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Discussion Starter · #1 ·
ZZ502 with a 572/620 cam and 106cc Victor Jr heads about 9.8:1. GM says the 572 should be 16 initial. I am at 12 and it runs poorly and seems to load up and die. I'm thinking of trying 16 initial. What do you guys think?

Also, my 454 ran 16 initial and was about 26-28 with full vacuum at idle. How do I do this with fitech timing control?
 

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Tell us more about your ignition system. What distributor, ignition box, etc.
 

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Your initial timing is set by the distributor. You need to advance it to what you need at idle and the FiTech adds to it as the RPMs rise.
 

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66 El Camino 57 Chevy pickup 2004 Tahoe
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What Paul said. bump the initial by moving the distributor. add 6 or so degrees. you'll probably have to subtract that 6 off the total by adjusting the setting in the computer.
 

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With computer control timing is NEVER adjusted just by rotating the distributor. Rotating the distributor may change the timing but usually not in the way you want it to change and will often screw up other things because the where the computer thinks the timing is and where it actually is is no longer in sync.

I don't have a lot of time at the moment so if the others don't get you on track I will try and respond in more detail tonight.

FiTech has an idle timing setting so if you want more or less timing at idle that is where you do it.

The timing reading on the handled should ALWAYS match the actual timing on the engine read with a timing light. If it doesn't you have a problem. The 'base timing' setting is used to align the actual reading with the display reading. That is only part of the puzzle after that is correct we get into phasing which is where the adjustable rotor comes in or you do some back and fourth between rotating the distributor and changing the base setting on the handheld. On phasing remember at idle the rotors should be just after the terminal assuming you are idle timing in the teens and your max is upper 30's. About a 20 degree range seems to be what most distributors are comfortable with.
 

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You do have both the mechanical and vacuum advanced 'locked' inside the distributor? And its wired like the FiTech instructions show? I only ask because I just talked to a guy on another forum that didn't have it locked and came up with a pretty creative way to wire things so I think he was actually getting multiple sparks.

Looking at the manuals I can sort of see how he went wrong. MSD doesn't talk about anything other than their 6 and 7 boxes and FiTech leaves out details like the wire colors on the MSD stuff. MSD also says you don't use the 'points' wire when using the 2 wire pickup so it sort of contradicts itself. Its true you don't use both on the box at the same time but you end up using both in the complete system of the car.
 

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Discussion Starter · #8 ·
I have the distributor locked and I'm using the points wire on the 6AL2, just like the FItech instructions show. I gapped the plugs to .40 and adjusted the distributor to 16 initial. Then I go to start it and there was no spark, the 6AL2 died. MSD and Jegs have been super helpful and I will have a new one next week. I'm hoping the odd running condition and poor target AFR readings I was getting was from a bum 6AL2. Fitech thinks I had a random misfire since AFR was reading 11.5ish and was suppose to be 13.5 at idle. We shall see soon.

Thanks
 

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A misfire will for sure screw up AFR readings. If the engine does not sound or feel right ignore the AFR readings. Problem is the computers we are dealing with may not be smart enough to do that on their own so we may have to help them sometimes which could mean a reset and starting over. For the reset to work you have to figure out how things got so far off to start with. If the misfire was due to the AFR being way off you have to figure out why? Maybe your fuel return line is blocked and pressures are running high? Maybe you have an air leak in the exhaust throwing off the reading so the computer was adjusting based on bad info that just led to an out of control death spiral? Stuff like that. In your case sounds like it was a problem is on the ignition side so until that is corrected a reset may not help.

If possible I would put the distributor back to stand alone then do a reset and see if things smooth out. Once you got a everything running good and stable that way take another run at the timing control using settings based on how the stand alone was running it. Theoretically nothing should change. If there is a change its in the setup rather than settings so you know to focus on the setup. If it works fine then the fun starts, you grab your controller and start playing with the settings to see if you can squeeze some more out.

Setup is things like how the distributor is physically installed, rotor phasing, pickup polarity, and how well the actual timing relates to what the computer thinks it is. Settings would be where you say you want 20* at 1500 and 40* at 5000. Once the setup is correct in theory you should never have to open the hood again. Any change you want to make can be done from the controller.
 

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I have the distributor locked and I'm using the points wire on the 6AL2, just like the FItech instructions show. I gapped the plugs to .40 and adjusted the distributor to 16 initial. Then I go to start it and there was no spark, the 6AL2 died. MSD and Jegs have been super helpful and I will have a new one next week. I'm hoping the odd running condition and poor target AFR readings I was getting was from a bum 6AL2. Fitech thinks I had a random misfire since AFR was reading 11.5ish and was suppose to be 13.5 at idle. We shall see soon.

