2JZ-GE NA-T IS300 RPM Limit Issue

[Pete Tee]

Hello All,

Link G4x 

I was just at the tuner today and we both were scratching our heads trying to figure out why the RPM limit was engaging between 6400-6500 RPM when the limiter is set for 7200. We tried going through most of the tables and even looked on the forums for similar issues and nothing would get it to work. I think this will end up being something silly but the help is greatly appreciated  I have attached a log file and a pic to show the runtimes and what is being displayed. Thanks in advance 

PC Datalog - 2021-07-28 6;11;57 pm.llgx

[Adamw]

There is no limit active in the log you attached, and all the common ones show off/inactive in your screenshot attached above.  

What makes you think there is an RPM limit active?

[Pete Tee]

Thanks Adam for the response. The car will not physically go over ( Engine Speed) 6500 RPM no matter what value we put and in  RPM Limit table. The screen shot shows the RPM goes Orange / Red at 6500ish. if we put 7900 RPM the same happens. So just so i clarify , with the car in neutral and the accelerator pressed once the tach hits 6500 the car starts to pop and bang like its hitting the limiter and won't go any higher no matter what values. Prior piggy back system when car was dynod RPM limit was 7400 and no problems, hence why we think something in the Link is limiting us to higher RPM. Hope this makes more sense. Thanks again 

[Vaughan]

I can't remember the exact details but I remember seeing something like this before which turned out to be related to dwell times and the factory igniter

[Pete Tee]

Thanks all for the help , I did a little playing around as I am a novice to this tuning stuff. I looked at the log file again and the E-Throttle target table and noticed the peak RPM correlated to the APS ( Sub)100% value which was set to 65% and when I increased it to 75%, I was able to get a new log and new peak RPM was 7100 RPM. 

[Adamw]

I dont think your issue would be related to throttle as that will just reduce torque rather than cause a misfire, but it does sound like you dont have that set up correctly if it is only commanding 65% so needs to be fixed anyway.  The ECU is not commanding any limit, you have a misfire related to something else.  The engine speed parameter changing to orange and red is a user definable warning, it is nothing to do with a limit.  

If it is still using the toyota ignitior then you have way too much dwell, those things dont like much more than about 1.8ms.

[Pete Tee]

3 hours ago, Adamw said:

I dont think your issue would be related to throttle as that will just reduce torque rather than cause a misfire, but it does sound like you dont have that set up correctly if it is only commanding 65% so needs to be fixed anyway.  The ECU is not commanding any limit, you have a misfire related to something else.  The engine speed parameter changing to orange and red is a user definable warning, it is nothing to do with a limit.  

If it is still using the toyota ignitior then you have way too much dwell, those things dont like much more than about 1.8ms.

thank you Adam . Yes the factory ignitor is being used and i did notice the dwell times are high. Do you suggest 1.8ms across the entire Dwell Control table or should i leave that up to the tuner to readjust since I don't know if it will  mess with the Master Fuel table. Thanks 

[Adamw]

The dwell table from our supra base map (below) will be a good starting point.  It may still need reducing further in some cases but it will be close.

You can adjust it yourself it wont mess up the tune.

[Pete Tee]

On 7/29/2021 at 11:58 PM, Adamw said:

The dwell table from our supra base map (below) will be a good starting point.  It may still need reducing further in some cases but it will be close.

You can adjust it yourself it wont mess up the tune.

great stuff appreciate the help and feedback. I will run with these numbers and see what happens.