MY04 Liberty GT - FrankenStien - EOI welcome / FS

[bigBADbenny]

Known to cause missing stumbling feel on cruise, & etc.

Nasioc EJ207 thread stated that coilpack were common to Wrx model iirc
Spec C could obviously be another matter

[<GB>]

So does it only do it on higher load?

What's the af gauge doing when it happens ?

[Deep Heat]

And the solution is

[dr20t]

So does it only do it on higher load?

What's the af gauge doing when it happens ?

Does it at 1.7-2.05 load range only, at 2000-2500rpm and 1-2psi of boost.

Afr bounces up and down to 14.2:1 and 13.5. But mostly wants to go back to 14.2 so leaning out

Could bad plugs really do this?

Another thing that I just tested out. If my aircon is on and set to medium/high, it stabilizes it out

I'm now hypothesizing that it could be alternator/ electrical related. I.e - voltage not strong enough and either fuel pump or coils are getting lower voltage than they should at that load / rev range. This potentially makes sense as once revs climb a little, its ok (and as you know, if revs climb then so does alternator output).

??

[<GB>]

I've seen bad plugs and coils do strange things before so any things possible... Can u hold it over that area and it continues to misfire? U logged roughness per cylinder?
You could log voltage and see if it's doing something but I've never seen something like that causing an issue like you described

[Deep Heat]

I'm now hypothesizing that it could be alternator/ electrical related. I.e - voltage not strong enough and either fuel pump or coils are getting lower voltage than they should at that load / rev range. This potentially makes sense as once revs climb a little, its ok (and as you know, if revs climb then so does alternator output).

Alternator RPM =/= Engine RPM. #cptobvious

[dr20t]

Actually smart ass - alternator rpm exponentially increases as engine rpm increases

GB - havent logged roughness will do that tomorrow.

Mechanically, will test alternator output first.

If that shows all clear, will change plugs. If still no change, will swap coils one at a time.

Failing all that, will check fuel pump and filter.

Finally. If all that doesn't work ill be pulling the twist mount adapter off and rewelding it then have it machined. I'm actually now thinking if it gets to that stage, might change to twin scroll headers, make a new twist mount adapter (twin scroll Subaru spec c bottom to t3 top) to make my setup a 1.5 scroll. Hopefully wont have to go there

Still keen on thoughts for this issue

Mick

[<GB>]

U might find a white ish spot on a coil that might be arcing out, it will be around the rubber that slides into the spark plug holes, the marks might look a little white/grey and see a hole where the spark can jump out

[Deep Heat]

Actually smart ass - alternator rpm exponentially increases as engine rpm increases

I.e not equal.

[dr20t]

U might find a white ish spot on a coil that might be arcing out, it will be around the rubber that slides into the spark plug holes, the marks might look a little white/grey and see a hole where the spark can jump out

Thanks mate that's a good start will look for it closely

Actually come to think of it, when idling at a set of lights I do hear like a hollow tapping sound very few seconds. Sounds like a spark arcing out onto metal. Maybe in the hole for the coil nose inside the rocker covers?

This is gaining momentum.

[bigBADbenny]

Do a full avcs log just for fun.
Hold it at the stumble point.

Coolant temp sensor is another culprit easily dismissed with a log according to ggl

[dr20t]

Do a full avcs log just for fun.
Hold it at the stumble point.

Coolant temp sensor is another culprit easily dismissed with a log according to ggl

Logged both those (all four avcs angles and coolant temp sensor) and all ok

[bates91]

mick I would just like to say you're a completely crazy mad scientist

I still come back here every so often to read up on a few threads, yours included. even though I don't understand 95% of what you've discussed here for the past 80+ pages. but i like reading it anyway
hope you get everything sorted although i'm sure it'll never be fully finished. best of luck

[Etho_7]

This ^
I can only follow half of what is said, but I feel safe in saying you're a mad man mick.
Hope you find out what is causing the issue soon.

[Deep Heat]

Yeah Mick. I've also learneded lots from your postings.