No Spark from coil - please help?

Hi,

my 1985 1800 GTi was running very rough, (less power & juddering when accelerating). I was advised that it was electrical and told to change HT leads, Coil, Distributer Cap and Rotor Arm. However when I changed parts, (pretty sure all in right place) the car wouldn't start. The guy at GSF swears all parts are correct.

The ignition turns the starter motor, but I get no spark from plugs or coil lead, (I tested by holding lead from Coil to Dizzy to engine and got no spark). I connected a Voltmeter and did notice signal going to coil, (even put old coil back in  to test but still no spark!)

I have read many posts but am confused when trying to relate the problems to my car, to solutions posted?!

I also noticed I couldn't hear the fuel pump prime, but it does work when connecting direct to battery - not sure if this is relevent?

I have read posts about ICU?? and Hall Sender?? But not sure of what these do or how to test!?

Please could someone give me a quick guide to order of what to check? i.e. if dizzy is wrong would that effect the coil from working?

All help greatfully received, starting to get very frustrated!!

Cheers!

it sound like your dizzy mate, wen it goes it takes the power to coil and the pump with it

thanks! that gives me a really good starting point - I was worried I'd done something more serious!

Is there a way of testing I have the Distributor all hooked up correctly. It seemed to all click into place properly, and the guy at GFS said it was the the correct rotor arm for my model, (had to wait for it to be delivered and it looks just like the old one that came out)

Should I pop the old one back in and see if it works? Or are there any tests I can perform to narrow problem down?

Many thanks!

its not the cap its the dizzy its self, check the plug that goes into it (3 wires)

Is there a guide to this anywhere that I can follow - as I'm not really sure what I'd be checking for other than connectivity or clean contacts?

If I hadn't seated the Distributor arm correctly would that also stop power to the coil? I did notice once that when I turned the ignition over that there was a whirring from the distributor so I guess it was going round inside cap?

Sorry for my ignorance on this!

Cheers

you would still get power to the coil if you put arm on wrong, the conecter plug is on the side of the dizzy mate

ok, I'll make sure the connector to side of dizzy is still connected properly when I get home! - hope it does the job!

Many thanks for your help!

PS - is there anything else I should look for whilst I'm at it?

a leggy brunnet for me

Ha!

Sorry, but I do know a lovely topless model - my MK1 Cabrio Gti!

DNT DO FLOPPY TOPS

I tested the 3 wires going into the dizzy with a voltmeter and they were getting power, and with the cap off I saw the arm turn round when ignition and starter motor running.

I also put voltmeter to the lead coming off coil and measured good voltage coming off that.

But I still got no spark from plugs or coil when held close to engine body as earth!

What the hell is wrong!?   Are there any tests I can do to spot where the problem lies?

Cheers

There's a couple of things you could check:

1. Have you knocked or dislodged any wires off the coil?
2. Have you pushed the new HT leads fully into the connectors on the coil and dizzy?

With these in place, and assuming it worked before, then it should produce a spark from the coil. If it does this but doesn't produce spark at the ends of the plug leads, you could check the HT connections on the dizzy cap and at the spark plug (some leads need the little screw on button on the top of the plugs, some don't), and check that the rotor arm is fitted properly and spins with the engine. Also check the dizzy cap is secured fully and in the right/same position.

If your hall sender worked before, and you changed a bunch of other parts, no reason why it shouldn't still be working. You can test it if you like, but I'd start with the above.

I checked all the leads to the coil - there's 2 spades on one side and a plastic plug with 2 leads on the other, (I tested them with voltmeter and they were delivering current)

I also made sure all HT leads were firmly pushed in. The dizzy cap was a bit difficult to get in properly but just needed to push the arm further in to get cap to get on - don't know if this may have caused damage?

The spark plugs don't take the screw top bits and fitted to HT leads in snug way - so assume problem is not here. I also tried taking HT lead off spark plug and holding it to engine block to check for spark - got nothing.

Is there any way of testing that the lead that comes from Hall sender, (which is sending voltage) is coming back out from arm? Or is the fact that it's spinning round proof that the Hall sender is ok?

I'm sure it's something really simple, as I only changed a few parts, and have been looking very carefully to see if something got accidentally dislodged!

There's a simple test for the Hall Sender in the Haynes manual.

thanks, I'll have a look again at my Haynes.

maybe the new coil isnt a good one.
it has been known.

Sorry it's taken a while to get back with a conclusion about this, but managed to get it started the other week. Was a faulty new distributor as was predicted, I managed to find my old one which I thought I'd binned, (luckily I kept it in back of a draw!) popped it back in and car started!

Which is all good, but I still have the original problem that led to me changing all the Coil / Spark Plugs / HT Leads / Dizzy Cap & Arm etc…

So I'm back to square one, (?80 the poorer!)

I'll have to look on Forum for ideas to slove the juddering rough running issue or start new post!

Many thanks!

good luck mate