1128 & 1130

[TerryT]

Hi,

I am getting cel with codes 1128 and 1130.

I have cleared the codes and things are ok if I don't rev too high.

So my first question is, is this related to the air filter... would changing the air filter help greatly or is this not really the problem ?

Why does the air filter I ordered off pelican parts not match the air filter I pulled out the car ? The one I have is a rectangle and the one I ordered seems to have a slice out of the corner.

Pelican Parts - Product Information: 996-110-131-04-M63

The one I have in my car is : 996.572.219.02

Where exactly is the MAF and how can I get access it to clean it ?

Any help would be greatly appreciated.

Thanks
Terry

[TerryT]

Originally Posted by TerryT

Hi,

I am getting cel with codes 1128 and 1130.

I have cleared the codes and things are ok if I don't rev too high.

So my first question is, is this related to the air filter... would changing the air filter help greatly or is this not really the problem ?

Why does the air filter I ordered off pelican parts not match the air filter I pulled out the car ? The one I have is a rectangle and the one I ordered seems to have a slice out of the corner.

Pelican Parts - Product Information: 996-110-131-04-M63

The one I have in my car is : 996.572.219.02

Where exactly is the MAF and how can I get access it to clean it ?

Any help would be greatly appreciated.

Thanks
Terry

Ok I see now...

Access the engine compartment

HOW TO: Access Engine Compartment on my Porsche Boxster - GSR Autosport Community

Clean or replace the MAF

HOW TO: Remove/Install Mass Air Flow Sensor (MAF) in Porsche Boxster - GSR Autosport Community

What I had referenced above was the cabin filter.

Terry

[Meir]

Hi Terry.
If can recommend you of something, get the following things (in that order)
1. Durametric diagnostic tool.
2. The book "101 projects for your boxster" from pelican.
3. The "Bentley" book.
If you need some help just drop a PM, and come over for a visit

[TerryT]

Hi,

So I did the following :

1. Confirmed I have a clean air filter.
2. Cleaned the MAF with a MAF cleaner from Advance auto parts.
3. Cleared the codes.

And then :

Car seemed to be fine, no problem... but then again there was no problem before really. CEL light came on again at about 100 miles.

So should I get a new MAF or could it be something else entirely ?

Or should I just take it to dealer and hope the warranty covers it ?

Thanks
Terry

[paulv]

Terry,

Here's the info for P1128 & 1130:

Fault condition:
Fuel/air mixture so lean that sensing has reached its rich threshold.

Potential fault areas:
– Incorrect signal from MAF sensor
-- MAF is failing
– Intake air system leaking
-- Air is introduced past the MAF causing the mixture to be more lean
– Fuel pressure too low
-- Not enough fuel to meet demand causing the mixture to be more lean
– Volume supply of fuel pump too low
-- Not enough fuel to meet demand causing the mixture to be more lean
– Fuel injectors fouled
-- Not enough fuel to meet demand causing the mixture to be more lean
– Exhaust system leaking
-- When the exhaust system has leaks before the front O2 sensor will cause the O2 sensor to report a lean condition (excess oxygen i the exhaust)

BTW, I agree with Meir's recommendation. I have the Durametric tool and could have ruled out the MAF sensor in a couple of minutes (with the service info) -- with the key on and engine off, the MAF voltage should be approx 0.9 to 1.1 volts -- at idle, the voltage should be approx 1.4 volts.

Regards,
paul...

[TerryT]

Originally Posted by paulv

Terry,

Here's the info for P1128 & 1130:

Fault condition:
Fuel/air mixture so lean that sensing has reached its rich threshold.

Potential fault areas:
– Incorrect signal from MAF sensor
-- MAF is failing
– Intake air system leaking
-- Air is introduced past the MAF causing the mixture to be more lean
– Fuel pressure too low
-- Not enough fuel to meet demand causing the mixture to be more lean
– Volume supply of fuel pump too low
-- Not enough fuel to meet demand causing the mixture to be more lean
– Fuel injectors fouled
-- Not enough fuel to meet demand causing the mixture to be more lean
– Exhaust system leaking
-- When the exhaust system has leaks before the front O2 sensor will cause the O2 sensor to report a lean condition (excess oxygen i the exhaust)

BTW, I agree with Meir's recommendation. I have the Durametric tool and could have ruled out the MAF sensor in a couple of minutes (with the service info) -- with the key on and engine off, the MAF voltage should be approx 0.9 to 1.1 volts -- at idle, the voltage should be approx 1.4 volts.

Regards,
paul...

Excellent post Paul, thank you!

I will be getting the Durametric tool, but possibly only within the next few weeks.

My CEL comes on with these codes when I am idling, not when driving... would that narrow the list down somewhat ? Any ideas why it would happen then ?

Thanks again.
Terry

[paulv]

Originally Posted by TerryT

Excellent post Paul, thank you!

I will be getting the Durametric tool, but possibly only within the next few weeks.

My CEL comes on with these codes when I am idling, not when driving... would that narrow the list down somewhat ? Any ideas why it would happen then ?

Thanks again.
Terry

Terry,

You're welcome!

My first guess would be to check for leaks in the air intake system which would allow air to enter at idle when the intake vacuum is very high. When driving, the intake vacuum is very low because you're [normally] drawing in air into the intake so very little air can be drawn in from the outside of the intake. A good way to see this is with a full OBD2 scan tool (which has Mode $07) to monitor the Long Term Fuel Trim (LTFT aka Fuel Adaptation) for each bank where you would see the LTFT reading going positive high (more rich) at idle and then coming back to normal at approx 2000 rpms.

