CIS fuel head and injector question

[PrimeMvr]

Subject is an 87 930 that screams at WOT, but feels like it's missing a cylinder at idle and light to medium throttle. I flow tested the injectors in the car. The outputs were all dead-on identical, but #4 had a noticeably different spray pattern. Not nearly as conical and atomized as the other 5.

Here's where it gets interesting.... I swapped it with #5 and the issue did not follow the injector, it stayed on #4.

My question is, if the output volume is identical, what in the fuel head could cause a different spray pattern? If the pressure was different in that line, I would expect the total output to be different.

I repeated the test 3 times with the same results.

Thanks for your thoughts. Steve

[jason2guy]

sounds like a line issue. ive heard of that happening. the metal injector line gets clogged, pressure decreases and then this happens. could be worth a shot. there is an adjustment at the FD for the individual injector outputs.