problem with my GSR

[Itab]

sifu-sifus out there,
i'm using a GSR engine on my wira,i've been using it for more than half a yr dee,b4 this it was all ok
till recently,i find tht the engine starts to jerk when i tekan on the accelerator,if normal driving then it doesn't jerk la,but once i press hard on the accelerator it jerks quite badly oh,and the power seems to be not so smooth as before also,when the boost starts to kick in,it goes like vrooooo...(then lag for a while)...VROOOOOM...like tht wor,b4 recent weeks,this has nv occured to me b4 leh....
wat could be the problem?engine mounting causes the jerking?then wat causes the lag then?if say i start to tekan at 3k RPM,then between 3.5k-4k(around this range la) there's the lag,y ah?

pls help me out here
thanks :)

 

[Getz]

Compression checked? Or fueling got problem?

 

[Itab]

i suspect fueling also lo....need to check my fuel pump...maybe buy a larger one like VR4RS fuel pump and replace mine
roughly how much does one cost?VR4 RS fuel pump from half cut shops?

 

[vestax]

normal vr4 or so called rs also no difference la , all runing on 100lph , same goes for the evo 2 & 3 . only evo 1 & gsr runs at 80lph .

 

[Itab]

ic thanks
bro vestax,do u think it could be fueling?wats the most probable cause in your opinion la? :)

 

[vestax]

what kind of jerking ? izzit like boost cut or jerk like runing on 3 cylinders ?. you have to be more specific , cause it can be your plugs , plug cables , ignition coils , fuel pump , injectors , but all those it depends on what kind of jerk .

sometimes intercooler hose leak or vaccum leak would lead to boost cut , and it jerks too , so it depends la , must specific what kind of jerk

 

[TE27levin]

you also can check ur throttle sensor.. suddently apply on full throttle the respond like delay 1 sec .. could be that also...
follow sifu said fuel pump check first B)

 

[ezwong2002]

hehe.. the sifu vestax has spoken.. wei.. ur rear disc brakes and handbrake solve already ka??

Itab.. like what vestax say.. hose leak/loose, spark plugs/cables and fuel pump. last time.. happened to me also..
1. jerks at 5K and above RPM (High RPM) car jerks.. while on-load(popopopo) changed plugs ok already.. sumtime cable also can kacau..
2. car hestitate at 3K rpm onwards at WOT .. fuelling problems
3. 4K rpm (lag 0.5sec) power comes back.. continue to feel the torque.. goes back to normal.. happens when u WOT... check your hoses.. from intercooler pipings to throttle body.

engine mounting if totally destroyed already.. the engine at idle oso can rattle.. :) hope that helps. or when u rev the engine at static position also u can see the engine swerve from left to right, front to back..

 

[kher]

looks like somethimng wrong wif the spark plugs or plug wires... i've tried that b4. accelerate that time izit feel like engine goin to die off???

 

[Itab]

ok,thanks for the info,i'll check the fuel pump and the pipings :)
but i don think it is the spark plugs la,coz i juz replaced them with new ones like 3 weeks ago wor....unlikely la,but i'll check them as well,juz to be safe

kher,it doesn't feel like it was going to die off la,it is more like how ezwong2002 described,so i guess most prolly its the fuel pump and the pipings problem lo

 

[vestax]

Originally posted by ezwong2002@Dec 4 2004, 10:12
hehe.. the sifu vestax has spoken.. wei.. ur rear disc brakes and handbrake solve already ka??

Itab.. like what vestax say.. hose leak/loose, spark plugs/cables and fuel pump. last time.. happened to me also..
1. jerks at 5K and above RPM (High RPM) car jerks.. while on-load(popopopo) changed plugs ok already.. sumtime cable also can kacau..
2. car hestitate at 3K rpm onwards at WOT .. fuelling problems
3. 4K rpm (lag 0.5sec) power comes back.. continue to feel the torque.. goes back to normal.. happens when u WOT... check your hoses.. from intercooler pipings to throttle body.

engine mounting if totally destroyed already.. the engine at idle oso can rattle.. :) hope that helps. or when u rev the engine at static position also u can see the engine swerve from left to right, front to back..

bro ,
i`ve been runing without hand brake's la , and it suck like hell man , im going to get it fixed , cause next week might be going in workshop , open up engine and shit's and change turbo , check for cracks in the manifold , cause now my car really no power la :lol: .

 

[delphinium]

it jerks when u floor the gas pedal, is it? but when u press the pedal slowly, car runs normally? sounds like what happened to me last time.

changed plugs, changed plug cables, changed petrol, changed fuel pressure regulator etc etc. all didnt work out until one day i got bored and my hands were itchy so i took out my ol-skool AFC to change the LEDs. re-wired the ECU and voila! no more jerking when flooring the gas pedal.

 

[Joeker]

Its either ignition or fuel.

Read your plugs.

 

[E V O L U T I O N]

Originally posted by vestax@Dec 4 2004, 03:44
normal vr4 or so called rs also no difference la , all runing on 100lph , same goes for the evo 2 & 3 . only evo 1 & gsr runs at 80lph .

does it cause u to have higher fuel consumption if u use a higher output pump than the stock spec?

 

[evo3]

Originally posted by delphinium@Dec 8 2004, 21:30
it jerks when u floor the gas pedal, is it? but when u press the pedal slowly, car runs normally? sounds like what happened to me last time.

changed plugs, changed plug cables, changed petrol, changed fuel pressure regulator etc etc. all didnt work out until one day i got bored and my hands were itchy so i took out my ol-skool AFC to change the LEDs. re-wired the ECU and voila! no more jerking when flooring the gas pedal.

sound familiar also....mine will jerk sometime when he boost start to kick in....sometimw is ok but is u accelerate slowly, it will be ok no jerk...sudden hentam, it will jerk...change most things, hoses, spark plug, cables, etc etc... but the problem still dere..might be the ECU ...hehehe need to check on that but this few days, it acted OK ohhh....donno why, even my mechanic pening palak....

 

[AlucarD]

Agree with Joeker, either fuel or ignition. Last time I had the same problem, it will jerk a full boost at high rpm. You are either too rich/lean or too advance/retard.

BTW, is this a boost cut? Does you boost still climb when it is jerking. What I did was to change injectors add a better fuel pump and a FPR. Problem solved. Plugs too, changed to No.7. Happily boosting without jerking at any rpm and no matter how I step on d paddle. Of course, get it tuned properly ler, by fixing your AF, you'll be amazed on the power gains.

 

[evo3]

mine when it start jerking, the boost drop, the BOV automatically open.....hehehe .... :D

 

[Joeker]

by reading the plugs u will able to know which cylinder misses under boost and also able to pinpoint whether the cause is due to fuel or ignition.

 

[evo3]

i see .... how to read the plug?

thx in advance....

 

[Joeker]

From the color of the plug tip and electrode.