy flickering and random power-ons to the accessories??

If I pull the water pump fuse or the engine fuse the problems stop, but then I cant start the car. I think its because those both isolate most things?

 

[The1]

it all depends on how the cell is stuffed in the battery, it could do different things with different amount of currents being draw, either way the first step is going to be using a multimeter to rule out to much current being draw whist nothing is in use.

 

[Cobra Clutch]

it all depends on how the cell is stuffed in the battery, it could do different things with different amount of currents being draw, either way the first step is going to be using a multimeter to rule out to much current being draw whist nothing is in use.

I think I fixed the shorting problem and there is no 'cranking' anymore. But not sure if its still losing charge.

The batt voltage when running is about 13.9, and when off its about 12.5