Notices
996 Forum 1999-2005
Sponsored by:

I am getting sick of replacing the MAF

Thread Tools
 
Search this Thread
 
Old 09-11-2009, 08:46 PM
  #1  
RAC
Racer
Thread Starter
 
RAC's Avatar
 
Join Date: Feb 2004
Location: looking for a job ... Colorado by bye 996 C4 :(
Posts: 401
Likes: 0
Received 0 Likes on 0 Posts
Default I am getting sick of replacing the MAF

uuuugghhhh .... I have been getting the double ABS and PSM and then today the check engine light with codes P1126 and P1133. I just replaced the last MAF about 2 1/2 years ago. How long is the life of these MAF?
Old 09-12-2009, 01:33 AM
  #2  
jrgordonsenior
Nordschleife Master
 
jrgordonsenior's Avatar
 
Join Date: Oct 2004
Location: Vacuuming Cal Speedway
Posts: 7,306
Likes: 0
Received 7 Likes on 5 Posts
Default

Bosch guarantees them for 1 year.....
Old 09-12-2009, 03:26 AM
  #3  
blinkwatt
Pro
 
blinkwatt's Avatar
 
Join Date: Nov 2005
Location: Sacramento
Posts: 619
Likes: 0
Received 0 Likes on 0 Posts
Default

What makes you think that combo of codes is the MAF?

Last edited by blinkwatt; 09-12-2009 at 03:43 AM.
Old 09-12-2009, 05:30 AM
  #4  
redridge
Nordschleife Master
 
redridge's Avatar
 
Join Date: Oct 2006
Posts: 7,446
Received 61 Likes on 48 Posts
Default

these dont blow that often as people think, if you still have the old, put that one in.
Old 09-12-2009, 09:35 AM
  #5  
Macster
Race Director
 
Macster's Avatar
 
Join Date: Sep 2006
Location: Centerton, AR
Posts: 19,034
Likes: 0
Received 246 Likes on 217 Posts
Default

Originally Posted by redridge
these dont blow that often as people think, if you still have the old, put that one in.
Yep. I replaced original MAF at 120K (wag) miles and then found out when symptoms still present cause of symptoms was a vacuum leakin from a leaking oil filler tube cap. Replaced the cap with a new one and continued to use new MAF. Saved old one, though.

Roughly 80K miles later engine started acting up a bit and traced problem to "new" MAF. On a hunch swapped out suspect MAF and installed original MAF.

Original MAF still worked (and is working) just fine. "New" MAF had gone bad in 80K miles.

Sincerely,

Macster.
Old 09-12-2009, 10:40 AM
  #6  
Miller_arch
Racer
 
Miller_arch's Avatar
 
Join Date: Jan 2005
Location: Kansas City, MO
Posts: 370
Received 8 Likes on 6 Posts
Default

I've been getting CEL about once a week for some time; either P1126 or P1128. What these codes are communicating is that the DME can’t make the fuel mixture rich enough. Because the codes are occurring on both the left and right sides its likely not a fuel injector issue. After some research I'm in a process of doing the following:

1. Check oil cap. This I have done, I think I will replace it or see if I can find a replacement o-ring.
2. Try and put a vacuum on the intake system and see if it holds. Researching how to do that right now.
3. Replace fuel filter, will likely just do it.
4. Replace air/oil separator, expensive item will make sure 1 to 3 are done first.

Then if all this fails replace the MAF.
Old 09-12-2009, 02:53 PM
  #7  
wwest
Drifting
 
wwest's Avatar
 
Join Date: Sep 2001
Location: redmond wa
Posts: 2,467
Likes: 0
Received 14 Likes on 9 Posts
Default

K&N involved...??

Regular OEM engine air filter change otherwise...??
Old 09-12-2009, 03:01 PM
  #8  
wwest
Drifting
 
wwest's Avatar
 
Join Date: Sep 2001
Location: redmond wa
Posts: 2,467
Likes: 0
Received 14 Likes on 9 Posts
Default

Originally Posted by Miller_arch
I've been getting CEL about once a week for some time; either P1126 or P1128. What these codes are communicating is that the DME can’t make the fuel mixture rich enough. Because the codes are occurring on both the left and right sides its likely not a fuel injector issue. After some research I'm in a process of doing the following:

1. Check oil cap. This I have done, I think I will replace it or see if I can find a replacement o-ring.
2. Try and put a vacuum on the intake system and see if it holds. Researching how to do that right now.
3. Replace fuel filter, will likely just do it.
4. Replace air/oil separator, expensive item will make sure 1 to 3 are done first.

5. Install a new OEM engine intake air filter

6. Remove the MAF/IAT module and clean it. Use a Q-tip and solvent to clean (CAREFULLY) any oil or dirt from the two little glass beads you will see in the airway. One of these is a HOT WIRE air flow rate sensor,MAF, and the other is a diode used to sense intake airflow temperature, IAT.


