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YOUR RESEARCHNewbie checkin' in
Leading reported evidence
Check injectors
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
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0
Unsuccessful attempts
1
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Discussions that performed work without a confirmed outcome
1
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Performed · outcome unconfirmed
Quite a few threads describe this issue, and how on several cars 02 sensors were replaced, fuel pressure checked, injectors checked, and the CEL's continued until the MAF was replaced.
Leading evidence: 'Check injectors' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check by an indy or dealer' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.
Install clutch, flywheel, rms, and ceramic ims bearing
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
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Performed · outcome unconfirmed · Original poster
So I took it to my local independent shop who installed new clutch, flywheel, RMS, and ceramic IMS bearing.
Replace quite a few threads describe this issue, and how
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed
Quite a few threads describe this issue, and how on several cars 02 sensors were replaced, fuel pressure checked, injectors checked, and the CEL's continued until the MAF was replaced.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed · Original poster
I took it back to the used car lot, they ran a diagnostics, and got a 1123 (O2 sensor).
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
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Performed · outcome unconfirmed
Also be aware that '99's used two different MAF sensors depending on the model/egas.
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Suggestion
Upgrade the rear IMS bearing if/when you put in a new clutch, maybe carefully check the filter and get an oil analysis on your next oil change to look for any signs of metals.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed
Quite a few threads describe this issue, and how on several cars 02 sensors were replaced, fuel pressure checked, injectors checked, and the CEL's continued until the MAF was replaced.
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
29 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.
0 acknowledgements have no verified action link; they do not establish a repair result.
Generation: 20261026T113718Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
Hey guys what's up?
Just purchased a 99 996 yesterday. Silver, gray, 6spd, 88k miles, $15.9K USD. Cosmetically fantastic with only 2-3 very minor paint chips.
Mechanically it seems good so far, except about 20 miles down the road the CEL came on. I took it back to the used car lot, they ran a diagnostics, and got a 1123 (O2 sensor).
Mechanically I'm very savvy, and I drive an E46 M3 daily. With code 1123, that's not a bad O2 sensor, but indication of a problem higher up the line, is this correct?
Probably no big deal, but I'm reading about all these failures in these cars and it seems pretty scary. RMS, IMS, D-chunking. OUCH. Give me some reassurance......
Welcome Joseph
Congrats on your acquisition. You mention the car is cosmetically fantastic; check for clues to any repaint or bodywork. How's the interior? Any electrical issues? Even though not 100% accurate, did you get a Carfax?
Not familiar with the 1123 code, pry have to troubleshoot at this point, unless the car dealer is willing to help you at this point.
Have you put the car up on a lift? Pretty much , you have to do a
POST
purchase inspection. Check for leaks from top to bottom. Inspect the coil packs and plugs, all filters, MAF, all hoses, suspension, tires, (alignment), brakes, fluids , coolant and pentosin reservoir and if you are up to getting an oil analysis. In what condition are the other fluids? Any proof they've been serviced?
If you're all in at this point, then get to learning all about these water-cooled cars.. From you're avatar pic and join date, seems you are already there mechanically....
Sunset, Suncoast, Pelican, et al...
Thanks 2K3TTMIA. It's a 6spd manual.
Carfax is clean, the VIN numbers all match, and there is no evidence of paintwork that I can see.
I plan to check the car out quite a bit here at home as the weather should be nice today.
No maintenance/repair records were included with the car. Is there any way to inquire about them through a Porsche dealer using the car's VIN number? I have no idea if the RMS has been updated.
Yes, if you ask the Porsche dealership near you to run the VIN, see if they can come up with some helpful info. The Carfax should show the last time it made it to a P dealer also, and location. If you are inclined to drop the trans to inspect the clutch and associated items (AOS, oil cooler, coolant lines, IMS, RMS), then take the opportunity to do some preventative maintenance if it shows no evidence of it being done.
Oh yeah, PICs or you're just trolling in the water cooled forums for sh*ts and giggles...
Welcome.
I too have a 99. Artic silver 6 sp coupe.
P1123 reads out as...
Fuel system
Monitoring of long term fuel trim factors.
Criteria... long term fuel trim additive, system too rich (Bank 1)
Hope that gets you in the right direction.
I got the info straight out of a On-board diagnostic trouble code list for
1999 996's.
The OBD2 hand held unit that you plug into your car is handy to have.
Some can actcually change parameters and more.
The one I have is a $69.00 unit that at least can reset the CEL and tell you what caused it.
Good luck.
ideally, this link helps with a PREpurchase Inspection (PPI) but in your case, can still be useful as a POSTpurchase Inspection: LINKY>>>
https://rennlist.com/forums/911-foru...immermann.html
Maybe look through
this thread
and
this thread
.
My guess is that it needs a new MAF sensor. You can try cleaning it with electrical contact cleaner, but that really only helps if the sensor is contaminated (does the car have an aftermarket oiled cloth filter like a K&N?) rather than just drifted out of spec as they will do over time.
The OE part is pricey (~$500?), but I think you can get acceptable Bosch OEM replacements for half that. Relatively easy to change as well, but you'll need a Torx T-20 security bit (post in the middle) to get the sensor out.
Also be aware that '99's used two different MAF sensors depending on the model/egas. Is yours a straight C2?
