Car running rich after MSD install
10-28-16, 02:30 PM
#26
wankel=awesome did connect it all correctly. The reason it is sucking is because the MSD is not really that great on a rotary.
On an old points setup, where the white wire is used, the MSD is a tremendous upgrade.
On a more modern electronic ignition, the MSD can still help.
But on a rotary where you can run direct fire, running the MSD through the cap and rotor makes very little sense.
The CDI output of the MSD is being asked to go through a kettering style coil which in effect forces the coil to act more like a step-up transformer rather than an inductive breakdown and kickback situation which is what it was designed for. What you are left with is a VERY short duration spark that must then go through a cap and rotor plus another length of high tension wire before it gets to the plug. And then you don't even get a late leading spark or what we all call a wasted spark (which is not actually wasted on a rotary) even though the coil is being asked to spark the exact same number of times per engine revolution, so you are not experiencing the benefits of the longer coil charge and saturation time a single leading spark could potentially have, such as what the RX-8 uses.
In the end, running an MSD through the cap and rotor on a rotary engine is one of the worst ways to get leading ignition. It's my opinion and I've stuck to it for 15 years.
On an old points setup, where the white wire is used, the MSD is a tremendous upgrade.
On a more modern electronic ignition, the MSD can still help.
But on a rotary where you can run direct fire, running the MSD through the cap and rotor makes very little sense.
The CDI output of the MSD is being asked to go through a kettering style coil which in effect forces the coil to act more like a step-up transformer rather than an inductive breakdown and kickback situation which is what it was designed for. What you are left with is a VERY short duration spark that must then go through a cap and rotor plus another length of high tension wire before it gets to the plug. And then you don't even get a late leading spark or what we all call a wasted spark (which is not actually wasted on a rotary) even though the coil is being asked to spark the exact same number of times per engine revolution, so you are not experiencing the benefits of the longer coil charge and saturation time a single leading spark could potentially have, such as what the RX-8 uses.
In the end, running an MSD through the cap and rotor on a rotary engine is one of the worst ways to get leading ignition. It's my opinion and I've stuck to it for 15 years.
Last edited by Jeff20B; 10-28-16 at 02:39 PM.
10-28-16, 03:36 PM
#27
im not sure why he doesnt do direct fire with the msd boxes all he would have to do is add a coil at this point
QUOTE=Jeff20B;12119267]wankel=awesome did connect it all correctly. The reason it is sucking is because the MSD is not really that great on a rotary.
On an old points setup, where the white wire is used, the MSD is a tremendous upgrade.
On a more modern electronic ignition, the MSD can still help.
But on a rotary where you can run direct fire, running the MSD through the cap and rotor makes very little sense.
The CDI output of the MSD is being asked to go through a kettering style coil which in effect forces the coil to act more like a step-up transformer rather than an inductive breakdown and kickback situation which is what it was designed for. What you are left with is a VERY short duration spark that must then go through a cap and rotor plus another length of high tension wire before it gets to the plug. And then you don't even get a late leading spark or what we all call a wasted spark (which is not actually wasted on a rotary) even though the coil is being asked to spark the exact same number of times per engine revolution, so you are not experiencing the benefits of the longer coil charge and saturation time a single leading spark could potentially have, such as what the RX-8 uses.
In the end, running an MSD through the cap and rotor on a rotary engine is one of the worst ways to get leading ignition. It's my opinion and I've stuck to it for 15 years.[/QUOTE]
QUOTE=Jeff20B;12119267]wankel=awesome did connect it all correctly. The reason it is sucking is because the MSD is not really that great on a rotary.
On an old points setup, where the white wire is used, the MSD is a tremendous upgrade.
On a more modern electronic ignition, the MSD can still help.
But on a rotary where you can run direct fire, running the MSD through the cap and rotor makes very little sense.
