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Morning lads!

I noticed recrntly when I'm WOT my car has a noticeable flat spot in power up around 5500-7000rpm.. I checked my power fc and it normally has injector duty at around 84-90% max at rev limit of 7500rpm and 25psi but now it's going strait to 100% before rev limit is reached...

Wile testing this I noticed it only does it in 3rd gear and the power drop seems to be coming from the fact it won't make target boost (25psi) in that gear... Hovers between 22-24psi. I use an eboost 2 ... Could it just be the tune?

I'll also say my fuel pump relay had been wired wrong and was like this nearly the whole time I've had the car.. It's been on the dyno around 7 times for multiple tunes without a problem also... but now it's fixed and has since been using a fair bit more fuel... Would a bump up voltage cause a bump up in fuel pressure causing the injectors to max?

I've done multiple boost leak tests now and found a couple of minuscule little leaks. Fixed them, car still does it. Swapped my z32 afm out for a brand new one... Still does it..

Assuming you have a normal airflow meter PowerFC setup? The duty cycle will only go that high randomly if the airflow meter THINKS it is moving more air than normal, a dodgy fuel pump or fuel pressure won't change the injector duty cycle - ONLY the ECU will decide to do that in response to how much load it thinks its under etc as it won't know what is happening to the fuel pump, etc.

To me it sounds a lot like you still have a boost leak as because you duty cycle has increased it indicates the airflow meter is metering more air than normal - which means the turbo is working harder than normal, which indicates that it has to spin harder to make your normal target boost but given you aren't reaching target boost the air the turbo is pushing must be escaping somewhere.

That seems like the most obvious and cleanest possible explanation to me.

 

Assuming you have a normal airflow meter PowerFC setup? The duty cycle will only go that high randomly if the airflow meter THINKS it is moving more air than normal, a dodgy fuel pump or fuel pressure won't change the injector duty cycle - ONLY the ECU will decide to do that in response to how much load it thinks its under etc as it won't know what is happening to the fuel pump, etc.

To me it sounds a lot like you still have a boost leak as because you duty cycle has increased it indicates the airflow meter is metering more air than normal - which means the turbo is working harder than normal, which indicates that it has to spin harder to make your normal target boost but given you aren't reaching target boost the air the turbo is pushing must be escaping somewhere.

That seems like the most obvious and cleanest possible explanation to me.

 

Boost leak was my first thought and as I said I've done multiple tests on the last two days.. I pressurised the whole system from the turbo inlet to 30-35 psi and fixed any leaks however small... Now I'm at a loss

I'll also say that in second gear boost builds no worries at all and even spikes to 26-27psi then drops to 24-25psi which is target...

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