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dporto, thanks for the information, and for the suggestion regarding the injectors. I considered servicing the injectors while I had the engine out, clean them and replace O-rings and feed lines, but neglected to do so. I believe I am suffering from some long repressed trauma attributable to an injector service I did on a previous Jag XJS V-12 that was miserable and went sideways almost immediately. Suppose I was a little gun-shy, and the 996 was running beautifully right up until I got the low coolant warning light by which point there was already oil in the coolant and a crack in the # 1 head. Since I've owned the car (6 years/15k mi.) I've run a bottle of fuel injector cleaner thru the system at every oil change (3k mi.).To do the injectors now with the engine installed would be a horror. I inspected the bores as best I could w/o splitting the cases when I had the heads and sump off, and the bores looked surprisingly good. I have been getting mis-fire codes for bank #2, and inactive pre-cat o-2 sensor code for bank #2, so I am in the process of changing out all the O2 sensors and if that doesn't do the trick then on to the air/vacuum leak, and if the injectors have to come out they shall come out! Thanks again!
So, when last we saw our hero, he was attempting to change out his old, yellowed and leaking expansion tank for a bright, clean new one. He removed the old expansion tank fairly easily after some yanking and twisting and turning. Installation of the new one, however, was destined to be a true test of character. He noticed that at first glance, the two tanks appeared similar yet, when compared side by side, there were slight differences, the primary one being a triangular section at the rear providing added capacity. He tucked all of the coolant and SAI hoses out of the way and commenced to attempt to put a square peg into an oblong hole. He undid the fuel rail feed/return lines and continued to push and twist and shove. He undid the motor mounts, lowered the engine as far as it would go, and continued the pushing, shoving and twisting. He removed the motor mounts altogether and attempted to wedge the engine sideways to obtain more space but, alas, there was no joy. Gentle readers, by this point the foul language had commenced, language so vulgar and cruel that decorum precludes its repetition on a family oriented forum. It is said, typically in hushed tones around a blazing campfire after several apertifs, that his head spun around 360 degrees on his shoulders, not unlike Linda Blair in "The Exorcist". Finally, he removed the upper black plastic bracket and, voila, the new tank fit where the old tank had been. Now our hero must deduce how to get the new tank past the bracket upon which it hangs in situs. In consideration of the amount of time, effort and foul language expended to this point, our hero was reduced to the most extreme of measures: surgery! He got out the dreaded cut off wheel and whacked off the first third of the black bracket, including the tabs, at an angle conducive to the tank's shape, and then there was joy and rejoicing, and candy!
So today I resolved three issues: the short throttle cable, the high oil pressure and the detergent rinse! The short throttle cable turned out to be the black plastic block at the end of the cable that snaps into the back of the throttle body. The block had separated from the throttle cable sheath, and when I removed the cable from the car this morning I saw what was going on, jammed the cable sheath metal tip into the block as far as it would go, reinstalled and, voila, the missing one quarter inch had reappeared! I was then able to adjust the butterfly and stop so that the butterfly closes without jamming, and the bellcrank rests on the stop! Now it idles at between 6-700 rpm, still somewhat ragged/erratic, and no more surging to 3-4K rpm. Plus, as an added bonus, the oil pressure sensor started working again! I had approximately 1.1 bar at idle and the oil pressure needle would rise and fall with the rpm's just like it used to, with 4.5 bar at 3-4k rpm. I ordered a new sensor which I will install anyway, but I'm gratified to know that my work on the oil pickup and swirl pots in the sump were not the cause of the high oil pressure. So, given that progress, I was able to get the car to operating temperature and then drain out the Shout detergent mix from the cooling system. There was not much if any oil residue in the drained detergent mix, but I'm going to do a 2nd cycle of Shout mix, then plain water, then install new coolant reservoir and low temp thermostat before finally filling with red antifreeze, which is what came out of the car originally. I did get a CEL and #2 bank #1 O2 sensor/cyls 4-5-6 misfire codes when the car was warmed up, which accounts for the ragged/erratic idle, so I am going to replace all 4 O2 sensors just to be sure. As they say in show business, that should be a wrap! Thanks to all whom took the time to consider and respond with their wisdom and suggestions, it is truly appreciated. I hope to pay it back by helping someone on this forum with their issues.
