Direct Coil Control

[ronsonol]

MSII v3 using Megatune 2.35. Have old style HEI with 4-pin with in cap coil.

I am hoping to get a few questions answered, on the same topic but relating to ignition control via "Direct Ignition Coil Control with MegaSquirt-II".

When assembling the v3 board, I choose to install both steps 50/51 for Hall circuit but the using section b for tigger off negative, and VR circuits. I got a little confused, and originally jumpered settings for VR sensor, since I knew the 4-pin hei had a vr sensor.

1- But after further reading, I realized that I want to trigger off negative coil for tach input to MSII on pin 24. So I think I need to jumper the Hall circuit: is this the correct approach for me?
Jumper XG1 to XG2 on the bottom side of the PCB, near the 40 pin socket,
Jumper OPTOIN to TACHSELECT on the bottom side of the PCB, near the DB37 connector, opposite the heat sink.
Jumper TSEL to OPTOOUT on the bottom side of the PCB, near the center.

2- after I get fuel going and tuned, I want to have MSII do ingition timing for me. I installed the VB921 dedicated coil driver IC, and did the jumpers IGBTIN to JS10 and IGBTOUT to IGN to bring out signal to pin 36.

The docs mentioned you could use the VB921 to control a single coil, but can I still do this using the 4-pin module I have? The setup page has you provide switched power to coil, and ground from MSII pin 36. But isn't this where I am triggering from? Am I missing an important step? - such as eliminate the ground in the coil, and let pin 36 do that for me? Tach is not really the negative to coil? I only have two wires going to the coil at the moment. Sorry I am confused.

3- I bought a 7-pin hei module, but if I do not need it then I won't bother. The last thing, I suppose I eliminate the vacuum advance, and mechanical too?

Thank you in advance.

[bleoh]

MSII v3 using Megatune 2.35. Have old style HEI with 4-pin with in cap coil.

I am hoping to get a few questions answered, on the same topic but relating to ignition control via "Direct Ignition Coil Control with MegaSquirt-II".

When assembling the v3 board, I choose to install both steps 50/51 for Hall circuit but the using section b for tigger off negative, and VR circuits. I got a little confused, and originally jumpered settings for VR sensor, since I knew the 4-pin hei had a vr sensor.

1- But after further reading, I realized that I want to trigger off negative coil for tach input to MSII on pin 24. So I think I need to jumper the Hall circuit: is this the correct approach for me?
Jumper XG1 to XG2 on the bottom side of the PCB, near the 40 pin socket,
Jumper OPTOIN to TACHSELECT on the bottom side of the PCB, near the DB37 connector, opposite the heat sink.
Jumper TSEL to OPTOOUT on the bottom side of the PCB, near the center.

2- after I get fuel going and tuned, I want to have MSII do ingition timing for me. I installed the VB921 dedicated coil driver IC, and did the jumpers IGBTIN to JS10 and IGBTOUT to IGN to bring out signal to pin 36.

The docs mentioned you could use the VB921 to control a single coil, but can I still do this using the 4-pin module I have? The setup page has you provide switched power to coil, and ground from MSII pin 36. But isn't this where I am triggering from? Am I missing an important step? - such as eliminate the ground in the coil, and let pin 36 do that for me? Tach is not really the negative to coil? I only have two wires going to the coil at the moment. Sorry I am confused.

3- I bought a 7-pin hei module, but if I do not need it then I won't bother. The last thing, I suppose I eliminate the vacuum advance, and mechanical too?

Thank you in advance.

Someone will (hopefully) correct me if I am wrong, but here is what I think.
1)For starting with just controlling fuel all you need is the negative side of the coil going in to MS. This is your RPM. The rest of the ignition wiring would remain stock. You will not be using the Hall/VR input at this point.

2) The 4 pin module essentially turns the VR signal into a Hall signal. So use the Hall signal option in MS. I just saw a post on this where lance gave some tips. I think it was in the assembly forum under "another step 50 question" Connect the positive side of the coil to the fuel pump relay (so it only gets powered when the engine is running) and the negative side can go to MS (for both RPM signal and the ground path) and to a tach.

3) If you are using the MS direct coil control you do not need the 7 pin module. You do want to lock down the distributer when you have MS control spark so there is no vacuum or mechanical advance on top of what you have in your timing table.

[ronsonol]

Thank you bleoh,

points taken on questions two and three, but am still confused about one.

If I do not need to use Hall at this point, and should only use default wiring for ignition, what jumpers do I do on the bottom of the board. The VR directions or the Hall/negative coil triggering jumpers?

Many thanks

[ronsonol]

I've since asked in the another step 50 question discussion, since this seems to be related to assembly.

Many thanks,

[CHB]

is it possible for us to run a fixed ignition timing? from idle all the way up the red line, let say fixed at 26 BTDC. possible?

[jsmcortina]

is it possible for us to run a fixed ignition timing? from idle all the way up the red line, let say fixed at 26 BTDC. possible?

Well, if you REALLY want to yes.
Assuming this is a fuel only setup with a distributor.
Set your dizzy to 26BTDC position and weld up the advance mechanism and remove the vacuum hose.

James

[CHB]

since i have F&E control from MS 2, how bout using the VB921 as the ignitor and set the ignition table like the table below?
by doing this, we can eliminate the use of an external ignitor and able to change the ignition setting without any 12mm socket or wrench..

[CHB]

Someone will (hopefully) correct me if I am wrong, but here is what I think.
1)For starting with just controlling fuel all you need is the negative side of the coil going in to MS. This is your RPM. The rest of the ignition wiring would remain stock. You will not be using the Hall/VR input at this point.

inside my 3TC distributor there is 4 tooths and a VR sensor. the VR sensor sense gives AC signal as the tooths goes pass it. this signal send to original ignitor which ground the negative side of the coil, thus creating a spark to distributor rotor.
Method 1
if we only using Fuel control from MSII, we only need to get a signal from the negative side of the coil, just like we normally hook up an external RPM meter.

method 2
if we using Fuel and Ignition Control from MS II, we need to take the signal from the VR sensor itself, cos we don't need the ignitor to control the coil. this meaning that we cannot tell the MS II how much RPM our engine rotating as in Method 1. that why i came out an idea in my previous post.

did i missed understand the theory behind all this? please comment..

[jsmcortina]

method 2
if we using Fuel and Ignition Control from MS II, we need to take the signal from the VR sensor itself, cos we don't need the ignitor to control the coil. this meaning that we cannot tell the MS II how much RPM our engine rotating as in Method 1. that why i came out an idea in my previous post.

The signal from the VR sensor IS the rpm (and position) signal.

James

[CHB]

jsmcortina,
do you think the ignition map i posted up will work?

[jsmcortina]

jsmcortina,
do you think the ignition map i posted up will work?

If you have the rest of the ignition wired up correctly then yes it will give 26BTDC all the time, however for most poeple that's a silly thing to do. Use a real ignition map instead.

James

[CHB]

I tried the ignition table generator and i only can calculate my engine capacity right. the rest i can get no where cause i don't know what power range or peak torque.. is there any method i can get it right(well, at least closer to an ideal ignition curve)?

[woh]

If you have the amount of mechanical advance and vacuum advance for your distributor, you can use that for a starting point of the ignition map. That will get you to the manufacturers ignition map.

Try reading through this thread.
http://www.msefi.com/viewtopic.php?p=102756#102756

or this spread sheet.
http://www.msefi.com/download.php?id=3677