The CDI output of the MSD is being asked to go through a kettering style coil which in effect forces the coil to act more like a step-up transformer rather than an inductive breakdown and kickback situation which is what it was designed for. What you are left with is a VERY short duration spark that must then go through a cap and rotor plus another length of high tension wire before it gets to the plug. And then you don't even get a late leading spark or what we all call a wasted spark (which is not actually wasted on a rotary) even though the coil is being asked to spark the exact same number of times per engine revolution, so you are not experiencing the benefits of the longer coil charge and saturation time a single leading spark could potentially have, such as what the RX-8 uses.
In the end, running an MSD through the cap and rotor on a rotary engine is one of the worst ways to get leading ignition. It's my opinion and I've stuck to it for 15 years.
[/QUOTE]
Then you'll have an even four.
10-28-16, 08:58 PM
#31
Waffles - hmmm good
iTrader: (1)
If that's your hangup just run leading only with one coil per plug. I did that for few years and it's not that noticeable and performed great. Right now I have trailing using an Ford TFI coil and leading using an FC coil. The FC coil for leading may be a compromise, I may go to two TFI coils for leading even though it's messy mounting them.
10-28-16, 09:28 PM
#32
My car has four coils = three FB coils and one dummy coil. The dummy coil is an old points coil that isn't used but is just a place holder in the coil holder which requires two to work properly. I'm also using one of its threaded studs to hold ring terminals with wires powering the other coils. It's kind of convenient.
11-02-16, 07:02 PM
#34
Something odd must be going on because I've gotten MSD 6AL's to work wonderfully. 1 more MPG, staring is easier, better throttle response etc... When working properly, without any carb changes, the plugs will be a touch lighter in color because your ignition system is working better and burning a tad more fuel.
The box may be bad.
They like a good power source, without spikes. Always put a fuse on the + power wire.
They can be setup to run for a 4, 6 or 8 cylinder engine. Did you check that?
The box may be bad.
They like a good power source, without spikes. Always put a fuse on the + power wire.
They can be setup to run for a 4, 6 or 8 cylinder engine. Did you check that?
11-03-16, 05:58 AM
#35
carb whisperer
Thread Starter
Something odd must be going on because I've gotten MSD 6AL's to work wonderfully. 1 more MPG, staring is easier, better throttle response etc... When working properly, without any carb changes, the plugs will be a touch lighter in color because your ignition system is working better and burning a tad more fuel.
The box may be bad.
They like a good power source, without spikes. Always put a fuse on the + power wire.
They can be setup to run for a 4, 6 or 8 cylinder engine. Did you check that?
The box may be bad.
They like a good power source, without spikes. Always put a fuse on the + power wire.
They can be setup to run for a 4, 6 or 8 cylinder engine. Did you check that?
they are set up for 4cyl.
I honestly think they don't work with my br9eix plugs. they are iridium and have a tiny gap.
11-03-16, 09:55 AM
#36
Banned
iTrader: (40)
Do the rx8 plugs, use one box as stated earlier to direct fire the leading plugs. Leave the trailing stock or even omit it all together. It works flawlessly. It is the best looking and performing system out there In my 30+ years of playing with rotaries.
01-14-17, 02:40 PM
#38
carb whisperer
Thread Starter
***SOLVED***
So I *finally* fixed this. Turns out there's some misinformation out there about our ignition systems that led me to all of my trouble.
1st) The RB recommended .015 gap is awful. The MSD melted down the plugs because not enough energy was being discharged at the plug, because the gap was too small. The remaining energy was just blipping inside the cap.
2) The RB recommended br9eix series plug that worked well with the stock system, even after gap adjustments was not functioning properly or burning evenly. I changed to FB plugs, and 80% of my issues were solved.
3)The factory plug wires ARE NOT HELICAL. After some research I found that the replacement NGK plug wires are standard automotive fare, and not all compatible with CDI. However, the mazda PN and item desc. clearly states them as helical core wires.
4) With my vacuum advance hooked up, the timing at idle was not consistent. It varied so much that I removed it, and am now strictly running mechanical advance. Why this was suddenly an issue with the MSD, and not with stock, I don't know.
Small boost to power, everywhere.