+1 RatboneRanch, other drivers seem to get very competitive when they see you're driving a Porsche, a lot of tailgating, engine revving and hard accelerating from traffic lights! I've even had guys (always the guys, never the girls!) ask me to race! I always say, "this is a 20 year old car, no thanks."
dporto, thanks for your input, yes, it does fell like I'm chasing my tail, but I think some of it has to do with how fragile these engines can be. The draining of the detergent: yes, I understand that it can be drained cold, but everything I have read about this detergent rinse process states that it should be drained at operating temperature for maximum effect. I am precluded from getting to operating temperature by the high oil pressure issue and the fact that I did disassemble, clean and reinstall the swirl pots and the oil pickup in the sump, and the apprehension that somehow I had botched that causing the high oil pressure. I've had this car for 6 years, am familiar with its oil pressure cycle from startup to idle to full operating temp, and can tell you for a fact that the oil pressure I am seeing is not normal. I've already ordered a new sensor, so hopefully that issue will resolve. Secondarily, ragged/erratic idle and sudden surge to 3-4k rpm keeps me from running the engine long enough to get to operating temp because, given the oil pressure issue, I don't want to blow out the main seals or cook the engine. Also, the rear throttle cable issue, which appears to be short one quarter inch, keeps the throttle butterfly slightly open which seriously compromises the car's ability to idle. So there's a lot going on at once, but your advice is sound, I'm going to focus on one thing at a time. Thanks again!
OP, dissing the Boxster, heinous!!! Just kidding, everyone is entitled to their opinion. I have a 1999 996 cab and a 1999 Boxster, and every time I drive the Boxster I find myself thinking that I love that car. It is somewhat underpowered, but the perfect balance makes up for it. I can take a highway on/offramp much harder in my Boxster than in the 996 which vaguely feels like the rear end wants to swing around due to the uneven weight distribution. For me, the Boxster is a different flavor of ice cream: the 996 is chocolate which is my favorite, however, every once in a while I feel like some vanilla which is the Boxster, and just as enjoyable but in a different way. If you are mechanically inclined, the 996 is a lot of car for the $ and the turbo even more so. If you can find a high mileage example with extensive maintenance records I would say jump on it with both feet! Both of these cars a an engineering miracle of packaging, cramming mucho technology into a limited space and, consequently, somewhat of a pain in the rear to wrench on. Seems like no matter what you're trying to do, there are three things in your way or an extremely difficult angle. But they are doable, and remember: extensive service records, particularly for high mileage examples, are a big plus for your search. Good luck and always keep the shiny side up!
Thanks for that link, first time I've seen it even though I searched Rennlist several times regarding the throttle cable issue. Anyway, reading through that link gave me accouple of ideas to follow up on, as well as your suggestion regarding the orientation of the square plastic grommet. I've been putting it through the back of the throttle body with the longer locking tab up, so I'm going to try it at 180 degrees with the short locking tab up, and if that doesn't work I'll try 90 degrees and 270 degrees to see if any of those orientations gives me that last quarter inch. Regarding my ragged idle issue (getting misfire codes), today I removed the throttle body altogether, and then removed the Throttle Position Sensor and the Idle Air Control Valve with the intention of swapping the known good ones on my 1999 Boxster into the 996 to eliminate those 2 possibilities. Also going to swap over the MAF sensor as that is also a known good one. I pulled the MAF sensor from the 996 and cleaned it with CRC MAF cleaner, but a swap test with a known good one should also eliminate that possibility. Today I got the 996 to idle somewhat better, turns out the K&N cold air kit rubber boot between the throttle body and the cold air tube had loosened. So cranked down on the screw clamps and it idled better, but still threw misfire codes for bank one. The spark plugs are brand new and the coils are 2 years old, having been replaced on both cars in summer of 2017, and haven't gone even 5K miles. If all else fails, I'll swap the Boxster coils into the 996 in my ongoing process of elimination. Also, neglected to mention earlier that I changed out the fuel filter when I had the 996 engine out. Maye the fuel pressure regulator or fuel pump are wonky? Thanks for you response, I'll keep at it until the car runs the way its supposed to.
Sir, thank you for your response and suggestions. I have already ordered a replacement sensor and hopefully that will resolve the oil pressure issue. Regarding the throttle cable, how would I achieve free play in the throttle cable? If the throttle body bell crank is contacting the stop causing the throttle body butterfly to be fully closed and the Idle Control Valve as the only air source, then the rear cable doesn't reach the front cable being one quarter inch too short at the plastic cable junction under the car below/behind the driver's seat even with the plastic cable junction fully adjusted in. When I pull the two cables together, the throttle body bell crank is one quarter inch short of the stop and the throttle body butterfly is slightly open. Is there any further cable adjustment available in the front cable from the gas pedal to the plastic junction? I did not disturb the front cable during disassembly/reassembly of the car, that's why I suspect the routing of the rear cable from the plastic junction, through the clutch slave coil, under the fuel injector rail and oil cooler feed lines, and over the top of the intake manifolds' crossover tubes as the source of this issue. Again, thanks for your input.