Thanks
Did you ever get this squared away?

According to the last wiring diagram in the FiTech installation manual, you can run timing control without the 6AL2 and a 2-wire distributor as long as you have a external coil. The throttle body can fire the coil.

Follow the wiring diagram to the letter, and the instructions in the Quick Start guide for setting up the distributor, and phasing the rotor with an adjustable rotor. They have an easy way example. I did it the easy way, but dropped my distributor in at 16 degrees BTDC, rather than 10 degrees BTDC, and instead of using 10 marks on the rotor I used 7. You might want to use 10, or phase the rotor correctly. I like to tell myself I'm a tuning whisperer and make stuff up to try. ;)

Idle (or initial) timing is set in the software on the handheld. To finish up, you can get away with just making sure your timing on the harmonic balancer with a timing light and handheld timing numbers are the same at 2000 RPM. It's covered in the Quick Start Guide. That's how I did it, and it works fine. I get no misfires at 4000 rpm, or above, and my 2nd and 3rd gear shifts still chirp if I push the pedal to the floor.

People have done it other ways with different distributors of course, but it is relatively simple with a 2-wire small cap distributor. Much easier than I thought it would be.

Short version is if the book for your motor says run it at 16 degrees initial, set 16 degrees for idle timing on the handheld.
 

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Discussion Starter · #11 ·
I got it all going. I went with the 572 initial timing since that's the cam I am running. 16 initial and 26 at idle. 40 at 3000 rpm cruise and 36 at 3000 rpm wot. Seems to run well. This 502 is an absolute rocket and gets around 10mpg if I stay out of it. 6-7 if I'm in it. I still have the 6al2 and hvc2 coil. I think I will add a relay for the automotive 340 pump though. The only problem I have is an off idle light throttle rich then lean stumble. Fitech can't seem to figure it out and I think it might just be the cam. 254/264 @.050 and .632 lift. Any ideas? I have messed with the accel pump shot, gone rich and lean with no change. Now I'm messing with extending the time that fuel is introduced. Seems like the engine just burns it too fast and the fitech can't keep up for a second, then you better hold on. Wot does not have this problem, only happens between 10-20ish % throttle.
 

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I got it all going. I went with the 572 initial timing since that's the cam I am running. 16 initial and 26 at idle. 40 at 3000 rpm cruise and 36 at 3000 rpm wot. Seems to run well. This 502 is an absolute rocket and gets around 10mpg if I stay out of it. 6-7 if I'm in it. I still have the 6al2 and hvc2 coil. I think I will add a relay for the automotive 340 pump though. The only problem I have is an off idle light throttle rich then lean stumble. Fitech can't seem to figure it out and I think it might just be the cam. 254/264 @.050 and .632 lift. Any ideas? I have messed with the accel pump shot, gone rich and lean with no change. Now I'm messing with extending the time that fuel is introduced. Seems like the engine just burns it too fast and the fitech can't keep up for a second, then you better hold on. Wot does not have this problem, only happens between 10-20ish % throttle.
Great you got the ignition figured out! I think the FiTech throttle bodies would be real nice on a large displacement motor.

I guess you are using the cam 4 selection. I don't have any experience with your motor or a cam with that much lift. My cam is about .172 short on lift.

Nothing is more annoying than a dual rich lean fuel condition. Are you playing with Dfco Return Fuel, Dry Ring Fill PW, dTPS Acc Gain and dTPS Acc Max as well as looking at Fast Accel 170F, and Fuel 195F? There are a boat load of parameters to mess with that can either help or make it a lot worse. Beats removing fuel lines, fuel bowls, and changing jets though.

I had a lean stumble off idle I fixed with a richer AFR at 1100 RPM, and lightly tweaking dTPS Acc Gain, dTPS Acc Max, Dfco Return Fuel, Dfco Ring Fill PW and a cam selection change from 2 to 3. Although fixing it that way, gave me a little rich muffled back fire in the exhaust if I come of 100+ MPH and lightly touch the throttle again. Fine tuning line I have not readdressed, because I don't run at 100+ MPH very often in a street car. The off idle stumble was the more annoying problem I wanted to go away.
 

