Masterchief83

Hello everybody,
it's been some time after my last Thread.

The Situation:
I still tried to solve any Problems myself, but in this Case i'm out of ideas.
Main matter might be the bad Situation of getting knowledge or even good Parts here in Germany(what u get is "wannabe knowledge kings" which tell u to buy very expensive parts, which later comes to light is fully oversized for the aim you have, the most ones don't even know why these parts are so good, also they even don't know anything about general functions, but nearly Everyone tells what a "Subaru Master Guru" this Person is,in some cases you find out that this Person is in some kind Sponsored by a "Big" Engine Tuner or something equal.Got really enough of that folks), also was some time without employment....

Now some Facts:
The Car is a 93 JDM WRX, it has a (i think) Toyosport equal length Header(its the one with uppipe included, which is separated by a Flame-Ring Flange directly after the joint pipe), then comes a Japspeed 3" Turboback.Adjustable Fuelpressure Regulator and a PolarPerformance Chip.Grade 7 Spark-Plugs (PFR7G), rest is still oem,yet.
(Chip is ok, problems occur with active oem ECU and with active chip)

It was running very good, but now its getting a little strange.

He shows the following behaviour:
Dangling from the front until its warmed up.(Only at accelerating sequences).
When its warmed up and u come to a stop at a Traffic light,push the clutch-pedal, RPM drops nearly to Zero, but then recovers and goes Straight up to normal neutral rpm.No rollercoaster-style neutral at all.
(Neutral Switch has also been renewed).
If you stepp off the gaspedal to let it roll a bit, it starts plopping without banging.(Feels kind of he wants to Bang but for some reason he can't)Power is builds up stable until it reaches about 0,85 bar (12.328 PSI), Boost goes straight up to 0,9 bar (13.05), but you can feel that there's a spot where Pressure Raises but Power stops raising and remains on the same Level.When Running on oem-map you don't feel that, think its because oem-Pressure is 0,75 bar (10.87 PSI)

Error Protocol has no errors, Neutral RPM Regulator is Pretty good in shape no hanging.MAF was renewed short after Problem occured, no effect.
Spark Plugs Changed to brand new PFR7G.Effectless(just a few degrees colder engine Themperature)

So i thought there might be a Oxygen-Sensor Problem, Sensor changed to a brand new one, nothing got better.
So last thought was, a gasket damage or something equal which let fresh air into the exhaust and causes the oxygen sensor giving wrong data to ecu which riches up the mixture.(Got also more fuel consumption).

After a lot of testing and searching i found a spot, it is the Flame ring of that Exhaust Manifold, but replacing that ring diddn't help, it still leaks downwards to the floor(glad it doesnt leak upwards straight into engine bay).

So im now on a strange idea, the manifold has got 3 possible locations for the oxygen sensor, first is direct in the Pipe of Cylinder 1, second is nearly direct after that damaged Flame ring flange, third is direct under the Turbocharger.So putting it more backwards on the exhaust might not help.
I think those Plopping is caused by fresh air mixed with the rest of gas, heated up by the charger(but in a wise which doesnt end up in Banging).

Well if it bangs in that case or still goes on plopping, i can live with it, at this moment after some time im also starting to like it.
But to get rid of those Power loss and the Falldown of the neutral rpm i need a solution.
I think moving the oxygen sensor to the spot inside the pipe of cylinder 1 could help, cause the negative pressure that comes from the other 3 pipes after they fired might prevent fresh air from getting up there.
But im still unsure of what happens then, does the ecu react, cause it might still get one Data-set instead of 4.Or it might get one with very few restoxygen and 3 with some more.Or might it have only the effect that the other cylinders run the same way that number one does?(which in my view might be good enough)

Can anyone in the Help?


thanks and greethings from Germany