VW MK1 1300 no spark

[ReynoDB]

Afternoon Everyone,

Can anyone maybe PLEASE assist me with my crisis?

My Golf MK1 1300 1989 model didn't want to start, although the starter cranked. There was no spark.

I've ended replacing the whole ignition system: Ignition switch, ECU unit, coil, idling valve on carburetor, complete harness, and distributor. The battery is still new and works fine.

After replacing everything, it still did the same - cranks but no spark. I realised that there was no spark, because the coil didn't get positive power.

Frustrated I got a mobile mechanic and after fiddling with the wiring here and there he took a positive from somewhere else and then got spark for me.

About a month down the line the car's wipers started on its own and there was clearly a short somewhere with the car cutting out again to such point where it did the same as before. I took the whole front console out exposing all wires and started looking for the fault. I found that there was a short on the wiper motor and disengaged it. I looked everywhere for touching wires and isolated all loose ends I could find and suddenly found positive power again.

Car started and after idling it for about 30 minutes and driving it for about 100m it suddenly cut out again!

When I used my test lamp with clamp connected to the positive of the battery, I found that the green light came on in all three points of the distributor plug and when I test the positive on the coil the green light also came on implying that there is a negative charge to the positive side of the coil.

I am really with my hands in my hair now not knowing where to find the short. I suspect that it could be the immobiliser (Autowatch 446R1i) being 15 years old creating the short, but then I think further and it doesn't make sense that the starter still cranks when immobiliser is turned off and I start the car.

Any suggestions PLEASE how to find the short as I am near the point to throw a match in the petrol tank...

[VAG Fan]

Hi Reyno,

Two things.

1) Regarding your testing lamp measurement on the coil, I wouldn't put too much importance on that, especially if it's an LED type. They require very little current. So, although the primary winding of the coil does have some resistance, it is not much - perhaps 1 or 2 Ohms. Therefore, in terms of your circuit tester, it actually behaves like a pretty good conductor. So it is quite normal that your test lamp would "see" the positive coil terminal as being connected to earth. [Edit: to my knowledge, the coil's negative terminal, which is switched onto earth for each spark by the TCI unit, is permanently connected to earth when the car is switched off. Therefore your circuit tester would be seeing earth on the coil's positive terminal.]

2) On your last point, the immobiliser: Terminal 15 (switched 12V+ from ignition switch to ignition system) and terminal 50 (signal from ignition switch to starter solenoid) are two separate functions, and if they both go through the immobiliser (which they should), then they need to be interrupted separately. It is therefore quite possible that the immobiliser still works correctly on terminal 50 (which lets the starter work), but has an intermittent open circuit on terminal 15 (which lets the ignition fail). I've just done some similar thinking on my 1990 Fox and need to investigate this possible fault myself. The easiest way to test this would be to bypass the immobiliser, connecting terminal 15 (coil positive) directly to the ignition switch.

[ReynoDB]

Thanks a lot Mark.

I understand not to be too worried about the negative reading then.

However I don't understand how I should bypass the immobiliser. Where are terminals 15 and 50? Sorry you are trying to explain something to someone who is not very much familiar with too much technical jargon.

I've removed all wires from the fusebox and found that two + wires were heavily burned. The one was a thin black wire which was the one giving + to the coil and the other was a black wire to the wiper switch (both were connected to my initial problem). I isolated it again but strangely no fuse popped and I'm worried that there is an overload which can trigger a fire hazard. I still don't know what the cause of the problem is.

[missioner]

Those autowatch piles of poop are installed by idiots and are just simply junk.

What they do is cut through the main wires to the ignition switch and then join the alarm in between the cut wires.

It's not very difficult to remove, just requires some patience.

The hard part is the post 1984 cars prior to 1998 are hard to get wiring diagrams for. The wiring was basically a golf 2 harness that was adapted to the Citigolf. Unfortunately it's not the same in any way.

Luckily for you the wiring is not difficult to navigate.

Since you have a few burned wires, I suggest pulling out the dash to get at the harness, I think once the alarm is removed and it's all open you will find the problem.

Please dont use an intelliprobe tester, it will drive you crazy. Rather get a multimeter and work with that. It's much simpler to understand and to diagnose problems if you are not a wiring genius.

[VAG Fan]

It sounds to me as though the burnt wire for the coil (+) is making only sporadic contact. It also sounds as though the mechanic may have bridged positive from the wiper switch to the coil. Difficult to say if he can't comment...