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Discussion Starter · #13 ·
I messed with some more settings with no real change, until I changed my timing. I have initial at 16. That is great for starting. Idle at 26. Now here is where the problems start. I was running 1100rpm down to 16-20. This gave me all sorts of hesitation and cruising misfires, little pops at cruise. So I started to play with timing. I bumped up 1100rpm cruise to 30 and WOT to 28. It seems to run better with more timing down low. Engine temps seemed to drop too. No more deiseling. I can run leaner AFR too. Does this sound right?
 

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By initial you mean the base setting on the handheld? Then you set the idle target to 26? And anytime you check it with a timing light the actual reading matches (or is +/- a couple degrees) with what the handheld reads?

Just curious, have you checked your rotor phasing with a timing light? It may have nothing to do with how yours is running. I'm mostly just trying to collect more data from people that are running timing control successfully in hopes of being able to help people that want to do it or have tried it and are having issues. For some reason its harder to get working than the fuel part and it really should not be. The way the instructions are written just don't make sense to most people and there is a lot of bad info out there on the subject.

Timing and AFR do interact, you really only get to see how they do that when you have control over both which is the cool thing about EFI and timing control. You can easily try stuff to see how or if it works and if it doesn't its real easy to get back to where you started.

You said dieseling? You mean when you shut the key off it tried to keep running? That is a very bad sign with an EFI system because that means there is still fuel in or getting into the engine after you shut the injectors off. IF you meant detonation - ping - knock then yes higher temps are more prone to having that problem. Many engines do like more timing in the lower mid range but with a mechanical distributor its really hard to get that without having too much for starting and at cruise so you end up with a compromise.

One thing I played with that really helped the engine feel better was the break points for the timing. The default break points I think are intended for something more like a high revving 350. Bigger engines make good power down lower so if you have your car geared to take advantage of that you will also want to make sure the break points are in that range too. Seems like the defaults were at like 3k and 6? My car hardly sees 4k so I was never getting my max advance. My goal was 40 so I had to set it to like 55 to get close to that at my cruise speed. Problem would be if the engine ever did get going that fast it would try to run at 55. Lowering the break points got my max timing to a realistic number at a speed my engine actually gets to.

Improperly setting things up like I did by increasing the number because the rpm break points were wrong or adjusting the timing by moving the distributor may sort of seem to work at first but are almost guaranteed to come back and bite you at some point.
 

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I messed with some more settings with no real change, until I changed my timing. I have initial at 16. That is great for starting. Idle at 26. Now here is where the problems start. I was running 1100rpm down to 16-20. This gave me all sorts of hesitation and cruising misfires, little pops at cruise. So I started to play with timing. I bumped up 1100rpm cruise to 30 and WOT to 28. It seems to run better with more timing down low. Engine temps seemed to drop too. No more deiseling. I can run leaner AFR too. Does this sound right?
Your 1100 rpm timing should be the same or higher than idle, so yes all that makes sense. Cruise 3000 RPM can be higher than 30. Just saying

I talked to FiTech about timing control last week. Even though we could never get on the same page, I came away with... if you clock your distributor with a high base timing, you'll have to play with the low rev timing numbers on the handheld, and generally it'll require more aggressive numbers. That is not a quote, because like I said we never got on the same page.
 

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Discussion Starter · #16 ·
By initial you mean the base setting on the handheld? Then you set the idle target to 26? And anytime you check it with a timing light the actual reading matches (or is +/- a couple degrees) with what the handheld reads?

Just curious, have you checked your rotor phasing with a timing light? It may have nothing to do with how yours is running. I'm mostly just trying to collect more data from people that are running timing control successfully in hopes of being able to help people that want to do it or have tried it and are having issues. For some reason its harder to get working than the fuel part and it really should not be. The way the instructions are written just don't make sense to most people and there is a lot of bad info out there on the subject.

Timing and AFR do interact, you really only get to see how they do that when you have control over both which is the cool thing about EFI and timing control. You can easily try stuff to see how or if it works and if it doesn't its real easy to get back to where you started.

You said dieseling? You mean when you shut the key off it tried to keep running? That is a very bad sign with an EFI system because that means there is still fuel in or getting into the engine after you shut the injectors off. IF you meant detonation - ping - knock then yes higher temps are more prone to having that problem. Many engines do like more timing in the lower mid range but with a mechanical distributor its really hard to get that without having too much for starting and at cruise so you end up with a compromise.

