S14 SR20DET rough idle and boost lag fix?

[1slowsilvia]

So I went to change my spart plugs today with BKR7E plugs from autozone when I did the car ran SOOOOOOO rough. it already has a rough idle. sometimes it will idle perfect and some days it will miss then idle will drop will struggle and jump back up.

I was forced to put my old plugs back in to fix this issue and it ran ok ish. now why would changing the plugs do this? also before you ask YES I GAPPED THEM PROPERLY!

I just don't understand why idle constantly misses and car wants to die.

second issue is boost lag like BAD

I am running a S15 T28 Dual BB turbo.

It lags like a mother fucker I only build up 3 psi until I hit 4k then boost spikes and hits 8 - 9 psi and jumps around like crazy between 7 and 9 psi.

After driving my buddies stock S15 his is at full boost at 2400 rpms which is 7 psi. mine I brake boost at 3k it will go right to 3 psi and hold even at 3700 rpm it will go to 3 and hold.

Can this be a timing issue causing this?

I did a compression test came out 135 across the board.

The car did come with Tomei pon cams but had them switched for stock s15 cams same as s14.

I didn't do the change but the car runs fine but man it fucking is slow as fuck until 4k rpm and even then it doesn't rip like my stock S13 SR does.

WHAT THE FUCK IS WRONG????????

wiring can't be issue as I am runing Wiring Specialties S14 Kouki to S14 Kouki Sr harness.


Please help I can take video of it too.

my only thought is timing is off for it to miss like it does and run like pur fucking shit after changing plugs.
but some days it runs 100% normal please help. here is engine bay pic just in case you wonder where hoses are going.

[1slowsilvia]

Also I have a leaky bov that is tightened all the way down could this be the one cause of all my issues regarding idle?

but then changing plugs made motor rock and kick and spit. so idk you guys help me out please. really pisses me off to have a nice car with a good motor that just wont idle.

[Dirtcanhurt089]

Is the ecu tuned to the old cams that it came with ?

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[Dirtcanhurt089]

Bad wastegate ?

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[1slowsilvia]

No I got rid of the power FC and went with a stock ECU from JDM OF MIAMI.

Also when getting into boost after a while I notice that white smoke comes out in a big puff after boosting and it really stinks bad if I have my windows down.

there is almost no shaft play at all so I wouldn't think turbo is bad. Could the person who put turbo on have put wrong restrictor on this? like the S14 Journal bearing restrictor?

how can I test if waste gate is bad?

[Dirtcanhurt089]

One way is put ur hand down there when everythings off and see if u can open it by hand usually that's bot a good sign

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[Daily_Drifter]

i have an s14 blacktop sr with that same blow off valve. when my blow off valve is releasing too much air, the car reacts the same way that you described above. i suggest tightening up the blow off valve and plug any leaks you can find, and play with the idle a bit. it should work

[1slowsilvia]

Originally Posted by Daily_Drifter

i have an s14 blacktop sr with that same blow off valve. when my blow off valve is releasing too much air, the car reacts the same way that you described above. i suggest tightening up the blow off valve and plug any leaks you can find, and play with the idle a bit. it should work

I have tightened the bov completely down and now its straight compressor surge until I get a replacement this weekend.

I'll try pulling on it but what does the white puff of smoke sound like to you guys cause its a big puff and only after getting into boost and it stinks like fucking burnt oil gags me.

[Shift n Drift]

check the wires going into the maf plug, one "could" be loose and cause your shitty ilde

[1slowsilvia]

Anyone else

[mr.srod]

it seems like u have a couple problems do u check the knock sensor or the ohms on the injectors what about a new fuel filter