Regarding terminals: All the connections (functions) in wiring looms are numbered, and many of these have standard numbers. They are also called terminals.
Clickety here and lookety there: https://en.wikipedia.org/wiki/DIN_72552

Terminal 15 carries plus from the battery, but is only activated by the ignition switch when it is turned to "on" (and "start"). It goes, amongst others, to the plus side of the coil.
Terminal 50 also carries plus from battery, but is only activated by the ignition switch when it is turned to "start". It goes to the solenoid of the starter.

Both of these wires are normally interrupted by the immobiliser box, i.e. they first go from the ignition switch into the immobiliser, and only then to their destinations. The immobiliser then creates or breaks a connection in each of the wires.

So, in order to bypass the immobiliser, you would need to
1) find the immobiliser box
2) find the 2 wires from the ignition switch to the immobiliser, let's call these terminals "15 in" and "50 in"
3) find the wires from the immobiliser to the coil ("15 out") and to the starter ("50 out")
4) wire a direct bridge from "15 in" to "15 out" and from "50 in" to "50 out".

If this solves the problem, then the immobiliser is not working properly.

[missioner]

Dont be so technical, I'm just a mechanic.

Open the cover on the steering column, follow the wires from the back of the switch till you find a groot ball of insulation tape the alarm box will be attached to the tape

[VAG Fan]

Dont be so technical, I'm just a mechanic.

My firm favourite for quote of the month.

By the way, my response was to Reyno. He did ask about bypassing terminals 15 and 50 at the immobiliser, after all.

But hey, no probs, I'll leave the thread to you guys.

[missioner]

Dont be so technical, I'm just a mechanic.

My firm favourite for quote of the month.

By the way, my response was to Reyno. He did ask about bypassing terminals 15 and 50 at the immobiliser, after all.

But hey, no probs, I'll leave the thread to you guys.

Dont run away.

Input is appreciated

[ReynoDB]

Thank you gents for your inputs. Mucjh appreciated.

My coil was connected to the thin (+) in the white fusebox plug which was burned. Obviously the wire was too thin to carry the current.

I've found the original thicker black (+) on the same white fusebox plug and suddenly got power to the coil and the car then started yesterday.

I drove around yesterday and today and suddenly tonight it again just cut out. I tested the wire (+) to the coil and there was no power again. I disconnected the terminal (+) on the battery, removed the white fusebox plug, checked all fuses which were all fine and reconnected everything.

Again I got (+) power on the coil and started the car again. When I plugged in the fan which is directly connected on the (+) of the coil and not through the radiator switch (someone once bypassed that switch) the car again cut out. Then I've struggled again as before from then onwards.

My logic tells me that if the fuses don't pop, the new black (+) wire I'm using on the white fusebox plug isn't getting hot/burn anymore, and the ignition switch is also brand new, the only remaining problem can only be the immobilizer.

It could be that the overload on the thin (+) of before damaged the circuits inside the immobilizer.

I'm going to try and bypass it by joining the 15's and 50's and will let you know whether that was the ultimate issue.

[VAG Fan]

Have you measured how much current the coil is actually consuming? I think 5-8 A or thereabouts is normal.

To me it sounds as though the contacts inside your fuse box or inside the white plug are overheating and therefore failing over time. The overheating could be
... because the coil is drawing too much current, or
... there is a bad contact inside the fuse box, causing internal resistance.

Have you been running the radiator fan off the coil before? The fan shouldn't be connected on the coil! It draws too much current for that circuit. This would cause overheating immediately. I'm not sure whether the coil circuit is fused. It not, then the point with the highest resistance is the one to overheat first. This would explain why the car cut out when you plugged in the fan. Your fuse box itself may have some damaged internals.

[hangar]

I have a citigolf 1.4 carb model. dunno the year. Starts in the moring no sweat. when I stop somewhere and come back later, it just cranks but won' start. Up to now it has sometimes started with a tow and somteimes not. Other times it won't start for a while but hen when I'm phioning for help and being told to check the battery, I crank it so that my friend can hear then it starts. It has an "ignitor" on the underside of the dashboard panel in the engine compartment. Measured the volts once - 12v L & R pins, 6v centre to R pin. Today the centre pin in the connector of the ignitor shows nothing.
Help pls