Check Engine Light issue
 

Hello to all,

Just purchased a 2000 boxster. After 2 weeks the check engine light came on. Had private porsche mechanic check the problem. He put a reader on it and it came back with undefined porsche code and the numbers p1130 and p1128. He said he would have to take it to the shop to completely diagnose the problem. Any ideas as to what would cause these codes to come up? Boxter Light Codes say this would be a Oxygen Sensing problem. Any ideas what needs to be replaced.
He reset it and said it would probably return after so many starts. It came back today after 2 more weeks and maybe 20 to 30 starts.
Any help would be appreciated.

Thanks,

MAF Sensor.. save yourself the trouble and just replace it. It's about $230, but you'll have headaches from throwing other parts/ideas at it. Ask me how I know :)

http://www.iwantaporsche.net/BoxsterCheckEngineLightCodes.htm

P1128 Oxygen Sensing Adaptation Area 2 (Cylinders 1 - 3) - Rich Threshold

P1130 Oxygen Sensing Adaptation Area 2 (Cylinders 4 - 6) - Rich Threshold

Thanks
 

Is this MAF something I can purchase and replace myself or does it need to go to a mechanic or dealer.
I have heard this is a common part that slowly goes bad.

You can do it yourself but you will need a Torx T 20 anti-tamper bit/driver to remove the sensor. You will also have to get to the top of the motor by opening the convertible top half way, remove the carpet, then remove the motor cover. See photo below on what one of the Torx anti-tamper bits looks like.

I just changed my MAF sensor a couple of days ago . Here's the interesting thing, every DIY article refers to a T-20 torx as the correct size bit, when in fact it was a T-10 that fit the torx bolts on my vehicle . So, before anyone runs out the hardware or auto parts store to buy a single bit, make sure what size torx you have . Or, buy a set like the one Jager is showing .

I find that interesting as the P1128 and 1130 codes are an indication that the car has a problem keeping the system rich enough to maintain the A/F ratio; typically caused by either an intake system air leak or low fuel pressures......and nothing in the diagnostic tree even mentions testing or replacing the MAF……….

My thoughts exactly . That's why I posted the codes . I can't imagine this has anything to do with the MAF sensor ??

In general, it does not have anything to do with the MAF; MAF codes are P0101, 0102, and 0103, depending on what the problem is.............

Just for chuckles, over on RennTech, someone took out his MAF for cleaning, and forgot to reinstall it before driving off to work leaving the MAF sitting at home on the bench, apparently without any codes or problems. Now he wants to know if he needs to have it towed home or if he has done any permanent damage………….

Also from Renntech:

P1128, P1130
Possible fault causes:
– Incorrect signal from MAF sensor
– Intake air system leaking
– Fuel pressure too low
– Volume supply of fuel pump too low
– Fuel injectors fouled
– Exhaust system leaking

A fouled MAF can certainly cause the car to run lean... or rich tripping these codes. It still might be a failed MAF but an intake air leak is most often the cause.

While you can "never say never", to date, we have not had a car throwing 1128 and/or 1130 alone turn out to be a MAF issue, it always turned out to be either a vacuum leak or fuel system issue. A fouled MAF usually throws one of the "implausible signal" (high or low voltage) codes, often in conjunction with other codes. As the RennTech case points out, you can run the car for longer than you might expect without a MAF, as long as you stay below 4K RPM’s and don’t have any WOT excursions, before the car throws any code, and then usually pops a P0102 and/or P0112 (low signal voltage for the MAF sensor and the intake air temp sensor).

I had those codes and found an intake leak on the oil fill tube - got it fixed but the light came back. Took it to a shop and got it smoke tested for leaks. Found a small leak but that wasn't it. Bought a Durametric and started tracking fuel adaptation. Finally I found someone who knew what the figures meant. They implied a bad MAF. I got a new one and totally fixed the problem. The Durametric shows normal values now. My point is normally I'm not the kind of guy to throw parts at a problem but in this case a new MAF was the cure.

You might want to get your car smoke checked for vacuum leaks first. Fix those and if no improvement you might need a MAF.

Thanks to all.
 

Thanks to all that left me some answers.
I wish I could narrow it down to one thing but at least I have a place to start.
Can anyone tell me if it is safe to drive the car with the check engine light on for any length of time. I do need to get it to a mechanic. That would mean driving it 10 to 15 miles.

Thanks again for the help.

As long as the CEL is not flashing, it is safe to drive, but I would not be flogging the car until the issue was corrected.

JFP I completely agree with the vacuum leak theory, but in my case it COMPLETELY fixed these codes. A failed MAF can cause bad readings and make the car adjust improperly, which may lead to odd codes (rich, lean, etc).

I know it seems unlikely, but maybe that's why the people posting these codes on the Internet usually never report back.. they may be chasing the wrong thing.

In my case (only offering suggestions here) is the MAF completely fixed my problem and even fixed my cold start "hunt". Car runs 10x better with the new MAF.

While it's not a cheap part per se, the amount of time, effort, lost weekends, owing friends favors, etc that I put into checking "everything else", I would have much rather spent the $250 up front and chased from there.

I completely understand your position. I have to go by what I’ve seen and learned personally, and as such have not encountered what you did. We have had several cars in the shop that threw these codes and the owners replaced the MAF only to have the codes come back. When we looked at them, we found air leaks and the codes did not return. But based upon your and other’s experiences, I will have to open up to the possibility that a dying MAF can apparently cause the fuel adaption to change, which can definitely lead to the lean condition triggering the codes.

You live and you learn…………..

I had these same alarm codes not too long ago... Bad AOS.

Fullthrottle52,
Remove your oil fill cap while the motor is running (after it's warmed-up), what happens? Is the cap hard to remove? Does the idle drop (almost stall) after removing the cap?

This should be easier with technology we have today.
 

Jager,

No it does not. I already removed the cap and had normal results, no problem at idle.

Im beginning to think it is a MAF or small vaccum leak.

I'll keep you informed as I get it checked.

Thanks for all the answers.

Thought I would send a pic of my new (used) boxster.