Since you're getting this code for both banks, then the problem is not bank-specific (at least it appears that way).

My second guess would be to check the exhaust for leaks, but then again, both bank codes are appearing which leads me to stay with my first guess.

Intake vacuum leaks are a hassle to look for unless you have a smoke machine (which most of us DIY'ers don't own due to costs), but you can still look. While the vehicle is idling, check all the intake plenum parts, the AOS*, and all other lines going into the intake for signs of leaks (noise, cracked hoses, etc). There are a couple of other methods but I don't recommend them because if misused, they can cause serious problems.

Since the car drives OK, then the fuel delivery system is probably OK.

Good luck.

Regards,
paul...

*AOS = Air Oil Separator, which is a sophisticated version of a Positive Crankcase Ventilation (PCV) system. Besides the PCV function, the AOS helps to prevent foaming of the oil. Also, check out Pelican Parts as Wayne has published some great and inexpensive books on Porsche repairs and also has many tech articles that can help you.

[fullthrottle52]

Get a new MAF Sensor. Cleaning does not always work. Also check for air leaks. A good mechanic will smoke test the engine and look for leaks. I had the same problem and found a slit in the oil filler tube. Replaced the filler tube and still had CEL. Replaced the MAF and gone for good.

[MN 986]

A new twist?
I got a CEL and checked for codes with my handy OBDII code reader. I got P1128 and 1130, but then the car would not re-start. It actually started once and ran for a few minutes until I turned it off, but now it will not re-start. It just turns over with no hint of firing. Has anyone had that problem, and how was it resolved?
Thanks for any help.

[sb01box]

I've also had recurring 1128/1130. only at idling at an intersection waiting for the signal to turn green.
did all the recommendations provided by the forum.
MAF cleaning worked the first time/
2 years later, cleaning only worked for a few days.
replacing the MAF worked.
it's been CEL free for about a year.

[MN 986]

Cleaning the MAF will be my first move. I just hadn't read in any of the other posts or threads on 1128/1130 that the car would not re-start and I was wondering if that pointed to any other possible problems/fixes.
If anyone has ideas or experience with the car not starting with these codes, please let me know.
Thanks!

[TerryT]

Hi, from what I've read the most likely culprit if the MAF. It will likely need to be replaced.

My codes were not MAF related though, I had a few hoses that needed to be replaced in my vacuum system.

Thanks
Terry

[MN 986]

Cleaned the MAF and the car still would not start. Called a local indy shop and he said MAF or AOS would not likely cause a 'no start' situation. He said based on what I had told him, he'd look at the fuel pump relay then the fuel pump. I could not hear the fuel pump run at all, so he suggested I jump the relay to see if that powered the pump. It worked! I briefly ran the car, and it sounded perfect. I will have to order a new fuel pump relay (dealer only part, not in stock), then I hope to be back on the road.

[MN 986]

Well, the solution to my no start problem was the fuel pump relay. I got a 1128 and 1130 'lean' code because the car was not getting gas, then it would not restart (luckily for me) in my garage. A local indy mechanic helped me work through the problem on the phone and saved me from spending at least a few hundred for a tow and his diagnostic labor. $25 at the local dealer, and I am back on the road!!

[coolbreeze551]

Thanks for the update, I appreciate when a problem has been brought up and the solution is posted.

[gerber28]

I've also had 1128 & 1130 codes on 2 occasions, both times while idling at a long traffic light. I've cleared the codes with OBDII reader and have not had a re-occurrence in the last month.
I ordered a Durametric and the scan showed a fault on the fuel pump relay.
My question is has the fuel pump relay caused the 1128/1130 codes or is the relay code a result of removing it to change the fuel filter?
I'm tempted to reset the fuel pump relay code to see if it faults again.
Even if it doesn't I'll probably order a new one, only $12.00 at Pelican.

[Joel-Box-ster]

I have a 1128 and 1130 codes before cleaned the MAF sensor replaced the clogged up air filter a new one and cleared both codes with a OBD II handheld scanner, 800+ miles later still no CEL I think that fixed the problem.

[MN 986]

Originally Posted by gerber28

I've also had 1128 & 1130 codes on 2 occasions, both times while idling at a long traffic light. I've cleared the codes with OBDII reader and have not had a re-occurrence in the last month.
I ordered a Durametric and the scan showed a fault on the fuel pump relay.
My question is has the fuel pump relay caused the 1128/1130 codes or is the relay code a result of removing it to change the fuel filter?
I'm tempted to reset the fuel pump relay code to see if it faults again.
Even if it doesn't I'll probably order a new one, only $12.00 at Pelican.

I don't think removing and replacing the relay would cause a CEL.
What I read and learned is that 1128/1130 basically mean the car is running lean. Usually the car is drivable and the problem is often fixed by 1) cleaning or replacing the MAF or 2) replacing the AOS.
In my case, the car would not start or even attampt to fire (luckily it happened in my garage). The mechanic at a local indy shop talked me through possibilities and due to the non-starting he suggested the fuel pump relay as a likely problem (or if the relay was good, maybe the fuel pump itself). He suggested jumping the relay to see if the fuel pump ran, and it did. I even started the engine,,, it started right away, just like usual. I ordered the relay from the local dealer and was back on the road the next day. I cleared the codes with my OBD2 scanner and they have not come back.
Bottom line for my situation is that it was running lean (hence the 1128/1130 codes) because the relay was not running the fuel pump correctly.

[Joel-Box-ster]

My CEL came on today and its the 1128/1130 codes again maybe its time to replace the MAF sensor..