It takes some experience to get new injectors behaving properly, maybe you get lucky and have a semi-compatible base tune, maybe...
I am still running the big injectors that I tested for Nigel and they work exceptionally well. I was always happy with the original ones, until they weren't big enough for me anymore. I can't imagine the small ones would be more difficult to tune As far as the o-rings, Nigel sent me a few different cushions and o-rings to try on the original ones, until it was right. He even sent me the spacer set after he developed it with savington along with new cushions and o-rings for free.

Flow Force injectors are high quality IMHO, as someone who has been running them since they were first tested. I'm not saying they are as good as ID's, but I haven't tried ID's on my own vehicle. My car idles beautifully, even with the 960's running gasoline and an 015 plug gap on MS2, thanks Nigel! I get nothing from those guys for saying this, but they are my friends after having good business experiences with them over the years.

Carlos

 

I'm honestly really surprised at the variance that we see in the GT500 injectors. I buy them new OEM, and they are packaged individually with no flow measurements or anything. They squirt gas into cylinders literally twice the size of those in a 1.6, so they never get to the same low PW as we see in our cars.

 

As data points, on my 1.6. I idle at 900rpm, 35kpa, and 1.95ms pw. AFR bobbles between 13.5 and 14.2 and this was a 35F MAT with 16* timing. Cruising pulse width (I do most of my driving between 40 and 55 in 5th) is only 2.6ms on average. This is all with the car running full sequential. I could not idle at anything less than 12:1 and 1300rpm with it wired for batch. My friend's set of untested injectors idle perfectly happy on the FM 1.6 Link basemap, in batch, at 14.7 and 700rpm.

 

Are you using the injectors that are matched or a random assortment of injectors?

For data points, on my 1.6 I idle at 850 at 35kpa and my pulse width is around 1.86ms. My afr's are set for 14.7 but they fluctuate a little bit from 14.5 to 14.9 give or take. After sitting a little while at idle ego correction seems to get them closer to target afr of 14.7. I am running full sequential and my injectors are the KA injection injectors that are not matched. I have not tried idling at anything higher or lower afr and I have not attempted to lower my idle rpm. My testing was at 70-75F MAT.

 

Read back. Mine are not flow tested and I got unlucky. They idle like crap. If I go any leaner things just start shaking.