Hi guys

Was wondering what boost I should be looking at on a z4 ecu car is a wrx 96 import
Mods as follows/full blitz nur specR exhaust./k&n induction kit/forge blow off valve/
Just had new plugs fuel filter and millers 10/60 oil couple of weeks ago.
The car has been boosting to 10 psi for the last year and then it started dropping to 5 psi so had it looked at and nothing came up.it would only drop to 5 psi once a week but then go back to 10 psi.

I have changed 3 port bcs and map sensor.car hits 9psi and has for the last two weeks
But sometimes it would shoot to fuel cut.
I changed my restrictor pill to the one i got with the secondhand 3 port boost controle and it hit 15 psi for a full day felt like that's the way it should be ran great then all of a sudden it went back to 9 psi.the pills in both pipes are the same size not sure on size tho
I reset ecu battery off for 45 mins.took car out and its back up to 15 psi.until it drops back to 9 psi

This has me going crazy as I am not sure what's going on changed all pipes to silicone and no leaks.
Can some one tell me what boost my car should be at.not sure if this is the ecu for the car a when I pulled the carpet and took the guard off there were two bolts missing were the ecu holds in its place.
I have done days of searching but keep getting different answers.

Please guys any info you could input would help so much as just want to no what is safe for the car don't want to end up buying another engine if its to much boost.

Thanks for taking the time to read my post.

 

0.5bar is limp mode...the car shouldn't rev over past 4000rpm??

standard boost is 12.6psi... I had same prob...I changed pill as it should be 2mm port hole I changed maf and still had problem.. so I changed ecu and cars been fine since...

 

0.5 Bar maybe the ECU dropping the IAM to Zero, Normally opens happens after a lot of knocking.. Try resting the ECU

 

If boost keeps dropping, its prob retarding ignition too. Could be a dodgy knock sensor. Possible something loose vibrating which is setting off the knock sensor.
Or worst case the engine is knocking.

 

go over every single vac pipe.. check everything is tight....check actuator rod tension...just take clip off end of rod. and release rod. if correct you should have to pull rod just alittle to fit back on...If not adjust rod either to shorten or lengthen depending what you need...

you say you see 15psi so is the ecu chipped??

 

Thanks guys.

How do you reset the ecu.and I am not sure if the ecu is mapped or anything I will pull it out today and see if all looks standard if it is modded in any way were would the chip sit or how would I know if it has be messed with.
Yes mate it hits 15 psi then after a day of driving it went back to 9 psi you could feel it holding back.its all ways whent past 4000rpm.
See the thing is I am not sure if its meant to be at 15 psi or if that's way to hight or is the 9 psi what it should be.but if 12.9 psi is standard I just don't know what's right.
I have had all the turbo pipes changed to silicone pipe and also put a secondhand top mount intercooler on just to rule that out.I also blanked the dump valve off and still no difference,
I appreciate the help guys I will get the ecu out today and report back in a couple of hours.

Thanks guys

 

.
This is the ecu I have in the car not sure what to look for as far as a chiped ecu.
Is this the ecu that would come with the car or should it be different and the z4 is an upgrade.
Just took the car out and its boosting to 15 psi then settles at 14 psi.
I really appreciate the help guys.

Any info on the ecu would be great I googled the numbers on the box but unfortunately I carnt read Japanese.

Thanks again guys

 

your pics haven't loaded pal....if you look at the ecu with yellow 4 plug at top the bottom right hand should be blank...a chip would go in this corner...

14/15 psi is not standard...14.9 is 1 bar

 

Just carnt seem to get them uploaded for some reason.I am using photobucket as well.
If its not one thing its another.

 

Thanks mate having a bit bother trying to up load them not to sure on how to post them up.
Will have another go see if they go up.
Would 14/15 psi be about right for my mods and a z4 ecu.just not sure what's it meant to be at.
Thanks mate.

 

 

Think its up now mate.

 

no it isnt chipped. so your over boosting and the ecu is picking that up and going into limp mode.... id say you have a boost leak

 

And the cover of the ecu.

 

with decat ect...you would get abit of boost creep...are you hitting fuel cut??? like the brakes come on!!! ud know lol

 

OK so your thinking boost leak somewere back to square one.I will get another look at it and see what's going on.
So what boost should I be looking at with this ecu and the mods I have.
just want the car running safe and the boost issue sorted.not planning on any more mods to the car just would be nice to have it running properly.
Really apriciate the info and help cheers.

 

Yes mate it did hit fuel cut last week now it just stops at 15 psi.some times it drops back to 9/10.to be honest its just all over the place doing as it feels.it was at 5 psi for over 3 weeks now 15 psi really need this sorted.
Cheers mate.
It starts really bad in a morning aswell struggles to start sort of boggy like its struggling to fire up it made a pop sound like a missfire sound thismorning on start up then fired up.its been like that for a good while just thought I would mention it in case it has something to do with the boost.
Apart from that the cars OK well for now.

