Calling All MAFs

[j3nks79]

£48 is very reasonable.

[Andrew J]

Just to confirm, the £48 was for half and hour and pre vat. £115/hr seemed quite a lot for a diagnostic/smoke testing.

[Andrew J]

In my experience a Maf either works or it doesn't replacement with oem brands Bosch or Seimens do not buy cheap replacements, they don't work and don't last long if they do have been down that route myself.
Fuel trims being high is a good indication of either air leaks or bad Maf. Do a smoke test to rule out any air leaks you haven't found so far then change the Maf and view the fuel trims with a decent scanner to see if they have reduced and back in spec. Do check the rear underside edge of the inlet manifold for missing rubber blanking caps that seal off some unused air ports, these do perish and fall off and go unnoticed unless a smoke test reveals them. There is also a rubber O ring in the dipstick tube if you have one and that can be a cause of air leaks.

I managed to get some live data whilst driving recently. The MAF is just not reading by the looks of it. Can see even under load there's no signal back to the ecu. Is this the nail in the coffin for a faulty MAF giving me the P0102 code? I'm still knocking together a smoke machine to test at the weekend but just wondered if this is curtains for the MAF?

[colb]

Certainly looks like the Maf is dead from your screen shot, no movement at all. If you unplug its electrical connector it will go into default settings and run better albeit the Maf signal won't be generated so you can't view it. If the Maf is the cause the engine control module will be affected and cause havoc with fuel trims as it tries to get the mixture right. Often it will see what it thinks is a lean mixture usually from air leaks entering past the Maf and not being measured so increases fuel at the injectors to richen what it thinks is a lean condition, it will continue to do this until its putting 20% more fuel in before it realises something is amiss and sets the engine management light to draw attention to the fault. Bad Maf will also cause the same issue. To me it looks like your fuel trims are in the minus which means its actually taking fuel away as it thinks its running rich probably as a result of the absence of any reading from the Maf. If you are going to replace the Maf only fit oem Bosch or Siemens brands don't buy cheap ones they seldom work or last long if they do. Do continue with your smoke machine, mine has proved invaluable for my cars and other members cars I have smoked, finding leaks is very easy with smoke. Ideally the trims should be around 0% or up to around 5% across the performance range.

[Andrew J]

Read the codes today with my friends AA set up (what a piece of kit that was). I got a 2783 code which is faulty maf sensor. Unplugging it confirmed it went to open circuit which shows the wiring is at least not shorting out. It would give a reading of 0.41 kg/h with idle supposed to be between 5-25kg/h (if my memory serves me correctly). I can't find a bosch maf anywhere but can see a VDO one on autodoc for £195 (https://www.autodoc.co.uk/vdo/1736813#m ... low-sensor). I believe Siemens owns VDO? Is there an alternative ego for boach aswell?