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BC EJ20G boost and Misfire issues


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#1 mjlqtown

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Posted 14 August 2016 - 5:09 AM

Hey Guys,

Calling for some outside idea's on this one as both Reuben and I are at our wits end on this issue.

The BC seems to have some electrical issue where it will boost fine, idle smoothly and performs without issue. All of a sudden at random running times you will go to over take someone and it just wont pull, usually with stutter as well when going though the rev range.
Sometimes it has a rough idle and popping from the exhaust. The slow performance and stuttering is usually an issue about 70% of the time you're driving.


Symptoms are:

The car struggles to do a clean pull though the rev range. As if it's low on power.
Stuttering while doing a pull though the rev range as well in any gear
Rough idle with small misfire
No CEL
Cold start idle is fine as well as cold starting it's self
Issues at any time during drive

Work we have done to try and fix the issue.

ECU ground's have all been done as well as engine grounds.
New battery installed
4 brand new coil packs installed
All new platinum spark plugs
Brand new fuel pump installed
Brand new fuel pressure regulator installed.
3x different ECU's have been fitted all produce the same symptoms
Main ignition relay changed
New genuine o2 sensor fitted
I have swapped my air flow merer a few times, I'm wondering if I try a again with another one.
Swapped out boost controller, igniter and atmosphere sensor
New knock sensor
ECU has been reset
All wrapped up with a fresh oil change

Video of the idle issue:





So has anyone got any ideas or tricks? Seems to be a real strange issue, but at least I can replicate it. As I said, it is intermittent but will guarantee to pop back on any drive.
We have 3 more things to try. Putting a multi meter on the 5V sensor circuit, replacing the temp sensor and replacing the drop resistor.
Posted ImageYea right by Mitchell Lindsay, on Flickr

#2 Leufkax

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Posted 14 August 2016 - 7:13 PM

Ignitor maybe.?

#3 mjlqtown

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      1997 Subaru Legacy GT-B
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Posted 14 August 2016 - 8:23 PM

Ignitor maybe.?


Possible, as these parts are old and I may have used a fucked one without knowing.
Posted ImageYea right by Mitchell Lindsay, on Flickr

#4 Sammy

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Posted 15 August 2016 - 4:06 AM

Seeing as you've replaced a bunch of things without a fix I'm going to take a swing and say the wiring to coil system somewhere, lose wire or bad connection in coil circuit. Check for resistance if you're lucky it will be obvious on a wire and not on the others ? I'm totally guessing btw.

When I had a coil issue it would miss a little on idle and but mostly would run and drive fine. When it did cut out it would drop the cylinder completely and the whole car would go from boost to juddering/jerking violently. Also popped and back fired when it cut.

p.s drive it to SAS or see if he would be willing to come over and check it out?
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#5 DacerX

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Posted 15 August 2016 - 8:41 AM

to qtown? doubtful, mitch has a few things missing to make richard do that kind of trek
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#6 mjlqtown

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Posted 15 August 2016 - 8:55 PM

Yesterday I swapped another green airflow meter. Reason being the one that was on the car currently was used to diagnose a fuel and lurching issue.

Turns out that green airflow meter might be bad and I created this miss fire issue by swapping it a year ago. The first problem was fixed by replacing the o2 sensor as we killed a few buy not wiring it properly.
So I with Reuben's green airflow meter as a test unit, it seems to be fine (For now). Looks like I need to order in another airflow meter after all this time.

Funny thing is because I swapped two of these over last year, in my mind it was not the issue!
Posted ImageYea right by Mitchell Lindsay, on Flickr

#7 DCVR

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Posted 17 August 2016 - 7:21 AM

so boosting well and no missing?
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#8 mjlqtown

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Posted 17 August 2016 - 8:09 PM

so boosting well and no missing?


With the test Airflow meter, we have reliable boost. The ECU did need a reset but started to behave it's self. Long time running with a dead airflow meter.
Posted ImageYea right by Mitchell Lindsay, on Flickr

#9 Dundaberg

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Posted 17 August 2016 - 9:20 PM

Cam and crank sensors checked??

35795048880_d41ef0a566_b.jpg

comic sans, just to annoy those who know





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