Finally finishing AOS/RMS/IMS

So after a full year of being out of commission I'm finally completing this project. To briefly recap a year ago my clutch started feeling funny and a few weeks later the transmission would not go into gear, namely reverse and first and eventually any gear. So I parked it till I had the money to fix it. Around summer I purchased parts to replace the flywheel, clutch, slave cylinder, AOS, and IMS bearing. Some of the parts I sourced from Pelican, some from Suncoast, the flywheel from Amazon - they had a killer price. So I removed the transmission and started with the AOS. I gotta' be honest here: the learning curve for working on this car is steep. Working on the thing is like peeling an onion. Parts have to come off and be installed in a certain order and many will only come off one way with this particular tool used precisely in this manner, or one of the notorious special tools. If I had to do it all again I would have just pulled the engine and been done with it. That's my official recommendation. So I did the AOS. Now that dark and cavernous area under the intake manifold and tucked back in the hole that serves as an engine compartment no longer holds any mystery - I have delved into all its secrets and emerged on the other side worse for wear, but wiser and confident. Next I tackled the IMS with a replacement from LNE. Seemed simple enough but here is where peeling the onion brings tears to your eyes. I determined to follow the instructions and loosen the third chain tensioner, remove it actually to replace the o-ring and washer per recommendations. To remove this tensioner one has to remove the AC compressor. The front two bolts are easy enough but the rear can only be accessed with a socket on an extension of a precise length and located blindly by inserting the socket and extension between the runners of the intake until it falls onto what must be the bolt head. Once the compressor is removed the tensioner is visible, but there's no way to access it without peeling back a few more layers. There's a sort of bracket mounted over the top of the tensioner that must be removed to reach the tensioner, but Porsche decided to use internal hex head bolts for this bracket and there is no way to fit a socket or hex wrench to loosen them because the power steering line, which the bracket secures, is in the way. SO the power steering line must be disconnected from the pump but - oh, wait - that can't be accessed with a wrench or crows foot either because the PS pulley blocks access. Now there's no way to secure the pulley so the bolts can be loosened so I had to rig the fan belt to hold the pulley enough to loosen the bolts. So now I've removed the pulley and the hose just to be able to insert a hex wrench, no access for a socket, into the bolt heads and remove the bracket. Way to go Porsche! Here's what happened when I tried to reinstall the pulley using vise grips to hold it: IMG_0433.jpg I didn't realize is was so delicate. I have a new one on order. The only other issue I had was trying to figure out how to properly torque the center nut. LNE decided to change the nut size from a stock 13mm to 11mm, so the special torque wrench adapter I purchased from Porsche to torque the nut was useless as well as the procedure outlined by Porsche detailing how to hold the bearing stud stationary with a screwdriver while torquing the nut with the tool. So now I'm searching everywhere looking for a 11mm tool that will allow me to huld the stud while torquing the nut but none are to be found - anywhere. I emailed LNE and after a few back-and-forths a link was provided to a video that showed the nut being torqued without holding the stud. Apparently one only has to snug the nut securely with a box-end and then the stud will not turn when the nut is torqued. I think if a company is going to change the the established procedure for installing a part they should provide something more descriptive in their written instructions than "...the nut can be torqued...". It would have certainly been helpful for me. Once the IMS was in the RMS came out and the new seal installed without a hitch with my handy-dandy RMS install tool. I wish every task went so smoothly. After that the new flywheel, clutch disk, and pressure plate went on: IMG_0437.jpg IMG_0440.jpg IMG_0443.jpg IMG_0445.jpg

Now I come to the "parts left over" section of my journey. I have a nut and a hose bracket I can't find a place for of remember where they came from: IMG_0430.jpg Perhaps someone can jog my memory. I also have a place where it appears something was attached but what I don't know. It's the hole in the center of the pic next to the wires (left side below the air pump on the engine crossmenber): IMG_0428.jpg As I went along most of the bolts I put in baggies or immediately back in the hole they came out of, but these are the inevitable stragglers that I missed. I also found some type of sensor tucked behind some wiring on the right side of the engine bay. It looks like a temp sensor perhaps with a grommet to fit in a hole? I couldn't find any unattached wires that might fit in the connector: IMG_0431.jpg IMG_0432.jpg

Tasks still to be completed: Install transmission - done Install slave cylinder - done Attach axles - waiting for tool - done Install transmission mount - done Reattach linkage - done Install crossmember and brace - done Replace transmission fluid - done Replace brake/clutch fluid and bleed - done Replace engine oil and filter - done Tighten motor mounts - done Reinstall shifter console - done Buy vacuum hose and reattach - done Replace PS vent hose - done Reattach sway bar - done Repair rear tire (nail) - done Reattach undertrays - done Install PS pulley - done Install fan belt - done cross fingers - successful!

