Ej20 boosting problems

guyph_01 · Post by **guyph_01** » Sun Jul 04, 2010 1:35 pm

Hi guys,

I have a problem with my car and i can't figure out what's wrong. I think it has a few issues:S

First of all it shakes when idling.

Always runs really rough when cold, idles but when i drive it, it feels normal until it boost then its like its running on one or two cyl and feels sluggish.

When it warms up its better, drives normal, boost to 15 but then suddenly it will only boost to 8psi. I then drive it normally without too much boosting for about 5-10mins and it will then boost to 15 again. This does not happen in any pattern and happens for different amount of times.

I tested the comp about 3weeks ago and it was between 150 and 160psi.

Now a bit of history on the engine, Its a rs block with 98heads and piston. It was put back together by a guy thats has a bit of experience with those engines about a month ago. Head where shaved and tested ok, Head gasket is new, Bolts were reused, Water pump and Tbelt is new. timing was checked and is spot on, coil are second hand but all give sparks, Injectors were professionally cleaned by rotomotion. It still has the WTIC system. No codes appears when tested.

Yesturday i got new 0.8 plugs and i swapped the AFM with another known good one again to test drive the car. The car still reacted the same. Its a bit rough when idling( you can feel it shacking) and still has this wired fluctuating boost problem.

I have also re-tested the compression and its exactly the same as i first tested it, between 150 and 160psi.

I noticed two things.
1) It boost to 15 when i first drive in it. If i then give it a hard push, it will but to 15psi and seem to have a boost cut, then it will only boost to 6-8.
2)When i drive the needle drops down to -25 but when i stop at the light its at -20.

Could it be the blowoff valve that's causing this? I'm using the std one.
Or what else could it be?

Any help would be much appreciated.
thx

steptoe · Post by **steptoe** » Sun Jul 04, 2010 6:12 pm

there is idle speed control circuits for idle. Look back last few months with Subarinos issues. Damaged crank angle sensor and afm have been past issues. Then there is that other valve thingy Subarino was looking at too

Is this in factory car or transplant

Did it just happen, or just happen after you did something, like lend it to someone, friend, missus?

Change the oil and or grade of oil? Degrease engine bay down - water in funny places?

Something that had me for a while was weak valve spring ON A HEAD THAT WAS DONE BY PROFESSIONALS ! Scoobidoo made correct diagnosis

guyph_01 · Post by **guyph_01** » Sun Jul 04, 2010 6:24 pm

well the engine was put back together and i just started to drive on it. its a transplant. its definitely not the AFM, will check the crank angle sensor.

sven '2' · Post by **sven '2'** » Sun Jul 04, 2010 6:44 pm

what leads +/- coil packs are you using? Stock items are known to be crap

Sven

Post by **Alex** » Mon Jul 05, 2010 2:55 pm

boost cut is 16psi...wind your boost down guy. You obviosuly have a boost controller? is it electronic or just a bleed valve?

make sure all your intercooler piping and stuff is tight. Can you hear a boost leak?

also yes a blow off valve can cause this. Chuck the stock one back on and see.

Is the bov an atmospheric, plumb back or semi plumb back?

alex

Post by **TOONGA** » Mon Jul 05, 2010 3:09 pm

shouldn't your plug gap be 1.1 mm as opposed to 0.8 ?

nothing else I can help with sorry

TOONGA

guyph_01 · Post by **guyph_01** » Mon Jul 05, 2010 4:54 pm

I was told turbo ej20 is 0.8 and ej22 are 1.1
The car has no boost controller on:S
Does not seem to have a leak:S
coils have been tested and seem to work.
It is also running a standard BOV
It still has the WAIC system
Its got a td04.
Could the wastegate cause this?

Post by **Alex** » Mon Jul 05, 2010 5:14 pm

okay...
1. make sure all the boost solenoids are hooked up correctly, i had a similar issue with my l-series when we hooked up the boost soleniods incorrectly. It would boost up hard to 16psi and bash boost cut, but only in 1st and 2nd gears.

theres definately something wrong if its boosting past the standard setting of 8psi without a controller. Id personally bet on it being the soleniods or actuators or whatever theyre called.

alex

steptoe · Post by **steptoe** » Mon Jul 05, 2010 6:27 pm

more than one issue here from sounds of things - careful not to confuse if so. What speed does it idle at shudder,shudder? Maybe someone could advise of what idle speed should be like on cold start up etc

AndrewT · Post by **AndrewT** » Tue Jul 06, 2010 12:52 am

yeah turbo gap is 0.8

guyph_01 · Post by **guyph_01** » Tue Jul 06, 2010 1:04 am

I'm getting nightmare's with this thing....

D3V1L · Post by **D3V1L** » Tue Jul 06, 2010 8:01 pm

boost solonoids are not hooked up properly or faulty if its hitting 15lbs or hitting boost cut with no boost contorller. thats the boosting issue.

the idle shaking issue sounds like classic coil's to me.... or has it been converted to the coil ontop of the manifold? i cant rememebr when i saw it last.

might be a bit more help if i come down and have a looksee at it

davo

guyph_01 · Post by **guyph_01** » Tue Jul 06, 2010 9:24 pm

i was liking the 15lbs.

I found a split in a hose 2day so i'll let you know how it is next time i drive it.
Also bought new coils and will put them on soon:)

D3V1L · Post by **D3V1L** » Wed Jul 07, 2010 12:24 am

cool. was gonna suggest a hole or split in a hose or something for the rough idle and shit...

seagull · Post by **seagull** » Wed Jul 07, 2010 12:56 am

got an olive in the turbo line ?

fit a very good earth to the motor

guyph_01 · Post by **guyph_01** » Wed Jul 07, 2010 3:28 am

What?

What do you mean by olive in the turbo line?

AndrewT · Post by **AndrewT** » Wed Jul 07, 2010 10:26 am

yeah check engine earths for sure.

Also check your plastic pipes, like the ones around the BOV and intercooler - must be NO leaks anywhere. Spray silicon spray around the outside of the joins to help see if there are any leaks - should see bubbles if there are.

Or take it to Doug's workshop, he can probably diagnose the issue in one standard hour's labor charge!

guyph_01 · Post by **guyph_01** » Wed Jul 07, 2010 11:52 am

ok i will check.
Doug is too busy at the moment.

guyph_01 · Post by **guyph_01** » Wed Jul 07, 2010 4:48 pm

hi guys,

Well that little hose that was hiding under the air box with its leak was causing most of the problems.
Car is much better to drive, didn't have the fluctuating boost since and also vibrates much less.

However i'm pretty sad cause its only boosting to 9-10Psi now:(
I want to put a boost controller in now:) but have a few questions:
Where can i put a boost controller valve?
Will it have a negative effect on the car?
Will it cause any damage?
Can i go back to 15psi or that's pushing it?

I'm new to turbo:) but loving the boost feeling and want more ever since i had a taste:D

Post by **Alex** » Wed Jul 07, 2010 4:56 pm

get a manual boost controller...or an electronic dual stage. The electronic will allow you to run a high and low boost setting at the push of a button.

obviously youll be pushing the motor harder but running up to 15psi is no worries. The trick is to get it set to just before boost cut. Remember it spikes in colder weather so winding it down 1psi or 0.5psi less wont hurt.

alex