Went on a mountain run last weekend, full tank from BP. Very cool weather. Around 1/4 tank left, car felt like it was losing power. Started monitoring Dynamic Advance, and ECU was pulling timing, -4.5 to 3.5 degrees on WOT, timing all over the place in-between. No CEL. Cleared the ECU, and the car pulled solid 10 degrees WOT all through the gears. Then after a few minutes, it degrades again until it's back to going all over neg/pos again. Details: Car: VF43 on 2004 STi, inlet tube/DP, APV2, plugs, TopSpeed tuned all 1+ years ago. Engine sounds fine, and runs great right after resetting the ECU. Then the timing degrades and it feels sluggish. Fluid levels are good. It's making full boost despite the timing. I took some logs if any other numbers needed. Still no CEL thrown. Could the knock sensor get wonky? Any ideas?
Have a short ram intake on there? Could be super high intake temps after the engine bay gets heat soaked. Otherwise, maybe a bad maf sensor or something. Or something internal, not sure.
Possible you are getting some oil in the combustion chamber...check the intercooler hoses for oil. Also check the turbo inlet tube. If it is coming pre turbo, it could be blow by from the engine. If it is post turbo only, could be the turbo finally starting to go. I noticed something similar and pulled the y pipe and saw it was actually a little wet with oil. If you don't see any in either location you are back to square one.
Post-turbo was bone dry. IC was off also, no oil there. I'm going to double check the connections on the IC piping and tuner asked me to watch the long-term fuel trim, so I'll do that tonight.
My car was doing this, it was a dirty MAF, MAF cleaner didn't really work so I used QD electronic cleaner, all was well..good luck
its that thing.. .its screwed in to the intake pipe. That thing at the end of the blue pipe ( on the left)
I'll watch the fuel trims tonight while driving. MAF sensor was covered in black on the inlet side. K&N filter was full of junk also. Now I feel like a bad daddy to my baby Hopefully that does it, I'll find out on the long drive to Asheville NC
Better, but still not cured, and here's the long term fuel trim numbers: After resetting the ECU, car runs great hitting solid +10 (dyn adv) on WOT. Sits at 0 on long term fuel trim at WOT, plus 3-4 on idle, and 0 during normal driving. Feels great, runs strong and responsive. After a while, dyn adv drops to 6.5 max on WOT. Improved from what it was doing (0-5 or negatives), but still not right. LT fuel trim at that point is plus 3-4 on WOT, 1 at idle, and from 0 to negative 6 on lift-throttle. Car doesn't feel as strong at WOT and feels sluggish on transition from neutral throttle to WOT. Car still hits full boost at WOT either way. Dunno what else to do, may have to drop it off at TopSpeed.
use Learning view from romraider and youll see it clearly Takes me 2 minutes to check it it you are near my place
Swing by.. if your ecu is adding a positive number in the ltft then you probably have a small leak between the maf and engine. It would be an easy check for us.
K i'll call on Monday to get a time. Going to re-check the connections today also. Was only hitting 4 Dyn Adv this morning. Screwy.
I think it's solved!! Took the clamp off the hose @ turbo cold side, it was a bit crooked. The hose was pinched underneath, making a small opening. Reseated and got the clamp right, and everything seems to be strong and stable now! Tnx all for the help. We'll see if she stays solid during the week. I think 1st problem was the MAF and my dirty filter, then the shop put that clamp on crooked when they pulled the IC to do the clutch and made more problems. TopSpeed: Thanks for the help, and see you when I finish saving for the 20G.
20G?!? If you are going that big, just go rotated I know the Tial 30R and the Bullseye S256 will both spool as quick as a 20G and make better power!