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Base timing and timing lock set up


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Apologies for noob like question, but i'm getting myself confused here.

I'm about to update the firmware to 6.20 and i want to be clear about the procedure for resetting base timing if needed .... currently the car was set up up with the timing locked to 10'BTDC when calibrating. However, I want to check the base timing first (with no ECU corrections) and make sure it is set to 15' BTDC (which is correct for this RB25DET engine) then recalibrate the ECU/trigger after the firmware upgrade.

So my question is, do I need to set base timing with the CAS to 15' without starting the car first? before i do the base timing calibration in the ECU? or does the 'set base timing' function in the ECU do all this anyway?

many thanks




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With engine idling:

  1. Open "set base timing" screen.
  2. Set top "lock ign timing to" box to 15deg.
  3. With timing light on coil #1 confirm if 15 deg mark on pulley/front cover lines up.  If it does go to step 5, if not go to step 4.
  4. If 15deg mark doesnt line up, then adjust it with the middle offset box.  A larger number advances the mark.  You need to hit enter after changing that offset number.  
  5. Now the 15deg mark lines up at idle, bring the engine up to say 5000RPM to confirm the 15deg mark stays on target.  If there is some drift then adjust this out using the bottom delay box. 
  6. Click done and perform a store.  

Make sure you connect the timing light to an old plug lead between the coil and plug, many timing lights dont give accurate timing if you use the timing loop at the back of the engine.

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  • 2 years later...

Hi Adam,

Need your expertise  here. I seem to struggle with setting up base timing. I've followed your above instructions and experiencing a behavior that don't seem normal. 

With Engine at Idle, i opened Set Base Timing. The Lock Ignition Timing is already set to 10 Degrees.

i entered -25 to offset ignition and hit Enter, the Timing light flashes with the crank pulley mark on 10 Degrees BTDC

It also stays at 10 BTDC on rev up. Engine also idle nicely as well.

When i click done and perform a store to ECU. The crank pulley mark moves behind away from the 10 BTDC mark and Idles rough. I did a small drive and gets a lot of trigger misses.


Hope you can give me some pointers on where i am wrong or where else i can check. Please let me know if you need any logs of any sort.'

appreciate your help


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15 minutes ago, terryep91 said:

When i click done and perform a store to ECU. The crank pulley mark moves behind away from the 10 BTDC mark and Idles rough. I did a small drive and gets a lot of trigger misses.

When you close the set base timing screen, then the timing is no longer locked, it will do whatever is commanded from the ignition table and other controls such as idle ignition.  

Will need a log and the tune to offer any advice.  What do you mean by "Trigger misses"? 

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Hi Adam,

sorry for the late response. Thanks for the clarifying the base timing setting. I've adjusted the distributor following the instructions for rotor phasing and I managed to set the base timing. The mark lines up at 10 BTDC. The car is more rough on idle now and AFR is averaging 18.4 

The log file is bigger than 500k. I've uploaded to a google folder. Hope it's ok for you to retrieve through the link below. The tune file is also in the folder location.

I am not very experienced so if there is anything else you need or i can make to improve will be highly appreciated.



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  • 2 weeks later...

Hi Adam,

The initial base timing degree set from the tune shop was 352 degrees. After I did rotor phasing and set base timing, the 10 degrees BTDC mark now lines up with 342 degrees locked at 10 degrees. Car idles rough and dies. I believe it's now retarded by 10 degrees. Do I need to change values in the ignition table and any other areas? Appreciate if you relook at my tune file in my previous message and advise the areas I also need to check and update. 

Many thanks

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