CEL codes again

Fullthrottle52 · Fullthrottle52's Garage

I have a 2000 box. I have owned it for only 3 months. Within a week after I bought it I got a CEL. Codes came up p1128 and p1130 indicating a rich fuel limit. I cleaned the air filter and cleaned the MAF sensor. I reset the CEL and have put about 2500 miles on it. This morning I went to start it up and immediately got a CEL again. The codes came up the same as before. Does anyone have an idea where to start. I hate to replace 3 or 4 parts and not resolve the issue once and for all. The car still runs strong with no other issues.

Any suggestions would be appreciated.

newlife · newlife's Garage

Quote:

Originally Posted by Fullthrottle52

I have a 2000 box. I have owned it for only 3 months. Within a week after I bought it I got a CEL. Codes came up p1128 and p1130 indicating a rich fuel limit. I cleaned the air filter and cleaned the MAF sensor. I reset the CEL and have put about 2500 miles on it. This morning I went to start it up and immediately got a CEL again. The codes came up the same as before. Does anyone have an idea where to start. I hate to replace 3 or 4 parts and not resolve the issue once and for all. The car still runs strong with no other issues.

Any suggestions would be appreciated.

Maybe dump some Techron in the tank....also did you clean the throttle body? If not I would start there.

Rod

Dale_K · 07-25-2011, 04:33 AM

I had some CEL's with my 2000 S. You can start by looking around and listening for any hissing sounds related to vacuum leaks. Or find a place that has the equipment to do a smoke test to find vacuum leaks. One of the most common spots is the oil fill tube, either at the junction near the throttle body or the accordian section near the rear bulkhead. You need to eliminate the leaks first but on my car it took a new MAF sensor to actually fix the CEL but search for vacuum leaks before doing anything else.

You probably should buy the Durametric unit. I didn't find it very valuable in identifying the source of the problems but I wrote down the readings for loss adaptation and kept trying different things. Finally the new MAF sensor fixed it and the Durametric readings went to "normal" values so at least I knew when something changed for the better.

mikefocke · 07-25-2011, 07:24 AM

You cleaned the air filter which implies you have a non-OEM air filter? Then assume that someone had to mess with the intake tubing in the past and something got loose as a starting point. There are small hoses that connect that could be cracked, junctions that aren't tight. Throttle body dirty. Etc.

Fullthrottle52 · Fullthrottle52's Garage

Mikefocke,

What I meant to say about the filter cleaning was that I took our the OEM filter and blew air on it to clean off the dust. It really was not that bad in the first place.

Thanks for the input.

ABQautoxer · 07-25-2011, 02:37 PM

Most everything I saw points to either a MAF issue or a post-MAF intake leak (letting unregistered air in the system and thus the car runs a bit leaner than it should). This thread might prove useful:

http://forums.rennlist.com/rennforums/996-forum/417032-p1128-p1130-error-code-opinion.html

Fullthrottle52 · Fullthrottle52's Garage

Just wanted to post that Dale_k was right. Ended up being a slit in the oil fill tube.
I was in the accordian area and was about 2 inches long. Problem fixed.
Total of $50.00 to fix.
Thanks to all.

Fullthrottle52 · Fullthrottle52's Garage

Drove the car about 24 hours and the CEL light is back on.

I give up. I have had this car 3 months and the CEL is on more then off.
I have owned 20 cars in my life and never dealt once with this kind of issue.
Engine runs strong and I love the car but i don't have time to keep taking this in to the shop, for what?
Porsche should be ashamed of it's self for producing such an expensive car with so many problems that I see on here.

I guess I'll keep chasing the mouse till I catch it.

Dale_K · 08-07-2011, 07:43 AM

At least you don't have an intermittant problem, lol. On my car it would sometimes go 250 miles before the CEL would return, which made it hard to track down. I too, am dismayed by the need for one repair after another and I kind of wish I'd bought a Miata.

If your problem is a vacuum leak it must be pretty significant. My car is a Tiptronic and there was a leak on the vacuum operated valve in the cooling line. Also a vacuum leak on the main brake booster pipe up near the left front of the engine. Right now my car is in the shop for yet another vacuum leak that only shows up when the engine compartment gets heat soaked.

Back to your car, you might want to talk to your local independent garage to see if they are willing to temporarily swap out the MAF sensor with a known good unit. My local place was so sure the MAF would clear it up that they were willing to give me my money back if it didn't work. I figured if they were that sure I might as well try it so I bought it and put it in myself (very easy job) and in my case it cleared up the CEL. I don't know it will work for you but I had the same codes and also relaced my oil fill tube (definitely leaking) and my CEL didn't get fixed until I changed the MAF sensor. If you decide to go that route be sure you take your old one out and check the part number because I think 2000 models came with 2 different ones depending on when they were built. O'Reily sells a set of tamper proof bits that has the right one included for less than $5 for the whole set.

ronster · ronster's Garage

Quote:

Originally Posted by Fullthrottle52

Drove the car about 24 hours and the CEL light is back on.

I give up. I have had this car 3 months and the CEL is on more then off.
I have owned 20 cars in my life and never dealt once with this kind of issue.
Engine runs strong and I love the car but i don't have time to keep taking this in to the shop, for what?
Porsche should be ashamed of it's self for producing such an expensive car with so many problems that I see on here.

I guess I'll keep chasing the mouse till I catch it.

