Surging and hesitating under boost

[Pappu1]

Car surges and hesitates as soon as u hit more than abt 9psi

Under that seems To run sweet

Idle is fine

Low boost run is fine

No Cel

Will sparks blowing off be a sign of this

Fuel pump been replaced with known good

Sparks were done few months back but were cheap coppers only

Car struggles to get more then 15psi even when pushing hard as surges a lot

Used to run abt 20

Have taken wastegate hose off and still surging and hesitating hard after 9psi and can't seem to get much over a bar boost

Turbo seems fine and nonunisual noises and no smoke

Will do new sparksand coil tomorrow but wondering of there is any other common cause of the surge and hesitation and inability to make more boost

[Guest]

afm?

[clintondane]

Afm or O2 sensor ???

[X]

most like afm...

i had this problem on the coupe awhile back turned out to be a dirty air filter

[Pappu1]

i removed the afm and it ran the same with hesitation at the exact point

hmm it has a chinese pod roughly setup currently

will remove pod and see if makes different

just to test - will try another known good afm..

dont think its 02 as does that hesitation in open loop mode..hmmm never know..

that will be the last change and see resort..

only started happening after i put on fmic...

[Sequence]

I had this problem after getting a new exhaust system, My plugs were fudged ;D

[Pappu1]

hmmm just looking at pod - its partially blocked with the airbox i was making - lol still in progress..

would a partly restricted pod cause these issues..?

maybe time to rip out the shielding and just see if the open pod makes a difference..

loving the daylight savings.. yay.. more light in avo for car work ;D

[G-unit]

would the shielding around the pod be any less then a stock airbox?

[Sequence]

I still recommend getting plugs checked,

Although Mine were pretty good

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[Pappu1]

hmm the shielding blocks the lower half of the pod

maybe will be a bit of pain but might as well do the plugs since i have another set..

will change the coils as well as have another set..

will report back tomorrow

did i say i love daylight savings ;D

[X]

yeah check the plugs, usually if theres a plug problem your car runs like its on 3 cylinders

[Pappu1]

Plugs changed

Coils changed

Pod removed

Ready to go for a run now

One of the plugs had a hairline crack in one o the plugs insulator

Just tapped it a little bit and the insulato had bits falling off

Anyway time for a run and let's see

[G-unit]

so did u make it home?

[Pappu1]

Yay

Car got it's mojo back

Boost real nice now just like a proper Sti should

Currently running no pod as a quick test

Will re-design the pod setup so it's less blocked

Perhaps issue may have been that crack in the plug insulater

[X]

glad u are sorted bro... im up Auckland this weekend/ next week should meet up?

[Pappu1]

Yea bro defenetly meet up

U getting The v4.8 coupe?

[X]

na im taking the forester up this time, got a engine drop to do on a v9 wrx and a clutch job to do on a Nissan GTR, and wiring job to do on a ver2 wrx

[xsvpwr]

I'm going to Taupo this weekend otherwise would have come and shown you the new car San. Hit me up next time your coming up

[X]

hopefully im up Auckland this weekend, for a week or two depending on the gf, if she's sick of me by then or not LOL

[Pappu1]

Loving how the vf22 has so much more over the vf30

No additional lag on butt dyno

Just way better mid and top end

Will do some data logging and see boost curves

[X]

 pappu said:

Loving how the vf22 has so much more over the vf30

No additional lag on butt dyno

Just way better mid and top end

Will do some data logging and see boost curves

finally someone agree with me on that!

[xsvpwr]

Yo San did driven performance ever get back to you about those Kinugawa turbos? I want to know what a good upgrade for better top end power on my v7 STI would be and they look reasonably priced, what do you reckon about a td06 20G? Would factory pinks with a walbro handle that turbo or need decapped?

[X]

what kinda power you after and what you using your car for?

-no i cant remember if they ever did... was also looking at our new sponser's turbo also but they are not bolt on kit

as long as the turbo comes with warranty it should be sweet....

20g is good... but then u got AVCS heads which helps spolls up the turbo faster

[Pappu1]

my exact next plan

td06-20g and retune

will see what stock afm can push and leave at that

but sure as hell will be a huge midrange and top end whack..

[ODB]

 X said:

na im taking the forester up this time, got a engine drop to do on a v9 wrx and a clutch job to do on a Nissan GTR, and wiring job to do on a ver2 wrx

man u should just get qualified as a mechanic and open a shop!