Can someone look at this please wierd fueling at dyno!

[Guest]

Hi,

on the dyno today with a series 2 rb25det, tuner found he required very large numbers in the fuel table to achieve the desired AFR at most notably off boost at 4000rpm (see attached picture), above or below that rpm and once on boost the values in the table are more as expected.

he was stumped and so are we.

fuel pres. is good,

when using more reasonable numbers in this range the car clearly behaves as if lean, confirming its not erroneous readings from the wide band, same behavior also seen on 2 wide bands in different locations.

this is off boost only so we have no idea how "more air" is there requiring more fuel.

if any one has any ideas as to what this could be, we would love to work out whats going on.

can up .pcl if needed

on the other hand car still made 240kw on 12psi so not to shabby.

[Kelly Gordon]

Are you sure there isn't an active 4D or 5D overly table that's removing fuel at those load sites.

[Guest]

I have looked and cant see anything wrong, the tuner has done a lot of link ecu's. It was his first time with a G4+ but I cant see that being a problem as the software is basically the same. any other ideas out there?

 

Thanks.

[Scott]

Hi Karl,

Can you please attach your base-map and a log of the area where the spike in the fuel table is.

Thanks,

[Guest]

here is the map you requested.

[Scott]

Hi Karl,

Thanks for the base-map, I have a had a look and can see what you mean about the fuel table. Do you happen to have a log also, with Lambda/AFR in the relevant areas?

Scott

[Crispin]

That phenonomen can happen with some injectors. Especially the old, large, injectors can have uneven flow at some pulse width's. 

[Daniel Bailey]

Is he getting this doing steady state loading on the dyno, or is the tuning being done in sweeps?  

[Daniel Bailey]

The areas those numbers looking like they are looking pretty high are where acceleration enrichment is often needed - if you have it off, or too small numbers - and are getting the lean conditions when you first get on the throttle then that could cover a bit.  

[Guest]

Hey guys, Sorry for the delayed reply I have been really busy. The injectors are brand new 1000cc Injector dynamics. he was using the dyno as steady state and sweeping pulls. ill get more information in the next few days. thanks heaps for all the help so far