Scirocco Register

Still no spark...

• Battery is good and freshly charged
• Coil is good (new and resistance readings within spec)
• Ignition module is good (new and-bench tested)
• Hall sender is working (bench-tested with new ignition module)
• Power at coil
• Power at ignition module
• Continuity on wires between ignition module and hall sender plug
• Engine earth straps are good
• Dizzy cap looks good (no visible tracking, no visible damage, centre pin present and working)
• Spark plugs look good (correct gap, light tan colour, no visible damage)
• HT leads, including coil to distributor, look ok and resistance readings within spec
• Rotor arm ok, resistance reading within spec
• Fusebox totally dry
• Tried disconnecting the rev counter wire from the coil on the off-chance but no difference

This is driving me crazy, what is it that I've overlooked? Next step is to call out the AA, but I don't have a lot of faith in that option, unless the guy they send is old-school, and understands old VWs.

Have tried grounding a connected spark plug directly to the battery with a jump lead, and cranking, on the premise that I should get some kind of spark, however feeble or badly-timed, but no joy.

Any thoughts? I could really do a with a break here...

marcus wrote: Have tried grounding a connected spark plug directly to the battery with a jump lead, and cranking, on the premise that I should get some kind of spark, however feeble or badly-timed, but no joy.

Were you grounding the threads only?

Marcus, I am on a train at present but when I get back to my flat I will post up the phone number for Alan at AJ Motors, in Chelmsford. Give him a call tomorrow and ask his advice, knows his VW's and loves Sciroccos. 30 plus years of VW/Audi experience!

Thanks Ian.

Mr Brown - what difference would it make? But yes, the jaws of the jump lead were around the thread, on the premise that's how it works when the plug is screwed into the block.

I had a friend who we could not get any spark on his car his dissy cap looked ok could not see anything wrong with it but tried another one from my car, it worked..
Might not be the answer but might be worth a shot, fit new dissy cap, rotor arm and HT leads?

Yes, I was thinking that, it would be sod's law wouldn't it...

Marcus, give Alan a call tomorrow at AJ Motors on 07855 464188 or 01245 464800. Tell him Ian gave you his number, this guy is pretty amazing with VW's and should be able to steer you in the right direction.

Hopefully if you get running it is well worth the 25-30mile trip up to Chelmsford to see him.

marcus wrote:Mr Brown - what difference would it make? But yes, the jaws of the jump lead were around the thread, on the premise that's how it works when the plug is screwed into the block.

Just checking. I've seen people try to earth the electrode.

Are you getting a signal from the TCI-H module to the coil (green wire)?

I bench-tested the TCI-H unit, eg hall sender and TCI-H unit out of the car, connected up as they would be in the car, with a 12V supply and a test lamp in place of the coil, rotating the 'wheel' (ie alternately interrupting the magnetic field in the hall sender) produced the expected result eg ignition module triggered the test lamp.

As mark1gls says, I should probably replace the obvious, leads, cap, arm, at least to rule them out.

I'd try a different TCI-H unit first. I remember an AA man years ago telling me it acts as a signal "amplifier" for the coil - it may produce a signal that's strong enough to light a test lamp but not strong enough to give the required output at the coil. My car was producing a spark but just not strong enough.

What car/year is it? And whereabouts are you?

Mk2 GTL, 1.8 8v carb, 1985, north London.

The TCI-H unit is new, I even tried a second new unit.

The old one failed the bench test ie didn't switch, and the voltages on pins 5 and 6 were identical, down to the millivolt, leading me to suspect an internal short, where pin 6 is the input from the hall sender and when on causes pin 3 (to the coil) to effectively short to earth to allow current to flow through the coil primary.

Did I read somewhere that if you disconnect the HT lead from the dizzy and hold it a few mil away from the engine block (with insulated pliers) you should get a spark? Might be a way of ruling the dizzy in or out until I can get a new cap, arm and leads.

marcus wrote:Mk2 GTL, 1.8 8v carb, 1985, north London.

The TCI-H unit is new, I even tried a second new unit.

The old one failed the bench test ie didn't switch, and the voltages on pins 5 and 6 were identical, down to the millivolt, leading me to suspect an internal short, where pin 6 is the input from the hall sender and when on causes pin 3 (to the coil) to effectively short to earth to allow current to flow through the coil primary.

Did I read somewhere that if you disconnect the HT lead from the dizzy and hold it a few mil away from the engine block (with insulated pliers) you should get a spark? Might be a way of ruling the dizzy in or out until I can get a new cap, arm and leads.

I was going to offer to bring the (known good) bits from my car over but you're a bit too far unfortunately. You're right about the HT lead test - I've done that before. With not thick enough gloves.....DIY taser.

Cheers, that's a kind thought but as you say, too far.

Marcus as I said yesterday give Alan a call, he will talk you though finding the fault. Use the mobile number, he is awaiting your call!

Will do, been madly busy today so haven't had a chance yet.