BigHead

Howdy, all. Some of you might remember my problem with the wife's 1999 996 back in July. See below for the full thread. I realized yesterday that I had neglected to post the solution to the problem, after I resolved it. With some great advice and e-mail diagnosing from Stephen Kaspar at ImagineAuto and Loren from Renntech.org, I concluded that the most likely cause behind the "check engine light" and the accompanying lose of power at higher RPM was basically just a failure of the Mass Air Flow Sensor (MAF). Stephen wrote: >I would say that the film is shot. The code that the car is throwing is a picked up from the 02. In other words the 02 are the eyes and the brain is picking up that something is not right. The 02 it self has a different code for out of range. When you look at this code it shows a lean under threshold which means that the control of the ECU is beyond the adjustments that are needed. This is not a problem with the 02 rather something up stream or bigger. The MAF often reads less air when bad hence causing less fuel and giving the lean condition according to the 02. The car doesn't know why since air flow at that given point doesn't not indicate it SHOULD be a problem, yet the AFR target for the map is off. The ECU tries to adjust, but is out of range. I vote a replacement MAF. FWIW I have not had good luck cleaning them. _______________ So... I bought a replacement MAF (for $245 from Jeff at Sunset Porsche, just barely beating the price increase), and installed it myself. It took, literally, about 30 seconds. Well, ok about 45 seconds, but that's because I dropped a screw and had to look for it. I then cleared the CEL with a really, really neat OBD-II tool from http://www.autoenginuity.com/. I actually bought it off of eBay, where the company has regular sales, and saved quite a few bucks from what they charge on the site. I got the Palm version, so I can use it more easily in the car. After clearing the light, I went on a long drive. Car ran FLAWLESSLY. Have been back to the track twice since too, and have had no problems. So it certainly appears to have been the MAF causing the headache. Thanks, Stephen and Loren!!!! ==== Oh, In addition to complete OBD-II functionality, the Autoenginuity tester ALSO came with an additional piece of software, "SpeedTracer", for FREE, which "is a performance analysis software for your PC or PDA. Are you curious if that new part worked? Is your vehicle performing to its fullest capabilities? With SpeedTracer, we can help you answer those questions. Save hundreds of dollars running dynos on your vehicles. What's more, you can run the performance analysis at YOUR convenience--not regular shop hours. What it can do: 0-60ft time 0-60 MPH 1/8 mile time 1/8 mile speed 1/4 mile time 1/4 mile speed G Forces SAE Horsepower Torque SAE Horsepower and Torque vs RPM graphing Speed vs Time graphing _____________ All way, way cool. Of course, I haven't had the time (nor the long empty stretch of flat road) to play with it yet, but for any of you considering getting an OBD-II tool, you might want to get this as SpeedTracer appears to be a really great way to validate all of the performance mods to your car. Now you can really see if that K&N air filter or new chip or exhaust has improved your performance.... vty, --Dennis

Excellent work. Thanks for the tips! vty, --Dennis

Ok, I too am curious - just how DOES one disconnect the harness? Chronos, how did you do it?!? Thanks!

Thanks, Loren. Excuse my ignorance, but what is the oil separator? And is it tucked away somewhere where I can't inspect it myself? Is there a TSB on this? TIA, --Dennis

Thanks (as usual), Loren! Ok, so where is the TPS located? Is it easy to replace? How do I test it (e.g., where are the two pins located)? BTW, I didn't pull an P0122 code - I pulled 1123, 1125, 1128 and 1130, which is why I thought it might be the MAF sensor. FWIW, I just tried cleaning the MAF wire with alcohol, and went for a test drive. The car seemed MARGINALLY improved, but it could just be my imagination. If it's not the TPS, what do you think about the chances that it's a cooked MAF sensor? Thanks, --Dennis

