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There's a couple of possible causes for your rich idle mixture. Firstly, check & adjust the external linkages to the fuel pumper diaphragm. Then, remove all of the idle mixture screws & confirm the tips are all the same & in good condition, these are very easy to damage if the idle mixture screws are bottomed out too aggressively during adjustment. Then, get the engine to operating temperature & check & adjust your float levels on flat ground, then take the car for a 10 minute drive & re-check your float levels again to confirm there's no variation. Once that's done, start the car with the air filter off & look down the throat of the carby & make sure none of the squirters are dripping fuel.

Also regarding your new dizzy, glad you're happy with it. The starting advance should only be 10 degrees though on all engines using this dizzy, which is why the setup specifies only to install the dizzy after the initial advance is already pre-set at 10 degrees, so what the dizzy does on startup is absolutely nothing which makes the engine very easy to crank over & start, but you state yours is 15 degrees, the only way that could happen is if you installed the dizzy with 15 degrees of preset advance, so you might want to check that too.

Setting up the dizzy is the same as a mechanical, it's trial & error. There's no other way & every engine is different unfortunately so no-one can definitively say exactly where it should be set, although as i'm sure you already know from your readings about timing there are certain settings that most big blocks are going to like. However, the best process is to take your time, and only adjust one parameter at a time so you can gauge the effects of the adjustment, test drive the car & readjust as you go. Alternatively get it on a dyno & have it adjusted, they're also able to see & set air/fuel mixture ratios very accurately and also able to identify any anomalies that shouldn't be there in the torque & horsepower curves. The time savings you've got because of the super fast adjustability of the dizzy will definitely make Dyno money very well spent, unless you prefer to tinker of course. If you do, there's quite a few videos on Youtube to help along the way.
 

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Just wanna say, I downloaded the app some time ago, I don't have this dizzy myself, I bought an MSD a couple of years before these became available, I'd love to have one though. So i'm curious to know how this all goes for you but also what settings you use when you generate a new table.

So what are your settings now? You also said you set vacuum to begin at 900rpm, I can't see anywhere where you can do that, unless you identified your vacuum at 900rpm then set vacuum to start at that Hg, is that what you did? and why? Have you stored any more maps? I watched a video some time ago also where they stored maps for different circumstances, like cold start, warm engine mild day, warm engine hot day etc etc.
 

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1965 Impala SS 396 Convertible
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Discussion Starter · #23 · (Edited)
Hi. Thanks for the tips on checking the carb. All looks OK except the secondary float bowl is low., so not affecting the idle, but perhaps drivability. When I tried to adjust it up a bit, the gasket disintegrated as it had become stuck to the carb and now leaks. I had no spare, so I had to clean it up and order another set from Summit! <sigh>
You are correct that the diz and cam are linked at 10* for initial setup, but the manual says that cranking is at 15* always, then after it fires up, it jumps to whatever your initial timing is set to. Pretty slick! I spent quite some time on the phone with Ted trying to understand the vacuum advance settings and I am not sure I understand it all. It does have a vacuum port which serves as a MAP sensor and can be helpful in setting up a turbo, but it doesn't really add any "vacuum" advance, even though the setup program asks for it. Perhaps their VA is a "shortcut" way of reprogramming the computer to increase the advance through the power curve. I meant "mechanical timing" not "vacuum timing" in my previous post. Anyway, here are my app settings:
Idle speed: 700 rpm
Initial Idle Timing: 22*
Max RPM-based timing (all-in): 36*
All in RPM: 3000
Agressive Mode + (uses initial timing as starting point for "mechanical timing", not 10*. Supposed to help with "big cam" engines that have low vacc need more timing at low RPM. Still trying to figure out if this is right for my cam.
Start Vacuum Advance @ 80 KPa (Default) = about 24", but I have been playing with this too, to see if coming on sooner will help. Jury still out... With the old fashioned diz, I think we wanted full vacc at 1-2" below MAP. which for me would be @ about 50 KPa
Max Vacuum Advance @ 20KPa (when it stops adding any more VA)
Rev limit: 5300 (been scared to test this for now! 😬)
Seems to run cleaner with these parameters but acceleration is not a good as at 18* No backfiring or throttle lag. I have played with some more maps, but as you say, you have to change one thing at a time, then test. It is easy enough, just takes a while to collect all the feedback! Increasing initial timing past 22* doesn't increase RPM at idle, but significantly improved idle quality @ 22* compared to 18* still trying to see if drivability is better or worse at 24* or higher. The app certainly makes it easy, as you can change things on the fly with the hood open, or while driving. IT seems to be infinitely customizable, which is its own curse!
Thanks, again
Rectangle Font Line Parallel Pattern
 