Then if all this fails replace the MAF.
....
Old 09-12-2009, 03:03 PM
  #9  
1999Porsche911
Race Car
 
1999Porsche911's Avatar
 
Join Date: Apr 2004
Location: Chicagoland
Posts: 4,159
Likes: 0
Received 7 Likes on 5 Posts
Default

Originally Posted by Miller_arch
I've been getting CEL about once a week for some time; either P1126 or P1128. What these codes are communicating is that the DME can’t make the fuel mixture rich enough. Because the codes are occurring on both the left and right sides its likely not a fuel injector issue. After some research I'm in a process of doing the following:

1. Check oil cap. This I have done, I think I will replace it or see if I can find a replacement o-ring.
2. Try and put a vacuum on the intake system and see if it holds. Researching how to do that right now.
3. Replace fuel filter, will likely just do it.
4. Replace air/oil separator, expensive item will make sure 1 to 3 are done first.

Then if all this fails replace the MAF.
You're right that the O2 sensors are trying to richen the mixture, but an 1126 and 1128 are totally different. 26 is a problem at idle and a 28 is a problem on throttle.
Old 09-12-2009, 05:49 PM
  #10  
Macster
Race Director
 
Macster's Avatar
 
Join Date: Sep 2006
Location: Centerton, AR
Posts: 19,034
Likes: 0
Received 246 Likes on 217 Posts
Default

Originally Posted by Miller_arch
I've been getting CEL about once a week for some time; either P1126 or P1128. What these codes are communicating is that the DME can’t make the fuel mixture rich enough. Because the codes are occurring on both the left and right sides its likely not a fuel injector issue. After some research I'm in a process of doing the following:

1. Check oil cap. This I have done, I think I will replace it or see if I can find a replacement o-ring.
2. Try and put a vacuum on the intake system and see if it holds. Researching how to do that right now.
3. Replace fuel filter, will likely just do it.
4. Replace air/oil separator, expensive item will make sure 1 to 3 are done first.

Then if all this fails replace the MAF.
You can check the cap. If it is leaking it should be easy to check. With engne idling try to move the cap. Pay attention to engine. If engine reacts cap leaking. You might even be able to hear the air leaking past the cap. I did -- or I should say a co-worker heard the leaking cap on my Boxster. Moving the cap around -- just wiggling it -- one could hear the leak noise change, even go away, then return as the cap moved around.

Cap cost $13. Do not think the problem was the o-ring. I appeared to me the problem was the cap's fingers that worked to pull the cap down and snug on the oil filler tube were just worn.

BTW, the air leaking past the cap is a lot at idle. But at engine speeds above idle represents very little of the air entering the engine so if the error codes represent failure to supply enough fuel at engine speeds higher than idle this suggests the problem is not a cap leak. It could still be a failing AOS though.

While you're there at oil filler tube cap check for excessive vacuum. One symptom when my car's AOS was failing -- before I knew what it was -- was excessive vacuum at oil filler tube. Was unable to pull the cap off against the pressure difference.

A bad AOS may not exhibit this symptom so if it is absent it is not proof AOS is ok, though.

Do not waste time trying to put a vacuum on the intake system. With the valves you won't be able to do this. Used to on engines where the intake more accessible with the engine warmed up and idling spray carb cleaner around where the intake bolts to the heads and intake ports. This was when an intake leak at one of these interfaces suspected. If a leak is present it will cause the carb cleaner to be pulled into the engine and the engine will react by speeding up or slowing down. Varies.

Others use a small bottle of propane or butane. If there is a leak the engine when it gets a whiff of the propane will react and you'll know.

If fuel filter not flowing enough fuel to engine at idle enough to trip engine controller at enrichening threshold error codes the engine should cut out at high rpms cause it can't get enough fuel to keep it running.

If cap found ok or replaced and symptom still present be sure oil filler tube not cracked. If this ok then suspect AOS.

A test for the MAF is to clear error codes -- which also resets fuel trims to 0 -- and disconnect the MAF from the wiring harness and drive the car and see if error codes return. Also, if the MAF bad enough to cause any other engine misbehavior disconnecting it can make these go away. If they go away...

IIRC there are voltage checks to use to help ID bad MAF but my tech resources are not with me and I can't recall the numbers.

