Technical How to install the 123-2R electronic distributor

[fiat500]

I have one of these to sell, so it's in my interests to put up the most stripped-back instructions I can.

Start by aligning the timing mark on the pulley with the arrow on the cover; highlighted in white paint here:

For ease of explanation and understanding, make sure the rotor-arm points towards the crankcase; if not, turn the engine clockwise until the timing marks align again.

At the coil, remove the low-tension wire which connects back to the distributor; in my case, the red one:

Slacken and remove the 13mm nut, washer and clamp which secure the distributor (504cc and 652cc engines),and then note how the rotor arm turns slightly as you remove the distributor by pulling upwards:




Fit the electronic distributor, bearing in mind the slight offset in direction needed of the rotor-arm in order that when fitted, it is aligned as the original; loosely secure the clamp-nut.
Connect the red lead to the positive post of the coil; the existing feed wire stays on this post.

Turn on the ignition and rotate the distributor clockwise until the green led illuminates. If it's already on, rotate clock wise until it goes off and then anti-clockwise until it just turns on; now clamp the nut securely.

Turn off the ignition and connect the black wire from the distributor to the other post on the coil.
Refit the distributor cap and check that the HT leads still connect to the same spark plugs as previously. I have found that the positions need reversing when using the 123.

Start the engine.. If it won't, the most likely cause is plug leads wrong as described. Go for a run and ideally, then set the maximumum advance using a strobe.



Have fun.

 

[the hobbler]

I have one of these to sell, so it's in my interests to put up the most stripped-back instructions I can.

Start by aligning the timing mark on the pulley with the arrow on the cover; highlighted in white paint here:

View attachment 401743

For ease of explanation and understanding, make sure the rotor-arm points towards the crankcase; if not, turn the engine clockwise until the timing marks align again.

View attachment 401744

At the coil, remove the low-tension wire which connects back to the distributor; in my case, the red one:

View attachment 401745


Slacken and remove the 13mm nut, washer and clamp which secure the distributor (504cc and 652cc engines),and then note how the rotor arm turns slightly as you remove the distributor by pulling upwards:




Fit the electronic distributor, bearing in mind the slight offset in direction needed of the rotor-arm in order that when fitted, it is aligned as the original; loosely secure the clamp-nut.
Connect the red lead to the positive post of the coil; the existing feed wire stays on this post.

Turn on the ignition and rotate the distributor clockwise until the green led illuminates. If it's already on, rotate clock wise until it goes off and then anti-clockwise until it just turns on; now clamp the nut securely.

View attachment 401746


Turn off the ignition and connect the black wire from the distributor to the other post on the coil.
Refit the distributor cap and check that the HT leads still connect to the same spark plugs as previously. I have found that the positions need reversing when using the 123.

Start the engine.. If it won't, the most likely cause is plug leads wrong as described. Go for a run and ideally, then set the maximumum advance using a strobe.



Have fun.

Although I don't require this information, you have put it over very clearly Peter; not only for those people newly fitting "123" ignition, but for people who already have this ignition and might be struggling a bit with it. One point though Peter--don't you mean "turn the distributor ANTI-clockwise until the green light comes on" when you initially set the timing up? However, thank you for the information and pictures.

 

[fiat500]

Although I don't require this information, you have put it over very clearly Peter; not only for those people newly fitting "123" ignition, but for people who already have this ignition and might be struggling a bit with it. One point though Peter--don't you mean "turn the distributor ANTI-clockwise until the green light comes on" when you initially set the timing up? However, thank you for the information and pictures.

Thank-you,......I do mean the thing should initially be rotated anti-clockwise; an important correction. But unfortunately it's uneditable now.
In practise, unlike with points ignition, all you need is the LED to be just on, so you can wiggle the distributor randomly until it is at the transition point where you see the green glow.

 

[Mozys]

Good day
I have done everything you recommend but im having a problem of the ignition coil stopping to work after I run for half hour. I have connected the red wire to the + side and the black to the - side. The power to the coil is connected to the +. What am I doing wrong?
Unfortunately the above videos are no longer available.