This morning, I found myself standing in the paddock garage at NHIS, with a problem with the wife's 1999 996. Doh. The Check engine light came on a couple of weeks ago. I read (then cleared) the codes, hoping that it was just a burp in the system. The codes were :1123 1125 1128 1130. The light came back on shortly thereafter, and I haven't had a chance to check the codes again since. Hadn't been a driveability problem in the intervening time, but on my way up to the track this morning, as I accelerated hard out of the tolls, with the throttle near the floor, the car stumbled badly at around 3500 rpm. Major loss of power, stumbling. I can accelerate to higher RPM just fine if I don't do it with full throttle. (Prior to this CEL coming on, I did sense a momentary hesitation at ~3800 rpm, but that was just a very minor little, split-second pause). Just did a couple of recon laps of the track, and same problem - if I try to accelerate it with anything more than half throttle, it sputters and hesitates and lurches. I can rev the car to redline using light throttle. It was raining there, if that makes a difference. FWIW, I did change the plugs about 2.5k miles ago, so I guess it could be a loose/bad plug or plug wire, but the CEL kinda points me in the direction of a bad throttle position sensor, O2 sensor, or MAF. Would a bad throttle position sensor cause an O2 failure? Or is it the other way around? Anyone know what code 1123 is? Comments about how easy/hard it is to replace a throttle position sensor and/or O2 sensors? . P1122 - Throttle Position Sensor 2 . P1123 - Oxygen Sensing Adaptation Area 1 (Cylinders 1 - 3) - Lean Threshold . P1124 - Fuel Pump Relay Output . P1125 - Oxygen Sensing Adaptation Area 1 (Cylinders 4 - 6) - Lean Threshold. (. P1125 - Oxygen Sensing Adaptation, Upper Load Range, Bank 1) . P1126 - Oxygen Sensing Adaptation, Lower Load Range, Bank 1 . P1127 - Oxygen Sensing Error By Means of Short Test, Bank 1 . P1128 - Oxygen Sensing Adaptation, Idle Range, Bank 1 . P1130 - Oxygen Sensing Adaptation, Idle Range, Bank 2 Last year, I had a CEL problem, related to the Mass Air-Flow Sensor. I didn't replace the MAF last time around - I pulled it, cleaned it with some alcohol, replaced it, and all has been right with the world for the last year or so. When I replaced the air filter, I found out that the prior owner had installed BMC filters, the oiling of which I suspect caused a film on the MAF. Should I try cleaning the MAF again? Or do you think it's a problem with the O2 sensors? But not because the signal isn't out of range elsewhere? Throttle position sensor? Gosh, darn it. Any suggestions/comments/advice would be greatly appreciated! thx, --Dennis

Thanks, Loren! (Loren sent me the diagrams for how to reinstall the belts.) As always, much appreciated. Next question: now if only I could figure out how to remove the trim pieces to get to the seat belt installation area.... Anyone have any experience/ideas on the best way to remove all of the side trim between the B and C pillars? Thanks again! vty, --Dennis

Howdy! Well, the baby is finally old enough to be facing forward, so I'd like to put the Roundabout in the rear seat of my wife's 1999 996. Especially as we're going away on a club drive this weekend, and I'd HATE to have to take the BMW wagon instead. :( The previous owner removed the rear seat belts. The (female) buckle ends are still mounted to the center tunnel, just the belts are missing. A friend sent me a set of rear belts. Can anyone provide some guidance as to how to install these suckers? What other parts do I need? Anyone have an illustration, perhaps? The same friend is sending me some bolts (he took all this stuff out of his 996tt that he's building into a race car), but he can't remember how everything came out. Any and all help would be appreciated!!! vty, --Dennis

Thanks for the link and info! But what you posted in that other thread remains my question, I guess. The plugs I took out of my '99 996 *are* four point plugs... does anyone know for sure that these are the same plugs as the new ones that just went in, and does anyone know why the replacement period went from 30k miles to 60k miles (other than, perhaps, a change in the plug itself)? In other words, if these are supposedly interchangeable plugs (between the Bosch and the Beru), then the change in recommended replacement period is just Porsche being conservative at the start but then modifying the maintenance recommendation when they saw how well the four point plugs were wearing? thanks! vty, --Dennis

Just finished changing the plugs on my wife's 1999 996. A complete PITA when I first started, but pretty easy by the time I finished. Took a little twisting, turning and serpentine routing of hands, tools and plugs to get it all done, but done nonetheless - THANKS, LOREN! Anyway, here's my question. The 30k maintenance guide states that plugs must be replaced on earlier 996s. For later cars, plugs don't need to be replaced until 60k miles. Is this solely because of a change in plugs? Do I need to change the plugs AGAIN at 60k miles, or am I now good until **90K miles**?!? The plugs I removed are Bosch Super R5 871 "FGR6KQC", and I replaced them with Porsche part #999 170 207 91, with "1 Zundkerze" on the box. The plug is a Beru Ultra R6 319, with 0.7 14FGR-6KQU stamped on the metal. Any ideas? Thanks! vty, --Dennis

Howdy! First, gotta say I LOVE this site. Just made a small donation to become a contributing member. Woo-hoo! Anyway, here's the query. I'd like to do the 30k mile service on my 1999 996 C2. Most of the actual WORK seems to be pretty straightforward - change air and pollen filters, change oil and oil filter, change spark plugs. And I'm planning on changing the brake fluid and bleeding the clutch too. How tough is it to perform the "inspections" that are part of the service? Specifically, can some helpful person point out exactly where to look, and what to look for? :) Here's what I would like some advice on: * Diagnosis system: Read out fault memory (how important is it to actually do this?) * Polyrib belt: Check condition * Coolant hoses: Check condition; * Coolant: Check the level and antifreeze protection * Fuel system: Visual inspection for damage, routing and secure fit of line connections * Power steering: Check the fluid level * Steering gear: Visually inspect the bellows for damage * Tie rod joints: Check the play and dust bellows * Axle joints: Check play, visual inspection of dust bellows for damage, check screw connections of running gear adjustment facility, front and rear, for secure fit * Drive shafts: Perform a visual inspection of the boots for leaks and damage Exhaust system: Visual inspection for leaks and damage, check suspension Everything else, I think I can handle. Thanks in advance! vty, --Dennis