And that is why I say the exact same thing. I wouldnt hesitate to drop the engine/trans again. The metal bracket with the plastic hose holder is bolted to the #1 intake tube bolt (driver side/front). The SAI hose goes in the clamp. The sensor looks like the engine bay temp sensor w/grommet. Goes between intake runners on 4-6 side. Look at #12 in pic. The nut looks like the ones on the elect. term bracket, 4-6 side or TB bracket lower left on PS pump. Like you said, it really helps if you put fasteners right back where they came from as you remove parts, take photos, and make notes. This will be easy for you next time.

I think you're right about the sensor. Now I have to locate the wire that connects to it.

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Ahh yes, I remember now making a mental note to self when I took that off. Thanks!

KrazyK, do you see anything attached to the hole on the engine crossmember?

I believe that if I am looking at the picture correctly, you will find that your air box has a plastic protrusion that drops in to the hole to position it ( the air box). There should be a rubber grommet in the hole to prevent the box from sliding around.

The sensor that you posted the pic of is the engine bay temperature sensor. It slides into a position on the 4-6 intake runners near the center. The IPB above shows it as #12

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Thanks Ed but I think you're looking at the hole in the bottom of the pic. That's a little higher on the body sheet metal. This hole is on the engine crossmember in the center of the pic with the wire next to it.

Sorry. I'll try again, the hole is actually in a small sheet metal bracket attached to the crossmember. It is an attachment point for a small plastic clip. The clip has a conical end that snaps in to the hole and clamp on top. Two wires going to the back of the engine compartment are held in place by the clamp. I took a couple of pictures with my cell phone and will try and post them later...have to head in to the office shortly.

Hmmm... Maybe there's a clip on the wire lying next to the hole. I'll check tonight when I get home. Thanks Ed.

I found the wire for the loose sensor tucked behind the harness. I just have to hook it up. Now if I can only find where that nut goes...

If IRCC, nothing goes there. Hopefully Im 3 for 3 on this but remember, Im just a "keyboard mechanic" to most here.

This is what I should have used to hold the PS pulley - a strap wrench: STRAPWRENCH.jpg Live and learn...

Dont feel bad. Most of us have done this.

WireClip.jpg

Thanks for the pic Ed. I have a Bentley's manual plus a subscription to Alldata DIY. Rennlist, Renntech, and Pelican all have forums with lots of pics. Auto Atlanta has parts diagrams. All are excellent resources but I've found most of the diagrams and pics of 996 repairs are of the MkI 3.4l. It's very difficult to find pics of the MkII 3.6 for reference. I don't think Porsche redid any of the pics or diagrams in the service manuals unless they absolutely had to, which wasn't often.

Well heck mine is a 3.4, so it may not be correct for you. Congrats on all the work you've done, I am putting my new AOS in tonight...but after all the fiddling, I believe I will drop the drivetrain when I do the clutch/IMS this spring.

I have a chart(s) that show the location of the transmission bolts for the bell housing but they conflict with each other and with the bolts that came out. Perhaps someone can help me out. Here are the charts: IMG_0463.jpg IMG_0464.jpg The first is from Alldata and the second is from my Bentley manual. The specs for each bolt is a little different - I assume for example a M12x90 and a M12x100 is referring to the same bolt. I can place all but 5-6-7 on the Bentley chart and 8-7-6 on the Alldata Porsche chart. IMG_0465.jpg I have the bolts laid out according to the diagrams but one bolt is longer(?) than is should be. My bolt lengths are (2)M12x100, (3)M12x70, (1)M12x50, (1)M10x50 w/ nut, (1)M10 sq drive. Notice bolt #6 on the Porsche chart is listed as a nut. #5 on my trans was a bolt w/ nut, but #6 was a bolt. Surely that is an error in the chart. Here's my concern: I have a 50mm and a 70 mm bolt to go where, according to the Bentley chart, two 50mm bolts should go. The Porsche chart doesn't list a length for #6------WAIT! I just figured it out!

