rb20 jerking stuttering prob solved (temporarily?)

[timbar32]

Just thought that I would share a problem I had, that some others may have had, and how I solved it. If anyone can give me some advice on this issue and if I am just covering up another prob. it would be appreciated.

I recently (seems like it was after it got pretty cold down here) had the problem of my car jerking and sort of stuttering when I floored it, and between 5000-7000 rpm. It only happened when I was on full throttle, and the car accelerated perfectly on part throttle. After cleaning the airflow meter and airfilter (didn't check plugs as they are 3000km old iridiums- gapped at the factory 1.1mm as my car is dead stock apart from a K&N pod) which didn't make a difference, I rememberd that I had once (10 months ago) adjusted the accelerator cable a bit tighter. I simply loosened the bolt adjustment off a couple of mm, and everything seems to be good.

Can anyone explain what happened??? Could I have any further problems?

[Cubes]

I experience this 'afm' cut at higher boost levels on cool nights/mornings it seems to be especially when the car is cold.

I generally knock boost down to around 14psi, I can then rev it out to just over 7000rpm where I change. I generally run around 1.1-1.2bar of boost on the stocker snail. For how much longer is anyones guess.

I'm still running the stock ecu so it does get a little rich up top so this will help keep the exhaust gas temps down which will help the turbo last a little longer.

Have you removed the mesh on the AFM by any chance?

Upon removing the mesh I noticed a slight decrease in lag and over all slightly more gutsy feeling. However I also noticed that the boost cut on cool nights/mornings began around that time also.

Who knows..

[timbar32]

No, haven't removed the mesh. So you think the cold air and the wide open throttle caused the prob? Maybe have to adjust the cable for summer/winter conditions? Anyone know why there are two mounts for the cable?

[bbenny]

I have an AFM cut when i run anything over 1bar of boost. i think its maxing out the AFM signal to the ECU. only way to remedy this is to get a fuel cut defender or new/rechipped ecu.

as for gapping the plugs, i gap mine at 0.8mm

[GTSR22]

if you have a boost controller get a new one.

my dad had the same problem with his car and at 5000rpm in 3rd gear the car would jerk and shake.

we found out later it was the boost controller so if you have one please exchange for a newy

cheers

greg

[GTSR22]

my dad said its either actuator is opening rihgt up giving u full boost, or the turbo has a crack in it, it may also be you might have a leak somewhere.

his one was becasue of the boost controller but your may be differnt.

cheers