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Joined: Dec 14 2018
Posts: 70

I am about to install a new set of O2 sensors due to a new fault code popping up during the last ride. At 105K I figure need to replace all.

I figure it is also a good time to remove the MAF and spray clean it with CRC MAF cleaner.

Two questions--

Do you remove the multi-connector by pressing down the arms on either side and pull-- or do you spread them and pull. Plastic at this age breaks too easy without first asking those who know. Tried pressing down like most connectors and no joy.

Once off is there any more disassembly required before spray down. On my Astro van, I can remove a metal mesh pre-screen to get a clear shot at the sensor. This Bosch look like it is all plastic so does not require more disassembly. Of course, I do not have it in my hand yet to confirm this.

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Joined: Sep 02 2016
Posts: 314

You are probably doing the right things but these MAF multi-plugs can be resistant to 'extraction.

However you are right as the sensor is a sealed unit and so spray cleaner has a very limited effect (unlike on the 'hot wire' type on your Astro)

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Joined: Dec 14 2018
Posts: 70

Thanks Dave- so best to leave it alone if it is working?

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Joined: Sep 02 2016
Posts: 314

Probably (if it is working Ok...) - depends on what made you change the O2 sensors (eg. was there an emissions issue/ Fault Code ?)

  • I tend to change 'suspect' things one at a time ; If you do change the MAF beware all the cheap clones !
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Joined: Dec 30 2015
Posts: 3077

The Bosch engine management doesn't like anything other than genuine Bosch MAF sensors and if they are starting to go, they rarely respond to cleaning. Best to just leave it alone unless it is showing signs of dying. At 105k,, it's barely run in, although you might have one lambda sensor showing signs of failing and you have 4 unlike the rest of us that only have two.

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Joined: Dec 14 2018
Posts: 70

Dave-- yup bank 2 fault code--- about 6 cycles worth.

Gilbert--Will follow your advice--- I backed away from the cleaning the MAF and will wait until I get a code.

Got lucky today--- three of the O2 sensors came out with a nice pull of my breaker bar using one of those claw foot style sockets. Much nice then the tall ones I used to use and break. This one has a 1/2 square on the end to slip in your breaker bar parallel to the socket- and a 3/8" square on the top side 90 degrees to the socket. Pretty neat setup.

Anyway, it was the last O2 sensor on the left before the cat which decided to leave its threads in the bunghole threads- and I had worked it back and forth 1/4 turn at a time with plenty of penetrating oil. I normally use my acetylene torch when I get a hard one- but this one kept moving so I just kept going at it cold.

My sparkplug thread chaser was useless at cleaning the treads---but one of those "way too expensive" buys I made 30 years ago came to my rescue as it often does.

About 30 years back I walked into a store which sold metric hardware which at the time was very hard to find. Had to travel an hour to another city. At the time I had a small set of metric tap and dies with most of the common sizes I needed for restoring 356 Porsches (which were also worth nothing back then). On a shelf behind the counter, they had a Huge complete set of metric taps and dies up to 18 mm with double taps for each size and pitch. It was a serious amount of money but I bit the bullet. One of the best investments I ever made. It keeps saving my butt.

Pulled out the 18 x 1.5 and cut the sensor threads out of the bung threads and was good to go.

A good torch and a complete tap and die kit are a must for any gearhead

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Joined: Jan 16 2017
Posts: 399

If its only one bank, it shouldn't be a reason to suspect the MAF really. And yes, the copies are useless, the one that came on mine was causing problems until I replaced it with the genuine Bosch one.

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Joined: Dec 14 2018
Posts: 70

Brian- I never suspected that there was an issue with my MAV- only my O2 sensors based on my fault codes.

I figured it would be a good idea to clean my MAF-- based on my experience with my Astro's MAF which needed cleaning at about 100K miles.

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Joined: Mar 22 2016
Posts: 1044

Gotta love that we only have 2 pre cat sensors to fight with, lol