Functional Rev limiters L/T
Hot starts are much better, starts the flooded engine without much drama.
Cold starts remain not as good as the factory system, no matter how much tinkering I do. It's still good, being a modded nikki, though.
Torque. Low end response is excellent, and it is handling much richer mixtures than stock without putting the fire out. (Which means slightly more torque than before, seeing as I can run the engine richer)
I'd say that the next step is direct fire with them, to witness the full effect. But so far these are not worth the sticker price, if I'm honest.
I paid 240$ for the entire system, then 100$ in new plug wires and some other little changes like plugs.
New, we'd be totaling near 700$, and it wouldn't be worth it.
So I *finally* fixed this. Turns out there's some misinformation out there about our ignition systems that led me to all of my trouble.
1st) The RB recommended .015 gap is awful. The MSD melted down the plugs because not enough energy was being discharged at the plug, because the gap was too small. The remaining energy was just blipping inside the cap.
2) The RB recommended br9eix series plug that worked well with the stock system, even after gap adjustments was not functioning properly or burning evenly. I changed to FB plugs, and 80% of my issues were solved.
3)The factory plug wires ARE NOT HELICAL. After some research I found that the replacement NGK plug wires are standard automotive fare, and not all compatible with CDI. However, the mazda PN and item desc. clearly states them as helical core wires.
4) With my vacuum advance hooked up, the timing at idle was not consistent. It varied so much that I removed it, and am now strictly running mechanical advance. Why this was suddenly an issue with the MSD, and not with stock, I don't know.
Small boost to power, everywhere.
Functional Rev limiters L/T
Hot starts are much better, starts the flooded engine without much drama.
Cold starts remain not as good as the factory system, no matter how much tinkering I do. It's still good, being a modded nikki, though.
Torque. Low end response is excellent, and it is handling much richer mixtures than stock without putting the fire out. (Which means slightly more torque than before, seeing as I can run the engine richer)
I'd say that the next step is direct fire with them, to witness the full effect. But so far these are not worth the sticker price, if I'm honest.
I paid 240$ for the entire system, then 100$ in new plug wires and some other little changes like plugs.
New, we'd be totaling near 700$, and it wouldn't be worth it.
01-14-17, 03:35 PM
#39
RB is "often wrong" in my experience.
Your findings with stock FB plugs were similar to mine when I ran one MSD 6AL in various formats ranging from through the cap and rotor, to direct fire across two FB coils. I never tried RB's recommended plugs, nor did I ever regap any plugs. My wires were always stock style carbon strings.
As far as power, the MSD in parallel direct fire was only as powerful as a single J-109 ignitor connected to the same two coils in parallel. Single J-109! Not two of them like it should have been. I didn't run either system for long, and both seemed to be lacking in performance.
The only good working ignition I tried that gave consistently higher performance whether NA or boosted across multiple platforms (REPUs and FBs mostly), is classic "DLIDFIS" which uses two J-109 or two GM HEI ignitors, and two stock Diamond coils or aftermarket replacements like Bosch oil filled coils, where the layout is one ignitor, per coil, per plug. This is the only ignition layout I will ever run these days as I've tried the rest, but this is the best.
Oh, speaking of the rest, I did try one FC leading coil and it was not as good. It was called 2GCDFIS if you want to search. Then it burned out the J-109.
I guess I could have tried it with a GM HEI but DLIDFIS was right around the corner so I swapped that in and it was already far better than the FC leading coil even when it was running fresh, long before the ignitor started burning out.
There's just no comparison. Easiest starts whether cold or warm, best cold to hot weather running, best low end torque, smoothest cruise, and takes all the boost I've thrown at it, and even seems to like 8000 RPM I don't need a rev limiter as I don't hang out up here, but it's nice to know it doesn't complain.
Even when my system floods when I test a carb with needles and seats that "ain't quite right", DLIDFIS still keeps the plugs pretty clean and doesn't break up with all the boost I've thrown at it (9psi) so far on stock BR8EQ-14 plugs. It is still good practice to take the plugs out and give them a quick cleaning after a flooding episode though. When I'm done with carb testing, I will probably never have to worry about cleaning the plugs...
