96 850 turbo dies at idle

[volvo850black]

Ok, I have a 96 850 turbo that is dieing at idle after it is warm. I am wondering if it is the MAF sensor. Saturday I noticed vacume lines attached to the airbox that were broken and replaced those and was cleaning stuff off. My son was helping and sprayed carb cleaner in the air tubing and got some on the MAF. Then the car ran fine but it was not driven much. Today I had to drive a lot more and it started "bucking" every once in a while while driving at speed and when stopping at a light it would run a bit rough and die. Would this be consistent with MAF issues and will carb cleaned mess it up? It was sprayed directly on the sensor.

[rspi]

That's possible. You can start the car and unplug the maf and see if the car runs any better. A common problem is fuel pump relays. You may want to check fuel pressure.
http://volvoforums.com/forum/volvo-850- ... lls-55928/

[jblackburn]

The bucking does indeed sound like a MAF issue. You can try some MAF cleaner spray and see if it helps the problem, or as said above, unplugging it is another test. If it runs fine without the sensor (it will be down on power and may belch black smoke, but it should run), the MAF is your culprit.

[volvo850black]

I did unplug it and it seemed to idle up for a few minutes and was a little better. Guess i will try cleaning it with MAF cleaner tomorrow.

[jreed]

I cleaned the MAF sensor on my 1997 Volvo 855 GLT at 153k miles today, just for general preventative maintenance and curiosity. I couldn't quickly find a nice illustrated write up of how to do this job on the 855, so I thought I'd go ahead and take photos of what I did:
Location of the MAF sensor:

MAF sensor next to airfilter box

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First, I disconnected the electrical plug from the sensor. There was some corrosion visible on the connectors, so I wiped off most of it with a clean rag and applied a little bit of "Deoxit" contact cleaner (http://store.caig.com/s.nl/sc.2/category.188/.f)

Light corrosion visible on metal pins of MAF sensor connector.

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Then, I made good use of my new Christmas present this year: a ratcheting driver with a T-20 Security Torx bit (shown in a couple of the attached pictures below) to loosen the two fasteners holding the MAF sensor in place.

Ratcheting driver with T-20 torx security bit.

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I got the security bit at HF as part of a great set ( http://www.harborfreight.com/36-piece-3 ... 97807.html ).

Torx T20 security bit (tamper resistant pin in tip)

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Once those screws were removed, I gently wiggled the sensor out. It took quite a bit of force to pry out with my fingernails. There are a couple of slots for putting a screwdriver tip into that would be helpful for prying the sensor loose.

MAF sensor after wiggling and prying loose.

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I took a photo of the sensing element, which looked clean even before cleaning.

Bosch MAF sensor from 1997 Volvo 855 GLT

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I used CRC Mass Air Flow Sensor Cleaner, which I bought at Advance Auto for $8 / 11oz. can. I sprayed the element with a few blasts. The element looked the same after cleaning.

Applying a few short blasts of CRC MAF Sensor cleaner to the sensing film

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The MAF unit has another circuit or sensor that is underneath a yellow plastic film. I didn't touch it or clean it... does anyone know what the purpose of this item is?

Sensor or circuit on backside of Bosch MAF unit, under a yellow plastic film

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I then reinstalled the sensor, screws, and connector, and everything is working fine (just the same as it was before I cleaned it!). It's a pretty simple job obviously, but it satisfied my urge to tinker for a little while.