RB20DET jerking

[fzee70]

guys need help from all u sifu regarding my converted RB20DET...problem is the engine was unable to launch properly from 1st gear until 5th gear...when the rpm is above 3k the turbo get in than it's ok...no problem to reach 180km/h...the problem is only when the rpm is from 1k to 3k, no pick at all...like sh*t... more worst when turning ON air cond. the idling drop below 500rpm..action had been done...
1) changed plug coil(2nd hand)
2) changed injector(2nd hand)
3) changed new plug
4) changed new semi-synthetic oil
5) swap ecu
6) new timing belt,marking ok
7 new clutch plate
....petrol pump not yet...fyi I'm converted from R32 to A31

 

[Danny]

sounds like symptoms of overfuelling before the turbo kicks in. Get a device to control your a/f ratio like safc and go for wideband tuning.

 

[MrNismo]

I don't think a simple piggyback fuel computer will correct this problem. Since you mention it's 1-3krpm, I would suspect it's a problem that occur when the ECU is in closed loop operation.

Things that could cause problem falling under this category would be:
1) TPS
2) O2 Sensor
3) Hmmm... and AFM maybe, but very slight possibilities

I suggest you post your problems under Skylines Australia Forum or Skylines Downunder Forum. Those people there might help you better.

 

[fzee70]

thanks guys for your feedback....will try it out tomorrow.

 

[eterna2772]

TPS... need to re-adjust... maybe...

 

[Danny]

let us know your outcome if you manage to fix it, I'm also curious because my next car is going to use RB20.

 

[polyxtroy]

TPS??? whats that?

 

[topui11]

TPS - throttle positioning sensor

check it... i also got problem with it before. but ok already now. other than that, check the AFM, but i don't think it's the problem though. another thing, check all the wirings are connected properly. Sometimes loose wiring could cost the car to be jerking.

I've changed to GTR fuel pump and wooo... fuelling damn good. hehe.. have to get FPR and maybe AFC to tune the a/f.

 

[speedchaser]

It might be like what Dan had said, over-fuelling at low RPM because you had change your injectors (to bigger ones, I assume). It's what happen to my 4A-GTE. A piggy will sort it out but a stand-alone will bring out multiple orgasms. And if topui11 is the MAN from Shah Alam and bunk in USJ then bro, u should know me...

 

[ltr]

other then that check the :

a) check the color of your exhaust smoke (blue lean and white is oil or my aunts an uncle) alternetively u can pull the plugs and 'read' it.

B) distributor plug cables

c) alternator (may not be giving enough power at low RPMs

but whatever u do....do item 'A' first. basic thing to do for any 'good' mechanic. instead of spending your hard earned $$$$ and encourage these ppl to do the same to the next person.