DIY - MAF Cleaning

[911porschefan]

Is there a DIY for cleaning the MAF and tightening the bolts for the Air Intake Throttle Body. I have tried everything to get rid of error code 1128. Replaced air filter with K&N filter, checked all hoses and no air leaks. Still, every 150-200 kms, the CEL comes on. I would like to try cleaning the MAF and tightening the bolts a try before I take to a dealer who will empty out my pocket.

[1999Porsche911]

Is there a DIY for cleaning the MAF and tightening the bolts for the Air Intake Throttle Body. I have tried everything to get rid of error code 1128. Replaced air filter with K&N filter, checked all hoses and no air leaks. Still, every 150-200 kms, the CEL comes on. I would like to try cleaning the MAF and tightening the bolts a try before I take to a dealer who will empty out my pocket.

Remove the MAF and spray liberaly with electronics cleaner you can get at an ACE hardware store. Put it back in. Remove the intake tube to the throttbody and open the butterfly valve slowly, all the way. Spray liberaly with carb cleaner. Reinstall intake tube. Reboot computer by removing negative battery cable for 2 minutes and then reconnect. You're done. It will take a few drive cycles to get your idle back to being smooth.

[ebaker]

2469 P1128 0-116 page 1

p1128

Printed in Germany – 4, 2002

0-116 P1128

360 Oxygen Sensing Adaptation, Idle Range, Bank 1 -

Below Limit

Diagnosis conditions

• Oxygen sensing system active

• Time elapsed after engine start-up: 250 to 350 seconds (USA)

• Time elapsed after engine start-up: 302 to 402 seconds (RoW)

• Engine temperature greater than 60 °C

Possible fault cause

♦ Incorrect signal from MAF sensor

♦ Fuel pressure too high

♦ Fuel injector leaking

♦ EVAP canister purge valve open

Affected terminals

-

Diagnosis/Troubleshooting

♦ If DTC P0445 (fuel tank vent valve - short to ground) is stored, correct this fault first. An open EVAP canister

purge valve can lead to the lean threshold being reached.

♦ For vehicles in the USA, the upper load range will probably not be reached. The only case in which a fault could

be stored is during driving while towing a trailer or caravan on a hill.

♦ Contrary adaptation values in connection with misfiring point to incorrectly adjusted control timescheck control

times and adjust if necessary.

♦ If the fuel tank reserve light is switched on, no fault is entered.

Work instruction Display OK If not OK

1 Check signal from MAF

sensor.

♦ Connect special tool 9637.

♦ Measure voltage at pin III/23

and ground

♦ Switch on the ignition.

0.9 to 1.1 V. Replace MAF sensor

♦ Start the engine. Approx. 1,4 V

2 Check fuel pressure

Note!

DME 7.8 DME 7.8

2469 P1128 0-116 page 2

p1128

0

Printed in Germany – 4, 2002

360 Oxygen Sensing Adaptation, Idle Range, Bank 1 -

Above Limit

Diagnosis conditions

• Oxygen sensing system active

• Time elapsed after engine start-up: 250 to 350 seconds (USA)

• Time elapsed after engine start-up: 302 to 402 seconds (RoW)

• Engine temperature greater than 60 °C

Possible fault cause

♦ Incorrect signal from MAF sensor

♦ Intake air system leaking

♦ Fuel pressure too low

♦ Volume supply of fuel pump too low

♦ Fuel injectors fouled

3 Check fuel pressure regulator,

vacuum connection

and fuel return line

♦ Remove vacuum hose from fuel

pressure regulator

♦ Connect special tool 9103/2 to

vacuum hose

♦ Start the engine.

♦

0.4 - 0.6 bar Check the intake air

system for leaks

and check vacuum

line to fuel pressure

regulator for restrictions.

♦ Check housing of fuel pressure

regulator for damage and deformation

Replace the fuel

pressure regulator if

it is damaged with

the result that the

spring pre-tensioning

is increased

4 Check EVAP canister

purge valve

♦ Disconnect hose from EVAP canister

purge valve to intake system

at EVAP canister purge

valve

♦ Remove connector of EVAP canister

purge valve

♦ Connect special tool 9160/1 to

EVAP canister purge valve

♦ Generate vacuum of approx. 0.7

bar

The vacuum must

not fall below 0 bar

after 10 minutes

5 Check fuel injectors for

leaks

Work instruction Display OK If not OK

DME 7.8

2469 P1128 0-116 page 3

DME 7.8

p1128

0

Printed in Germany – 4, 2002

♦ PCV valve leaks

♦ Cap of oil filler neck not closed correctly or seal is damaged

Affected terminals

-

Diagnosis/Troubleshooting

♦ Air leaks ahead of the oxygen sensors can lead to a fault in adaptation Check exhaust system for leaks.

♦ Contrary adaptation values in connection with misfiring point to incorrectly adjusted control timescheck control

times and adjust if necessary.

♦ If the fuel tank reserve light is switched on, no fault is entered.

Work instruction Display OK If not OK

1 Close cap of oil filler neck

properly or replace the

seal

2 Check signal from MAF

sensor.

♦ Connect special tool 9637.

♦ Measure voltage at pin III/23

and ground

♦ Switch on the ignition.