 

ecu controls the boost...and standard is 12.6psi...boost creep or spike would be right at the top of the rev range and shouldn't hold...

without a remap or chip you don't really want to go over standard boost as the fuel will be wrong...

 

reset ecu disconnect batt and put foot on brake 30secs

reconnect drive easy for a day let ecu relearn..

its so cold now it could well be boost creep...

 

Will do that tomorrow mate and let you know how it goes.
Thanks for all your help really appreciate it.so what do you think the boost should be 12.6 ish would be about right for the ecu would you say.so looks like its over boosting.

What's the most likely things to look at I have changed three 3port boost control solenoid s and still the same I will put my old one back on tomorrow and see if that makes any diffrance.
So to reset the ecu battery off foot on pedal for 30 secs.
Thanks mate.

 

more think about it more i reckon you have boost creep...turbos love cold air and its cold!!!

its spikeing hitting fuel cut then ecu ****s its self and backs everything off..

has it only started since the temp has dropped?? did it do it back in the summer??

 

No mate its never been past 10 psi it used to hit 10 psi everyday then one day it hit 5 psi for about 10 mins then jumped back up to 10 psi then it started to happen more hitting 5 psi a couple of times a week but 4 weeks ago it hit 5 psi all the time till you reset the battery for an hour then it would go back up to the 10 psi but after driveing for a bit it would go back to 5 psi was told to change bcs maf act I did and no change.took it to a local garage he fixed a split pipe next to the rear coil pack on the driver side the car was stalling after boost so that's why I took it to the garage and now he fixed the split pipe no stalling now just get 15 psi or back to 9/10 psi.
It is a pain in the **** like.when i got it from the garage last week it was boosting 9/10 psi i put my ristrictor pipe back on and it hit 15 psi.
I have two pipes with the pills in but there both the same size pill it came with one of the bcs I bought.
Could this be down to the restrictor pill as it hit 15 psi when I put it on and when I took the pipe off and had a quick drive it was a 9psi ish with no pipe on and boost gauge was jumping up and down.

 

your 3 port..bottom pipe, that should have a pill init and the port hole of that pill should be 2mm
if you take that pipe off so no pipe at all the car should over boost and would 100% hit fuel cut.
on my car that bottom pipe iv cut 3" long with pill in...iv then blanked off were that pipe did go.

what your saying is with pipe off its only 10psi...thats not right..should be other way round with pipe off it should go mental

 

I possibly did mate I have tryed that many things I have lost count.
Is the pill directional and can it be anywhere in the bottom pipe.I have. K& n induction kit but on the filter there is a drilled hole for the pipe fit in to but I just have it hanging at min with all the messing around with it.do you think it could be the bcs not working properly.I have had two secondhand ones and they don't seem to have made any difference apart from now I get over boost and not under boost at 5psi.
I could take a pic of the restrictor pill if need be not sure what size it is.
The one I got with the secondhand bcs is the same and same size.not sure what size tho

 

Exevo3.
I have just took the car up the road I took the bottom pipe with the pill in off and it hit fuel cut.
I put the other pipe I had spare on and it went back to 10 psi for a couple of mins then back up to 15 psi.hope this helps I just don't have a clue what it is.tryed both the pipes I have with pills in and both do the same thing.

Could it just be boost spike like you say not to sure what that is.

 

well id say boost creep or spikeing is likely but what is odd is under normal conditions you only see 10psi....when you should see and hold 12.6psi.

have you checked actuator?? they do get old and loose there tension?

with the pipe off boost went right up which is correct...

really you could do with a chipped or remapped ecu....your get fuel cut raised..its a shame your not local as iv another ecu you could of tried..

every change you make you should reset ecu...

the pill on mine is just in the pipe deep enough that I can fit pipe on the nipple

 

OK mate I have just reset the ecu think I did it right I took battery off then went back into the car and pressed the brake pedal for around 30sec.I will put the battery back on in 45 mins is that about right.
If I was closer I would of had a shot like.
Will see how this goes after the reset will take it out tomorrow as the weather has just set in and starting to snow a bit.

 

when you reconnect batt take it for a easy drive as the ecu needs to relearn...

 

OK mate will do thanks for all the quick replys.

 

ECU will only relearn fuel trims and maybe advance the IAM.

If when you reset it the boost is back to normal, and then reduces over time. You ECu is detecting knock. When this happens it first retards the ignition (IAM reduces) and with more knock it will reduce boost to the point of waste gate pressure only.

My money is beat you plumbing is fine. Either a bad knock sensor, something rattling or engine knocking(hopefully not)!