Mid-range power loss

[HOL71]

Hello everyone.

I need advice regarding mid-range power loss and on-road sluggishness in my MY04 GT 5sp SA. My car had the MRT XC power kit installed almost 12 months ago (turbo, TMIC, CAI, fuel pump, turbo back exhaust and ECUtek tune). The problem developed quite subtly - over time, it just felt like the car was not responding to throttle inputs at low/mid revs but top end was good.

A dyno run has confirmed a maximal power loss of 34awkW at 3600rpm. There is only a 7awkW difference at the top end. The boost curve shows a 1-2psi discrepancy at low revs but maximal boost is obtained at 3500rpm and then maintained as usual.

The tuner is certain that the torque converter is to blame. An auto tranny specialist has checked for codes and done a stall test and told me that all is well. I had the tranny serviced and although the shifts are smoother, the power loss remains.

Otherwise, there have been two episodes of spontaneously remitting rough idle with horrendous shudder in the last year. No other running problems are apparent.

What do you think?

[Arith]

Did the dyno run yield anything? Running too rich? Running too lean? Have you tried a re-tune?

[adhar]

I can't really comment on the power loss but i believe the rough idle is very common in this model and can sometimes be attributed to the injectors. I ran some injector cleaner in mine and it seemed to idle much better. But I now have a problem where the rough idle has returned but only with just the aircon on... i have no idea what the problem could be and it is not quite bad enough to warrant taking it somewhere to have it checked...

Good luck with sorting out the power loss though. Keep us updated as we would all be keen to learn what the solutions are if you find one.

[HOL71]

Unfortunately, the dyno run revealed no additional info. I have not tried a re-tune as the tuner feels it would not correct the problem.

[parso_rex]

know anyone with a diagnostic cable down that way ? if your ecu has been detecting too much knock for example it will wind back ignition advance, switch to a richer fuel map and then if bad enough cut boost.I hate to say it but I've seen this a bit on ecut3k'd cars a bit recently.

[Adrian2627]

What fuel are you running?

[HOL71]

I use BP Ultimate. The car was tuned for 98RON.

[parso_rex]

This is a tuned car not doing too well in this state at all. For what ever reason It just had too much timing midrange and was not happy. Removed timing & picked up 15~20 kW atw and he'll have better economy too

[Arith]

if your ecu has been detecting too much knock for example it will wind back ignition advance, switch to a richer fuel map and then if bad enough cut boost.I hate to say it but I've seen this a bit on ecut3k'd cars a bit recently.

Had this happen multiple times on my previous EcuTek'd tuned ECU. Every so often I'd accelerate and the CEL comes on.
Oh well, glad I got a new ECU and got out of that EcuTek prison lock.

[parso_rex]

if your ecu has been detecting too much knock for example it will wind back ignition advance, switch to a richer fuel map and then if bad enough cut boost.I hate to say it but I've seen this a bit on ecut3k'd cars a bit recently.

Had this happen multiple times on my previous EcuTek'd tuned ECU. Every so often I'd accelerate and the CEL comes on.
Oh well, glad I got a new ECU and got out of that EcuTek prison lock.

Yeah Its weird the shelf tunes used to be pretty good so maybe it depends on if its had a road tune carried out on it afterward. That one above is from the same mob

[04GTLIB]

Jim and Mark.

With the Ecutek tunes are they a generic based tune as in one suits all or are they tuned to suit each individual car/engine?

Sorry to post a question on your thread HOL71.
Best of luck getting it sorted out.

Cheers,
Rusty.

[parso_rex]

Jim and Mark.

With the Ecutek tunes are they a generic based tune as in one suits all or are they tuned to suit each individual car/engine?

Sorry to post a question on your thread HOL71.
Best of luck getting it soughted out.

Cheers,
Rusty.

Well they are both, the A and B are generic although some places can opt to make adjustments for the B tunes. The C is custom tuned and comes down to the skill of the tuner. There are some very capable tuners too. The product isn't bad if you have a decent workshop and you ignore the ecu lockout that occurs. Thats my opinions anyway

[HOL71]

Jim & Mark: Thanks, I will get an ECU diagnostic done and see what's what.

Rusty: No worries.

For the record, I think that my tune is custom (I believe that is the deal with the XC kit).

I am trying to think of any event that may have upset the tune. I remember that shortly before I noticed this problem, the bottom of the ring clamp on the silicon hose connecting the turbo and TMIC came off when I released the accelerator during max boost in 2nd. This caused the bottom of the silicon hose to bulge away from the piping, creating a huge air leak which almost eliminated the waste gate noise and sucked away the power until I repositioned it. Could an event like that mess with the ECU map? The slipping ring clamp is actually a recurrent problem - it slipped off again just recently so it is now double-clamped: fingers crossed.

Just two more questions for the experts:
1) Could a dirty/bad MAF sensor cause a problem like mine.
2) Is it possible that a torque converter may pass an electronic diagnostics and stall test despite poor functioning? I have read about bad torque converters causing problems similar to mine.

Michael.

[parso_rex]

With stuff like this you just have to eliminate things one by one because there are several things that can cause a power drop. Some simple things don't require a reset or they reset are a certain number of restarts other ones stop your cruise control from working and give you a CEL and drop you boost to wastegate pressure.The AFM is hotwire so its pretty reliable but if they fail they can give you the shits, o2 sensors go too.
You've no doubt given your ECU a bit of temporary grief with the leak but its easily checked and if its still for some reason unhappy its easy to clear. I would doubt its the torque converter but if you check your boost and timing and its fine then you look elsewhere. For $29 or whatever the ebay cables are and free software I'd start there. If you know someone up there with an ECUdatascan it can do it too

[smythie]

I can't really comment on the power loss but i believe the rough idle is very common in this model and can sometimes be attributed to the injectors. I ran some injector cleaner in mine and it seemed to idle much better. But I now have a problem where the rough idle has returned but only with just the aircon on... i have no idea what the problem could be and it is not quite bad enough to warrant taking it somewhere to have it checked...

From what I have read in here that can be a symptom of a dodgy O2 sensor