OK, tranny is in and torqued. Now to bolt up everything to it...

Stupid piece-of-junk Craftsman hex sockets: two of them stripped out trying to torque the last two axle bolts. Had to order new ones but this time from Snap-on so hopefully they're made of higher quality steel. More delays...

Updated my Durametric software today. I'm pleased it will now allow activation of the ABS/PSM for bleeding. The only downside is I had to buy a new laptop to run it on since it will not run on a Mac. Add another $750 to the cost of owning a Porsche...

$60 for parallels then run durametric under a windows VM on your Mac

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Yeah...looked into that and everything involved in installing W8.1 on my Mac and decided against it.

Injured my back on Tuesday - now I have a herniated disk that will take about 6 weeks to heal so I'm on limited duty. I was at work in my cubical and I bent over slightly and turned and WHAM! One thing after the other, I can't catch a break...

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wow, that's no fun! Strange how slight movements like that can mess up your back so severely... I feel for you. 2003 Carrera 4S Speed Yellow / 1955 356 Continental 1500 Rust Red

Ok, so even with the herniated disk I was able to finish putting everything back together, bled the brakes and clutch, and started the engine which seems to run fine other than my PS pump is making noise. The Bentley repair manual I'm using said before starting the car after the IMS replacement to remove the DME relay (behind the back seats) to prevent the car from starting and turn it over for 30 seconds to build up oil pressure. Unfortunately with the relay removed the starter would not function at all, so I had to plug it back in to start it. All was OK and I had good pressure after about 3 seconds. With the engine running the dash said I had ABS Failure and PSM failure. Here's the printout from Durametric: Work Log Bosch Digital Motor Electronics Motronic 7.8 Module Identification Part Number 996.618.660.12 Supplier Part Number 004161004210 Current Fault Codes P0607 Porsche fault code 407 - Computer monitoring: reset P0102 Porsche fault code 115 - Hot film MAF sensor ABS/PSM 5.7 Module Identification Part Number 996.355.755.54 Supplier Part Number 11 Current Fault Codes 5525 Incorrect data transfer with DME master control unit ABS/PSM 5.7 Module Identification Part Number 996.355.755.54 Supplier Part Number 11 Current Fault Codes 5525 Incorrect data transfer with DME master control unit Instrument Cluster K21 Module Identification Part Number 12 Supplier Part Number 69010202 Current Fault Codes 9110 DME control unit Bosch Digital Motor Electronics Motronic 7.8 Module Identification Part Number 996.618.660.12 Supplier Part Number 004161004210 Current Fault Codes P0607 Porsche fault code 407 - Computer monitoring: reset P0102 Porsche fault code 115 - Hot film MAF sensor Bosch Digital Motor Electronics Motronic 7.8 Module Identification Part Number 996.618.660.12 Supplier Part Number 004161004210 Current Fault Codes P0607 Porsche fault code 407 - Computer monitoring: reset P0102 Porsche fault code 115 - Hot film MAF sensor Short Test Bosch Digital Motor Electronics Motronic 7.8 No Faults Found ABS/PSM 5.7 No Faults Found Instrument Cluster K21 No Faults Found Airbag B05 Automatic Air Conditioning H01 No Faults Found Alarm I32 No Faults Found Litronic headlights HBA No Faults Found Park Assist Seat Memory No Faults Found Work Log

Any ideas? Maybe I forgot to hook something up or did so improperly. I find it hard to believe my DME ($2351.00) would have failed.

Research found several posts here and elsewhere indicating a bad MAF sensor will give the codes I have. Since I did not reinstall the air filter and connect the MAF wire perhaps that is the reason. I'll do that tomorrow and recheck (fingers crossed)...

