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Very high VE and injector duty in low boost...

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Hey,

I got this 1.8L turbo I tune, in the VE table the idle area will be 70~ cruise 80~ but boost (200kpa) will be 184-191 5400-7200rpm

The injectors duty show 95%

Injectors: 640cc @ 3bar (dead times are set as the manufactor publish)

car fuel pressure: 4bar

Other car - same car model/year same injectors - about the same power/turbo show 60-70% duty @ 200kpa

Where should I look ?

Bad fuel pump ?

Low pressure ?

False reading ?

Thanks !

Elior

does the fuel pump keep up? is it dropping pressure and/or voltage?

I don't have real time pressure data, I just ask what's the probable cause.

I would be checking the actual fuel pressure as a first step.

Check fuel pressure and also voltage at the pump when your on boost.

Is your fuel pressure regulator static or vacuum/boost referenced? The reason I ask is that I had a customer last year who had fitted an aftermarket pump and kept losing pressure, it turned out that although the pump could flow high volume it couldn't handle high pressure and it's built in pressure relief valve would release resulting in lost pressure in the rail.

IIRC it is a vacuum/boost referenced regulator.

The ecu logs show 14v~ at all rpm... do I need to check at the pump ?

Thanks

yes, if you probe the wires as close to the tank / pump as possible you'll see what voltage it's recieving

The car was fine - running 200kpa @ 120% VE, now after an engine swap (same engine only stronger rods) it needs 180-190% at the same boost...

You need to very carefully check everything that could have changed when the engine was swapped. The original values you were seeing sound quite realistic. I wouldn't be surprised if the fuel pressure is dropping at high rpm/boost and you're compensating in the VE table.