Mk2 electrical problem

[ML-MK2]

Hi guys, I seem to be having some sort of an electrical bug. Tried starting my car, but just won't start. When switching the ignition on I noticed that the fuel pump don't prime at all, i checked fuse and relay(need to take power straight to the fuel pump to see if it will work).

What i found strange is when I turn the ignition on, the indicator light on the dash is on(but dim), if I switch the indicator on it only goes bright but does not flash( but the hazards works fine). The horn/hooters does not work, but the relay "clicks". Reverse lights and handbrake warning light is also not working, everything worked fine last week friday when I last drove the car.

Car is a mk2 jetta cli (kjet fuel injection).

[PapaJo]

Dead battery??

[ML-MK2]

No,I also thought so and so i charged the battery monday. Fitted this morning and still does the same.

[smitbrandon]

Sounds like your alternator went, my fiances cars alternator fried and in result her car did the same. Have it checked by an electrical specialist maybe he can just recon the wiring inside the alternator

Sent from my E5823 using Tapatalk

[ML-MK2]

@smitbrandon
Was it the same type of car?
Wouldn't it affect all the electrical components, and not just those 4?

[Wolf Mk2 16V]

My alternator stopped charging a while ago... blue wire was broken off... had the same indicator issue that turned out to be the battery being low -too little juice to work....I now know that the fuel pump sounds a lot more brisk hehehe so +1 on the alternator needing a recon

[ML-MK2]

Thanks for the input guys, battery is just over a year old and was just below 14v after charge. Will go look at alternator wires after work, will also check if i can find someone who's alternator i can borrow just to test and see if it is mine that has failed

[panic-mechanic]

make sure that the battery actually retains that charge not check it right after charging. A full happy battery must sit at 12.7 volt and only drop a little with just the ignition on.

[ML-MK2]

So today I sat and thought this thru, but had my doubts that it is the battery/alternator. I thought what i do know is that the fuel pump has a - wire on the coil, so I thought it might have a + on the coil also. When I tested for a + on the coil, there was nothing.So I tested for spark at the plugs and also nothing.

I then took a + wire from the battery to both + connectors on the coil and then everything started working. Indicators, reverse lights, pump primed and even the dim indicator light went off. But I still don't seem to have any spark on the plugs. I'm thinking it's the coil or module, any ideas on which it is, or can it be something else?

[ML-MK2]

Hi guys just to update, over the weekend i swapped out the coil and module, but still not any spark.I'm thinking problem on fuse box or a relay, Any advice from your side?

[PapaJo]

How is the wiring to the ignition module? Are you getting 12v on pin 4 and have the ground wire on pin 2? Pin 1 is the negative pulse out to coil negative. Pin 3 and 5 is the power and negative to distributor.

See picture for reference to wiring. The pin 6 wiring in your case will be from signal ( centre wire) on distributor.

[ML-MK2]

Thanks papajo, im gonna test 2nite and get back 2 u

[ML-MK2]

I tested for a + and had no luck, the grounds on the other hand is fine. Took a + to the no 4 pin and everything works and the car starts and idle

Now can you plz help me find cause/permanent fix, not sure where to next.

[PapaJo]

Ignition ON have to be wired from ignition to coil + and tp100 pin 4. You should have a black/yellow stripe or black/red stripe wire (depending on the year model of your car) coming from ignition on to the coil +.

[ML-MK2]

I have a 88 model, mine has black/yellow stripe and a red/black stripe wire. Does this wire go straight to tp100 and coil or does it go to the fusebox/relay?

[PapaJo]

I have a 88 model, mine has black/yellow stripe and a red/black stripe wire. Does this wire go straight to tp100 and coil or does it go to the fusebox/relay?

Goes from ignition via fusebox to coil and from coil to tp100

[Supervan II]

Your ignition switch is shot.

[ML-MK2]

Thanx supervanII, I've actually bought a new switch the same day that papajo sent me the diagram, but its still the same with the new switch connected. I can start it when I connect a + from the battery to the no.4 wire on the module. I had a look the other day and I've noticed that the black/red wire papajo referred to,is cut and the alarm(aftermarket) is connected to both ends of the cut wire. It might be the alarm thats acting up?

[Supervan II]

Thanx supervanII, I've actually bought a new switch the same day that papajo sent me the diagram, but its still the same with the new switch connected. I can start it when I connect a + from the battery to the no.4 wire on the module. I had a look the other day and I've noticed that the black/red wire papajo referred to,is cut and the alarm(aftermarket) is connected to both ends of the cut wire. It might be the alarm thats acting up?

I'd remove/replace the alarm as a first option.

[ML-MK2]

I hope thats not the case, but i need to make time and go thru it before taking out stuff

[PapaJo]

Remove that black/red wire from the alarm system and check if all is working fine. Rhat black/red goes through a relay contact inside the alarm immobilizer box.