Installed the air filter and hooked up the MAF. All the fault codes are gone. On the down side there is something bad definitely going on with my PS pump. It's groaning and making a clacking/rattling noise. Replacement is $400 so I guess that's not too bad if I need it. The fluid is topped off and I follower the bleeding process of turning the wheel lock to lock. More research...

Played a hunch and added more PS fluid with the engine running and the pump quieted down, so I guess it's OK. Engine was clicking for a few minutes but after warming up completely quieted down also; sticking lifters from sitting for so long. Camshaft deviation measured with Durametric is Bank 1 = 2.4 and Bank 2 = -.66. I didn't measure before I started so I can't compare, but it seems to run normally. I still have to take for a test drive...

So I took it for a test drive and the engine exploded and the car burned to the ground. Bummer...

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Pls tell us you are joking...

Yes, I,m joking. Test drive was uneventful, thankfully, but the engine just doesn't sound or feel right - it feels kinda' ragged, like an air-cooled engine. It idles fine, no codes, good power and acceleration, I just don't remember it sounding and feeling that way. Maybe that's only because I haven't drove it in a year or my other thought was perhaps because the battery was disconnected for so long it needs to relearn the engine mapping? Anyone with ideas please share your thoughts...

Yes, I too was sorry hear about the latest M96 engine explosion. I have updated the poll for you. (OMG JK'ing) Great job on your DIY.

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Check and make sure all vacuum lines are installed correctly. After I did my AOS my car was running like crap too. Couldn't figure it out so I took it to the dealer and they showed me where I had misrouted some lines. Was a relatively quick fix for them and my car was running great again.

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Yes, I'm considering taking it to the dealer and let them put it on their scanner and test drive. They listen to Porsche engines every day and I haven't heard one run in over a year so at this point they know better than I if it sounds like it's running properly. Thanks for the advice. The last thing I ever want to do in life is jerk around with that AOS again...

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I know the feeling. My heart sank when I heard my engine sputtering when I turned it on. I mean it ran so I was happy for that but it ran very badly. Fortunately when I took it in they said my install was good ( ) but I just hadn't connected all of the hoses/lines correctly. Whew!

Okay fellow Rennlisters - here is my Word of Warning and some advice. Some background: Car - 1999 C2 w/128,700 miles. AOS casing cracked and coolant was running down back of engine. Also car was starting to run like crap, although no smoke, so it was time to head in. Me - 57 years young and been DIY wrenching on everything mechanical since I was like 15. Navy Machinist Mate and Engineering degree. I have two complete tool benches with just about every tool imaginable. I figured with the advice of those who have done this, helpful hints from Rennlist, RennTech, Pelican and so on...well, how hard could this be? I've done many other engine projects on the car (starter, plugs, coils, sensors, SAI, water pump, thermostat, oil changes, filters, window regulators, all the usual culprits that everybody here knows with a higher mileage PCar). Here is my Word of Warning - this is definitely not a job for an amateur or faint of heart! Do not undertake this job if you have any questions about the exact procedures to follow and just about every mechanical trick in the book up your sleeve. Getting all of the front components out is challenge enough, but getting those manifold bolts out is the job of the century. Getting that manifold back in place in line with the resonance chamber is really tough. Add to the job, remove rear bumper, heat shields and all that so you can drop the engine to the lowest point you can. Also, getting the AOS out is a challenge unto itself, and getting the new one in is a pain with the limited space you have to work with, along with the accumulated crud of 15 years on the road built up in those areas. Like others have said, one main key is to place that back bolt in the manifold and secure it before putting the manifold back in. I did that as well as used painters tape to secure it and the socket before reinstalling. Still a bear of a job. You will never get that bolt in any other way. Besides the AOS and hoses, I replaced the intake gaskets, throttle body gaskets, marked every vacuum hose and other lines, took many pictures before taking stuff apart. It is amazing where you can cram an IPhone and take pictures. Really helpful! Additional suggestions - my greatest friends for this job: Advil, Ace bandage to wrap left arm (you will bleed on this one, I think I have some new scars now for a lifetime), beer, mechanics gloves, latex gloves, Advil, beer, a stubby swivel head ratchet, hose clamp pliers, magnets for locating all the dropped bolts (one I could not locate for 1.5 days), did I say Advil...and most of all, a really loving/understanding wife that was patient for 6 days to complete this project while I hogged the garage. She also worked with me for 5 hours in the driveway detailing all the removed stuff, de-greasing the engine, cleaning parts and reinstalling the bumper cap. A woman to love!! My hands (and body) ache like never before, but....fixed and the car runs great! I will never attempt this again with the engine in the car! AutoAtlanta Porsche parts was a dream. Ordered parts on 1/6, started removing stuff on 1/8, had parts in hand on 1/11, finalized work on 1/14 (I do have a day job but spent almost two complete days working on car along with nights). Cost was around $300 for parts, the experience was one of a lifetime. Just in time because the PCar is our ticket into the Rolex 24 and the Porsche parking paddock...we have the tickets and parking pass...number 91. Ha!

