Hi


The engine is VR4 Cyclone

Cyclone is 200bhp right?
The RS 240 bhp and written Cyclone ECI Multi right ?

All is standard, except E3 intrcooler, Nissan RB fuel pump and 3" piping exhaust

When speeding, at high RPM there's sudden jerking and kind a brrp brrrp brrrp sound. (sorry..dunno how to xplain).

What the possible cause and what should i look for?

Is it bcos of standard ECU? No performance chip upgrade yet.
Is it bcos of fuel supply system ? Too rich or to lean...?
Is it bcos of airflow sensor?

Also need to know VR4 injectors cc...

Forgot everything about VR4 stuff. Helping a fren sorting out his wira VR4

thank u

vr-4 injector is 450cc.u can check ur plug,tr unit,plug cable n ur fuel pump.

spark plug not hot enough...

it is either not enough fuel or incorrect heat range spark plugs is used.
another to check is the plug cables.

try hks iridium racing plug with side gapping?
prepare 2-3 brands like denso, ngk and hks coz each of them having different ability

any misfiring when it jerks?..
a friend has this kinda prob before and it was fuel supply related...

yeaps u guys are right

truth is , there are many possibilities
u need a mech to troubleshoot

fueling , ignition system , bov
these are the possibilities

there could be a very high possibility that the problem could be with the fuel pump

Hi si fu there.... Can further explain why the BOV can cause the car jerking?

Currently my BOT also having the same problem. When i try to press a little harder on the throttle, the car start jerking. My car last time was having ignition coil burnt problem. COuld it be the ignition coil cause this thing happened? On the other hand, when i boosting, sometime my BOV will release the compressed air but sometime it will rebounce back to the turbo :-s. THis will cause jerking as well??

fuel cut maybe??

Fuel supply...Put fuel regulator will solve it..
Or SAFC also can...
Mine also the same previously...
Air that going to filter not enough also can face such problem...
Good Luck...

but I'm using walbro fuel pump, the fuel pressure should be enough right?

Too much fuel also can cause trouble...

high rpm means when it reach 7k ke bro?
if so, then it is fuel cut..

lolz
if fuel cut then get a good ecu or piggy back to solve it haha