New to the forum/Electrical problems

Hi there everyone, I've been a long time viewer of the forum but have only just registered.

I just had a starting problem on my '81 1.6 GTI Cabby.

When I'm turning the key to start she's starting but cuts out instantly once I let go of the key. Any obvious reasons why this is happening?

Another problem I've had is a bit of a battery drain. Brand new battery is dead when left hooked up over night. I've tested it using a multimeter and removing each fuse one by one and checking if that solves it but nothing. Perhaps a dodgey earth?

Thanks for your time, I'm a bit of a novice at this! Haha!

could be you dont have an ign live feed to the coil. the early cars with points ign have a starter motor feed to the coil as well so this would explain why it fires then cuts out!

check for power at the coil with the ignition on, lookfor a loose or damaged wire that is purple/white thats your coil live feed. its a resistor wire so you wont see 12v with the ign on, im not sure what voltage you should see but as long as you have some voltage then you should be ok 6v seems to pop into my head but i could be talkign rubbish

Your starting issue sounds like it could be more fueling. If you rev the engine for a bit after your starting does it then run after its warmed up for a bit?

Is your battery getting any charge when the cars running? You are probably right to suspect a bad earth as this is very common. Are your earth leads green and tatty?

Cheers for the replies dudes!

I just worked on the car for a good two hours once I got in from work and managed to get her to start again thanks to Jeevesraf's method. She seems to be alright now?

I then moved on to the battery drain issue again and checked all the earths and noticed that the earth cluster (not sure if this is the correct term?) above the fusebox was super rusty and some of the spade connectors were corroded/rusty too.
Could this be root of the problem? And what's the best way to clean these up?

Thanks so much for your help!

take it all off and buff it with sandpaper till clean, long term if it was me id find rust free claw and cut all spades off and put fresh ones on. but i do have wiring ocd you understand

with your starting problem maybe look at the AAV if it has one, make sure its nice and clean. also look over the engine for split hoses and air leaks, especially in all the folds of the inlet manifold boots.

could be the 5th inj isnt firing too, look for a spade on the starter motor with a black wire remove and clean it all up nice sto ensre its making good contact. follow wiring from 5th inj looking for damage and check the 5th inj thermoswitch in the front coolant flange for damaged wires as well while you're there

I cleaned up all the earth connections last night.
Took her for a spin to help the battery charge a bit and left the battery hooked up over night. Went out this morning and there was hardly anything left in the battery. Poop.

I've read in a few searches that it could also be a relay problem? Or perhaps one of the circuits that don't use a relay? Headlights?

I'll look into the starting problem once I've found the source of the drain, thanks for all the pointers though, I'll add them to my to-do list!

I should note that the starting problem only developed after I ran the test on my fuses and relays with the multimeter…  

prime suspects for draining battery are radio, alarm or a boot light thats stuck on. you can start by pulling off the battery +ve terminal and leave it for the same amount of time. if theres still no juice in the battery you can rule out a volt drain!

one thing, does the battery light come on with the ignition then go out when running?

I've unplugged the radio completely, don't think there's an alarm and the boot light seems non existent but I'll take a more in-depth look at it!

Yeah, the battery light comes on with the ignition and eventually goes out when it's running.

eventually goes out is a clue, it should go out immediately. if it stays on this suggests alternator is tired or the battery cable needs cleanign up or replacing. i use mk3 golf battery cables as they're much thicker and have a really nice battery clamp design. i recommend you use the mk3 golf rear gearbox mountign bolt as well, it has a stud on it for the battery earth which is much better design than the mk1 earth to the upper gearbox bracket. you#'ll see what i mean when you nick em out the scrappy!

only thign is you'll have to make up a length of battery cable from the earth to the chassis leg as mk3 ring terminal wont reach. all i did was get 2 mk3 earths and cut the battery terminal end off at the ring and use that to bridge the gap between the chassis leg and mk3 ring using a nut &bolt to secure the 2 rings together.

harder to explain than it is to actually do the job!

That sounds cool, I'll see if I can get down to a scrappy at some point and replace these battery clamps/cables. I suppose it's all fairly simple to do?

I'll check the battery light this evening and let you know how long it takes to go out.

As a quick fix (just to keep me going) do you think it would be a good idea to fit a cut off switch on the negative terminal? Just so when I'm leaving it somewhere for a few hours I can cut out the drain?  :dontknow:

nah i wouldn't bother its only a 13mm nut!

just had a thought, the mk1 alternator might have a pair of spades on it? if so you'll have to keep the mk1 starter->alternator wire for the time being and just use the -ve and battery + to starter wires off the mk3.

I would still get the mk3 alternator->starter wire though, you can use it to fit a later mk1 and mk2 alternator which would be easier to find if your alternator turns out to be bust!

you just need to put a ring terminal on the mk3 blue wire for the alternator end, and run a wire from the other end to the blue spade on the mk1. when you take the mk3 alternator wire grab the plug off the car loom with a good length of blue wire, you'll see what I mean anyway!

I guess you're right, it's not too much hassle to pop the bonnet and whip it off really quickly.

Thanks for the wiring advice! I'll be sure to keep it in mind when I'm next down the scrappy!

If you checked the drain using a multimeter and pulling one fuse at a time didn't you find the circuit drawing power?
Have you tried pulling all the fuses at one time?
If it still draws too much power will all the fuses out there may be a diy power wire hooked up to the battery.

Rubjonny; I checked the battery light, it goes out once the engine is started. Is that a good sign?

Pearcestu; I couldn't find any difference in any of the currents. Each were drawing 0.02 amps. I've been told this is fine?
But the earth strap and other earth wire that connects to the neg. terminal on the battery are both drawing 3.42 amps. Is this normal?

Hi,

I would say that you should be looking at a total draw of about 0.05 it can vary depending on the kit in the car.
You are best to leave the car for a while when you have switched off and make sure you have switched the interior lights to off so that you can avoid any confusion with open doors etc.

Nothing should be draining 3amps when the car is off. Did you use a normal multimetre or one of those clip things that goes around wires?

that suggests the alternator is starting the charging ok, but check the battery voltage with engine off and then started, should be over 12v off and 13.5-14v ish when running