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Ok I found the videos I watched some time ago. I haven't rewatched them again I just skipped through, so you might want to watch. If I remember correctly this is a 455ci engine & I can't remember specifically if it has a cam etc but what is notable to me is how completely different your table looks compared to theirs & I would expect them to be much more similar but not exactly the same. They're quite conservative on max rpm @ 4500, which I think at 5300rpm maybe you are a little too, a mild cam would be more around 5500 (which is where yours is I think) whereas performance cams will range anywhere from 6500-8000 ish. The other thing I find a bit odd is they've also set timing to be all in by 2400rpm which to me is very low for an automatic.
Now it doesn't matter whether you go to 5500 or not when driving but it's important to understand that whatever numbers you input changes the table, in terms of how much timing variation from one cell to the next but also at what rpm each cell starts & finishes at.

The videos are Here and Here the first one is more about setup so you might want to skip through too.

Below is a screenshot of their warm engine table.
Computer Gadget Font Software Electronic instrument


Here's what I would do if I were you once your carby is sorted to try & get close to optimum settings. I would create & save multiple tables, making note of the settings you use for each, then get the car to operating temp & take it for a drive over a set route, then try each table over that same route until you find the one that works best which you can then tweak if you need to. But what you need to do for now is ignore all of the information you've read except Total Timing. Whatever idle timing you end at doesn't really matter because once you're on the right table for your engine adjustments to idle air/fuel mixture will give you optimum efficiency.

Below is a table I created with the parameters of...
700rpm
16 initial
36 total
3000rpm all in
10 max vac
80 start vac
20 max vac
5500 rev limit

As you can see, it's much more like theirs & very very different from yours, give it a try, can't hurt.

Also take a look at the table they've generated, it's probably why the father is saying in the video that he thinks it needs more fuel. At low vacuum the advance jumps 8 degrees in the space of 190rpm, they obviously haven't noticed.

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Also, I think I understand where you're going wrong with info you're reading on the net, I'll tell you but you'd get there in the end anyway I think.

You've said previously people have said 20-24 idle advance, someone else said up to thirty. These numbers are being read with a timing light and will be a combination of Initial & Vacuum advance at whatever rpm they're being read at. So in your case now, you shouldn't be trying to replicate these numbers in the table. The way for you to understand your idle timing total is to watch the number in the icon in the app when your engine is running at idle, which is determined by the initial & vacuum timing you preset in the table, use changes in the vacuum number if that's what you want to experiment with, bearing in mind the app will only allow 50 total. Can't really say much more for now. Good luck.
 

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1965 Impala SS 396 Convertible
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Discussion Starter · #27 ·
Thanks for all the great help! I’ll get on it as soon as I get my carb bowl to stop leaking! I noticed that the engine seems to run cleaner and at a sl. Higher RPM with some higher initial timing, which is why I have it set now at 22* instead of your 16*. I have been assuming that this means that at 22* I am closing in on the “correct” initial timing for the engine. Would this be an incorrect assumption?
 

