originalmotorhead

Hi Guys,
Out of the blue my car threw a check engine light this morning. I stopped by Autozone on the way home and the code reader spit out a P1128 & P1130 error codes. We tried to look them up and came up with o2 for the 1st code and something else for the second code. Any ideas ? Also, I reset the codes/cleared the codes and I have driven about 10 miles since with no check engine light.

Here's somebackgroud info that might be helpfull
2000 boxster 5 speed with 52k miles
desnorkeld intake a year ago,
removed muffler and ran streight pipes a year ago.
all stock else where and current on maintenance.
Saturday night I changed the plugs, replaced with same Bosch plugs. The ones that came out looked almost like new, except for a slightly wider gap then the new ones that i installed. Car was at 1/4 tank full this morning and i topped it off this afternoon.(doubt the gas had any affect but...)

Car ran fine sunday and monday, and is running fine today.

Any idea what the problem may be ? failing O2 sensor ?

Also, is there a online database with these trouble codes ?

thanks in advance to all,

Tom
Columbus, Ohio

deliriousga

Your codes are "Oxygen Sensing Adaptation Area 2 (Cylinders 1 - 3) - Rich Threshold" and "Oxygen Sensing Adaptation Area 2 (Cylinders 4 - 6) - Rich Threshold". The first, cheapest thing to do is put a bottle of Techron in the tank. Cleaning out the system will get rid of the problems many times, and if it doesn't fix it, at least you know it's not poor quality fuel or dirty internals.

Make sure you're using the right octane gas. It should be 93, but I know several areas only have 91. 91 seems to run fine, but don't try to get by on 89 or 87.

When you replaced the plugs, did you get the exact OEM plugs from the dealer or an online Porsche parts supplier? The ones sold at AutoZone are not the same. The OEM plugs are copper, not platinum, with a heat range of "7". The platinum ones have a lower heat range.

Next is the O2 sensors. I've had one bad one replaced on my '00 model at 30K miles, so it's possible. They should normally last about 100K miles so replace them all when you get to that mileage to keep from having huge headaches.

Here's a list of the codes:
http://www.renntech.org/forums/index...pcode&code=dme

originalmotorhead

Well, the plugs I installed were the esact same ones as what I took out, 4 tipped bosch and not platinum ones. I had to goto an imports place to get the plugd but they were exact part numbers on the side of the plug as what came out.

Gar runs excellent, as it did before. Even when it had the error codes it still ran great.

OK, kick me now. I am a cheep person (haha) and I have run 87 octaine in the car ever since I have owned it because I drive it every day to work. I have popped a tank full of 93 here and there but for the most part I have always used 87 octaine. THe knock sensor takes care of pre ignition. I drive the snot out of the car and it seems to have no trouble with the 87. Today when I filled it up, I did fill up with 93 thinking I possibly got a bad batch.

I got the car with barely over 30k on the odo and it immediatly needed one O2 sensor which the dealer replaced under warranty. I'm now about 52kish and I hope they are still good but O2 is a easy replacement and Autozone sells the bosh replacements for I think around 160ish but i can't say for sure.(didn't write it down when he told me). I'll also check my local import place if the codes come back.

I didn't put any techron in yet cause I wanted to see if the codes come back and I have heard mixed Do's and Don'ts abut additives. Seems older porsche's reccomended periodic fuel cleaners but newer ones say never add anything but plain gas. Maybe it's their marketing gimmik for the dealer to sell you overpriced stuff.

Thanks for the reply and I will check out those codes. I'll post back in a few days if I have not had a repeat of the codes. I drive about 50 miles every day to make round trip for work.

Tom

deliriousga

Glad to hear you found the OEM plugs locally without getting soaked. Hopefully the codes won't return.

The Techron is in every tank of Chevron gasoline so it's not like other additives. I would change it to higher octane gas, though. It's worth the extra $3/tank to keep the engine from working so hard.

It will run fine on 87, but you're stretching the limit of adjustment available to the computer. 87 is much more volatile than 93 so your timing and fuel mix is adjusted lean to keep it from firing early and knocking. You start pushing it hard and the adjustments go as far as they can while keeping the engine lit. If it can't adjust the fuel to be any more lean, you have more fuel coming in than the engine burns. The O2 sensors "smell" left over gasoline in the cats after combustion and give you a rich mixture code.

