I own a 1988 Mazda rx7 gxl and this is what has been done to the car

J-spec S5 TII 13B (bough used from Japan and no internal upgrades at all)
MegaSquirt II V3.0 (or so I think, was sold to me by someone a while back in 2008)
Stock CAS (modified with 2 teeth taken out/ 180* from each other)
Stock N/A leading coil
Stock N/A trailing coil that has been modified as well
1000cc primary and 1200cc secondary
Aeromotive A1000 fuel pump
E85 with premix (need help getting afr's correct for E85 usage...)
All emissions have been taken off
NGK PowerDex AFX wideband
No name brand boost controller
T61 (70mm) turbo
44mm Wastegate

I'm currently using TunerStudio MS V2.0.6
as for the firmware: ????? not sure

I have 3 documents and a vid of the rx7 idling:

"megasquirt_harness_pinout_chart"


"megasquirt_trigger_settings"


"trailing_coil_mod"


"rx7 idle" CLICK ON THE IMAGE BELOW TO GET TO THE VID


Coil timing (approximate advancement) "approximate" due to the timing light shifting back and forth from the yellow mark/in-between/ and red timing mark.

I have the CAS stabbed 4 notches counter-clockwise from the timing dimple

L1 = 0* advanced (closest to the yellow timing mark)
L2 = 0* advanced (closest to the yellow timing mark)
T1 = 15* advanced (closest to the red timing mark)
T2 = 5* advanced (closest to the red timing mark)

Spark Mode: Toothed Wheel
Trigger Angle: 0.0
Ignition Input Capture: Falling Edge
Spark Output: Going Low (Normal)
Number Of Coils: Wasted Spark
Spark A Output Pin: D14
Dwell Type: Standard Dwell
Maximum Dwell Duration: 3.0
Trigger Wheel Arrangement: Single Wheel With Missing Tooth
Trigger Wheel Teeth: 24
Tooth #1 Angle: 5.0
Wheel Speed: Cam Wheel
Second Trigger Active On: Rising Edge
And Every Rotation Of: Crank
Enable Rotary Mode: Rotary On
Output Mode: FC Mode
RX8 Mode: Disabled


I'm not sure how to upload msq files...but I did upload it to the "symtech laboratories (msq file repository)

MSQ File Repository - SymTech Laboratories

my msq file should be on page 5 at the very bottom with the name "Matthew K" and with the long description.

Any other additional info needed will be posted to the best of my knowledge.

Thanks,


Matthew K.

 

In the video the engine ignition sound, doesn't sound right...I don't know exactly what is going on, but definitely the timing is off. Could be multiple things such as the modified CAS or the modified trailing coil as well. First off I want to see what my parameters should be (when utilizing the cut-toothed CAS) and a good explanation of why as well.

I tinkered with the trigger settings as well with the "dual wheel/dual wheel with cut tooth" etc but it doesn't run as well as the current set up I have right now. I've changed the ignition input capture to "rising edge" as well but I get a loud misfire and horrible pinging sound (probably having to deal with timing as well).

I was also told to mess with and utilize the "data-logger", but I don't really understand what I am really looking at contrast to what the EMS is telling me.

I am registered/own the DIY autotune that is now integrated with my MSII V3.0 EMS and from what I understand it only tweaks the fuel (VE Table). How do I correctly utilize this feature? do I let the engine idle and then click "autotune" and let it go from there or do I need to drive it while it tweaks the fuel table?

and before anyone goes off on a rant to tell me "to use the search/advanced search feature of the forum"...I have and have done so relentlessly. I've seen so many different threads on the megasquirt side that the info just jumbles together in a mess. Unless I know exactly what I'm looking for, the search function doesn't help very much. There is also a lot of misguided information or not descriptive enough information out on the rx7club forum. I show the "pin-out" of my wiring harness to be a visual reference as to what wires are going to where. I have received help from many other enthusiast on the forum as well and I am grateful, but sometimes the info is not thorough or is mixed with specific jargon that I am not able to fully understand.

I appreciate any help and criticism, I am trying to understand the MegaSquirt basic tuning process...and will later start a thread to help beginners like myself go through basic "tuning" steps and then later, more advanced tuning steps.

Thanks

 

I'll have to take a look at your msq when I can find some time.

Please also provide a datalog with the issue occurring.

Ken

 

The settings you have for your CAS are for an unmodified CAS and will not work properly with a modified one. For a modified CAS you'll want to set it up as a single wheel with missing tooth, 1 missing tooth, 12 trigger wheel teeth, crank wheel.

With a modded CAS, you don't even need to connect the 2nd trigger.

