Machinenoise Posted April 19, 2014 Share Posted April 19, 2014 Hey guys! Have a real headache maybe you can help shed light on... I had the dealer replace my head gasket on my 05 Subaru Imprezza. They did they the job and gave the car back. The next day the car had power loss and the turbo was glowing bright orange. Basically the turbo sounded like it was spooling but the car would go no where. The vehicle was running super rich, felt like the timing was retarding, gas mileage was horrible, and idle was a little rough. I brought it to a local performance shop and it took them 3 weeks to duplicate the problem because it came and went as it pleased. Eventually the car had complete turbo failure - shaft cracked and the fins were curled inward. They replaced the turbo but the hesitation was still present. Fast-forward 3 weeks and the issue is back in a different capacity. When the vehicle is running – after the motor and turbo are nicely heated up – it runs like a new car. But up to that point, or driving conservatively, it hesitates with power loss. What do you think it could be? Link to comment Share on other sites More sharing options...
BoostSLUG Posted April 19, 2014 Share Posted April 19, 2014 So i understand that there was once a serious issue. But it seems as though after you replace the turbo, everything is fine. I think your expecting the car to have full power even when the engine is stone cold. Am i assuming correctly? To me it sounds like your trying to drive the piss out of it and revving high when the engine isn't ready for it. I know that you had an issue before. But if the car drives perfect when warm, i think the issue is that the car isn't ready to be driven like that. On my stage 2 with a pro-tune, my car feels so slow when i first start it and drive. Then when it has reached the optimal temp, it goes like a stabbed rat. Let me know if i'm making incorrect assumptions, but to me i think that your trying to drive a cold engine hard. Link to comment Share on other sites More sharing options...
Machinenoise Posted April 19, 2014 Author Share Posted April 19, 2014 I have never driven it stone cold, I always let it warm up prior to driving. I should have said prior to highway speeds or fast accelerations the power hesitation is profound. There is no smooth power gain. It's either a poor, stuttering build or full power. Link to comment Share on other sites More sharing options...
chato Posted April 20, 2014 Share Posted April 20, 2014 does the hesitation go away for a while after an ECU reset? Link to comment Share on other sites More sharing options...
rob-2 Posted April 20, 2014 Share Posted April 20, 2014 Have you checked your compression cold and hot? Are you burning any oil? If the ecu protects the motor by pulling timing you'll get all these issues. Link to comment Share on other sites More sharing options...
Machinenoise Posted April 20, 2014 Author Share Posted April 20, 2014 @chato: The dealer put in a new (used) ECU. Originally we thought it went away after ECU reset, but once 100 miles were driven it came back. But after a few more resets it came back immediately. @rob-2: compression/leak-down show fine. It is not burning oil. It almost feels like the waste-gate is failing. What are the chances this power hesitation is caused by the down-pipe cat being clogged by whatever oil that may have gone down it after turbo failure? Would that have caused the previous turbo to glow orange after a 5 minute (non aggressive) ride around the block? The new one hasn't done that, at least yet. Maybe a temp sensor? Link to comment Share on other sites More sharing options...
chato Posted April 21, 2014 Share Posted April 21, 2014 sounds like bad learned timing behavior. have you done logs or pulled a learning view? Link to comment Share on other sites More sharing options...
rob-2 Posted April 21, 2014 Share Posted April 21, 2014 Pull it and look at the DP and turbo. If you're actually 'feeling' timing being pulling its something knock related. Link to comment Share on other sites More sharing options...
Machinenoise Posted April 21, 2014 Author Share Posted April 21, 2014 Today I replaced the waste-gate solenoid and so far so good. It was gunked up a bit which may have been preventing proper vacuum. I will have to put in some drive time before chalking up a victory. Link to comment Share on other sites More sharing options...
700watts Posted April 22, 2014 Share Posted April 22, 2014 scribed cause im sure the prob is coming back Link to comment Share on other sites More sharing options...
Machinenoise Posted April 23, 2014 Author Share Posted April 23, 2014 Most likely will. In the meantime checking the timing tomorrow. It's not idling as smoothly as it should. Link to comment Share on other sites More sharing options...
Max Capacity Posted April 23, 2014 Share Posted April 23, 2014 You might want to get the car to a Tuner. Have him datalog and make some adjustments during a street tune. If you tell us where you live, may be we know someone close to you that could help. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
Max Capacity Posted April 23, 2014 Share Posted April 23, 2014 No way, so many great Tuners around here. EFI logic's is somewhere close to you. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
GEE-OTTO Posted April 23, 2014 Share Posted April 23, 2014 Also this isnt the typical 4th or 5th gear hesitation while under load? My 09LGT does this but it is a characteristic of the stock map, I've looked at dyno graphs and it is very apparent. A good tune could correct a lot of this, basically a smoother pull to redline no hesitation. Just a thought, let us know what a datalog produces Link to comment Share on other sites More sharing options...