If you end up replacing the O2 sensor, Bosch has a universal one you can splice into the existing connector for much less $$$.

ar38070

The P1128/P1130 codes can take up to 100 miles of driving to reoccur. You need to look at you MAF readings at speed to see if it is reading correctly.

Here is a thread showing what I did to eventually determine the root cause:

http://www.renntech.org/forums/index...=6267&hl=p1128

xclusivecar

I had the same codes and it ended up being the MAF. Apparently when a MAF goes bad in these cars it can and will set codes for a bad 02 sensor. Do a search and you will find many a person who have replaced all of their 02 sensors to still have the CEL. Then they replaced the MAF. Lots of money to "take a guess". You need Porsche or someone with the computer program to actually look at the variables all of your sensors are reading and only this will tell you the true problem.

originalmotorhead

Well, it's been almost a week and I've driven 300 miles and no CEL! Hoping to borrow a friends diagnostic reader and pull the MAF sensor values at the different RPM's and compair against ar38070's to see if my MAF is kaput. Also watching eBay to possibly buy one of the scanners so I have it for future problem resolution.

Tom

mackgoo

I too replaced the MAF to finally fix the same codes.

ar38070

This is the laptop based scanner that I use:

www.bowserelectronics.com

They auction one off every day on ebay starting at $125.

originalmotorhead

So you like the Bowers scanner ? $125 is a lot cheeper than the tool I was looking at, plus I would prefer the laptop so I could save the data for later comparisons. I will check ebay this weekend.

Tom

deliriousga

That is an excellent price! I use AutoTap http://www.autotap.com which looks to have all of the same functions as the Bowser unit, but was more expensive when I got it at $180.

This kind of tool is a must with '96 and newer vehicles. It will drop your troubleshooting headaches exponentially!

originalmotorhead

Well, the two codes have returned.

I am planning ot either attempt to clean the MAF sensor or just replace it. I took some MAF sensor readings at various RPM'S with a scanner but the reader spit out numbers at LB/M which is a different scale than what r38070's scanner read. I'm guessing there is a conversion but not sure.

Autozone sells the sensors(actual Bosch) for near the same price as one of the online parts places so I may pick it up this coming week. I just hope that is the root cause of the problem.

Tom

originalmotorhead

I cleaned the sensor today, I'll drive for a week or so and see what happens. BTW, that was the easiest thing I have removed/installed on this car besides the floor mats : )

I think I will be ordering one of the code scanners for myself so I don't have to continuously goto AutoZone or my friends place.

Tom

originalmotorhead

I forgot to ask onething. Hey ar38070, the part number for the MAF in my car is matching up with the on on autohaus that says with M620 e-accelerator, any idea what the difference is ? Mine is a 2000 model with 2.7 and yours is a 98, correct ? Autozone told me they could get the Bosch part in 2 days. If i have to order, I will just get the one that matches the #'s to the part I took out of the car but I was just curious what the difference is for the M620 e-accelerator.

thanks,
tom

ar38070

The readings I took from the MAF are grams/second. You can do the math to convert lb/m (which I assume is pounds/minute).

The cheapest place to buy a MAF that I know of is:

http://www.autohausaz.com/catalog/lo...Token=80622876

You lucked out. You can use the cheaper one as it is for Egas cars like yours (egas is the electronic throttle control). The earlier cars (1997-99) like mine have a mechanical throttle linkage.

FYI when you clear the CEL, unless the problem is really bad, it will take a while for the CEL to reappear. The ecu monitors the problem but will not turn the CEL back on until the ecu has seen the problem for a certain period of time. So if you clean the MAF, clear the CEL, it will look like things are okay, but if something is still wrong the CEL will eventually reappear.

The cheap scanners only report a code once the CEL is lit. The more advanced scanners (like the Bowser) will actually show a pending code sooner. When I was troubleshooting my problem the pending code would show up in about 10 miles. So a pending code is where the ecu has detected a possible problem and is monitoring the situation to see if the cause was something transient or a real problem. If after a while (I do not know what the time parameters are) if the reason for the pending code has not gone away the CEL is triggered.