I'm not sure why you would have cut teeth out of the CAS as it is not necessary and make the setup more prone to noise issues.

Do you have VROUTINV wired to TSEL or VROUT wired to TSEL. With VROUTINV wired to TSEL you should trigger on falling edge. Otherwise you should trigger on rising edge. If it acts weird when set up correctly, you'll need to adjust and/or restab your CAS.

The tooth #1 angle should be the angle that the E-shaft would be at with the first tooth after the missing directly under the sensor in the CAS. Based on how you say you have it stabbed, 0 is not going to be the correct number once you switch to missing tooth. If you could take a picture of how the CAS looks when the engine is on the -5 timing mark I could help you set the proper tooth #1 angle.


The autotune feature only tweaks the VE table. BAsically you need to have a wideband O2 sensor and controller, and have the controller wired to the MS. The MS needs to be calibrated for that controller. Then you just go to the proper tab in TunerStudio, and tell it to automatically tune.

The best thing you can do for yourself there is read everything you can get your hands on, then read it again, and then read it again, and keep reading it until you get it.

You'll want to look at the manual pages on MegaSquirt Engine Management Systems for specific settings and tuning advice. You can look at www.megamanual.com for general tuning information. The megamanual should not be used for ms2/extra or ms3 firmware-specific settings, just general tuning advice.

Ken

 

Thank you for posting muythaibxr, I appreciate your help. My answers to your questions will be in bold lettering.

Thanks

 

I believe you chose the right timing mark, but if your tooth #1 angle is 0, that is most definitely wrong.

The tooth #1 angle should be 175 based on the way you stabbed the CAS (assuming I'm remembering right and it turns counter-clockwise). The way it is now, leading is probably firing around the correct timing, but trailing will be firing on the wrong rotor every time.

Ken

 

"The way it is now", you mean this CAS stabbed position right? 5 teeth before the gap.



and then my settings should be:

Spark Mode: Toothed Wheel
Trigger Angle: 0.0
Ignition Input Capture: Falling Edge
Spark Output: Going Low (Normal)
Number Of Coils: Wasted Spark
Spark A Output Pin: D14
Dwell Type: Standard Dwell
Maximum Dwell Duration: 3.0
Trigger Wheel Arrangement: Single Wheel With Missing Tooth
Trigger Wheel Teeth: 12
Missing Teeth (teeth): 1
Tooth #1 Angle (deg BTDC): 175
Wheel Speed: Cam Wheel
Second Trigger Active On: Disabled
And Every Rotation Of: Crank
Enable Rotary Mode: Rotary On
Output Mode: FC Mode
RX8 Mode: Disabled

 

The new settings look correct, though since the wheel spins counter-clockwise, you want to count the teeth after the missing tooth passes, not before, so you're counting from the sensor to the wrong missing tooth.

Ken

 

so I should interpret this as 7 teeth after the gap...So with the "Tooth Angle #1 (deg BTDC) @ 175, the engine should run a little better with this CAS stabbed the way it is.



Matt K.

 

Actually you want to count the gaps not the teeth really. there are 6 gaps between the missing tooth and the one under the sensor. 6 gaps * 30 degrees per gap = 180 degrees. If the tooth under the gap is -5, then the actual tooth #1 angle is 175 BTDC.

So if you leave it stabbed the way you have it, then you'll want 175 for the tooth #1 angle. That shouldn't really change how leading works, but it will change trailing, and should make the engine run better.

Ken

 

That makes so much more sense now...I was wondering earlier what the gap measurement was (30* per gap). I'll enter these parameters in and will post a vid of the ride tonight sometime.

Thanks


Matt K

 

The 7 didn't run too well

Spark Mode: Toothed Wheel
Trigger Angle: 0.0
Ignition Input Capture: Falling Edge
Spark Output: Going Low (Normal)
Number Of Coils: Wasted Spark
Spark A Output Pin: D14
Dwell Type: Standard Dwell
Maximum Dwell Duration: 3.0
Trigger Wheel Arrangement: Single Wheel With Missing Tooth
Trigger Wheel Teeth: 12
Missing Teeth (teeth): 1
Tooth #1 Angle (deg BTDC): 175
Wheel Speed: Cam Wheel
Second Trigger Active On: Disabled
And Every Rotation Of: Crank
Enable Rotary Mode: Rotary On
Output Mode: FC Mode
RX8 Mode: Disabled

Here is the video

DSCF5783.mp4 video by Snaple07 - Photobucket



I might be running low on E85, so tomorrow morning I will fill the tank up with premixed e85.


Matt K.

 

Wheel speed should be "crank" not "cam" with that setup.

Ken

 

It's Alive!!!

Click on the VID