9 posts / 0 new
Last post
mo_spec
Offline
Last seen: 2 years 9 months ago
Joined: 07/10/2014 - 07:45
Timing sync and Ignition type Mazda RX7

I am doing a start up on an RX7 for a friend, I got the car running with a few small changes to a base map from an out of state tuner. The tuner set up most of the wizard for the sensors etc, that the customer is using.  This is my first time with doing a rotary so I have a few questions and would like to make sure I am doing this right.

The session has the ignition set up as Mazda Rx7 OEM Igniter, but this car has individual coils for each plug. Should the wizard be set to Sequential Coil on plug?

EDIT: The session is set to "coil on plug"

Next is the timing sync. The only mark on the crank pulley is 20*ATDC for the trailing spark plug on the front rotor. So here is the method I was going to use, please let me know if this is correct.

 

Trigger offset set to 20*

Lock timing at 0*

Timing light "clamp" on trailing plug wire on front rotor housing and set timing light to 0*

Adjust timing until it is in sync with notch on crank pulley. (notch is 20*ATDC)

 

Thanks in advance for the help.

 

 

 

AEM_SB
Offline
Last seen: 4 hours 40 min ago
Joined: 06/07/2014 - 14:29
First you need to note that

First you need to note that the ECU is calculating and displaying ignition timing in degrees Before Top Dead Center, so the 20 ATDC timing mark on that rotary engine should line up when the ECU fires the front trailing ignition coil at (-20 degrees BTDC).

Rotary engines have two ignition coils per rotor, the leading fires first (using the standard Ignition Map in the ECU) and the trailing fires after (using the offset specified in the 2D table TrailingIgnSplit [deg]). In order to sync timing on a rotary, recommended procedure is to set the table TrailingIgnitionSplit [deg] = 30 , then use the Igntiion Sync Page of the wizard to Lock Timing at 10 degrees BTDC. This will result in the trailing coils being commanded to fire at -20 BTDC (20 ATDC), so you can sync timing and make sure the front trailing coil lines up with the mark on a factory 13B-REW rotary engine.  Don't adjust the value for Trigger Offset unless that is necessary to line up the actual coil firing event on the 'crank' pulley to line up with the timing mark on the engine's front cover

 

Hope that helps,

SB

Wankel88
Offline
Last seen: 2 years 1 month ago
Joined: 09/22/2016 - 22:45
I would like more information

I would like more information on this. The pdf for the rotary is very vague on this topic. So I set my ign split map to 30. The whole map or just an area? Then lock the timing at 10 btdc and shoot the light on the mark while cranking? Should I pull my fuel pump relay to prevent the engine from firing?

AEM_NS
Offline
Last seen: 1 year 3 weeks ago
Joined: 06/06/2014 - 09:31
The timing is already set in

The timing is already set in the base cal. You should be able to start and run the engine unless you're running something besides the stock trigger. Then once the engine is running, check the ignition sync. It doesn't matter if you set the whole map or just the section around the current live cell to 30 but obviously setting everything to 30 makes it pretty easy.

Wankel88
Offline
Last seen: 2 years 1 month ago
Joined: 09/22/2016 - 22:45
Thanks I got it. I was unsure

Thanks I got it. I was unsure if the engine had to be operating or while it was done during the cranking process. Thank you for your time.

Panrocks1
Offline
Last seen: 6 months 3 weeks ago
Joined: 12/27/2018 - 20:16
I have a FC cas system on my

I have a FC cas system on my motor witch is a 12A.  I am having trouble getting the system to sync. I can't get the car started with the base map. To check if my timing is at it's base. I don't know what I am doing wrong. If i did not set the CAS correct from the start of if my smart coils are not set up correctly. I get a little of a back fire when trying to start the car but it's more of a miss timing thing. Also my spark plugs get wet with gas very fast when trying to start. 

AEM_SB
Offline
Last seen: 4 hours 40 min ago
Joined: 06/07/2014 - 14:29
I'm not a fan of the

I'm not a fan of the distributor-style CAS sensors from the older rotary engines. They have lots of downsides including:

1. The pre-1992 pickup sensors send a weaker signal than the ones from the 1992+ FD3S front cover. Weaker signals are more susceptible to interference.

