Hesitation and 10psi max

[Greenbeast]

Hi I'm new to this . First forum joined first thread I have posted so hope I put this down right

I have a 1999 wagon sport with a 1997 ej20k turbo lump and running gear this is a td04 motor 

Known mods in 3'' cat back . Hks filter. Bailey bov .lightened flywheel 

Car is a puzzle to me . I have found very limited info on standard specs. We have been eating plugs every 4 thousand miles.by eating I mean we get hesitation at WOT change them and it's gone . Untill recently . Same thing occured around 4-5 k since last change and hesitation occured. Very aggressive may I add which was slightly different this time. But we did the same motions and changed the plugs . For NGK standards which I gapped to 0.7 as I have read that's a good gap. Hesitation still there and just as aggressive and at most rev ranges and gears at most throttle possitions So changed coil pack .. this improved things slightly but none the less we had the stutter . Across all most areas of the throttle and gear . Fitted a boost gauge and Changed the maf and air filter as the mounts were broken .. this made the most difference. Now the car pulled far better but still hesitated and felt just lacking the grrr. We were holding boost around 11-12 psi and hit a spike of 13 on a 4th gear pull. Vac read -20 .. regardless I removed all intercooler piping cleaned and reconnected them and change all vac pipes .Replacing the restrictor pill in the same possitions as removed . Vac read -20 again however now at full boost we peak at 10 psi and never go above .. still hesitating and lacks the grr of the beast we know. I've looked and looked and cannot definitely say what my standard boost should be can someone please help me . I'm gonna change the plugs again incase all previous misfiring blew a gap . See if that cures the hesitation and I will be cleaning boost controller today . Maybe the car had a split hose blowing pressure on boost controller line, allowing us to hit more boost and now we are running correctly with no boost issues and a misfire non related. Or maybe I should be running more boost and lack of causing hesitation. Or we have 2 issues lol .I found plenty of info for specs related to saloons but no wagons I'm pulling my hair out it just stopped working all of a sudden no progression to its demise and all new items have improved things but not cured it. just I don't know need some gurus to throw ideas at me plllleeeaasssee 

 

Jamie

 

[Linx]

Try a smaller plug gap.

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[Greenbeast]

It ran fine at standard gap of 0.8 . I gapped the new ones to 0.7 based on forums . No requirement just thought it would be more efficient and or it was the reason We were using a lot of plugs. And this was a suggested gap What gap would you suggest 

Thanks for the response 

[JamesJDMwagon]

Reset the ecu and do a 4th gear pull it should come back when you put load on the engine. If that doesn't work perhaps the leads are damaged you can check restance with a multimeter. Sadly it can be a lot of different things to that cause this problem. 

I had a similar problems with mine I gapped the plugs to .5 and the car was a new beast (in run 15psi) 

[JamesJDMwagon]

Also might pay to check for vacuum/boost leaks hope it helps

[Greenbeast]

Ok seems I think i have resolved my boost issue with a hose connector. Must of twisted it in the replacement of pipes. Well I cleaned the bcs and changed this connector believe it was the connector that fixed it not the cleaning of bcs .. however now hesitation is far worse .. I've to pick up a multi meter to check leads tomorrow .. all vac pipes are new and have good seals boost gauge indicates good vaccum and now a peak of just shy of 13 psi which seems correct ... Haven't changed plugs yet I can try regap to 0.5 .. or try standard gaps .. is there such a thing as a gap that's to small ? 

Thanks for responses 

[JamesJDMwagon]

I wouldn't go anymore then .5 personally. But don't think plug gap is the issue. What boost controller are you using? 

[Greenbeast]

It's on the standard 2 port setup all factory settings . Like I said cleaned it today had car in test mode. Clicked on and off as should blew through pipe couldn't blow when off could blow when had power so seems to be functioning correctly ... Flushed it with carb cleaning dried it hosed it back up ..

[Phillip1993]

It sounds to me like your ecu is dedicated knock for some reason

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[Greenbeast]

I've done the old under the dash plug in to check for codes and it's throwing nothing at me . Would a knock be highlighted by a code or is that not always the case .

 

Thanks for responses 

[Phillip1993]

No it wouldn't show a code unless the sensor was no good and sometimes it doesn't even giv you a code then. The problem you will have is it can be caused by so many things.

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[Greenbeast]

So if sensor was reading knock just want to clarify which sensor that would be and would this result in the hesitation 

Thanks

[stants]

Not necessarily, could be o2 or any other number of sensors, if you did have a knock sensor issue it will more than likely have stored a code (#23 off the top of my head)

Had mine go last year, was more like a fuel cut when it kicked in

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[Greenbeast]

Hmm this is what I figured .Car would boost or fuel cut .. any diy ways to check these sensors without replacing them .. after to changes weve done and Christmas I'm at the bottom. Of the money pit at the minute :) 

[Mark D]

I think the knock sensor is basically a microphone, could maybe just tap on/near to it with a screw driver?

Maybe exhaust is clogged up?

If it didn't store codes, I think there is a way of connecting the connectors then driving the car with them still connected, then it'll flash anything it picks up.

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[Phillip1993]

I found driving on a motorway can throw up a o2 sensor fault when thay our on thay way out

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[Greenbeast]

Hmmm didn't realise they could be that sensitive ...And the symptoms of this would match mine ?

 

[Mark D]

On 2 classic Imprezas I know of, one a sport and one a turbo, the o2 code comes up but not symptoms like yours.

I can't remember which ones were plugged in, but you can clear them, drive with some plugged in and as soon as it detects something it will start flashing.

Also, does your check engine light work? Steady flashes to indicate no code?

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[Phillip1993]

Green plug contacted black 1 not contacted

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[Greenbeast]

First of all checked for codes .. steady flash nothing in memory ..Went for a drive to replicate issue and checked again still no codes .. left it a week or so with a few more changes and more test drives and checked again still clear .Never ran it in any check mode because previously read that I shouldn't but if it's fine then by all means instruct me and I'll do it 

[Mark D]

I think they mean you shouldn't as in leave them connected all the time as I read to clear them you need to have some connected and do a little drive to clear them.

On the obd2 system I know there are some codes that only show up if it was detected more than 2 times after certain criteria met, on my scanner would show up as 'pending' codes that would not set off a light.

Try as Phillip suggested, maybe do a search to be on the safe side but I think green are diagnostic and black are read, with some/all connected would clear codes, with some connected + driving I have had the car flashing a code (o2 sensor) after driving about 2 minutes even though in that car (and Impreza sport) everything felt fine.

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[Greenbeast]

Which system is the obd2 system . This is a 1997 ECU I have had to take the car off the road as I have no air filter at the minute so all testing on hold for a week .. trying to save money to get it on a rolling road because I'm at my wits end