No Spark suddenly

[Stesaw]

OK so I'm scratching my head a bit with this one.
Couple of days ago I replace my vac advance on the dizzy as it was full of oil and its movement was a bit rough. After fitting new one ran the van to pick the mrs up, engine down on power.. hm guess better check the timing.
Checked timing today as it was way out, set timing to what it should be running fine sounded better and had better pick up on revs, bits of black smoke out the back, was smelling of of petrol the other day so running rich I guess, so shut off the engine and pulled a plug and it was black, so wound the mixture screw so it was only two turns out, (was 2 3/4 before). 

Went to restart, engine turns over doesn't catch. Checked all grounds aside from the gearbox strap, Coil primary and secondary tests OK, Leads test OK. Dizzy has a new Arm, swapped that back to old one as I know that works, no spark still. Different known working plugs, no spark.

Could the control unit have just gone? I did have an old one in the van from the PO but that didn't help either.
I noticed that on the control unit two of the pins were fairly black as were the connectors on the cable end, so I cleaned them up but still no joy.

I suppose tomorrow I can put a cable to the coil and scrape the other end on the engine block to see if I get sparks.

Any thoughts?
 

[maxstu]

I guess it's the 1.9DG engine you are having issues with?
I would test there is 12v getting to dizzy. Simply turn on ignition and put a multimeter between coil lead and top of dizzy. It should read around 12v. If good and engine refuses to start, then it's likely the ignition amplifier has a loose connection or failed.
What control unit do you mean? Hall sender?

[davidoft1]

I would check wiring in the distributor hasn’t been dislodged and damaged, check for 12v feed to the coil and distributor to start

[Stesaw]

I guess it's the 1.9DG engine you are having issues with?
I would test there is 12v getting to dizzy. Simply turn on ignition and put a multimeter between coil lead and top of dizzy. It should read around 12v. If good and engine refuses to start, then it's likely the ignition amplifier has a loose connection or failed.
What control unit do you mean? Hall sender?

Hey Stu

Yeah 1.9, the 2.1 is entombed behind whats left of a syncro shell currently. 

When I'm saying control unit, I mean ignition amp. I did suspect a loose connection there as the current one is a push on connector with no clips so it sometimes works itself loose. 
 

I would check wiring in the distributor hasn’t been dislodged and damaged, check for 12v feed to the coil and distributor to start

Thanks David, I'll give what you've both said a go and see what happens. Was just odd how a couple of mins before adjusting mixture screw on the carb I had spark and it all ran fine then after get no spark. I thought I mighta unplugged a connector somewhere so I went looking and checked everything about three times.

[Stesaw]

Well,
Tested for power to coil, attached a spark plug to king lead and a lead from negative on coil and just tapped the engine case, got sparks off the wire so getting power and the spark plug gave off a spark but it wasn't a bright strong spark. Ill be cleaning up the ground on the gearbox.

Swapped out the ignition amp and coil from the 2.1, engine started. Put back the old amp engine ran, put back the old coil...engine ran.

Oh well. Mystery. Might have been a connection somewhere I suppose but I double checked everything the other day. Spare coil and amp in the van just incase.

[maxstu]

Good!

My opinion is the ignition amp connector needs firmly securing, and a touch of dielectic (?) grease wont go amiss.

[Stesaw]

I did give the connections a clean so maybe that helped, did think about using some dielectric grease but didn't have any of that stuff. I'll get some after xmas and when the 2.1 goes in give everything a good clean and sort out any funky wires or connections that are there when I take stuff out.