Hay I really need some help on this one? I installed a larger blower on my 383 went from a p600b making 10psi to a D1 making 15psi, Went to the dyno for tuning and discovered my 55lb per hour injectors and aromotive pump just wasn’t doing the job. So I installed a set of 72lb per hour injectors and a Weldon pump with voltage regulator.

Went back to the dyno today and have a really strange thing happening no matter what rpm you try to go wide open throttle I get a lean spike I mean really lean like off the scale data logs look like 12.5 then a half second 17 spike then back to rich like 10.5. All of this caused a sever tip in hesitation.

Any ideas would be greatly appreciated.

Oh by the way after installing the injectors only with the old pump no tip in problem the lean tip in hesitation only accrued after installing the Weldon fuel pump. Fuel pressure is normal.

Any and all explinations welcomed

Thanks Keith