Front inlet flow limited when I choose split ratio 200:1

There is a maximum total flow that the inlet EPC can deliver.  It is dependent on the gas type configured.  Limits are listed in the data sheets for the GC:

8890 Data Sheet: https://www.agilent.com/cs/library/datasheets/public/datasheet-8890-gas-chromatograph-5994-0492en-agilent.pdf

7890A Data Sheet: https://www.agilent.com/cs/library/datasheets/public/5989-6317EN.pdf

7890B Data Sheet: https://www.agilent.com/cs/library/datasheets/public/5991-1436EN.pdf

If you really need the split ratio that high, use a smaller injection and reduce the split ratio so that the same amount of sample goes on-column.  For example, if your method has 1 uL injection with 200:1 split, change the method to 0.2 uL injection with 40:1 split.

Thankyou!