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Showing results for tags 'camshaft deviation'.
Found 2 results
Hello all, New to P-Cars but not to engine rebuilds. Have done my share of SMB 350 rebuilds so not shy about what it takes. That being said, I just took ownership of a 2000 911 3.4L 996 with 99.5K miles. They had all service records demonstrating responsible care and appropriate service intervals. Like all cars, I like to do my due diligence to "reset the clock" (change oils, fluid, etc). I've read across many posts and all very informative, especially JFP! The first thing I did was put this on a Durametric and getting some data. Let me first say that I put it on the scanner because the car got a CEL after some vigorous driving and stopped at a light. The codes were P1128 and P1130. Thanks to this forum, I've already run some diagnostics and tests and they seem to point to the MAF. Some slight rough idle when codes were cleared and some slight surging. This corresponded with symptoms and readings. Now, as recommended here to check for possible IMS bearing issues I ran a diagnostic for the Camshaft position deviation 1 and 2 (NO Fault codes for this condition). After a brief 30 min vigorous drive up and down a main street, the readings at idle were: Camshaft position deviation 1 : - 10.02 Camshaft 2 : - 2.55 Angle for camshaft bank 1: 0.17 Angle for camshaft bank 1: 0.19 They held there rock steady throughout the drive with slight variation from cold start. According to this forum, this seems to be an indication of a possible chain tensioner pad replacement due. If this is the case, what else should I consider as "wear and tear" replacements and is this a DIY situation? Would I need adjust timing, special tools (besides camshaft tool), etc? Does anybody have a how to guide or is this available in the Factory Service Manual? If this is too complicated a task, what can I expect a small specialized shop to do this for? Also figure it might be a good time to do IMS... Many thanks in advance to all of you. Txs.
Car in question: 1999 C4, M96.02, 41k miles (had it since 20k miles), original/stock IMS bearing Alright, so I stumbled on some posts regarding durametric readouts for camshaft deviation to check into the health of the IMS. I remembered I logged a bunch of real-time parameters back in 2012 just to establish a baseline with my new Durametric tool at the time. I finally found my old hard drive with the data and to my surprise, my camshaft position 1 deviation read -8.97 cold at idle and varied down to -9.53 when driving around. Camshaft deviation, position 2 is solidly at -3.19 regardless of engine speed. On another post, I read that the durametric software may have had issues logging this parameter at the time. No CELs, no logged errors, been running fine for the last three years, and yes, I drive the snot out of it. When I cut the oil filter I find the random tiny shards brown plastic from the variocam guides. I have a magnetic drain plug and have only seen a light amount of the typical fine metal on it. The previous owner kept meticulous records of all work done at the dealer, and no major engine work was ever done other than oil changes. I found a post about a potentially bent sensor plate on the cam where the engine is correctly timed but the sensor is reading the parameter incorrectly?? My thought at the moment is to not drive the car, pop the green plugs and check timing as well as pulling the sump pan for inspection. I also plan to log the camshaft deviations this week with the newer version of the software and see what I get. Assuming I get the same numbers, I have some questions: 1. Since the position 1 is moving around a little bit between running and idle (~0.78 degrees), should I start having my heart attack now? 2. If the timing is off by this amount, is it a simple re-timing of bank 1 if all else looks OK? 3. Dumb question also is how much timing adjustment can be made since the sprocket appears to have large slots for adjustment? 4. Another dumb question is if bank 1 skipped a tooth, would I know it already? 5. Should I just open up the bank 1 valve cover to inspect/replace the variocam pads? (trying to do the least invasive first) 6. Anything else to check/do? Thanks for reading.