Distributor pick up operation
- Thread starter Sean
- Start date
Took me a while to sort out
exactly what you mean. (I think!)
The POSITION your dizzy shows in the photo is in the position where the Bosch ECU senses spark.
There's a large magnet under those rings that creates a field to produce a relatively low voltage pulse.
The Bosch ECU amplifies the pulse (it's an analog pulse) to trigger a spark. The EXACT position of where those moving veins line up vs. where the spark plug fires will vary slightly from one dizzy to another, but that doesn't matter.
The position of your dizzy is what determines your "spark position" in the end.
This help you at all?
exactly what you mean. (I think!)
The POSITION your dizzy shows in the photo is in the position where the Bosch ECU senses spark.
There's a large magnet under those rings that creates a field to produce a relatively low voltage pulse.
The Bosch ECU amplifies the pulse (it's an analog pulse) to trigger a spark. The EXACT position of where those moving veins line up vs. where the spark plug fires will vary slightly from one dizzy to another, but that doesn't matter.
The position of your dizzy is what determines your "spark position" in the end.
This help you at all?
Sean
new to Fiat
Yes, but.....
...bigger problems now.
Ok, the story. Installing my timing belt. The picture in the first post was taken before I started installing the new belt, old belt was removed a while ago. In the picture above the rotor is pointing towards #4 on the cap. I installed the new belt and bared the engine over one cam revolution to check the marks to line up again. I noticed the pickup tabs were no longer lined up so I removed the belt again to adjust and it was then I noticed the rotor no longer lined up with #4 on the cap when the pickup tabs are aligned. When the pickup tabs are aligned the rotor is in between wires on the cap like the pickup rotor has turned on the distributor shaft. I pulled the snap ring thinking the pin was missing but it looks like all is well. If anyone has a distributor loose and could take some pictures like the ones below it would help me out. :mallet:
...bigger problems now.
Ok, the story. Installing my timing belt. The picture in the first post was taken before I started installing the new belt, old belt was removed a while ago. In the picture above the rotor is pointing towards #4 on the cap. I installed the new belt and bared the engine over one cam revolution to check the marks to line up again. I noticed the pickup tabs were no longer lined up so I removed the belt again to adjust and it was then I noticed the rotor no longer lined up with #4 on the cap when the pickup tabs are aligned. When the pickup tabs are aligned the rotor is in between wires on the cap like the pickup rotor has turned on the distributor shaft. I pulled the snap ring thinking the pin was missing but it looks like all is well. If anyone has a distributor loose and could take some pictures like the ones below it would help me out. :mallet:
eflexter
Eddie Flexter
!
The only reason this could be possible is that your advance/retard mechanisms have broken, or are stuck, or whatever in the fully advanced position. The rotor position, relative to the four "spokes", will change when the spark is advanced by the vacuum unit AND the spring loaded weights underneath the "spoke" assembly.
You'll have to take everything apart to get to the bottom of the problem. Look for:
BROKEN SPRINGS on the advance weights.
LEAKING OR STUCK vacuum advance mechanism.
If everything is attached and moving properly, the rotor will point to one of the sparkplug towers when the 4 "spokes" are aligned.
Note: The vacuum unit may retard or advance the spark depending on the particular design. Don't get hung up on my terminology. Just recognize that there are two mechanisms that change the position of the rotor: THE VACUUM UNIT and the CENTRIFICAL UNIT. Both may require repair.
The only reason this could be possible is that your advance/retard mechanisms have broken, or are stuck, or whatever in the fully advanced position. The rotor position, relative to the four "spokes", will change when the spark is advanced by the vacuum unit AND the spring loaded weights underneath the "spoke" assembly.
You'll have to take everything apart to get to the bottom of the problem. Look for:
BROKEN SPRINGS on the advance weights.
LEAKING OR STUCK vacuum advance mechanism.
If everything is attached and moving properly, the rotor will point to one of the sparkplug towers when the 4 "spokes" are aligned.
Note: The vacuum unit may retard or advance the spark depending on the particular design. Don't get hung up on my terminology. Just recognize that there are two mechanisms that change the position of the rotor: THE VACUUM UNIT and the CENTRIFICAL UNIT. Both may require repair.
Sean
new to Fiat
Yes......
...I dissasembled the distributor today. The weights and vacuum advance mechanisims looked OK. The two points I'm looking at should be fixed together by the little pin that can be seen in the pictures. Thomas at Bayless sent me some pictures and I can see my distributor is not right so I will probably change out the whole distributor since I can't determine what happened. Very frustrating.
...I dissasembled the distributor today. The weights and vacuum advance mechanisims looked OK. The two points I'm looking at should be fixed together by the little pin that can be seen in the pictures. Thomas at Bayless sent me some pictures and I can see my distributor is not right so I will probably change out the whole distributor since I can't determine what happened. Very frustrating.
eflexter
Eddie Flexter
!
The rotor is fixed to the star wheel, yes. The part that moves is the 4 spokes (the ones that stick up from the bottom). As the spark advances, the 4 spokes move around, so when the spokes and the star wheel line up, the rotor isn't pointing to the spark plug wire tower any more.
This is really hard to describe in words.
It's really common for the advance mechanism to rust in the fully advanced position. Apparently the mechanism guts crusty, then jams full advanced while driving, then rusts stiff. Replacing the whole thing wouldn't be a bad idea anyway.
The rotor is fixed to the star wheel, yes. The part that moves is the 4 spokes (the ones that stick up from the bottom). As the spark advances, the 4 spokes move around, so when the spokes and the star wheel line up, the rotor isn't pointing to the spark plug wire tower any more.
This is really hard to describe in words.
It's really common for the advance mechanism to rust in the fully advanced position. Apparently the mechanism guts crusty, then jams full advanced while driving, then rusts stiff. Replacing the whole thing wouldn't be a bad idea anyway.