And the 3.6 AOS is even harder to replace. I axctually whacked off the bottom 3 threads of the manifold bolt closest to the AOS, as there was NO way to get my socket in there without doing that. I agree, dropping the engine is the smart move.

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I agree the most difficult aspect of working on these engines is the learning curve of the procedures and exact progression of removal and installation of parts and the necessity for specific tools used in a specific manner to access certain fasteners. Learning it by trial and error the first time one dives into a 3.6 results in serious frustration, major irritation, and occasional periods of complete exasperation. I imagine dentists sometimes feel the same way - working in a dark hole that constantly fill up with slobber and the tongue is always in the way. That being said, now that I'm aware of these things the next time will go much quicker since I know which tool to use on which fastener in which order.

First I would like to thank all of the pioneers that figured out a way to do this and documented the procedure. It is actually humbling in retrospect. And you are correct sandersd, I don't know how many times I stood back in complete (and utter) exasperation with the difficulty and frustration (as well as aches to every arm, limb, fingers and back in my body). I spent many moments just staring in there and wondering how much the flat-bed and Porsche dealer was going to cost me....then dove back in. In the end, I'm proud of what I did, but I never want to do it again like that. Just sharing my experience so hopefully others will know. On a good note, my wife is encouraging me to have a lift installed in the garage! So perhaps something really good came from this.....

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Me too!!!

I drove around the neighborhood this evening, came home and hooked up the Durametric. When I checked the ready status it says the oxygen sensors fail. So I recorded actual values for all the )2 related sensors and exported the file: 2014_01_14_17_35_57.zip Perhaps some of you with a Durametric could do the same and I can compare values to see if mine are out of range. I would really appreciate it.

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No worries about it. "Fail" actually means "Not ready" which means the conditions of which to run the O2 sensors have not been met yet. Once met and tested, it should say "Pass" if the sensors are good. Don't ask me what if the sensors indeed fail since I don't know So just drive your car more and recheck later.

The sensors fail or are not ready after startup and after driving for 20 minutes. I'm curious what conditions must be met and tested, if their status is the result of disconnecting the battery, and if the rough feel of the engine is somehow related and will clear up once I've driven enough for the relearning process to finish. I'm reading another thread: changed-cats-but-still-getting-po430.html that has a wealth of info on cats and o2 sensors but I haven't finished going through it yet. Perhaps these questions are answered there.

I just had a thought: the gas in my tank is over a year old. Tonight I'll add a dose of injector cleaner and refill with fresh gas and see if that makes a difference. I suppose I should drain the old but what would I do with it?

Attached is a small portion of the readings from the Durametric. The full file has 450 separate samples - I've selected 33 that show the range of values for the pre and post cat O2 sensor voltages. Each individual line shown actually repeated for 10 to 20 samples - it varies - but that can be seen in the full file available in a post above. Snap1.jpg Notice how in the last half of the readings the voltage of the pre cat sensor varied wildly.

O2 sensor tests should not be too difficult to set (e.g., compare with Evap test). Normally, O2 test will complete in a 20 min drive for me. Maybe you can drive the car for another 20min or so with some local and highway speeds. Regardless, if the DME really thinks your O2 sensor(s) have failed, it WILL trip the CEL and give you those O2 sensor related codes. Some generic OBDII reader can retrieve exactly which test(s) failed using mode 5 or mode 6 (there are multiple tests to test the voltage swing, response time, voltage range, etc.). Battery disconnect and DTC reset will clear all readiness codes, which will become ready one by one as you drive the car more. One year old gas is definitely stale!

