No spark

Hi all, looking for some advice as I'm a bit stuck.

mk 1 golf 1.6 8v is cranking but won't fire up, after a bit of investigation I've found that there is no power going through the black and red wire that is connected to the coil and there is no spark coming from the coil.

What at would be the next step to investigate why there is no power going through the red/black wire? I've checked all fuses and they're all ok.

im learning as I go with this and can't seem to find the best way to fix this.

Thanks in advance. 

Check the ICM if you have a hall sender.
It fires the coil.

Thanks for the reply. Unfortunately it doesn't have a hall sender…

Points/condenser is usually the first suspect, as the Radio on with key in, will burn the condenser if the points are making contact….

ie: Brother bought an old 23 window bus in California, and planned to drive it across the country.  He was in Death Valley, at a rest area to have a rest, while his wife stayed in the car with the key in and the radio on…..

He got in and dang the car wouldn't start,,,,,,
Instead of calling his brother a VW nut.  He rented a truck and trailer and towed it home.  When I found out about it, I said did you did what as it was the first I had heard of his purchase…..and trip.  I said, Change the condenser 2 bucks, later he was motorvating.  I could of saved him 1400 bucks, but would he call me?  NOOOOOOOOO.

Try the condenser it very cheap and very prone to frying.

I've literally changed everything: coil, HT leads, spark plugs, distributor cap, rotation arm and my last attempt to sort it was the points and condenser. After that didn't work I started from the top again and that's when I realised that the red/black wire going to the negative doesn't seem to have read anything when I tested it and there's no spark leaving the coil HT lead. My last hope is to find out why there's no spark going through the red/black wire and hope that will get it going? If not I'm out of ideas 😢

Looking at a 77 golf, the red/black that is supply in from the Fuel pump relay via the points.
 

red/black from the coil negative is the rev counter feed to the fusebox for the clocks. on the GTI its also used to trigger the fuel relay.

you can bin the wire entirely and it should still run, its not needed for the engine.

if its points ignition there is a wire from them to the coil negative, which goes to ground whenever the points trigger and this in turn makes the coil spark.

the rev counter picks up on this negative pulse as does the fuel relay if its a GTI.

Thanks for the info guys. It all makes perfect sense and has cleared a few things up for me.

I was checking the wires the other day and they all seem fine so I'm going to check the coil with a multimeter. The guy I bought the car from had put a new coil in the car as well as the old coil so I presumed that it was working but there's no spark coming from the coils at all so I'm gonna have a check. Failing that I'm guessing maybe a bad earth and after that I'm all out of ideas…

make sure its the right coil, electronic ignition ones wont work properly on points if at all. if the coil power is purple/white this is a resistor wire so the voltage wont be as high as 12v (let me know what it is, I'm curious )

if it has the resistance wire you should have a black from the starter motor pin 15a which bumps the coil voltage up to full 12v while cranking, to help it start./ be sure to check this as well

So I found the culprit yesterday! Long story but the earth wire inside the distributor had come loose which I think had caused the green wire from the distributor to the coil negative to fry. I soldered the earth wire back to the distributor wall and replaced the green wire which almost sorted it.

 I used a multimeter to test the coil and the original was knackered. The guy that I bought the car from had supplied me with a new coil but when I tested the secondary coil resistance it was only 6000 ohms. I'm guessing that this is a coil for an electronic ignition? Anyhow I bought a new coil and now I have spark! 😬😬👍💪🏻

On to the next problem now…

Although the car is starting it's not idling very well and it's popping at lower revs. I've tried to adjust the carburettor but no luck yet. If anyone has any advice that would be great, I'm going to trawl the forum for info though. 

how are the points condition wise? might have been damaged by the same issue. check the gapping is all good too

check the carb over carefully for air leaks, the rubber flange it sits on may be split or leaky vac hoses, loose inlet etc

I've changed the points and set the gap for them so that should be all good now.
  I've literally just removed the carburettor and I have a servicing kit arriving in the post tomorrow so it's going to get a good clean and I'll change the gaskets o-rings etc and check the jets. The hoses all looked okay so hopefully a good clean and service will work? The car had been sat in a car park for 4 years before I bought it and not started so I'm hoping it just needs  a bit of tlc…

 Whilst I have your attention rubjonny, the brake pedal has stuck down since I parked it up which is next on my list of jobs to tackle. Whats the best way to start troubleshooting that problem? Completely off topic I know but your advice  is much appreciated. 

id probably styart by disconnecting the brake servo, then you can see if the servo is duff or the linkage has seized up somewhere.

the cross bar comes off relatively easily then you can give it a good clean and re-grease.