The way fuel trim works (oversimplified, of course) is the MAF sensor tries to measure the air accurately to get the fuel ratio right, but then the 02 sensor sniffs the post-combustion mixture to see how well it did (a closed loop system). If it's too rich (or lean), it adjusts the 'trim' in the ECU which are used to calibrate the MAF readings. When the calibration adjustments start to get too large, the ECU throws up CEL codes, usually an early warning for MAF (or O2 sensor) failure. The mixture is likely still being trimmed perfectly, the CEL is often just a warning that the ECU is starting to make quite large corrections to the MAF readings.
LOL, here's a quick photo from yesterday. Was cleaning out the second garage so I have a place to put this thing. The M3 daily is in the background.
pfbz - good guess!! yes it does have a K&N filter on it (as well as one of those awesome GFORCE PERFORMANCE CHIPS!!!). When the mechanic pulled the code, his comment was it needed a new throttle position sensor. However, in either case.....wouldn't I get a code for both banks of cylinders instead of just one? with only one cylinder bank, that tends to indicate either a leaky injector or higher fuel pressure for the one side from what I've read.
I've read through as many of the threads I can find on that code and overall it doesn't seem a big deal really. I may just clear it out, drive the car again and see if the code returns.
EDIT.....as for things not working......the turn signals don't cancel (looks like I need a new stalk unit), spare is shredded, and headlights are terribly flaky. The car has clear paint protection film on the front end so I'm sure that accounts for the beautiful lack of paint chips
You can buy a new MAF sensor from Autohaus AZ for way cheaper than $500. A 99 with throttle cable is even cheaper than the egas MAF. It should be around $200.
I would look to clean out the throttle body instead of replacing the throttle position sensor FYI.
Car looks really clean and digging the sport seats.
I guess there will be people who comment on Mk1 996s worth above $20K hiding from this thread.
Thanks guys. I bought the Excellence online review prior to purchasing, and the price for this car seems in line with what was documented there.
It's hard to convey in photos, but the car truly is very clean with the exception of some minor surface defects in the center console between the seats and some wear on the shifter ****. No oil drips on the ground yet.
I made a snap decision without a PPI, but it looks like a nice car so far.
Congrats that's preeeeetttttyyy
and exceptionally clean. Any plans for modifications ? The MAF for cars with the throttle cable is
99660612300
, the MAF for cars with electronic throttle is
99660612400
.
Looking good! Similar to the '04 C2 I picked up a few months ago... $16K seems like a nice price for a very clean, semi-low mile '99. Most that are cheaper than that are not going to be beat up, high miles, bad carfax, or some combination of the above! I definitely paid more for a newer, lower mileage '04, but would have happily grabbed a '99 if I found one similar to yours...
I wouldn't worry bout the RMS, it's only a leak and will let you know when it needs changing. Upgrade the rear IMS bearing if/when you put in a new clutch, maybe carefully check the filter and get an oil analysis on your next oil change to look for any signs of metals.
I'd dump the K&N, go back to a stock paper filter, and
try cleaning the MAF
to hopefully prevent more CEL's, but even if it needs replacing, not a big deal. I highly doubt it is the TPS... Bosch MAF's just plain wear out, I've had to replace them on several vehicles and I don't think TPS's are known as a problem area.
On the cosmetics, there are a
few companies
that refinish the paint on the consoles, and 3M Dinoc can also cover it nicely and cheaply if the paint is chipped up. Clear front side markers are cheap, and 996.2 or 997 style
depo/dectane rear taillights
pop right in at reasonable cost and can take several years off the car.
Quick shot of my '04-996-C2 in Polar Silver...
P1123 indicates an over rich condition on one cylinder bank (cylinders 1-3) that the 02 sensor and DME fuel trims cannot adjust for, usually caused by either a leaking injector or excessively high fuel pressure.
MAF will not fix your problem.
Disagree. The ECU knows the mixture is rich and that it is applying excessive trim, but several things can cause the condition and the OBD code is not definitive in the diagnosis of the problem.. High fuel pressure and leaking injectors are much less common failures than MAF or 02. Quite a few threads describe this issue, and how on several cars 02 sensors were replaced, fuel pressure checked, injectors checked, and the CEL's continued until the MAF was replaced.
Replacing the MAF is a 15 minute backyard mechanic job with a pretty low parts cost. If I'm wrong, your out $200 and a half hours time, but have a fresh MAF. If I'm right, you'll save tons of $$ and time having your fuel pressure and injectors checked by an indy or dealer.
man you guys are fantastic.
ECS tuning- I was just watching your youtube video last night on headlight restoration. Do you sell that product? Couldn't find it on your website.
pfbz - thanks for all the links!! Very helpful
no plans for modifications at this time. Between my job, family, and passion for cycling, I barely have enough time to enjoy the car in stock form. But I know the bug will hit eventually. I just put some H&R springs on my M3, so the 996 will probably see some action later.
Thanks for all the help
Sorry for that, I would just advise that you mask and protect the paint directly surrounding the headlamp.
Click Here
for more information about the headlight restore kit.
update to this thread. The headlight polishing kit from ECS was amazing for the lens clarity. thanks!!
3 weeks ago at 90k miles the clutch started slipping. So I took it to my local independent shop who installed new clutch, flywheel, RMS, and ceramic IMS bearing. old IMS bearing was almost gone so I dodged a big bullet!
I love the way this car drives; now I'm looking at HID upgrades and some 18" wheels
Woah, wait, holdup. You cant just post this and sign off. Can you give more details about the bearing condition and pics? A little play is completely different than almost gone. I for one would like to know more. Thanks.
no pics but the mechanic said it may have lasted another 5000 miles at most before failing completely.
he showed it to me; it was noticeably loose - I'd venture to say 1-2mm of lateral play