Sincerely,

Macster.
Old 09-12-2009, 06:47 PM
  #11  
RAC
Racer
Thread Starter
 
RAC's Avatar
 
Join Date: Feb 2004
Location: looking for a job ... Colorado by bye 996 C4 :(
Posts: 401
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by blinkwatt
What makes you think that combo of codes is the MAF?
Well that was what the problem was 2 1/2 years ago.
Old 09-12-2009, 06:58 PM
  #12  
RAC
Racer
Thread Starter
 
RAC's Avatar
 
Join Date: Feb 2004
Location: looking for a job ... Colorado by bye 996 C4 :(
Posts: 401
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by 1999Porsche911
You're right that the O2 sensors are trying to richen the mixture, but an 1126 and 1128 are totally different. 26 is a problem at idle and a 28 is a problem on throttle.
What is 33? Something to do with bank 2 I am guessing. I will get the the ABS/PSM lights after lifting the gas pedal under hard acceleration.
Old 09-12-2009, 06:59 PM
  #13  
1999Porsche911
Race Car
 
1999Porsche911's Avatar
 
Join Date: Apr 2004
Location: Chicagoland
Posts: 4,159
Likes: 0
Received 7 Likes on 5 Posts
Default

Originally Posted by Macster
You can check the cap. If it is leaking it should be easy to check. With engne idling try to move the cap. Pay attention to engine. If engine reacts cap leaking. You might even be able to hear the air leaking past the cap. I did -- or I should say a co-worker heard the leaking cap on my Boxster. Moving the cap around -- just wiggling it -- one could hear the leak noise change, even go away, then return as the cap moved around.

Cap cost $13. Do not think the problem was the o-ring. I appeared to me the problem was the cap's fingers that worked to pull the cap down and snug on the oil filler tube were just worn.

BTW, the air leaking past the cap is a lot at idle. But at engine speeds above idle represents very little of the air entering the engine so if the error codes represent failure to supply enough fuel at engine speeds higher than idle this suggests the problem is not a cap leak. It could still be a failing AOS though.

While you're there at oil filler tube cap check for excessive vacuum. One symptom when my car's AOS was failing -- before I knew what it was -- was excessive vacuum at oil filler tube. Was unable to pull the cap off against the pressure difference.

A bad AOS may not exhibit this symptom so if it is absent it is not proof AOS is ok, though.

Do not waste time trying to put a vacuum on the intake system. With the valves you won't be able to do this. Used to on engines where the intake more accessible with the engine warmed up and idling spray carb cleaner around where the intake bolts to the heads and intake ports. This was when an intake leak at one of these interfaces suspected. If a leak is present it will cause the carb cleaner to be pulled into the engine and the engine will react by speeding up or slowing down. Varies.

Others use a small bottle of propane or butane. If there is a leak the engine when it gets a whiff of the propane will react and you'll know.

If fuel filter not flowing enough fuel to engine at idle enough to trip engine controller at enrichening threshold error codes the engine should cut out at high rpms cause it can't get enough fuel to keep it running.

If cap found ok or replaced and symptom still present be sure oil filler tube not cracked. If this ok then suspect AOS.

A test for the MAF is to clear error codes -- which also resets fuel trims to 0 -- and disconnect the MAF from the wiring harness and drive the car and see if error codes return. Also, if the MAF bad enough to cause any other engine misbehavior disconnecting it can make these go away. If they go away...

IIRC there are voltage checks to use to help ID bad MAF but my tech resources are not with me and I can't recall the numbers.

Sincerely,

Macster.

Hooking up a vacuum gauge to the intake is simple and everyone who works on their own cars should know their normal vacuum reading as well as how to read the gauge.
Old 09-12-2009, 11:24 PM
  #14  
Miller_arch
Racer
 
Miller_arch's Avatar
 
Join Date: Jan 2005
Location: Kansas City, MO
Posts: 370
Received 8 Likes on 6 Posts
Default

Originally Posted by 1999Porsche911
You're right that the O2 sensors are trying to richen the mixture, but an 1126 and 1128 are totally different. 26 is a problem at idle and a 28 is a problem on throttle.
Well...it looks like I got some research'n to do...

Originally Posted by RAC
What is 33? Something to do with bank 2 I am guessing. I will get the the ABS/PSM lights after lifting the gas pedal under hard acceleration.
This looks to be the codes from a search...
P1126- Oxygen Sensor Low Adaptation, Lower load range, Bank 1
P1128- Oxygen sensing adaptation, Idle range bank 1
P1133 Oxygen sensing adaptation, Lower range bank 2

I had the ABS/PSM problem show up one time as well.

Perhaps these issues are better left to the pros to figure out...
Old 09-24-2009, 08:36 PM
  #15  
Miller_arch
Racer
 
Miller_arch's Avatar
 
Join Date: Jan 2005
Location: Kansas City, MO
Posts: 370
Received 8 Likes on 6 Posts
Default

^^^
And so I did just that. From the ticket:

"hooked up tester. Checked fault codes. p1126, P1128, P1130, has both rich and lean fault codes. needs mafs. replaced mass air meter. cleared faults, tested system. all OK."

I will report back if CEL comes on again. And btw it was covered under my CPO Warranty.



Quick Reply: I am getting sick of replacing the MAF



All times are GMT -3. The time now is 02:27 AM.