The A / F becomes lean after restarting.

[nos]

hello.

I am setting RB26 with G4X.

From the engine start when it is cold (20 °) to the end of warming up (80 °), there is no problem.

After warming up, warm up the IAT to 60 ° and stop the engine.

At the end of warming up, it is around A / F14.5: 1.


It has been stopped for about 10 minutes from there, and when it is restarted again, the fuel becomes extremely thin when the restart (post-start enrichment) is completed.

It will be A / F17.0 to 18.0: 1.
If it is idling for about 5 minutes, it will return to about 14.5: 1.

[Electredge]

where is the IAT located? still in the intake plenum? and what does the IAT read when you go to restart it? It is common for this to occur on warm restart as the IAT temp sensor reading has gone up but not the actual air temp and takes a little bit of time to come back into normal operation as temp sensors move fairly slow at idle. are you using charge temp table? is this tuned in modeled mode or traditional? 

[nos]

Hello

AT has changed to a LINK sensor and has moved from the genuine plenum to the turbo pipe side.

When the engine is stopped, it is around 55 ° C.
After waiting 10 minutes, the IAT when restarting will display 60 ° C.


Fuel control is not modeled.

I also don't use Charge Temp Correction.

Thank you

[Adamw]

If IAT is not the cause of your issue then the other common cause of lean hot restart is due to the injectors getting hot since they are sitting in a very hot environment and attached to a hot cylinder head, with very hot intake valves right underneath them and without the usual fuel flowing through them to keep them cool. 

The way to work around this is to use a 3D IAT trim table with IAT Vs engine runtime on the axes.  Then at hot IAT's you can add say an extra 15% fuel at initial startup and fade it out over say 2 mins.  

[nos]

hello.
Thank you for your detailed explanation, Mr. adamw.

Let's test controlling the IAT with the engine start time.

I feel like I can do it well.

Thank you