0.9 to 1.1 V. Replace MAF sensor

♦ Start the engine. Approx. 1,4 V

3 Check exhaust system for

leaks

4 Check for air leaks in

intake air system

5 Check PCV valve for leaks

6 Check fuel pressure

7 Check volume supply of

fuel pump

8 Fuel injectors fouled ♦ If preceding Check Points were

negative, the fuel injectors may

be fouled

♦ Clean fuel injectors (ultrasonic

cleaning device) or replace them

Note!

[viper501]

.... error code 1128. Replaced air filter with K&N filter, checked all hoses and no air leaks. Still, every 150-200 kms, the CEL comes on. I would like to try cleaning the MAF and tightening the bolts a try before I take to a dealer who will empty out my pocket.

My MAF issues disappeared after removing the K&N style oiled filter and replacing w/ dry paper OEM element. I'd try that plus the electronic cleaner mentioned above.

[Stefan]

Check out this thread over at ppbb:

http://www.ppbb.com/boards/ppbbphp/showfla...rue#Post1058760

[diego996]

2469 P1128 0-116 page 1

p1128

Printed in Germany – 4, 2002

0-116 P1128

360 Oxygen Sensing Adaptation, Idle Range, Bank 1 -

Below Limit

Diagnosis conditions

• Oxygen sensing system active

• Time elapsed after engine start-up: 250 to 350 seconds (USA)

• Time elapsed after engine start-up: 302 to 402 seconds (RoW)

• Engine temperature greater than 60 °C

Possible fault cause

♦ Incorrect signal from MAF sensor

♦ Fuel pressure too high

♦ Fuel injector leaking

♦ EVAP canister purge valve open

Affected terminals

-

Diagnosis/Troubleshooting

♦ If DTC P0445 (fuel tank vent valve - short to ground) is stored, correct this fault first. An open EVAP canister

purge valve can lead to the lean threshold being reached.

♦ For vehicles in the USA, the upper load range will probably not be reached. The only case in which a fault could

be stored is during driving while towing a trailer or caravan on a hill.

♦ Contrary adaptation values in connection with misfiring point to incorrectly adjusted control timescheck control

times and adjust if necessary.

♦ If the fuel tank reserve light is switched on, no fault is entered.

Work instruction Display OK If not OK

1 Check signal from MAF

sensor.

♦ Connect special tool 9637.

♦ Measure voltage at pin III/23

and ground

♦ Switch on the ignition.

0.9 to 1.1 V. Replace MAF sensor

♦ Start the engine. Approx. 1,4 V

2 Check fuel pressure

Note!

DME 7.8 DME 7.8

2469 P1128 0-116 page 2

p1128

0

Printed in Germany – 4, 2002

360 Oxygen Sensing Adaptation, Idle Range, Bank 1 -

Above Limit

Diagnosis conditions

• Oxygen sensing system active

• Time elapsed after engine start-up: 250 to 350 seconds (USA)

• Time elapsed after engine start-up: 302 to 402 seconds (RoW)

• Engine temperature greater than 60 °C

Possible fault cause

♦ Incorrect signal from MAF sensor

♦ Intake air system leaking

♦ Fuel pressure too low

♦ Volume supply of fuel pump too low

♦ Fuel injectors fouled

3 Check fuel pressure regulator,

vacuum connection

and fuel return line

♦ Remove vacuum hose from fuel

pressure regulator

♦ Connect special tool 9103/2 to

vacuum hose

♦ Start the engine.

♦

0.4 - 0.6 bar Check the intake air

system for leaks

and check vacuum

line to fuel pressure

regulator for restrictions.

♦ Check housing of fuel pressure

regulator for damage and deformation

Replace the fuel

pressure regulator if

it is damaged with

the result that the

spring pre-tensioning

is increased

4 Check EVAP canister

purge valve

♦ Disconnect hose from EVAP canister

purge valve to intake system

at EVAP canister purge

valve

♦ Remove connector of EVAP canister

purge valve

♦ Connect special tool 9160/1 to

EVAP canister purge valve

♦ Generate vacuum of approx. 0.7

bar

The vacuum must

not fall below 0 bar

after 10 minutes

5 Check fuel injectors for

leaks

Work instruction Display OK If not OK

DME 7.8

2469 P1128 0-116 page 3

DME 7.8

p1128

0

Printed in Germany – 4, 2002

♦ PCV valve leaks

♦ Cap of oil filler neck not closed correctly or seal is damaged

Affected terminals

-

Diagnosis/Troubleshooting

♦ Air leaks ahead of the oxygen sensors can lead to a fault in adaptation Check exhaust system for leaks.

♦ Contrary adaptation values in connection with misfiring point to incorrectly adjusted control timescheck control

times and adjust if necessary.

♦ If the fuel tank reserve light is switched on, no fault is entered.

Work instruction Display OK If not OK

1 Close cap of oil filler neck

properly or replace the

seal

2 Check signal from MAF

sensor.

♦ Connect special tool 9637.

♦ Measure voltage at pin III/23

and ground

♦ Switch on the ignition.

0.9 to 1.1 V. Replace MAF sensor

♦ Start the engine. Approx. 1,4 V

3 Check exhaust system for

leaks

4 Check for air leaks in

intake air system

5 Check PCV valve for leaks

6 Check fuel pressure

7 Check volume supply of

fuel pump

8 Fuel injectors fouled ♦ If preceding Check Points were

negative, the fuel injectors may

be fouled

♦ Clean fuel injectors (ultrasonic

cleaning device) or replace them

Note!

Has anyone used the special tool 9637 to check the MAF? Where would I find it?

[Loren]