And you are right. The MSD boxes are not worth it. I ended up selling mine to an air cooled VW guy and never regretted it.
Your findings with stock FB plugs were similar to mine when I ran one MSD 6AL in various formats ranging from through the cap and rotor, to direct fire across two FB coils. I never tried RB's recommended plugs, nor did I ever regap any plugs. My wires were always stock style carbon strings.
As far as power, the MSD in parallel direct fire was only as powerful as a single J-109 ignitor connected to the same two coils in parallel. Single J-109! Not two of them like it should have been. I didn't run either system for long, and both seemed to be lacking in performance.
The only good working ignition I tried that gave consistently higher performance whether NA or boosted across multiple platforms (REPUs and FBs mostly), is classic "DLIDFIS" which uses two J-109 or two GM HEI ignitors, and two stock Diamond coils or aftermarket replacements like Bosch oil filled coils, where the layout is one ignitor, per coil, per plug. This is the only ignition layout I will ever run these days as I've tried the rest, but this is the best.
Oh, speaking of the rest, I did try one FC leading coil and it was not as good. It was called 2GCDFIS if you want to search. Then it burned out the J-109.
I guess I could have tried it with a GM HEI but DLIDFIS was right around the corner so I swapped that in and it was already far better than the FC leading coil even when it was running fresh, long before the ignitor started burning out.There's just no comparison. Easiest starts whether cold or warm, best cold to hot weather running, best low end torque, smoothest cruise, and takes all the boost I've thrown at it, and even seems to like 8000 RPM
I don't need a rev limiter as I don't hang out up here, but it's nice to know it doesn't complain.Even when my system floods when I test a carb with needles and seats that "ain't quite right", DLIDFIS still keeps the plugs pretty clean and doesn't break up with all the boost I've thrown at it (9psi) so far on stock BR8EQ-14 plugs. It is still good practice to take the plugs out and give them a quick cleaning after a flooding episode though. When I'm done with carb testing, I will probably never have to worry about cleaning the plugs...
And you are right. The MSD boxes are not worth it. I ended up selling mine to an air cooled VW guy and never regretted it.
01-16-17, 07:57 PM
#42
Moderator
iTrader: (3)
Join Date: Mar 2001
Location: https://www2.mazda.com/en/100th/
Posts: 30,796
Received 2,574 Likes
on
1,830 Posts
the factory plug wires were not NGK's. the factory wires were made by Yazaki. in fact Yazaki made a lot of the wiring for these cars, and many many many others
01-17-17, 06:13 AM
#43
carb whisperer
Thread Starter
So the very first time owners replaced their plug wires on FB, they were slightly downgrading the ignition. Kinda shitty.
01-17-17, 08:35 AM
#44
I am glad you found the issue. Some clever sleuthing going on. I did want to mention, I have seen cars run with the coil polarity wrong. They had drivability issues, but started, idled and ran. It will simply make the spark jump to the center electrode instead of from it, which gives a worse quality spark than is needed.
I realize this was not your issue, but earlier in the thread, I read that the car wont run if some wires are reversed, and wanted to clear this fact up for anyone with a future issue.
I am surprised that RB recommends .015 gap. Newer cars with high energy ignitions are running some very large gaps today to gain the hottest spark.
The one thing I do like about the MSD is the ability to set a hard redline easily. This is very useful for a boosted application.
Thank you for sharing, these type of threads make us think, and help us learn!
Rich
I realize this was not your issue, but earlier in the thread, I read that the car wont run if some wires are reversed, and wanted to clear this fact up for anyone with a future issue.
I am surprised that RB recommends .015 gap. Newer cars with high energy ignitions are running some very large gaps today to gain the hottest spark.
The one thing I do like about the MSD is the ability to set a hard redline easily. This is very useful for a boosted application.
Thank you for sharing, these type of threads make us think, and help us learn!
Rich