 

[fiat500]

Good day
I have done everything you recommend but im having a problem of the ignition coil stopping to work after I run for half hour. I have connected the red wire to the + side and the black to the - side. The power to the coil is connected to the +. What am I doing wrong?
Unfortunately the above videos are no longer available.

Did you fit a new ignition coil? If not, what does your existing coil look like? You may need new ignition leads. Photos of the coil will help diagnosis.

 

[Mozys]

Good day, yes i did and drove car beautifully for 20 minutes and stopped. No spark. Replaced the coil and leads and started first time, drove for another 15 minutes and stopped with no spark again. I have attached a picture of the 123 and one of the coils

 

[fiat500]

Good day, yes i did and drove car beautifully for 20 minutes and stopped. No spark. Replaced the coil and leads and started first time, drove for another 15 minutes and stopped with no spark again. I have attached a picture of the 123 and one of the coils

A few things I notice; in the first image, maybe it is the lighting, but is the second wire from the distributor black as it should be? It looks grey.
The distributor is fitted at the wrong angle. It may be that you would find it difficult to get the timing correct. The clips for the cap should be in aposition that makes them easier to unfasten....see my photo.
Although it is a lighting wire, you seem to have a blue cable that is damaged and maybe touching the coil.
There is a lot of non-original wiring and unless you are certain that it's all properly connected and insulated, I would strip it all back and carefully tidy things up.
Without seeing the writing it's not possible to be sure about the coil. It must be one rated at 3 ohms. Are you sure that you have the + and the - wired correctly?

 

[Mozys]

Thank you for your response. The grey wire is the oil pressure sensor. The ignition has a black and red wires. You say the distributors is in the wrong position but that is exactly how the old one was, and the car runs perfectly. The problem is that its damaging the coils which i dont know the reason. The car was rebuilt and some of the wire colours dont much the original. You will see a blue wire connected to the coil, that brings the 12V. The other blue wire “touching” the coil is a light wire and its not damaged. I moved it away just in case.
You ask if im sure to have the + and - correctly wires. I have the blue (12V feed) and the distributir red wire connected to the + and then the distributor black wire connected to the -
I assume its all correct.

 

[fiat500]

Thank you for your response. The grey wire is the oil pressure sensor. The ignition has a black and red wires. You say the distributors is in the wrong position but that is exactly how the old one was, and the car runs perfectly. The problem is that its damaging the coils which i dont know the reason. The car was rebuilt and some of the wire colours dont much the original. You will see a blue wire connected to the coil, that brings the 12V. The other blue wire “touching” the coil is a light wire and its not damaged. I moved it away just in case.
You ask if im sure to have the + and - correctly wires. I have the blue (12V feed) and the distributir red wire connected to the + and then the distributor black wire connected to the -
I assume its all correct.

It sounds like all is wired correctly and I assume that you have had to change the coil and it's been damaged a second time? You need to be sure that it's not a coil designed for ignition systems with a ballast resistor; that would burn out on a Fiat 500.

Did you check the dynamic timing to 28 degrees witha strobe? But if it's wrong I don't see how it could damage the coil. Have you checked the system voltage when the car is running? The generator may be giving over-voltage.

 

[Mozys]

Thank you. I have not check the 28 degrees, dont have a strobe. Will look for and and test. Have tested the voltage and its 12V.
I dont know all the details about the coils but both were sold to me has ideal for electronic ignitions. I will have to investigate. The first coil was running fine with the previous electronic ignition.

 

[fiat500]

Thank you. I have not check the 28 degrees, dont have a strobe. Will look for and and test. Have tested the voltage and its 12V.
I dont know all the details about the coils but both were sold to me has ideal for electronic ignitions. I will have to investigate. The first coil was running fine with the previous electronic ignition.

The instructions from the manufacturer say that you need a particular quality of coil. The 123 does pack a very strong spark and will make a big demand on a coil.
Although you might think that because of the electronics everything on timing is taken care of, it is very important to be sure that the actual timing at high rpm is the same as the setting of the distributor. The standard setting is 28 degrees. A strobe reading may show that you still need to rotate the distributor a few degrees.

 

[Mozys]

I was just reading on the 123 that the coil must be a 3 ohms. Will check that.
Once i have the strobe, will check the 28. Thank you for advise.