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The swing is normal and expected. You have a problem if the precat sensor voltage does not swing. Everything after 35:25.691s looks fine (precat swings about once per second) and post-cat is close to 0.6v steady. I don't understand those "128" and smiilar values though since O2 sensor voltage should be between 0.0v and 1.0v. BTW, at cold start before the O2 sensors get up to their operating temp, the reading should be 0.45v, which is a biased voltage supplied by the DME.

Ahsai, thanks for the read! I'll fill up and drive it more this evening,

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Does this mean you've been repairing this for a year?

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No, it means it's been sitting for a year. The clutch went out in Dec of '12 so I parked it till I could afford the parts (2 kids in college). Removed transmission in April or May for inspection and found my IMS was leaking oil, RMS was dry. Ordered parts and tools in August and started working on it weekends as parts came in but, as this is my first foray into Porsche maintenance, it seems I was always finding some other part or tool I needed to perform some task that I didn't have, so I'd have to order it and wait. Then there were many weekends I couldn't do anything either due to weather, travel, or illness, plus I did everything by myself. Speaking of illness I was driving my other vehicle, a 2000 F150 4x4, to work one morning and kept hearing a squeaking noise from the engine. As I exited the tollway I heard it again and it sounded like a kitten. When I arrived at the parking garage I popped the hood and found a five week old calico kitten behind the fusebox. As I pulled it out it scratched my pinky, not bad, but it did break the skin and bleed a little. I took it back home to drop it off and washed my hand but apparently it was too late - three weeks later I came down with cat scratch fever which is a real disease caused by a bacteria. Let me tell you the flu is a cakewalk compared to this. I would go to bed with a fever, shivering so hard I could barely breathe and wake up soaking wet from sweat for three days. One week later it happened again and I went to the doc for antibiotics after the lymph node in my elbow swelled up like a walnut, red and burning. It came back one more time a week later but much less debilitating. Anyway, then my son graduated from college so I had to go to that, Thanksgiving, Christmas, etc. Now that I've done it and have all the requisite tools I could probably do it by myself in a three day weekend without breaking a sweat, not that I'd want to. So, no I haven't been repairing it for a year but it's taken me this long to put it back in service.

Holy S#$%! Man you have had a really tough year. Hope this year is much better for you. What works for me is, whenever I start thinking "wow, this day,week, month, etc, couldnt get any worse, I remember our fallen and maimed, brave service men and women, then realize I dont have it so bad after all!

Thanks, I appreciate that.

Drove to the gas station with the Durametric hooked up and took a bunch of readings on the way there and different readings on the way back. When I returned I checked the ready status and all were pass except now the cat fails. I checked the after cat temps and they were around 500 C so I think that's OK. Ideas? Observations? Comments?

BTW here are some of the values after warm up: RPM = 700 Mass air flow (HFM) = 16 Supply voltage 13.48 Hot film MAF = 1.25 Oxygen sensing bank 1 = .99 Have no idea what their significance is yet or what is the acceptable range, except for RPM of course...

Good news on the O2 sensors that they passed. Regarding the cats, add techron on a fresh tank of gas, run through the whole tank and then retest. There is a good chance this failure is due to the stake gas and engine inactivity in the past yr. It may go away once you drive the car more. If not, 200 cell sport cats is always a great option for folks outside of CA and NY.

Btw, the warm up numbers look fine. For cat diagnostic, you need to log all 4 precat and postcat readings. Too early to look anyway...

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The tank was half full when I filled up. I added Lucas Fuel Treatment and injector cleaner to the tank but after reading up a bit on old gas and its related issues I think I'll add the Techron also. After researching I realize I should have just drained it.

I reinstalled the Bose subwoofer and shifter console and now everything sounds like I remember it. It's amazing how much engine, transmission, and suspension noise is dampened by the console and sub. If you really want to hear the engine take out the sub and you'll get an earful. It makes me wonder if cars without the sub are as noisy as mine was. I'm still getting the cat fail but I'll run this tank empty and refill with fresh gas and see if it changes. Maybe I'll add a can of cat cleaner too.