Car is 99 Passat TDI - PD engine
Head gasket just replaced and now fear MAF sensor kaput. I will get to garage tomorrow morning but in meantime I've been having a fiddle to see if the MAF sensor is broken.
There seem to be two sensors on the pipe after the airfilter box. One has two prongs and the other has five. The sensor with five seems to be security bolted to the pipe but the one with two has a couple of small (vacuum?) pipes and is held by a screw. I presume one of these is the MAF sensor - can someone let me know which one and what is the other one?
Cheers
{amended header to make use of make/model drops downs that weren't available at the time post was composed}
Edited by Dynamic Dave on 30/09/2008 at 19:36
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The MAF has five pins. Its kind of oblong shaped connector with a curve at one end.
The other part you describe is (IIRC) a soleniod valve.
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A 99 with PD engine, are you sure?
Unplug the electrical connection from the MAF and drive the car, if some of the performance returns you've found the fault. The ECU will log a fault if you do so and may give the tech the wrong info and the wrong diagnosis may be made, so tell him if you do this.
If the performance was ok before the HG was fitted maybe the tech has fitted some of the various vacc pipes the wrong way around
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A 99 with PD engine, are you sure?
PD 1.9 was introduced in '98 IIRC.
Lots of things could cause it to be down on power - too many to guess at.
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yep, you could definately get a 1.9PD (with 115BHP) at the tail end of '99
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Definitely a PD (AJM engine code - late '99 registered) and it worked fine before HG done.
I've driven it connected and disconnected and performance seemed to be better disconnected! Typically the security bolts look well shot and I couldn't get them to revolve with a Torx security bit
I'll agree that there's too many things to guess at so I'll let the garage look at it first before I do anything else.....I'll let them know that I've probably logged a fault code with disconnecting the MAF.
Thanks for help everyone.
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they are probably not torx, often a 5 star pattern rather than the 6 star torx pattern. - could be why they are knackered.
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I think it was a five star pattern - any ideas where a suitable removal tool can be sourced?
I know the Bosch MAF's are notorouisly unreliable on VAG cars - I had one replaced at a main dealer 50K ago for £200 for the sensor and £65 labour - now that's what I call an hourly rate given I think I could do the job in 10mins if I had the right removal tool. I was thinking of holding a spare for the inevitable failure - no doubt at 2am one Sunday morning whilst on some sort of life or death mercy dash.
I see they can be sourced for £40-odd on a certain auction site - not sure what the quality is like though. Anyone got any experience?
Cheers
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you can get an exchange one from vw at a reasonable cost, say ~ £70 thats just for the element so you'll need the tool to remove the security bolts.
Your local motor factor should also offer a good deal. Bosch offer exchange and reconditioned ones.
There are aftermarket ones available from pierburg (and I presume other makers) which are cheaper (£50) but are not the thin wire type like the bosch. You get slightly worse response but possibly slightly better fuel economy (prob because the response isnt as good) but they are more reliable.
Try and find a Franklin tool stockist they do the security bits you need. My set cost ~ £7 or so
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I've replaced my MAF twice in the last year, it's a real pain in the backside. One was a Bosch, can't remember the brand of the second. Whatever it is, it didn't last long as I now need a third...
The heads of the two screws are exposed - I simply made a slot in them with a junior hacksaw, no special tools required, just a slotted screwdriver!
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