help please, missing 12v at coil but have spark when bypasse

[toothio]

Hi everyone,
I've recently installed a weber 32/36 on my 1600dp. Went to fire her up and the engine turns over but no pops n bangs. I have diagnosed this down so far that I am not getting 12v TO the coil, which means no spark. I have rigged a wire straight from the battery to the +ve terminal of the coil and boom, spark at the plug but still not starting up. One strange thing is that when the key is turned, the fuel guage USED to read the level, then went to not working at all, and then now it reads as normal with ignition on. Timing advance etc is as I had it with the original pict 34 that leaked hence the change. As I had bypassed the fuses etc I know that they are good so I'm a bit lost, the help I've had so far has been great by another early bay member, just need that little bit extra if that's not cheeky.
Anyways that's the short version!!
Many thanks
Andy

 

[TeamBrian]

Are the wires definitely on the correct terminals?

 

[toothio]

Hi, many thnaks for your reply, Ive got the green wire going from the dizzy to the -ve, a black wire from the main loom and carb choke wire going to +ve, also there is another black wire going from the loom to the oil sensor.as far as I can see that is correct. They're the only wires I have to play with.

 

[ozziedog]

Hiya mate, It sounds like the wires may be a little mixed up somewhere. Try this,, take all the of the wires off and put a bit of tape over them, then run one to the coil and try to start it again. If that works,, and it should,, then you have a process of elimination. Have you pulled a lead off and stuck an old plug in it and watched it sparking ??

Another thing you might want to try, is put a capfull of juice down the carb/s just to see what happens with an alernative supply of fuel, but not too much and don`t spill it everywhere And don`t blow yourself up :shock: :shock: :shock:

Ozziedog,,,,,,,,,,,,,Good luck :mrgreen:

 

[TeamBrian]

Good call, Ozziedog. Never thought of that!

 

[toothio]

Thanks for more replies guys, only when I run a wire straight from the battery to the coil do I get a spark with the ht lead removed etc. I'll try with just the one wire to the coil, even disconnected the green one from the dizzy?

 

[bluenose]

the +'ve black wire to the coil from the ignition switch doesn't go through any fuses, your ignition switch must be ok as your getting fuel gauges and shit come on.

are you sure the black wire connected to your oil sensor isn't your ignition wire?? the wire to oil sensor is normally blue/green. Black cables are normally ignition wire and reversing lights going to +'ve on the coil. Although someones probably changed all your wiring colours

the green wire to the -'ve on the coil will be going to the condenser on the dizzy so that would be correct

 

[toothio]

Hi mate,
The previous owner has labelled the two black wires "oil sens" and "coil" luckily for me. Interestingly the reverse lights come on, but I see no other wires apart from the two black, choke from the carb and green from the condenser.even more interesting is that when I do get a spark after I go directly from battery to coil. The engine still doesn't start.
Many thanks