Max Capacity Posted April 23, 2014 Share Posted April 23, 2014 Before you meet for a tune, make sure your air filter is clean, MAF is clean, everything is in great shape, may be oil change too. When were the plugs changed last ? If your good with a Lap Top you can get the cable, and then learn how to data log, send them to a Tuner fora e-tune. My Tuner www.tuningalliance.com, a Vendor on here is great. He's been keeping my cars happy for years. Check out his Forum in the Vendor Forum, lots of good info there. He's just off rt84 exit 65 in Vernon if you don't mind the nice drive on a Sunday morning to meet up with him for a street tune. When we do that, we use RT84 up to exit 70 and back. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
Machinenoise Posted April 23, 2014 Author Share Posted April 23, 2014 @Max Capacity: Thanks for the lead to EFI Logic. Went down and talked with the guys there today. I'm gonna start with the timing, if that's straight, then check the up-pipe cat. The oil was changed 400 miles ago, the air filter is new, MAF is clean, and plugs done (again) when the turbo was installed. Since the car is bone stock EFI Logic didn't advise a tune. Link to comment Share on other sites More sharing options...
Max Capacity Posted April 23, 2014 Share Posted April 23, 2014 Really, it's a well known fact the factory tune is less then perfect. My wagon has been off the OEM tune since 8000 miles. The other thing most of us do is remove the catted up pipe. You might want to contact Mike at TA and meet up with him. Tell him what your car is doing. He can do a street tune and get it running smooth. Tell Mike I sent you. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
Machinenoise Posted April 23, 2014 Author Share Posted April 23, 2014 @Max Capacity: the guys at EFI said an STI up-pipe would do the job. Is that what you did? And if so, how did you defeat the lack of that temp sensor from throwing a light? Link to comment Share on other sites More sharing options...
chato Posted April 23, 2014 Share Posted April 23, 2014 you can have a tuner disable to code or search for the 2.2k ohm resister mod. Link to comment Share on other sites More sharing options...
Machinenoise Posted April 24, 2014 Author Share Posted April 24, 2014 @chato: thanks for the info. If it comes down to that I will definitely look it up. Link to comment Share on other sites More sharing options...
Max Capacity Posted April 24, 2014 Share Posted April 24, 2014 That or any catless up pipe, I have a Invidia catless up and down pipe. The 2.2k ohm resistor comes from Radio Shack you just stick one in the connector where the probe came out of. Or the Tuner can delete the CEL. With your mileage there are a couple of things you should do while your doing the up pipe, remove the banjo filter and replace the oil return line from the turbo. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
Machinenoise Posted April 27, 2014 Author Share Posted April 27, 2014 @Chato: you asked if the symptoms go away when the ECU gets reset, do you know what the cause could be if that's the case? @Max Capacity: are there photos or a link in this forum for installing the 2.2k ohm resistor in the probe? So, yesterday I inspected the timing and it was off 1 tooth. I fixed the timing, added new pulleys and belts, took it for a test drive it kind of ran like shit still (power hesitation). I then reset the computer, and cranked it. It turned over 8 times before it finally fired up, but when it did it was idling perfectly. I then took it for a test drive, and holy crap it ran like a champ! After adding CatClean to an almost empty tank I drove it for 20 miles, then filled up with super at Mobile and drove another 60 miles - perfect. So, I take the car out today, the idle is a little rough at first then smooths out, then BOOM, power hesitation. When I press the pedal down slowly to go through the power band it hangs up about halfway down with no power. And when its mashed to the floor it goes nowhere - but I hear the turbo *swishing* and start smelling sulfur. I'm stumped and guessing up-pipe cat is my last option. Would a cam/crank/MAP sensor failure cause this? Did resetting the computer do the trick until it learned otherwise? Any ideas? Link to comment Share on other sites More sharing options...
Max Capacity Posted April 27, 2014 Share Posted April 27, 2014 When you disconnect the probe wire from the shock tower, just stick the resistor in the connector on the shock tower. When you reset the ECU it will crank a bit before it fires. I would guess that a sensor could cause the issue, but you should have a CEL for that. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
chato Posted April 27, 2014 Share Posted April 27, 2014 the ecu reset has to with learned timing behavior from either knock or perceived knock events. Often caused by a vacuum or boost leak. Can you log, or do you have any way you can pull a learning view? If it is learned timing, it will show up there. Sounds like you might have bigger fish to fry though. Link to comment Share on other sites More sharing options...
Machinenoise Posted April 27, 2014 Author Share Posted April 27, 2014 @chato: thanks, I'll look up how to do that, and the equipment (or app) I'll need. When you say "bigger fish" what are you thinking? @Max Capacity: would you recommend Flex or Fixed up-pipe? I know you have an Invidia, but are there any other reputable brands? Link to comment Share on other sites More sharing options...
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