Hello. I have 550cc primaries and 1680cc secondaries, T04S single, PFC. I tuned with Jeff48 and we had a max of 78% injector duty at 15 psi with 10 afrs for the whole day. On the way back from tuning it was the same. It rarely went above 72%. It was fine for around 2 weeks. Then one day I did a highway punch to about 7k RPM. Boost was normal and peaked at 15psi, but my max injector duty was 95%! Now it consistently does that and I am a little frightened. I have the resistors in the 1680s if that makes a difference. What can explain the change? While we were tuning we could do 7.5k RPM runs over and over and have consistent 70% duty. I am afraid to push the car now because something is certainly wrong. I have talked with Jeff and there is no reason it should be doing this. Any idea why it is doing this? I installed the injectors correctly. I've had 2 people check my work there.

Thanks everyone, your help is appreciated.


-----This is also in the PFC section, but this area gets more traffic.

 

I have noticed that my AVC-R boost controller (which can monitor injector duty) often records peaks of nearly 100%. I know that my true injector duty is not that high, but there seems to be something about the way the AVC-R reads the injector duty that causes the false peaks. It seems to happen when I let off the gas. I am not sure if my PFC does the same, but my point is that peak/hold values can be misleading (or wrong ).

I assume you are reporting peaks as reported by the PowerFC. If you do the little graph mode for injector duty (keep your eyes on the road!), do you get a sweep at 70% with a spike to 90%, or are you getting a true 90% for more than a brief spike?

-Max

 

I'll have a passenger ride along and check it out. It seems to build up to the 90s though.