Question on Spark settings in MT

[92notch]

i have a 92 mustang before i took out the stock ecu i check the timing with the spout removed and i had to make sure it was still at 16degrees where i left if before and it was. then i put the spout back in. Hooked up my Mega Scott adaptor and in the Spark setting s of MT i have the trigger angle set to 16 is that correct? Now thing i dont understand is what do you set the Cranking advance Angle to is it the same as your trigger angle? because that is what i have it set at right now at 16? And if you look up the setting for TFI for MT is says used FIXED DUTY and its at 50% which is where i have it as well . how am i looking? because this post has a link to MS setup with TFI which shows one way and then Megascott has it set alittle differently which is right?
thanks in advance

[jsmcortina]

Yes, for TFI use the same cranking number as your trigger number.

Megascott has more experience of TFI that I do so his site may be more accurate that the TFI pages. If there are enhancements required to the MS1/Extra site please let me know (or submit revised pages.)

James

[MegaScott]

i have a 92 mustang before i took out the stock ecu i check the timing with the spout removed and i had to make sure it was still at 16degrees where i left if before and it was. then i put the spout back in. Hooked up my Mega Scott adaptor and in the Spark setting s of MT i have the trigger angle set to 16 is that correct? Now thing i dont understand is what do you set the Cranking advance Angle to is it the same as your trigger angle? because that is what i have it set at right now at 16? And if you look up the setting for TFI for MT is says used FIXED DUTY and its at 50% which is where i have it as well . how am i looking? because this post has a link to MS setup with TFI which shows one way and then Megascott has it set alittle differently which is right?
thanks in advance

Hi Paul,

Normally with TFI using MSnS-extra you input a trigger angle of 0 (zero) if you have 10dbtdc dialed into your dizzy, you say you have 16dbtdc, that means you should probably have the trigger angle set to 6?. You can calibrate this by running the engine at idle and checking the advance that Megatune reports, versus what you read with a timing light on th balancer.

I usually use Trigger return which does not use the cranking angle. If I were using timebased cranking I think that some experimentation would need to be done to get the best starting, but I would think with a static setting of 16dbtdc you would need no cranking advance. i have not spent much time on this option, but I think you would set this to -16 for no change?

As far as dwell is concerned, the dwell settings in Megatune do nothing to change the dwell, when you have TFI selected as your ignition option the code outputs a fixed width waveform as Spout, and the TFI module figures out the dwell based on coil charging.

The adaptor board does nothing to change the timing or dwell. It just gives you a place to solder the TFI pullup resistor instead of adding it to your Megasquirt.

I use the Factory dist advance of 10dbtdc, and trigger return, so that's why you see differences.

You have the option to change the values to try to get a better running car, just be sure to only change one thing at a time so you can easily change it back if it doesn't work the way you think it should.

[92notch]

i have a 92 mustang before i took out the stock ecu i check the timing with the spout removed and i had to make sure it was still at 16degrees where i left if before and it was. then i put the spout back in. Hooked up my Mega Scott adaptor and in the Spark setting s of MT i have the trigger angle set to 16 is that correct? Now thing i dont understand is what do you set the Cranking advance Angle to is it the same as your trigger angle? because that is what i have it set at right now at 16? And if you look up the setting for TFI for MT is says used FIXED DUTY and its at 50% which is where i have it as well . how am i looking? because this post has a link to MS setup with TFI which shows one way and then Megascott has it set alittle differently which is right?
thanks in advance

Hi Paul,

Normally with TFI using MSnS-extra you input a trigger angle of 0 (zero) if you have 10dbtdc dialed into your dizzy, you say you have 16dbtdc, that means you should probably have the trigger angle set to 6?. You can calibrate this by running the engine at idle and checking the advance that Megatune reports, versus what you read with a timing light on th balancer.

I usually use Trigger return which does not use the cranking angle. If I were using timebased cranking I think that some experimentation would need to be done to get the best starting, but I would think with a static setting of 16dbtdc you would need no cranking advance. i have not spent much time on this option, but I think you would set this to -16 for no change?