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Yes I think so, I think you're trying to set the timing to suit what your carb is currently doing. The focus of timing is not primarily idle quality that's the carbs job once timing is correct. You said previously that the car accelerates better at 18 but idle quality is better at 22, engine performance is your goal. If the carb is setup correctly you should really be able to get good idle quality at both of those timings as long as the idle fuel mixture is set correctly, because there's no load at idle, but you shouldn't automatically assume that because you're now getting a better idle that it is going to translate into the whole rpm range with your table.
When you're mobile again, load your table & drive it, load my table & drive it (i'm not saying mine is exactly right btw either but it's much more traditional), focusing on acceleration, if you look at the two tables they're completely different, compare them on the top line with low vacuum & see how much timing variation there is at a given rpm it's huge. The Progression ignition isn't a new way, it's the old way packaged & delivered differently, all the same concepts & settings from a mechanical dizzy still apply, they're really just more refined & more customizable.
 

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Yes I think so, I think you're trying to set the timing to suit what your carb is currently doing. The focus of timing is not primarily idle quality that's the carbs job once timing is correct. You said previously that the car accelerates better at 18 but idle quality is better at 22, engine performance is your goal. If the carb is setup correctly you should really be able to get good idle quality at both of those timings as long as the idle fuel mixture is set correctly, because there's no load at idle, but you shouldn't automatically assume that because you're now getting a better idle that it is going to translate into the whole rpm range with your table.
When you're mobile again, load your table & drive it, load my table & drive it (i'm not saying mine is exactly right btw either but it's much more traditional), focusing on acceleration, if you look at the two tables they're completely different, compare them on the top line with low vacuum & see how much timing variation there is at a given rpm it's huge. The Progression ignition isn't a new way, it's the old way packaged & delivered differently, all the same concepts & settings from a mechanical dizzy still apply, they're really just more refined & more customizable.
Agree; especially '... that's the carbs job once timing is correct...'. Timing first, then carb. The car won't run at its best until both are compatible with the engine as built.

And 'yes' all my comments/recommendations were based on the 'timing light'.

Recommend staying tuned to Jynx. He has more experience in your current equipment and (in my opinion) is string you in the right direction.

Pete
 

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Hey japete92, my comments weren't directed at you or anyone else, just info on the net in general. Also, i'm not trusting my memory anymore, I've been re-reading their Tech info & have realized my earlier comment regarding idle timing in the app isn't a combination of Initial & Vacuum timing in the table generator, as would normally be the case using a mechanical with a vacuum canister connected to full manifold vacuum, they don't add any vacuum numbers at all at idle in the app, so it mimicks a ported vacuum connection on a mechanical dizzy where vacuum is only added off idle. Sorry for any confusion.
 

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1965 Impala SS 396 Convertible
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Discussion Starter · #31 ·
Yeah, that is my understanding as well . Although the diz. is hooked up to manifold vac, the computer chip treats it like ported vac. So, does any of this change your recommendations for initial setup? Thanks
 

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Nah not at all. That table is just far too aggressive for an engine that'll idle at 700rpm with 16Hg of vacuum (12-18Hg is considered mild). If you were below 10 Hg with a much much higher idle speed because the engine simply won't idle at low rpm then it might be different. Give that table a go & see how it goes, but you'll very likely need to adjust the idle mixture once it's loaded. If your idle mixture screws are close to correct, turning one in should almost stall the engine, that's on a four corner, not sure what yours is. If that doesn't happen, the engine is getting too much fuel at idle & you'll need to understand why & correct it.
 

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Hey japete92, my comments weren't directed at you or anyone else, just info on the net in general. Also, i'm not trusting my memory anymore, I've been re-reading their Tech info & have realized my earlier comment regarding idle timing in the app isn't a combination of Initial & Vacuum timing in the table generator, as would normally be the case using a mechanical with a vacuum canister connected to full manifold vacuum, they don't add any vacuum numbers at all at idle in the app, so it mimicks a ported vacuum connection on a mechanical dizzy where vacuum is only added off idle. Sorry for any confusion.
We're good; always were. I never took anything negative from your comments.

Here's truly a couple of questions. Does that distributor actually use manifold vacuum (from either ported or full) to physically rotate the distributor 'internals' to adjust timing? Does it use weights and springs?

I simply curious. Thanks.

