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BA XR8


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I have a boosted ba xr8 , cold start great , have it performing well etc everywhere alse , only challenge left is hot start.. to fire during a hot start it Needs WOT to fire, assuming its getting too much cranking enrichment, as idle is very rich for around 10 seconds before the inj pw halves and runs great at target afr. Where would I start looking for the over commanded fueling at crank during operating temp. Thanks 

 

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BAXR8 boosted tune file_CustomOS.tec

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Look at "fuel cranking lambda (ect)" for cranking fuel.

There is another table that has a timer for the fuel coming in, but be farked if I can remember what is called or can find it in the editor. The closest thing I found just now is called "startup open loop enleanment table for exhaust warm up".

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Do you have an aftermarket fuel rail? 

You could be getting vapour lock in the rail. Aftermarket rails also suffer from more heat soak. 

There is a heat soak model to account for fuel density changing on a hot start. The workshop edition has all of the tables mapped. 

You could also just fudge the cranking lambda and that may work.

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Also check your IAT/ACT sensor locations, if they are heat soaking badly you may be getting incorrect air density measurements at startup. In the turbo cars the PCM compares the turbo boost pressure vs the manifold pressure when the engine is stalled (before cranking) to estimate barometric pressure and heat soak.

If you don't have a boost sensor then you'll be losing this compensation. Next time you do a hot start, datalog your barometric pressure before cranking the engine and see if the value matches the weather station within some reasonable accuracy.

Being a turbo V8, I suspect you have some seriously high engine bay temperatures during a hot start.

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