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123/tune+ Redux


Chris_B

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4 hours ago, Chris_B said:

One thing I didn’t mention was that tonight I swapped my original Bosch dizzy in place of the 123 dizzy (changed nothing else including the MSD unit/wiring) and it worked perfectly. 

When you install your 123 dizzy, what are you doing for the yellow wire? Just letting it dangle? Also, what if you unplug your headlights and see if the car still dies when you "turn them on"? Do you still have the factory ballast resistor relay installed?

 

Also, this is how I have mine installed:

 

https://www.alfabb.com/bb/forums/electrical-chassis-lighting/572993-123-distributor-question.html#post7535314

 

Edited by RobC
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4 hours ago, RobC said:

When you install your 123 dizzy, what are you doing for the yellow wire? Just letting it dangle? Also, what if you unplug your headlights and see if the car still dies when you "turn them on"? Do you still have the factory ballast resistor relay installed?

 

Also, this is how I have mine installed:

 

https://www.alfabb.com/bb/forums/electrical-chassis-lighting/572993-123-distributor-question.html#post7535314

 

I don't have a yellow wire. If I unplug my headlights the motor does not die when I "turn them on" because they are not connected. I do not have ballast resistor relay. At the moment, I am using a relay to take direct power from the battery for the ignition system, switched by the original +12V circuit from the ignition key. My MSD is connected as described in the alfa board, except I am not using either of the MSD tach outputs.

Chris B.

'73 ex-Malaga

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Your headlights being "on" is causing a voltage drop on either the +12v side or even the ground side.  You could have a poor connection supplying +12v to the distributor and/or a poor chassis ground or engine ground.  Double check all wiring for loose connections including the grounds running from the battery to the chassis and the engine block. The 123 may be more sensitive to a small voltage drop vs the regular ignition. 

71 2002

06 330i

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I think this is the crux of the issue- the 123 being hypersensitive to voltage drops. In order to reduce the effect of system load causing voltage drop, I ran a separate circuit from the battery to a relay that is triggered by the normal +12V circuit from the ignition key (a green wire on '73 cars). My battery is well grounded to the chassis and motor. When the motor is running, system voltage typically is >+14V if the alternator is spun up a bit. Note that the spec sheet on the NL site states that voltage requirement is " 4,0-15,0 Volts" which doesn't square at all with my experience- presuming that system voltage fluctuations are causing the problem. Before I installed the relay, even running the turn signals would cause the motor to cut out. I just don't get it. 

Chris B.

'73 ex-Malaga

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It might be that particular 123. I have mine powered from the green ignition + wire along with a tacho adapter and the turn on signal for my Summit Racing multi spark ignition with no problem. 

 

The 123 is designed to work as a 6v car device so I doubt it is a conventional volt drop that’s affecting it. It could be seeing a raised potential difference at a grounding point that may be confusing it. Where do you have the blue wire connected and is there anything else connected at that point?

rtheriaque wrote:

Carbs: They're necessary and barely controlled fuel leaks that sometimes match the air passing through them.

My build blog:http://www.bmw2002faq.com/blog/163-simeons-blog/

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What blue wire are you talking about?  The manual says if you suspect a bad ground use the tapped hole in the distributor housing for a grounding wire.  You may want to try that or maybe use an alligator clip for a ground of the dist. body.

71 2002

06 330i

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Same place. 

 

It it just seems so weird. Have you tried it without the tacho adapter in circuit yet?

 

Have you tried measuring the voltage across the red and blue wires on the 123 while you are suffering an ‘event’? And the MSD is grounded at the battery?

rtheriaque wrote:

Carbs: They're necessary and barely controlled fuel leaks that sometimes match the air passing through them.

My build blog:http://www.bmw2002faq.com/blog/163-simeons-blog/

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12 minutes ago, DRedman said:

What blue wire are you talking about?  The manual says if you suspect a bad ground use the tapped hole in the distributor housing for a grounding wire.  You may want to try that or maybe use an alligator clip for a ground of the dist. body.

 

There is a blue wire on the M10 model. The version for the Rover V8 (I think) grounds through the case. 

rtheriaque wrote:

Carbs: They're necessary and barely controlled fuel leaks that sometimes match the air passing through them.

My build blog:http://www.bmw2002faq.com/blog/163-simeons-blog/

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9 minutes ago, Simeon said:

Same place. 

 

It it just seems so weird. Have you tried it without the tacho adapter in circuit yet?

 

Have you tried measuring the voltage across the red and blue wires on the 123 while you are suffering an ‘event’? And the MSD is grounded at the battery?

Without the tach adapter in circuit is the one config I have not tried yet. The brown wire on the battery neg post is directly from the MSD. The +wire (red) from the MSD is connected to the bus bar above my battery.

 

I have not tried measuring the voltage during an "event" (need a helper for that operation), but the voltage on the 123 dash board reads ~+13V when this happens. IMG_1143.thumb.jpg.fd0edf365cc9921176fa6f7bb87278b8.jpgIMG_1143.thumb.jpg.fd0edf365cc9921176fa6f7bb87278b8.jpgIMG_1143.thumb.jpg.fd0edf365cc9921176fa6f7bb87278b8.jpgIMG_1143.thumb.jpg.fd0edf365cc9921176fa6f7bb87278b8.jpgIMG_1143.thumb.jpg.fd0edf365cc9921176fa6f7bb87278b8.jpgIMG_1143.thumb.jpg.fd0edf365cc9921176fa6f7bb87278b8.jpgIMG_1153.thumb.jpg.91081345182f93542ff6b99801854915.jpg

Chris B.

'73 ex-Malaga

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1 hour ago, Simeon said:

Same place. 

 

It it just seems so weird. Have you tried it without the tacho adapter in circuit yet?

 

Have you tried measuring the voltage across the red and blue wires on the 123 while you are suffering an ‘event’? And the MSD is grounded at the battery?

I keep coming back to the fundamental mystery here. In one test, I took the MSD out of the circuit. Motor ran fine with the 123; a go no-go test (turning the headlights on) had no effect. I didn't actually drive the car. The motor runs well with either the analog or digital MSD unit and the original Bosch dizzy.

Chris B.

'73 ex-Malaga

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