Nordiques posted a topic in 996 Series (Carrera, Carrera 4, Carrera 4S, Targa)Good afterlunch, new member here with a 1999 996 Cab, 79k mi, manual trans, ocean blue metallic with saddle leather interior, Porsche Sport Design 18 inch wheels painted gold, K&N cold air kit, muffler bypass, and lowered 3 inches all around. I love this car! Resurrecting the car from a cracked head/intermix and am encountering some strange behavior. Running Shout detergent through the cooling system to clean out any residual oil, had disassembled and flushed all the cooling system hoses/rads when I first took the car off the road in 6/18, so the current flush is more for the engine block. The strange behavior consists of extremely high oil pressure (4.5 to 5 bar) even at idle, ragged idle with plug fouling and, if I blip the throttle to overcome the ragged idle, the engine rpm"s hang up at 3-4k rpm whereupon I immediately shut off the engine. Consequently, I can't run the engine long enough to get it up to operating temperature so that I can then drain the detergent mix from the cooling system. I've had the car since 2014 and whenever I changed plugs, the old plugs had a light tan appearance. When I had the engine apart, I de-carboned both heads and all piston tops. Upon reassembly, I put 5 gallons of fresh gas in the tank. Now when I pull the spark plugs they are fouled and sooty, so today I installed new NGK platinums but the idle was still ragged and the rpm's would still hang up at 3-4k if I blipped the throttle. When I pull the new plugs tomorrow, I expect they will be fouled. Today I also drained the fresh Castrol 20W50 oil and replaced with fresh Castrol 10W30 thinking that the 50W oil was causing the high oil pressure. Even with the 30W oil, the pressure was still 4.5 to 5 bar. Prior to the cracked head I ran 40W and had 1.5 bar oil pressure at idle and 3 to 4 bar in normal driving, but had read that 50W was preferable which is why I tried it. I also removed the oil pressure sensor and could hear a slight rattle when I shook it (not that that means anything) and have read that when they fail electrically you can get either a zero reading or an extremely high reading, so perhaps that issue is a s simple as a failed sensor. When I had the engine out and apart, I took the sump cover off and cleaned out the oil pickup tube and the swirl pots. I only found one small piece of gasket sealer, everything was clean as a whistle which was gratifying. I just pray that I didn't reassemble the pickup tube/swirl pots incorrectly resulting in the oil pressure issue, although I did them one at a time so as not to mix anything up, and they are very simple and straightforward to reassemble. I replaced the AOS and the oil cooler, could those be the culprits for the rpm and oil pressure issues respectively? One final comment, the throttle cable appears to have shrunk by about one quarter inch in the 16 months the car was idle, no matter how I route it, the throttle butterfly bell crank is about one quarter inch short of the stop. Even routed it through the clutch slave coil and under the fuel injector rail feed lines, no luck but it will idle raggedly between 6-700 rpm. Apologies for the long post, look forward to your collective wisdom, thanks!
New member here, first post/reply, I have a 1999 996 Cab that came with an uninstalled K&N cold air kit. So I install the kit and get an error code (don't recall the code number), delete the code, same code pops up a second time. Delete the code again and it never came back. Suspect the computer gradually adjusted to the increased air flow. I like the look/sound of the K&N kit, but its kind of hard to hear over the muffler bypass pipes! I am actually just now resurrecting the car after an intermix/cracked head episode attributable to a cracked coolant expansion tank. Bank one head cracked between #1 spark plug hole and # 1B exhaust valve stem. Sent the head to Len Hoffman in Georgia for repair, can't say enough about his services and the ease of the transaction, plus saved quite a bit of $ over a new or even used head. While I had the engine out/apart, I replaced the lifters, did a valve job on both heads, new valve stem seals, new head gaskets and bolts, new AOS, new fuel filter, new low temp t-stat, new exhaust hardware, new coolant expansion tank. Got an Air Lift tool to fill cooling system, currently running Shout through the system to get any residual oil out, although I flushed out all hoses and rads when I first took the car apart last summer. All in all, an interesting experience, total outlay of about $2300 including the head crack repair. I know a lot more about the car now than when I started, knowledge which is also directly applicable to my other car, a 1999 986 Boxster. So, anyone in a similar situation be advised, no need to part your car out or sell it as a roller, a cracked head is not a death sentence and can be remedied economically. Final word: stay on top of your cooling systems!