Originally Posted by Croustibat

Try lowering your plug gap a bit first. It is free.

If your problem happens "most of the time but not always", chances are the plug gap is a bit too big (and of course, it could be both)

Also, it is much better to change things one at a time. Otherwise you dont know what was the problem (or what caused a new problem)

Check the voltage at the pump too. The oem pump wiring is very thin and sometimes pump voltage drops to 10ish V (instead of 14).

I happen to had a mix of these problems, to get correct AFRs i was at 100% duty on 1000cc, with 1.2bar boost which was not right at all. Changing the wiring allowed a 10% duty drop to get the same AFRs, which was good but not enough.

Then we plumbed a fuel pressure gauge and i saw my pressure go down when reaching boost ... new pump allowed the duty to drop to a normal 65/70% duty.

Funny thing too; with big injectors like these, a Z32 fuel filter will create bubbles, that can go through the injectors. Which dont really like that ... i had to change the filter to a metal one.

But i am still running an SR20 oem FPR, with 1000ccs and an uprated fuel pump ... nothing these cant handle.

I really dont recommend changing the FPR, as they mostly dont have the same response (changing it means updating the fuel map... )