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123 Ignition - Unsure how to Proceed


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So I just recently installed my Bluetooth 123 ignition. Got the car to fire up right after installing, but had a difficult time finding the correct curve. Using the standard curves from the Haynes manual, and the blue book curves from this forum the car was constantly backfiring.
I ended up using a curve i found online for the 008 Bosch distributor that was in the car prior. Curve is shown below. This curve is much more successful and no backfiring and seems to run well.  

when using the 008 curve i had the vacuum hose removed from the distributor and capped. Now once installing the hose again I am introducing another set of problems as the car begins stalling. Any ideas on the MAP curve? 
 

I am hoping someone can give me direction as I am unsure if i did any of what i mentioned above correctly. Thanks in advance, pun intended. 
 

Car Info: 1974 2002. 32/34 Weber. 292 Cam. 

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Yeah you need at least 30 degrees of centrifugal advance to run right. I'm at 33 degrees of CF advance. You are also not running enough advance to idle properly. Healthy idle (total) timing will be 12-18 degrees BTDC and should be in the 800 RPM neighborhood. MAP curve is essentially there to add timing when there is a high vacuum (throttle closed) for more efficient and complete combustion at low load conditions and also to allow timing to be pulled when cranking. My MAP curve is 9 degrees from 0 to 55 KPa, decreases linearly from 55 KPa to 85 KPa, and zero from 85 KPA to 200 KPa. You will need to fine-tune the MAP curve to your motor as the vacuum characteristics will be different depending in condition and configuration. Make sure you use manifold vacuum, as to use ported vacuum you would need a vacuum retard feature or do some gymnastics with the two curves.

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12 minutes ago, paulyg said:

Healthy idle (total) timing

Paul, when you say total timing, my understanding is that the static is added to the degrees at every RPM breakout. For example if static is 10 and 15 degrees advance at 1000 RPM then my total would be 25 degrees advanced at 1000 rpm’s. Am i understanding correctly?

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Do you have a timing light to make sure the 123 is properly installed?

 

Assuming you do, programming a curve that holds 25 degrees of advance between 2400-2600 rpm and then holding it within that range, you can look to make sure the BB on the flywheel is aligned with the driver's side of the oval hole in the bellhousing.  If it is not, rotate the distributor until it is and then tighten it down.

 

 

   

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Also you have too many unneeded data points, take out any in between straight lines like points 3, 6, 7, & 8 so the processor doesn't need to work so hard.  Also, bracket your desired idle rpm with data points slightly higher and lower so the engine doesn't hunt as advance changes with slight variations in rpm.  For example, if you want your idle to be 900 at 8 degrees advance, have your data points be at 8 degrees at 800 and 8 degrees at 1000.

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8 hours ago, DoubleA said:

Paul, when you say total timing, my understanding is that the static is added to the degrees at every RPM breakout. For example if static is 10 and 15 degrees advance at 1000 RPM then my total would be 25 degrees advanced at 1000 rpm’s. Am i understanding correctly?

The 123 has you step through a setup process of identifying TDC. You should have seen a green LED in the distributor body. That is 0 degrees. “Total” timing in my comment refers to centrifugal advance+vacuum advance. 
 

You have to set your idle timing with the 123, nominally 16-18 degrees BTDC in my opinion. 

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18 hours ago, DoubleA said:

the static is added to the degrees at every RPM

True. The static timing is the initial offset from TDC for the whole advance (centrifugal and vacuum).

 

Are you using vacuum advance with your 123 dizzy?  If so, it should be connected to manifold vacuum, not the ported vacuum on the Weber 32/36.

 

My '76 has the stock 264 cam and a Weber 32/36. Stock vac advance/retard distributor (for CA cars).

I use 3 degrees of static advance. This starts the car on the first click of the ignition switch.

Then the manifold vacuum advance kicks in to provide additional 10 degrees advance, so the car idles at 900 rpm with a total of 13 degrees advance (3 static + 10 vacuum). I do not use the vacuum retard "feature" on my dizzy.

 

This should give you a starting point for your advance map. The more load (open throttle), the less vacuum, so the centrifugal advance + static advance determines the max limit.

John

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12 minutes ago, John76 said:

True. The static timing is the initial offset from TDC for the whole advance (centrifugal and vacuum).

However, to be clear, the term static timing does not apply to the 123 tune,  Any advance not matter how it's called is within the 123 program file, no turning the distributor housing once TDC is confirmed with the timing light.

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A radiator shop is a good place to take a leak.

 

I have no idea what I'm doing but I know I'm really good at it.

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4 hours ago, jimk said:

static timing does not apply to the 123 tune,

Yep ... I'm not familiar with setting up those "high-tech" dizzies.

So, is the 500rpm setting for the advance at cranking/starting? This could be the 3-degree static on a manual diz ?

Then set the advance for idle speed and rpm's up to redline using the total advance desired.? 

How does the vacuum feature on a 123 influence the advance at high rpm w/ light load (vacuum at cruising speeds)?

The manual dizzy can have as much as 50 degrees advance at cruising speeds when the throttle is barely open (higher vac) at high rpm when centrifugal (and static) advance is maxed out.  

 

 

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1 hour ago, John76 said:

So, is the 500rpm setting for the advance at cranking/starting?

The 123 has by default, I believe, 0 degrees advance while cranking, 500rpm is the earliest you can tell it what advance you want.

 

1 hour ago, John76 said:

Then set the advance for idle speed and rpm's up to redline using the total advance desired.? 

Yes, bracket the idle advance setting you want like I mentioned above.  I have my bracket from 500 to 1100 because I want 1000 rpm at idle and want the advance also in at 500 to help with idle quality while the engine warms up.  Then put in the number of the rpm you want the advance to be all in at (like 34 degrees at 3000 rpm), then straight across to the redline.  Your all in number and red line number will be the same.

 

1 hour ago, John76 said:

How does the vacuum feature on a 123 influence the advance at high rpm w/ light load (vacuum at cruising speeds)?

Any way you want it to.  I have 12 degrees of vacuum advance pulling from manifold vacuum ports so I get that plus 33 mechanical for 45 total at cruise.  By using manifold vacuum you can set it to add advance at idle which I do, or higher rpm off the idle if you want to simulate ported vacuum.  The cruise advance is set after road testing to see what vacuum your engine pulls at cruise, just make sure your MAP curve doesn't drop out at a vacuum higher than your engine is at cruise.  But make sure it drops out before your engine goes under load so it doesn't ping.  There is a sweet spot here found by road testing in all gears and different driving conditions, then choose an appropriate MAP to cover how you drive.  I have vacuum advance drop out at 2.5 Hg to zero at WOT.

Edited by Stevenola
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