I have a Jeep CJ7 with a slightly modified 258ci 6 cyl with a Howell EFI system. I thought I read that the injector duty cycle should never go over 85%. In this engine it is consistently over 100% and in the higher rpm ranges (2800-3200) and higher MAP values (70 -90) I have logged over 400%. In this higher range the engine stumbles and I assume it is due to the injectors being very unhappy with the work load. The fuel pressure never drops from 12 psi and volume test of the pump showed approx. 42 gph. According to Howell this is within specs. This EFI kit reportedly uses the injectors from a 4.3 engine. It would seem the injectors can't flow enough fuel. Can they be too small for this application? Any guidance here would be greatly appreciated.
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