As far as dwell is concerned, the dwell settings in Megatune do nothing to change the dwell, when you have TFI selected as your ignition option the code outputs a fixed width waveform as Spout, and the TFI module figures out the dwell based on coil charging.

The adaptor board does nothing to change the timing or dwell. It just gives you a place to solder the TFI pullup resistor instead of adding it to your Megasquirt.

I use the Factory dist advance of 10dbtdc, and trigger return, so that's why you see differences.

You have the option to change the values to try to get a better running car, just be sure to only change one thing at a time so you can easily change it back if it doesn't work the way you think it should.

\\

So what you are saying is since i have the trigger angle set to 16 i should have the cranking advance set to 6? if so i will do that.
Now you say you use trigger return should i use the same for my setup the car starts fine so im sure that the settings are ok so that is not an issue, But if Trigger return is better what should my settings be for that ?

[MegaScott]

So what you are saying is since i have the trigger angle set to 16 i should have the cranking advance set to 6? if so i will do that

Yes, I believe that's how it should work. but it's been awhile since I tested it out on the bench.

I am a big supporter of the "try it, if it's better leave it, if you don't like it, go back" form of testing. If you are happy with the way it starts now why change it?

"trigger return" is the only setting, you can try it, and see if it improves your starts, if not, revert back to your other settings.

[92notch]

So what you are saying is since i have the trigger angle set to 16 i should have the cranking advance set to 6? if so i will do that

Yes, I believe that's how it should work. but it's been awhile since I tested it out on the bench.

I am a big supporter of the "try it, if it's better leave it, if you don't like it, go back" form of testing. If you are happy with the way it starts now why change it?

"trigger return" is the only setting, you can try it, and see if it improves your starts, if not, revert back to your other settings.

Ok i will set it to 6 thanks scott. I have a question for you since you are a Ford guy . My car at idle with MS runs very rich. so rich the cats were starting to glow and my wide band got clogged because of it. Now the question is i see alot of guys 5.0's start their spark table at low RPM with around 22-24 degrees of timing for the idle area. now i think but im no sure since i had my spark table set to 16 degrees around idle that was too low and causeing a very rich condidtion causing it to dump alot of raw fuel which made the cats get too hot. is this true?
if it helps can i send you my new spark table and Ve table that i DIDNT test yet and you can let me know if im in the right ball park for a not too rick or lean condition at idle?
thanks again
Paul

[MegaScott]

The Factory 5.0 spark map idles at 26 degrees, but that has little to do with how rich it is, I think you need to tune it.

i don't know if you ever tuned a Carb, but the principle is the same. You should be doing this with the Idle PWM set at "warmup only". Start out rich, which is apparrently what you have, then lean out the VE table while watching the Map values and watching RPM.

Lean it out until the map starts to increase in value, or when the rpm starts to slow down or you get hunting, then richen it up a little until the hunting goes away. with a stock cam you should be idling at 800-900rpm.

When I was racing, at first I would run the same setup that everyone else was running, and i struggled, then I realized that if I tried things that worked best on my car and that made a difference, no matter how small, I would eventually end up going faster than everyone else. Whenever I would ask the top dogs what they were doing, they would just give standard answers that everyone else would give, but in time I found that the big dogs would always hold back some secret to thier succes, because they know if they told everyone what they were really doing, they would have to work harder to be the top dog.

[92notch]

so i will set my idle timing to 26 in the spark map and lean it out even more in the idle area in the VE and see how that works out. Im just tired of clogging my WB with a overly rich condition and it seemed like no matter how much i leaned it out it wasnt enough and clogged the WB so thats why i though the timing would have somthing to do with it at idle. either way i have to change ti to 24-26 degrees at ldle because 16 is just way to low and probly is adding to my problem.
My car is not running a stock cam i am running a Trickflow Stage one cam. which is probly goin to make it tricky with the kpa becuase i dont know how much vaccuum it will pull at idle i think about 17psi. but thats not impt at this sec. just want to get it to idle first so i can get out there and start to tune it for no load.. i will attch my Ve table and spark table if you can take a look to see if im goin in the right direction for idle when i get home i will do that if that is ok with you?
thanks again scott