123ignition troubles

[2000Touring]

Hey BMW enthusiasts,

 

I'm having troubles getting a spark from my 123ignition tune (USB only). I did everything according to the manual. First made sure the engine was at TDC, installed the 123ignition and found the green LED lighting up. After that I installed the black wire to the coil, like the manual told me. Then put the rotor in and then installed the cap on the ignition and installed the wires according to firing order (CW) (first one to where to rotor was pointing). 

 

Then tried to start the engine. Engine turned over but nothing happened. Got a spare spark plug which I connected to a wire to see if there was any spark. Still nothing. Also used a multimeter to read the Bosch Blue coil, but the coil is OK. 

 

Is it possible that there is no curve selected or something?

 

Thanks in advance for you help! 

[iinca]

try slightly rotating the distributor a few degrees..TDC isn't always where the green light says it is

 

 

Edited August 21, 2019 by iinca

[2000Touring]

But there still needs to be a spark when cranking, right? Even when the timing is off

 

Edit: i'm testing the spark by putting a spark plug on the engine (with good ground) while cranking. 

Edited August 21, 2019 by 2000Touring

[Oldtimerfahrer]

Yes, if it's off it should still spark. Have you checked the rotor / cap? I find it tough to get the cap to positively seat on the 123.

Andrew

[2000Touring]

I've had the rotor and cap off of the distributor a several times, so I guess that shouldn't be the problem. I will check it again tomorrow. 

 

Also checked for power at the coil with a multimeter and that seems fine. And I have no tachometer in my car, so that cannot be the problem. 

Edited August 21, 2019 by 2000Touring

[Oldtimerfahrer]

Check the rotor closely, no sign of undue contact with the cap and the middle contact on the cap, that it can press against the rotor? Since you got a green light by turning the body of the distributor at tdc, the distributor is fully seated and actually spinning...? Take the cap off and turn the engine to confirm. then you could check the coil ht lead to the cap for proper connection....

Andrew

[2000Touring]

10 minutes ago, Oldtimerfahrer said:

Check the rotor closely, no sign of undue contact with the cap and the middle contact on the cap, that it can press against the rotor? Since you got a green light by turning the body of the distributor at tdc, the distributor is fully seated and actually spinning...? Take the cap off and turn the engine to confirm. then you could check the coil ht lead to the cap for proper connection....

Andrew

Thanks Andrew, I will check those things you said tomorrow and I will report back here how things work out. Thank you for helping me!

[arminyack]

USB version has a blue wire that needs to go to ground.

[2000Touring]

7 hours ago, arminyack said:

USB version has a blue wire that needs to go to ground.

I connected the blue wire to the minus/negative of the coil, which is the same as ground, right?

Edited August 22, 2019 by 2000Touring

[dlacey]

1 hour ago, 2000Touring said:

I connected the blue wire to the minus/negative of the coil, which is the same as ground, right?

No, it's not. 

Coil negative goes to the contact breaker in the dizzy (or its electronic equivalent).

To ground something connect it to the bare metal of the car body.

 

[2000Touring]

2 hours ago, dlacey said:

No, it's not. 

Coil negative goes to the contact breaker in the dizzy (or its electronic equivalent).

To ground something connect it to the bare metal of the car body.

 

Ahh, so that might be my problem. Thank you for helping me!

 

I wired it this way because the negative coming out of the wiring harness is broken. So I made a cable from the negative ground > coil and figured I could just put the blue wire on the coil negative since it's the same as ground negative.

 

Hopefully the minus from the wire harness is still fixable by putting a new spade connector to it. 

 

Will keep you guys updated.

[Simeon]

19 minutes ago, 2000Touring said:

So I made a cable from the negative ground > coil and figured I could just put the blue wire on the coil negative since it's the same as ground negative.

 

Run that by me again?

 

The coil negative terminal is not directly connected to ground. In your case, with a 123, you connect the black wire coming from the 123 to it. If you have no tachometer then there shouldn’t be any other connection to coil negative.  The 123 then switches the black wire / coil negative to ground to charge the coil before making it open circuit for each cylinder as the rotor goes around. This collapses the inductive field of the coil and makes a spark.

 

If you have a constant connection between ground and the coil negative via a wire then you will never get a spark. That is how the ‘kill switch’ used to stop a motor bike engine works. 

[Stevenc22]

Just ground the blue wire right into the hole in the firewall bracket.

 

[2000Touring]

2 hours ago, Simeon said:

 

Run that by me again?

 

The coil negative terminal is not directly connected to ground. In your case, with a 123, you connect the black wire coming from the 123 to it. If you have no tachometer then there shouldn’t be any other connection to coil negative.  The 123 then switches the black wire / coil negative to ground to charge the coil before making it open circuit for each cylinder as the rotor goes around. This collapses the inductive field of the coil and makes a spark.

 

If you have a constant connection between ground and the coil negative via a wire then you will never get a spark. That is how the ‘kill switch’ used to stop a motor bike engine works. 

Thanks Simeon, that makes sense! Learning something new everyday.

 

So the only connection to the minus on the coil should be the black wire from the 123. There shouldn't be any other connection to the minus on the coil. 

 

And the positive side of the coil? Is it right that a wire from the wire harness would connect to the positive side of the coil?

 

1 hour ago, Stevenc22 said:

Just ground the blue wire right into the hole in the firewall bracket.

 

Thanks, makes sense!

[Stevenc22]

The red and black wires from the 123 connect to the coil.

 

The coil will also have a positive connection from the factory wiring harness that goes to the ignition.

 

The coil will also have a negative connection from the factory wiring harness that goes to the techometer