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Ahsai last won the day on October 28

Ahsai had the most liked content!


About Ahsai

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  • Present cars
    2003 996 Coupe

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  1. Good. I think it's not related to the MAF sensor then. It would be nice if the shop can perform a smoke test to check for intake air leak and crankcase air leak. Sticky lifter(s) are entirely possible but so are sticky injector(s).
  2. Actually based on your latest logs, I'm not sure it's a single cylinder issue anymore (there were misfires on cyl 2 & 3) so I doubt a leak down test will reveal anything. May want to just drive it with the MAF unplugged for 1/2hr or so. The performance will be reduced but at least you can feel if it helps the rough idling. Your cam deviations look excellent so I doubt IMS and cam padding are the issues. BTW, the AOS on your car (MkII) uses a rubber hose and not a bellow.
  3. Btw, also check the variocam+ and intake valve lift control solenoids. Two on each cam cover. There's a metal bracket with rubber seal on each one. They need to be air tight. Air leak here will cause misfires.
  4. Very interesting data and I don't think I have any conclusion though. Now I'm not so sure it's a single cylinder issue. In the 1hr file, you got some misfires on cyl #2 and #3 @ 2k+ rpm. In general cyl #2 rough running has more variation than other cylinders. In the 1 min file, the idle rpm varies quite a bit and cyl #1 has the highest rough running variation. I assume you feel rough idling during that time? Going back to what John (JFP) was saying about the MAF, did you ever try to clean the MAF? Also, will the rough idle disappear if you disconnect the MAF?
  5. Leak down and compression tests are best done by pros if you're not familiar with those. Basically the test will reveal if the cylinders are more or less the same in terms of compression and sealing capability. If one cylinder has a very different number than the others, clearly that cylinder has a problem. If those tests check out, the next step may be the fuel injector.
  6. Ideally, it would be good if you can drive the car until the engine has been fully warmed up (about 1/2hr of driving). Then do a log for steady idle for a couple of minutes (assuming the rough idling occurs). For reference, I have a stock '03 996 and a '02 3.8L LN nickies 996. Both have the rough running values for all cylinders close to 0.2~0.3 most of the time and from time to time jump to +/- 0.6 per second^2. So it seems all your cylinders have numbers close to the numbers above except cylinder 2.
  7. 36s of idling here (time from 15:20:41.27 to 15:21:16.82). Red is cylinder 2 (per your second spreadsheet heading). You can see clearly all the other cylinders are approx +/- 0.8 per second^2 I wonder if you should do a leak down and compression test on all cylinders to compare them. If the numbers are OK, maybe replace the cylinder 2 injector? plots.pdf
  8. In your second spreadsheet, the rough running columns are in the order 1, 2, 3... The typical order is 1-6-2-4-3-5 (firing order). Did you reorder the columns or change the title? Second spreadsheet column G says Rough running cylinder 2. It has higher variations and magnitude than any other cylinders at idle.
  9. In this excel file, did you start with the engine already fully warmed up? Or the first row begins with a cold start?
  10. ignition wire question

    Check fuses C1 to C4 and E1. Also bypass the clutch interlock switch is you have one. Try another key. If not those, it's likely the ignition switch then.
  11. The first video is the SAI pump. Needs lubrication or replacement. I can't hear the noise you're talking about in the second video.
  12. 1) from memory, only one sensor in the front and one in the rear, each connected to the control arm via a plastic arm. 2) not sure 3) there are no other sensors. My guess is this sensor only compensates for the passenger load of the car so the adjustment may be relatively small and difficult to notice
  13. Got you. If the above doesn't work, you may need to reopen the cluster and retrace all your steps. Maybe something inside has been disturbed.
  14. I take that those gauges swing to their full range when tested by the Durametric? The next thing to try is remove fuse B1 and reinstall it. If that doesn't work, I suggest you remove all the connectors at the back of the gauge and reconnect them.