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Ahsai

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Everything posted by Ahsai

  1. Ahsai
    0.018" is definitely way too small. I think it's worth changing them out with the correct spec'ed ones. The new plugs should come pregapped but it's also good to verify before installing. Bte, are you sure about 0.06" is proper? That's greater than 1.5mm, which sounds too much to me. Edit: googled a bit and 0.06" indeed is the proper gap
  2. Ahsai
    The plug looked worn but its gap looks Ok and much larger than 0.015" in the photo. Are you sure you are measuring it correctly? The gap should be the min distance between the central metal cylindrical tip and each prongs.
  3. Ahsai
    Thanks, binger. Yes, I understand the pressure transducer + scope analysis. However, most shops are not equipped with the knowledge and equiement hence my question on a simple leak-down test.
  4. Ahsai
    Agree with Silver's thinking. Nothing much to add. The only thing is the cam deviation is still varying 10min into engine warm-up. I understand the actual cam angle changes all the time but you would think the cam deviation should not. On my car (M96, non-Turbo), the cam deviations remain the same regardless of rpm once the engine is running, even at cold start. They do change a little bit though across start ups (max +/- 0.2). Maybe the cam deviation jitter behavior is specific to Turbo engines but I can't exlpain why they should though. @Binger: would a leak-down test reveal the valves are not sealing due to carbon deposit or it's too small to be detected but yet can still trigger misfires? Also, if the carbon buildup is on the exhaust valves, will techron still be effective given it's injected on the intake side?
  5. Ahsai
    So did you have misfiring problems before the coil and plug change? If so, probably the new parts are not the culprit.
  6. Ahsai
    That's interesting to know.
  7. Ahsai
    The fuel trims and cam angles seem to look fine. Coolant reading is fine? You have misfires even 12min after start up so it seems not just at cold start.
  8. Ahsai
    Just noticed that your actual cam angles are close to 0 the whole time. According to this thread http://www.6speedonline.com/forums/996-turbo-gt2/260463-anyone-durametric-996t-ten-minutes.html (posts #1 and #2), looks like they should be closer to 30 degree for both banks at cold start during the 1st minute. Were the logs above taken as soon as the engine started to run? Concur with Silver on checking the fuel trim values (TRA and FRA).
  9. Ahsai
    Can you also log the coolant temp, TRA and FRA on both banks?
  10. Ahsai
    Agree with Silver about coils and plugs. Obviously cylinder#4 is having misfire. The other thing is your cam deviations are varying a lot as the engine warms up. Not sure if hat's the thing with turbo cars. Mine is N/A and the cam deviations are rock solid regardless of revs. The values can change from start to start a little bit (say +/-0.1) but once eninge is running, the values stay the same regardless or revs. I think if it's consistently only cylinder #4, you may need a compression and leak down test to verify its health.
  11. Ahsai
    Typical. My '03 leaked at the exact same spot. All you need is the cover plate and not the gasket. http://www.autoatlanta.com/tinyresults.php?pn=99610101600;TB_iframe=true&height=550&width=875 The cover already has a built-in rubber gasket that comes with it. Btw, you need to drain the coolant first. Otherwise, coolant will gush out when you remove the plate.
  12. Ahsai
    Are you saying that may be the problem? Wouldn't a misfire create a whole lot of pressure in the engine? This is a snapshot of when the misfire occurs.My durametric will be here tomorrow. Any tips for use in diagnosing this would be appreciated. I've never used one. Thanks again! I don't think misfire will create pressure in the intake (you may be thinking about backfiring). I don't know enough about 996 TT but I would not expect the engine to be on boost at idling in general. Maybe the pressure sensor is sending wrong measurements, or the engine is really on boost, or the scanner is wrong. I hope someone who knows could chime in with typical intake pressure value during cold idling for your car.
  13. Ahsai
    "Intake Manifold Absolute Pressure 75.51 inHg". That is 2.6 bar absolute pressure. The engine is on boost when idling? Doesn't seem to make sense...
  14. Ahsai
    Well done! Good to see the solid 14v there.
  15. Ahsai
    So did the new cable fix your dropping voltage issue?
  16. Ahsai
    Np. It's just a theory for now since I have not replaced mine and verify. However, I don't see where else would the oil/oil vapor come from in that area. Let us know how it works out. I should replace mine soon.
  17. Ahsai
    Yes and yes.
  18. Ahsai
    Mine is similar and I suspect it's sweating from the o-ring inside the push ring connector at the top left corner of your 1st photo.You can just squeeze the top and the bottom of that ring and pull straight to the left to disengage the hose. You will find an o-ring inside the connector. I planned to change mine but didn't have a chance yet.
  19. Ahsai
    Dave, no need to trail and error. All you need is a $15 multimeter to measure a few points for voltage drop. If you have already replaced your alternator, then it's likely your starter cable but again only way to be 100% sure is to do some measurements.You can use a jumper cable to connect the airbox negative bolt and the engine (exhaust will be fine). If you see improvements, that means you ground strap is bad.
  20. Ahsai
    Thanks Loren! Exactly the info I was looking for.
  21. Ahsai
    I've searched but didn't find anything. I plan to pressure test my coolant system to track down a leak. How much pressure is safe? 20PSI? Also, at what pressure is the coolant cap suppose to open if I pressure test it? TIA
  22. Ahsai
    Good job getting that sucker out.
  23. Ahsai
    The purge valve is a black plastic valve above the alternator and it's connected to the throttle body by a rubber hose. You could just remove the idle control valve and spray some carb cleaner inside to clean it.
  24. Ahsai
    Ok, saw the video now. S11 = bank 1 precat S12 = bank 1 postcat S21 = bank 2 precat S22 = bank 2 postcat Precat should swing between 0.1 to ~0.7v about every second at idle so yours look fine. Postcat should read about 0.7 solid most of the time when cruising. It will go high when you give gas and low to 0 when you decelerate. Have you cleaned your idle stabilizer? Also check the purge valve beside the throttle body. I doubt the rough idle is due to O2 sensors.
  25. Ahsai
    What year and model? Your link does not seem to work for me...
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