One thing I played with that really helped the engine feel better was the break points for the timing. The default break points I think are intended for something more like a high revving 350. Bigger engines make good power down lower so if you have your car geared to take advantage of that you will also want to make sure the break points are in that range too. Seems like the defaults were at like 3k and 6? My car hardly sees 4k so I was never getting my max advance. My goal was 40 so I had to set it to like 55 to get close to that at my cruise speed. Problem would be if the engine ever did get going that fast it would try to run at 55. Lowering the break points got my max timing to a realistic number at a speed my engine actually gets to.

Improperly setting things up like I did by increasing the number because the rpm break points were wrong or adjusting the timing by moving the distributor may sort of seem to work at first but are almost guaranteed to come back and bite you at some point.
Yes initial or base timing is 16. My idle target is now at 28, this seemed to help a run on/deiseling situation I was having. It only does it now if I shut down when the coolant temp is above 176. I might try some colder spark plugs, the are currently Autolite AR3923. Timing light matches the handheld give or take a few. The cam makes it a chore. At 3000rpm I had a large discrepancy though. I have the VR Advance 4000 set to 8 now, and it looks better.

The rotor phasing seems fine, but I have no idea how to check it with the light. I do know it advances correctly. I would like to use the laptop Pro software, however, this seems more like a joke. The software could be great, but it turns out to be more of a gauge monitor... Not to mention the navigation sucks in the program. My experience shows this efi to be alot like the Harley Thundermax ecu and software I have been using for years, its just way too basic. Timing control would be better if I could adjust every 100rpm, hell, I would like every 1000rpm. Then it would be worth while. It does work, just not very tunable.

It's definitely not detonation, ping, or knock. I have been playing with 87 and 89 gas, and that is when it happens, but it doesn't ping or anything. I think it is just burning up the plenum film the instructions talk about. The plugs don't show signs of detonation either. I'm pretty familiar with that from my Harley that pings like crazy with 93 at low rpm. And more timing seems to fix this, or get closer to fixing this. I'm just paranoid about blowing a brand new engine with too much timing. Currently I have 16 initial, 28 idle, 30 1100 45kpa, 42 3000 45kpa, 36 6000 45kpa, 28 1100 WOT, 36 3000 WOT, 34 6000 WOT.

I will mess with the breakpoints. I plan on a little track time and I can rev out to 6500 without float, but like you I drive it to work and around town and rarely see that.
 

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If you have run on you have some other issues. The timing changes are apparently just lowering cylinder temps and hot spots that fuel that should not be there was being ignited by. The timing doesn't explain why there is fuel available when you turn off the key.

With a carb you get run on because you can not shut the fuel off, if the engine is turning it can and will draw in some fuel. You shut off the spark but if there are hot spots in the cylinder you can still get the fuel to burn. With EFI you are turning off both the spark and injector so there should be no fuel so even if there is a hot spot there won't be anything to burn.

If you have run on at this point that means you have fuel getting or already in the engine. With most EFI systems and some age the common places for leaks would be the fuel pressure regulator or an injector itself. With the TBI systems you could get a leak around the injector because the pods they were mounted in were under pressure so it could get past the O rings. With multi port injectors like we are dealing with that can't really happen because the fuel rail doesn't connect to the intake or throttle body so a leak would be external unless it was through the injector itself.

With everything being fairly new you would not expect a bad regulator or injector but it may be worth pulling the vac line off the regulator to make sure its dry and have a look down the throttle bores with the fuel pump running to make sure you don't see a dribble of fuel. If there isn't a leak you must have fuel pooling somewhere when its running which isn't good because its fuel you are no longer in control of. Hopefully we are not going to find out that in addition to crap sensors they are using crap regulators and or injectors.

You say your engine overall appears to run good?
 

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I talked to FiTech about timing control last week. Even though we could never get on the same page, I came away with... if you clock your distributor with a high base timing, you'll have to play with the low rev timing numbers on the handheld, and generally it'll require more aggressive numbers. That is not a quote, because like I said we never got on the same page.
This is so annoying. This should not be this complicated. This is why I keep grilling anyone that seems to have been successful to see how they did it and what their settings and readings are. I hope at some point I will find someone that can explain what they did in such a way that anyone can understand it and do it.

What really bugs me and I think where a lot of the issues come from is no one seems to properly explain the separation between the mechanical setup and the electronic part. How you 'clock' or 'stab' or otherwise physically change the relationship between the distributor and engine is not part of the 'tune'. What I am calling the 'tune' is the part where you want to crank at 10* idle at 20* wot at 30*. If you want to idle at 30 you don't touch the physical distributor, you just change the numbers in your programmer. You don't add any of the numbers you used in the physical setup into the timing numbers. If the computer says you are at 30 you should read 30 with your timing light.

