Problem with car at High Revs (fuel cut?)

[RB20DET_Silvia]

Hey guys when i really give it to my car it starts to gurble and burp i hear the engine going but cars shutters and does not move any faster will that be the fuel cut or will i need a fuel reg it has a new fuel pump and has the speed limiter still?

If i turn the car off and leave it then turn it back on if i smash it straight away there is no problem but after that little bit of smashing it gets back to its habbit.

I really need to fix this as my car suffers so much if i cant get all the power.

I have a RB20DET on 13psi in a silvia just to let u know when there is no fuel cut my car flys like shit out of an ass but with it on it sucks balls on 10psi it has the same issue.

I could not tell u at what revs this is happening as rev meter dont work.

What do u think the problem could be. and how would i got about fixing it.

Thanks guys. :Pimp2:

- Luke

[RB20DET_Silvia]

Can anyone help?

- Luke

[SECURITY]

can you describe the sound a bit better? is it a misfire?

if its a fuel cut the car will completely back off.

[RB20DET_Silvia]

its not a complete backoff its just like misfire....like u can hear the engine still going buts it just not moving any faster then it might start climbing up the speed then starts the misfiring sound again.

- Luke

[SECURITY]

sounds like your coils are rooted

[RB20DET_Silvia]

I believe if my coil packs were stuffed it would run rough the whole time i drive the car. This does not happen, it only happens once i start to really push the car at high revs as stated above.

It runs perfect normal driving and through out the medium rev range just not the high revs.

I might try cleaning my spark plugs and getting a new fuel filter any other comments anyone.

- Luke

[SECURITY]

im 99% sure its your coils

[RB20DET_Silvia]

I have spoken to my mechanic he said he thinks it would be my spark plugs.....he also said am i getting this misfire and etc through out the whole rev range im like nope he said well it wont be your coils as it would cause rough driving the whole time not just at high revs, if it was the coils u would know cause u would get rough drive the whole time due to one not causing any or enough volts to ignite the spark plugs.

He said buy or clean spark plugs and get new fuel filter and then go from there.

Dead coils would cause rough ride the whole time.

- Luke

[SECURITY]

im not saying your mechanic is wrong.... ok, yeah i am.

if there was backfire throughout the rev range then it would be something like your fuel filter or plugs.

but if you read through the sticky about the coils then you will see that everyone gets their misfire at around the 4500 mark.

[RB20DET_Silvia]

I thing is i dont get my back fire at the mark i get mine at high revs not medium revs......thats why im thinking it wont be the coil my mechanic did not say it would never be them just that the chance is slim and i should try sparks plugs first.

If its not the spark plugs i will check the coils.

- Luke

[SECURITY]

at what rev does it start doing that?

[RB20DET_Silvia]

Im guessing around the 6000 grand mark.

- Luke

[SECURITY]

thought u said ur rev meter didnt work. is that an estimate?

[RB20DET_Silvia]

Im not sure if u missed the part where i said "guessing"

im guessing around the 6 grand marks as i can generally tell what rev range its in by the sound of the car and compares the sounds to my mates RB20DET cars.

in second gear ut starts at 70kph when i max out at 100kph in 2nd.

- Luke

[SECURITY]

oh yea.. my bad. im still a bit hammered from work.

try swapping parts from your mates rb20.. swap your afm, then if that doesnt sort it out then try swapping your coils around.

[R31 POWER]

It sounds like plugs or coils.It probally wont break down low in the rev range coz theres not enought pressure on the plugs/coils to work,more pressure = hard time on them.

Do plugs anyway if you have'nt before,wont hurt.

[BHDave]

You could well be hitting the rev limiter you know.....But i doubt it.

Just an idea.

RB20's dont seem to suffer the same coil issues as rb25's for some odd reason, considering they share the same part number in alot of cases. Youd find you have the occassional misfire under load at lower boost if the coils are on the way out, and then complete breakdown at higher boost.