2. The pickup sensors inside the CAS are mounted physically near each other which can result in cross-talk between the two signals.

3. The CAS module itself is mounted relatively near the spark plugs, which are a source of interference.

4. The slop in the CAS drive gears is not helpful in terms or measuring eccentric shaft position accurately.

5. It's possible to misalign the CAS drive gear into the each time it's removed and replaced, so if you don't check with a timing light after reinstalling the CAS the engine could be receiving more ignition advance or less ignition advance than you've configured in the ECU. Rotary engines are not forgiving of over-advanced timing.

 

 

If you are able to install the Full Function Engineering trigger kit, that's a very good idea. If you want to use the OEM CAS, you will need to change the settings for the VR_PWMDuty table to compensate for the weaker signals. Base settings are [60,80] for the FD sensors, other customers have gotten engines to start and run using [20,50] for the FC CAS.

 

To sync timing without flooding the engine, unplug the fuel pump or disable the fuel injectors and use the timing light while the engine is spinning on the starter. Be sure the battery is fully charged, and also be careful not to overheat the starter motor by running it for too long without taking a break. If you are trying to configure a new smart coils setup, be sure you've configured Ignition Type = Sequential (Coil On Plug) in the first page of the wizard. Be sure the coils are wired to the correct pins on the ECU, as described in the instructions. Coil1 is the front leading , Coil2 is the rear leading,   (coil 3 is only used for a 20B engine),   Coil4 is the front trailing, and Coil5 is the rear trailing.

 

Hope that helps,

SB

DLRtuning
Offline
Last seen: 1 month 1 week ago
Joined: 06/07/2019 - 00:38
I am looking at purchasing

I am looking at purchasing the FFE crank trigger. Are you able to provide settings for their 36-1 hall effect crank trigger? Thanks

AEM_SB wrote:

I'm not a fan of the distributor-style CAS sensors from the older rotary engines. They have lots of downsides including:

1. The pre-1992 pickup sensors send a weaker signal than the ones from the 1992+ FD3S front cover. Weaker signals are more susceptible to interference.

2. The pickup sensors inside the CAS are mounted physically near each other which can result in cross-talk between the two signals.

3. The CAS module itself is mounted relatively near the spark plugs, which are a source of interference.

4. The slop in the CAS drive gears is not helpful in terms or measuring eccentric shaft position accurately.

5. It's possible to misalign the CAS drive gear into the each time it's removed and replaced, so if you don't check with a timing light after reinstalling the CAS the engine could be receiving more ignition advance or less ignition advance than you've configured in the ECU. Rotary engines are not forgiving of over-advanced timing.

 

 

If you are able to install the Full Function Engineering trigger kit, that's a very good idea. If you want to use the OEM CAS, you will need to change the settings for the VR_PWMDuty table to compensate for the weaker signals. Base settings are [60,80] for the FD sensors, other customers have gotten engines to start and run using [20,50] for the FC CAS.

 

To sync timing without flooding the engine, unplug the fuel pump or disable the fuel injectors and use the timing light while the engine is spinning on the starter. Be sure the battery is fully charged, and also be careful not to overheat the starter motor by running it for too long without taking a break. If you are trying to configure a new smart coils setup, be sure you've configured Ignition Type = Sequential (Coil On Plug) in the first page of the wizard. Be sure the coils are wired to the correct pins on the ECU, as described in the instructions. Coil1 is the front leading , Coil2 is the rear leading,   (coil 3 is only used for a 20B engine),   Coil4 is the front trailing, and Coil5 is the rear trailing.

 

Hope that helps,

SB

AEM_SB
Offline
Last seen: 4 hours 40 min ago
Joined: 06/07/2014 - 14:29
I'm seeing CamSyncAdjustment 

I'm seeing CamSyncAdjustment =26 and TrigOffset = 4.5 on a customer calibration that was using a 36-1 trigger. That was probably the Full Function Engineering kit, I'm not aware if any others exist. Disable injectors and use a timing light to double-check this works correctly on your own car before running it, I'm not sure if there are different brackets or sensor installation angles possible for different setups.

Hope that helps,

SB