rushi

Hi! I'm new to this forum, had my IX only for four months, but been working/building/tuning with automotive/engine/ECU stuff for about 15 years.

I'm having a serious issues with my Evo IX GSR (Euro model, ECU 88840016, 80k miles). It lacks a lot of power. Here is the symptons:

- Boost is only around 0.9bar/13psi (on gauge; EDM models have no MAP-sensor at all). Sounds like actuator pressure?
- Max. load it hits is around 180, while BDEL+offset is 260
- It starts to boost OK, but before 4k rpm load drops a lot (to about 160) and won't get back up until 5k. There is huge dip there.
- No boost tuning gets it any higher, but I can lower the boost a bit with lower WGDC. BCS gets atleast the +12V supply.
- O2 voltage drops to nearly zero after 5400rpm, but it does not feel or function like it actually runs lean.
- There is no CEL or DTCs
- Sometimes the idle feels a bit erratic or rough.
- No air leaks, changed to T-bolt clamps and tested with smoke
- Need about 8 seconds for 0-100km/h acceleration. Very difficult to get to 200km/h, needs 40sec!
- Recently cleaned and re-gapped the spark plugs. IIRC I put 0.7mm there. No change to operation.
- Turbo shaft spins very easily, but feels like having some side play.
- Fuelpump makes a LOUD whine all the time. Clearly audible inside car with full tank. AFAIK, its stock unit.
- Passed emissions check very easily.
- When driving hard at high rpm, I can clearly hear quite loud and high-pitched spool sound from turbo, but its not hissing like at leak. Sounds like the turbo is working real hard, trying its best to make boost.

Car is pretty much stock. Has properly adjusted TurboSmart Dualport BOV and K&N drop-in filter (just cleaned). Also cleaned the (K&N-oily) MAF, no effect in operation.
ECU tuning I've done is pretty much some minor tweaks to fuel/ignition maps to get rid of knock, JDM 9 RS Mivec map, and zeroed EGR duty cycle and ignition advance maps. Right after I got the car, I could hit 200% load sometimes and load response curve was quite flat, with no O2 voltage drop. It still didn't feel quite as strong as my old 05 WRX with 280hp.

Today I installed GrimmSpeed BCS and set baseline WGDC to flat 70%. Low rpm boost responce feels clearly better, but its still limited to 0.9bar (hits 1.0bar at over 6k at 5th/6th gear).

Any ideas, what to check next? Any typical fauls like this in IX? I searched a lot, many have had similar issues but there is no clear "standard" fault/fix. IMO this sounds like a mechanical breathing issue. Clogged cat? Leaky WG? Or maybe bad MAF? Load curve looks like its starting to boost OK, then at 3800 something happens (like if WG cracked a little open) and it get back to 180% at 5k.

Aeromotive 340lph pump and Omni 4bar MAP should be on their way here, TBE is next in shopping list. I will try it with completely stock ROM (except WGDC reduction for GrimmSpeed BCS) tomorrow. I can also post some logs tomorrow when I get them from my laptop.

Thanks, will highly appreciate any help and tips.

rushi

Here is a WOT 4th gear pull from last night:



Notice the Inj. DC% jump at 5k. I tried to tune it pig rich (around 9 in maps) to prevent it running lean. It obviously is not lean (atleast by engine behaviour and smell), even though O2 voltage falls. Other than that, O2 sensor and closed loop is working fine. About 3% STFT at idle, nearly zero at other load areas.

Will get 3" DP asap. so I can install one of my Innovate LC-1s into it. Don't want to bother welding the bung to stock DP...

Any ideas? That 170...180% load just plain sucks, considering it has GS BCS that's been driven with 80% DC after correction (that I didn't tune yet)..

slowsrt4:(

iTrader: (13)

when you did the new boot controller did you use new vacuum lines? from the factory in the US there is a pill in the line which limits boost, idk about the non-usdm models

rushi

Yes I did put new lines without restrictor. There is same pill in EDM models too, but when I got the car, there was no secondary pill near the BCS. I actually had made a smaller pill (1.0mm) earlier, but it didn't help with boost at all.

Even with GS BCS and 100% WGDC, it won't boost any more. Well, goes to about 1bar at high engine load (uphill, 5th or 6th gear and quick stomp on throttle). I think it must be a mechanical problem with wastegate, like busted actuator spring, or crack or something in turbo. Will get to lift at monday, I'll take DP + heat shields off and check the WG. When changing the BCS, took intake tube off and I could get my fingers to feel the WG actuator rod. It didn't feel loose and couldn't push it open either (with very limited force available from fingertips)...

Turbo response is fine, until it hits that 0.8bar and then it falls on its face. The low-rpm response clearly got better with new BCS.

rushi

Took DP off and checked the WG. Actuator works fine, doesn't leak, and it just cracks open at 0.8bar pressure. At 1.4bar its fully open. Sounds like normal operation to me.
There was nothing visually wrong with the wastegate flap itself or around it either.

First cat honeycomb in downpipe is loose. It rattles, moves back and forth maybe a half of inch, but doesn't look molten or orherwise bad. It just is loose and moves. Since its metal substrate cat, it's not chipped either.

The question is, can that cat really be causing such an enormous restriction? Didn't have time to gut it today. Ordering 3" DP and turbo elbow ASAP.

bone100

I would try and do a open down pipe pull if you suspect cat to be the problem.

rushi

These EDM models have one smaller cat in the downpipe right under the oilpan, and the bigger one in same place as USDM models. These also have 2nd. O2 sensor right in front of the big cat.
I'll take the cat off from DP next monday, and apply the 2nd. O2 sim patch to ROM.

I've started to think that because there doesn't seem to be any clear mechanical or electronic fault, could it be ignition problem? I just don't notice it misfiring or anything typical ignition issues (except occassionally a little rough idle), it just hugely lacks power, torque and boost. Unburned Air/Fuel mixture would explain the "lean" O2 reading, and there clearly is some disturbance in O2 voltage between 3500-5000rpm where the huge load dip is.

Another thing that came in my mind, the car had timing belt replaced some time ago before I got it, so I better check the timing if its off. Won't still help anything with the fact that when I bought the car, there was no load dip and no O2 voltage drop either. It also got upto 200% load too, but somehow I felt the car was slow. Took ages to get 200kph, when my old 280hp/400Nm(engine) WRX took it very easily.

rushi

Problem solved. It was the small cat in downpipe, it was completely clogged and exhaust could only flow around the loose honeycomb. Going to log some runs very soon.