Pete
 

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1965 Impala SS 396 Convertible
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Discussion Starter · #34 ·
Yep, plugged into the manifold, not the timed port,but the software starts to advance the timing as soon as you come off idle, so it works like a timed port. Nope, no weights, springs, or any internal moving parts. (the rotor spins, and there is a reluctor and magnet to pulse the spark but that's all) They could probably figure out some way to use the computer to get rid of the rotor, but we need something to drive the oil pump anyway!
 

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Yep as Magnetocheck says. The real beauty of this dizzy is adjustment on the fly with your smartphone while the engine is running without even lifting the hood which is priceless. An rpm readout that you can also use under the hood on your smartphone while adjusting the carby, the extra added anti-theft security feature of an ignition lockout again from your phone, and the ability to load & save multiple tables for various different running conditions that the engine might encounter. Wish I hadn't bought the msd now of course, msd do do a digital dizzy but all adjustment is still inside the cap of the dizzy & it just doesn't have anywhere near the flexibilty of this dizzy. I'm jealous.
 

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1965 Impala SS 396 Convertible
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Discussion Starter · #36 · (Edited)
Hi Jynx: Again, thanks in advance for any advice. I used your program, and the car runs strong with those settings. I also modified yours to another program with 20* initial and seems to run a little cleaner. Only problem left is that idle is still rich and if I set idle screws hot to max manifold vacuum, they are only about 1/4 to 1/2 turn out. (It is a "2-corner" Holley) I can even turn in the primary idle mix screw in all the way, and it still idles ok hot, but at that point, the car won't idle cold. - I need to back it out 1 to 1 and 1/2 turns (Holley "standard") to get it to idle cold. If I then set mixture to allow idle cold, it runs real smoky. The electric choke works fine, comes on and off like it should, and followed your advice about pulling and checking mixture screws, vacuum leaks, and float levels - all good. No fuel dripping from the metering block into the venturis at idle. This really has me stumped. Carb seems fine overall, but maybe it isn't. I still want to try all I can with the timing before I get a new carb. I did watch a You tube video about rich, stinky idle. He agrees with you that problem is almost always not enough initial timing and recommends locking out the distributor so no mechanical advance and setting initial at 42*. Sounds crazy far to me, but maybe not? He had a "hot rod" diz with no vacc advance can and this was on a 427 Nova with a hotter cam than I have, but I am not sure what settings would be comparable to 42* initial on my PI diz. I can set the total timing to 42 easily enough but that won't affect the idle timing with this diz since it can be set separately. Then I can play with the vacuum advance. Any suggestions?
 

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I can't really say much more than I already have, other than I still feel like you're adjusting timing to suit carburation. Personally, I would be starting to pull the carburetor apart & inspecting the metering block where the mixture screws seat. If it will still idle with the mixture screws turned all the way in, bearing in mind this is supposed to be the idle mixture circuit & should be very sensitive to adjustment, then it's still getting fuel somehow that it shouldn't be.

Also again, anything you read on the net you need to quantify before you try to apply it to your engine & in most cases it simply won't apply, so in the case of the 42* locked out timing ask him these questions.

Why did he lock it out
What ignition system is he using
How did he arrive at 42*, was it on a dyno
What is his idle rpm
What is his idle vacuum
What compression does he have
What oversize pistons does he have
What cylinder heads is he using
What valve sizes do the cylinder heads have
What is the redline of his engine
What fuel does he use
What is the normal operating temperature at city & highway speeds
What starter is he using to start it

I strongly do not recommend anywhere near 42* btw, but it's your engine & wallet so what you do is entirely up to you. So, to answer your question, to obtain a locked-out setting on your dizzy you would choose the "fix timing at" setting.
 

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1965 Impala SS 396 Convertible
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Discussion Starter · #38 ·
" it's still getting fuel somehow that it shouldn't be. " Yep, that's what I figured, just wanted to confirm. Time now to take a closer look at the carb. Thanks for all the detailed advice about how to interpret other's recommendations.
 
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