Nistune Forums

I have just replaced stock injectors with Bosch 520CC injectors. After using Change Injector size operation TIM reduces to 265 , however K Constant remains at 601.

Realise TIM is designed to automatically override other values , however is it necessary to manually reduce K value manually ? . Also is it necessary to adjust Injector Latency which is at 750 .

Engine fires but will not start , a lot of exhaust is being produced symptomatic of a lot of fuel being dumped

There is no K constant adjustment when TIM is used instead.

K is used to adjust load indexing and affects overall fueling in the ECU, where TIM just adjusts fueling

TIM sounds adjusted correctly. However what are your 'crank enrich' tables looking like. Were they adjusted during injector resize? Have you tried lowering these further if it is overfueling

Is it kicking to attempt to start during crank, or is it just cranking over?

First try crank enrich tables until it kick and then attempts to use normal fueling afterwards. Then adjust TIM manually until AFRs are around 14.7:1 on cruise

Thanks for response.

Solved most of the problem today. After uploading/resync for some reason new values did not change until Burn command was used. Most of my work has been with Z32 maps and uploading has always resulted in changes being made temporarily prior to Burn.

Issue was exacerbated by a boost leak which has now been fixed. Testing can now commence to check AFR's.

Adjusted TIM to 272 , engine runs fine with AFR's across powerband spot on.

Excellent. With the changes, watch for 'uploaded' indicator at bottom of the screen when you make changes. Burn normally only required at the end of the tuning to keep changes permanent

This is a good future reference!