Lucas pump occasional high rev problem?

[Mitch]

hey guys i'm new to the forum, (have read a lot on here before coming a member). Basically every now and then my car seems to what i can describe as stop delivering fuel at around 4100-4300rpm, when i hit that amount of revs it seems to just 'drop off' and not want to rev anymore/higher, but other times it will rev to 4900-5000rpm without the hesitation, any ideas? i know the Lucas isn't the best for high revving but surely if it was cutting the fuel at 4k ish it would always happen in every gear? not just when it feels like it? Thanks! Mitch.

[4WayDiablo]

maybe a fuel delivery problem, check the fuel filter, maybe even as far as the pickup in the tank

[Mitch]

maybe a fuel delivery problem, check the fuel filter, maybe even as far as the pickup in the tank

Thanks for the quick reply, had a new filter a few weeks ago! also on start up sometimes it will idle then drop to 500-600 rpm, then rev by it self to nearly 2k, then just drop back down to normal idle speed, i dont know but maybe the 2 problems could be linked together?

[CJ_Derv]

Tis a strange problem to be honest as for the top end revs, i found mine when running lucas used to drop off around the 4k mark as its the gov kicking in and the turbo knocking off but shouldnt be that noticable really on a lucas

Id definitly check filter and pickup in tank as 4waydiablo mentioned then if no luck the following

Definitly a fuel delivery problem id say, could be drawing air into the system somewhere, may be worth putting a clear pipe from filter housing to pump and seeing if any air getting in, usual places can be the actual lid of the fuel filter if not sealed properly, copper washers on feed pipe on pump. is the grenade functional does it go hard when you pump it or stay soft giv it a good squeeze this can usually locate small leaks

[Mitch]

Tis a strange problem to be honest as for the top end revs, i found mine when running lucas used to drop off around the 4k mark as its the gov kicking in and the turbo knocking off but shouldnt be that noticable really on a lucas

Id definitly check filter and pickup in tank as 4waydiablo mentioned then if no luck the following

Definitly a fuel delivery problem id say, could be drawing air into the system somewhere, may be worth putting a clear pipe from filter housing to pump and seeing if any air getting in, usual places can be the actual lid of the fuel filter if not sealed properly, copper washers on feed pipe on pump. is the grenade functional does it go hard when you pump it or stay soft giv it a good squeeze this can usually locate small leaks

Yeah it can be annoying at times, the grenade goes hard, will have to check for any obviously places of where air could be getting drawn in, if it was drawing air surely it would be a constant problem? :/