my mate has a vlt (RB30) and it misses on full boost (anything above 7psi) standard ecu, only has a front mounted cooler, turbo back exhaust, pod and a gizmo ebc.. it has had those items on the car for ages, but a while ago it started running like **** at idle and driving.. so we checked over it and found an injector had no resistance.. replaced that injector with a newie, and all was good now recently the car misses under excess load.. what we have done : s/plugs leads reaplaced a leaking injector fiddled with timing (as it had the dizzy out previously for repairs) and yeh, were kinda stumped... anyone have any bright ideas?? cheers Some original photos have not been recovered yet.

The pumps for the fuel system are getting older and wearing, they can work fine on a n/a or on low boost but can struggle with reasonable flow and pressure. Here is order of things to do:- If fuel filter is in car for more than 18months then get a new one - but *not* an economy filter as they have restrictors that are bad for turbos. If you are interested reverse flush the fuel filter and you'll see lots of black crud, this can restrict flow quite a bit...! If that makes no difference then swap out the high pressure pump and give it a try but with a full fuel tank. if the problem is still there only when the tank is low on fuel then swap out the low pressure pump, Cheers

oh sorry, i forgot to mention the fuel filter has also been replaced.. yeh, thanks for the idea bud.. will give it a go cheers Some original photos have not been recovered yet.

ok mate i had the same problem check your spark plugs i found number 6 plug with no tip left on it but it idled fine and ran fine till you put your foot down and they are cheap too replace

Quote: Originally Posted by milla1122 ok mate i had the same problem check your spark plugs i found number 6 plug with no tip left on it but it idled fine and ran fine till you put your foot down and they are cheap too replace That seems to be a popular problem, I had the ends off my cyl 6 and cyl 5 splitfires completely melt away - there was "very little left"... That shouldnt happen and could also be an indication of reduced fuel flow at higher boost, ie Leaning out or plugs are too hot a type for that level of boost, either way its worth checking fuel pressure on boost and that both fuel pumps can handle the flow as melted plug ends are consistent with older pumps etc.

cheers guys, ill chuck a set in tomorro.. also forgot to mention that i have clamped off the return line to up the fuel pressure and it still missed cheers