The catch to the not touching the actual distributor is they seem to have a happy range of about 20* or +/- 10. If you started out with your phasing good with idle at 10 and a max of 30 then you decide that you now want to idle at 20 and max at 40 you can easily punch that into your programmer but your phasing will be off. 20 was the center of the terminal in your original setup so 40 is going to be 20* off the terminal which may be fine with a new cap, dry conditions, and a stock coil but you add some voltage, miles, or humidity and you could have a problem. Now if you wanted to make that 10 degree change across the board you could move the distributor by 10 degrees but then your readings are going to be 10 off and your starting will have also changed by 10 which you may or may not have wanted. Could it work that way? Sure. Is that the right way to do it? Probably not. Will you remember that your readings are going to be off 10 degrees in a couple years when you make other changes to the system and play with the tune? When your balancer slips? I guess it really should not matter that the handheld reading matches actual timing, if it runs good it runs good. Problem comes when you fix your balancer or want to help a friend with pretty much the same setup, if the readings matching the actual numbers it may be difficult do duplicate the results.

There are things about the mechanical setup that effect what you can do with the tune especially in the case if FiTech. What they call a base setting does not get added to the other tune number you have set. You can use the base setting to adjust rotor phasing and then with a combination of that base setting and clocking get it so that the actual timing matches what the handheld says it is and have your phasing correct. Other systems have a setting number like that that has nothing to do with any of the other numbers, once its set you can forget about it and never think about it again. For some reason in FiTech land what ever that setting is becomes the minimum possible setting which is apparently what it uses for a cranking setting. I don't know what its range is but say to get everything happy you had to set it at 20, this means you will be cranking at 20 and can not set your idle timing any lower than 20.

What gives you that setting is the physical mechanical relationship between the pickup coil and the terminals on the cap. In my case if I wanted to go to a lower number I would open up my dizzy and slot the mounting hole for the pickup coil and rotate it a few degrees hopefully in the right direction then go back and re adjust (lower) the base setting and move the distributor so it all jived again but this time with a lower base setting number. Note during this whole theoretical process so far I have changed a bunch of stuff but my actual timing has not yet changed other than cranking. I don't remember if here is an actual cranking setting or not, I am basing this on what others have said about the base number being the crank number so in theory if my base is now 10 I will be cranking at 10. When it starts my idle will still be at 20 and the rest of my curve will be unchanged. My timing light will still match what the handheld says. If I want to now idle at 15 I can go into the handheld and change that to 15 and my idle should go to 15.

I re wrote this several times trying to make it simple but I don't think I succeeded. I'm about 90% sure I have the theory correct in my head and using that theory I made it work in my car. It seems to run well, actual timing matches the handheld, phasing is good as checked with a modified cap and looking at the carbon deposits on a fairly fresh cap. I just can't figure out how to simply explain it to others.

I suspect people that have basically been able to plug and play have just had pretty good luck but it could run out on them at some point because the phasing isn't correct so with some miles and humidity they could get misfires and or their actual timing doesn't match the readout so at some point they will make a change and all the errors will add up and cause confusion and problems.
 

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I should also add that it is certainly possible that I am one of the lucky people that got it to work without really understanding it and all my theories are wrong.

My car seems to be working so my main reason for staying with this is to try and help other people get theirs working since timing seems to be difficult but a place where you can see some improvements in the control just like you get with the fuel side.
 

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I should also add that it is certainly possible that I am one of the lucky people that got it to work without really understanding it and all my theories are wrong.

My car seems to be working so my main reason for staying with this is to try and help other people get theirs working since timing seems to be difficult but a place where you can see some improvements in the control just like you get with the fuel side.
The call to FiTech was just for my information after the fact. I learned something about my mad science being wrong, but it turned out to be irrelevant. My car was already running great with timing control when I phoned them. I think what I took away from the conversation was also wrong. Scratch that aggressive timing BS I mentioned.

Setting it up was very simple to do following the FiTech Quick Start Guide using the recommended parts. Talking about it is the only difficult part about it. ;)

Anyway, I got a hair up my arse and wanted to find out how much difference setting the adjustable rotor at mark 10 made compared to where I set it at mark 7. The answer is none at the balancer or on the handheld. It probably made a small positive difference with regard to phasing with the plug tower, but not enough to be noticeable from the drivers seat either way. I still have not bothered to check rotor phasing, since my car shows no signs of lost power or misfiring. If it aint broke, I be done with it.
 
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