Here's another simple suggestion, have you checked your gas cap? Is it tightened three or more clicks when you refuel? Is it in good condition and sealing properly?

bklyn · 08-07-2011, 11:31 AM

Fullthrottle, put a new air filter in and remove the maf and clean it really well with some CRC Maf cleaner and see if that does the trick. Inexpensive and should be done anyway!

Fullthrottle52 · Fullthrottle52's Garage

I already cleaned the MAF sensor a month or so ago.
It did work for a few weeks before the codes came back. I disconected the battery that time and cleared the codes. I think I will just change out the sensor and see what happens. I just had the CEL codes read and it only showed p1130 this time. NO 1128. So it is just limited to one side of the engine this time. I'll take it back to my indy and see what he thinks. I will ask if he is willing to loan me one to see if that if the problem. Thanks to all for the help.

mikefocke · 08-07-2011, 05:07 PM

Recall as you read the forums that most of the people who post are those with problems, the ones that don't are out enjoying their car.

Is ever thus on any car forum though perhaps the P-car owners are a little more involved and know more about their cars.

Owned 2, each fantastically reliable and cheap to maintain.

ronster · ronster's Garage

I had a few problems with my '99 Boxster after I bought it including a CEL but it was a ten year old car at the time and I expected some issues with it. After clearing them up I've had over 20K carefree and fun miles with it including track and AX time. Hope this is encouraging.

paulv · 09:28 AM

Quote:

Originally Posted by Fullthrottle52

I already cleaned the MAF sensor a month or so ago.
It did work for a few weeks before the codes came back. I disconected the battery that time and cleared the codes. I think I will just change out the sensor and see what happens. I just had the CEL codes read and it only showed p1130 this time. NO 1128. So it is just limited to one side of the engine this time. I'll take it back to my indy and see what he thinks. I will ask if he is willing to loan me one to see if that if the problem. Thanks to all for the help.

FT52,

The diagnosis of this fault (P1130 or P1128) is to:

(This is when the the air/fuel mix is so lean the adaptation has reached its maximum rich boundary.)

1a) Check the signal coming from the MAF sensor
1b) Check the exhaust system for leaks -- a leak ahead of the O2 sensor will cause a fault in fuel adaptation
1c) Check for air leaks in the intake air system
2) Check the fuel pressure (too low)
3) Check the volume supply of the fuel pump (too low)
4) Check to see if one of more fuel injectors are fouled on that bank.

(This is when the the air/fuel mix is so rich the adaptation has reached its maximum lean boundary.)

1) Check the signal coming from the MAF sensor
2) Check the fuel pressure (too high)
3) Fuel injector leaking
4) EVAP canister purge valve is open or not fully closed

Good luck!

Regards,
paul...

Fullthrottle52 · Fullthrottle52's Garage

thanks again to all that have given their advise here.

Got a call from my indy today and he recommended the AOS be replaced. I told him that the car was not exibiting any of the usual systems for that failure. I pulled the cap off the oil spout and very little to no vacuum. A little vacuum at the oil check tube with the dip stick removed. No smoke at start up. We then decided to change out the MAF sensor and try it for a couple of weeks. If that took away the light then so be it. If it did not then he would put the old sensor back in and replace the AOS.

Long story short, when he pulled the MAF sensor out of the car to check the part number, he discovered that it is the wrong sensor for my model. I have a 2000 and they made 2 different sensors that year depending on chassis numbers. We think someone replaced it with the wrong sensor for the chassis number. We have ordered the correct one to be put in today.

My question is, how much of a change was made to the sensor and could this alone cause the CEL light to throw p1128 and p1130 constantly. I would assume it would or they would not have changed the part number. Does anyone out there have any experience with this issue. I would love to hear from others who have knowlegde of this.

Thanks again to all.

Dale_K · 08-11-2011, 09:15 AM

I don't know how the mechanic would know which one came on the car from the factory. Maybe it's possible based on build date. My 2000 S had the expensive "125" sensor. I remember reading somewhere that the other style sensor eventually had a revision that required a remap of the ECU. I don't know how you'd check that on a specific car. Maybe the Durametric can read the software version. I hope I'm not throwing you off track with these comments.

Fullthrottle52 · Fullthrottle52's Garage

It is done by chassis number or vin number.

The mechanic showed me on his computer where he orders his parts and it let's you put in the vin number and it tells you what part to order.

Unfortunatly, he read the numbers wrong. I showed him that the correct MAF sensor was in the car all along. He had a new one on the shelf that was the same one that was already in the car so we put in a new MAF.

This is really getting confusing and I am convinced that most indy's don't know what they are doing some of the time.

Very discouraged! Well we will see what happens now that there is a new sensor in the car. Hopfully I won't be back.

teamwenz · 08-13-2011, 07:06 AM

Full Throttle there are only two MAF sensors. One is for mechanical throttle and the other is electronic or e-gas. 97-99 are mechanical or non e-gas and starting in 2000 they switched. Here is a plug for the pelican website who hosts this forum. Look up the part and you will see what I mean. I am suprised your car even ran. If your indie did not know this I would search for a new one. Even if he is your brother in law

Fullthrottle52 · Fullthrottle52's Garage

Teamwenz, You are wrong.

There is a 124 and a 125 part number for 2000 Boxters. Which one you use depends on the chassis number or Vin number. 2000 was the only year you have to worry about this. Look up the part on this web site and you will see this for yourself.

Thanks,