MAF problem

[uglymug]

Hi All, as title says, am having some MAF sensors probs. Flashing coil light comes up a few weeks ago so got the code. P0101 coming up as Mass or Volume air flow sensor"A" circuit range. So removed and used correct mass cleaner . Nothing changed. Bit the bullet and bought a new genuine replacement. Ah bugger, still no change as coming up with same code. It seems to come on but only my imagination about 10 secs after a throttle off scenario eg going down a long hill. This led me to small bleed off of vacuum maybe ?

Have had all vacuum pipes off-all OK ........... as to the best of my ability the associated wiring to the MAF, one 3 pin push fit connector etc. Air filter pipework with 5000 mile filter, concertina duct to turbo. Still no luck.

I take it that the MAF is only a flow come temp sensor sending its findings to the ECU. Its obviuosly finding something outside of its parameters. But what / where.

Does anyone have any more suggestions for me to check please ?

kind regards.............

Octavia MK2 - 1.6tdi Cr with CAYC engine.



Bit of an update on the ongoing MAF sensor problem. Its still making itself known all the time while what I consider normal driving. So on the weekend I needed to drive to my local airport to drop of my BIL etc. Literally 5 mins into the journey it comes on. Now what I consider normal driving is changing down the gears and gently braking until you have to slow down or stop. It comes on when doing this. And driving down a hill where you just throttle off and let the car roll, after 10 seconds of doing this it comes on.

Fast forward to the journey home circa 50 miles. Instead of changing down the gears I take it out of gear and coast, either until I need to engage a gear or come to a stop. Done this at every opportunity and low and behold it didnt happen once. Just a mile from the house comes a long hill so kept it in 5th and throttle off letting it roll and 10secs later on it comes. ( did not touch the brake ) What the hecky peck is going on.Trying to get my head around this.

Any sugestions guys ..................

[stevemcs]

Very rarely is it a maf sensor yet people change them. Have you smoke tested the intake side ? It could be something simple, possibly even the intercooler split.

[Belle427]

Id go with a split or detached hose too.
http://wiki.ross-tech.com/wiki/index.php/16485/P01...

[mercedeslimos]

Go for a good hard drive, MAF issues on a modern TDI are either EGR sticking (closed or open - the MAF expects a certain amount of EGR at a certain point according to the map, if it's sticking open the MAF air is reduced so it picks this up - vice versa), or a boost leak, as the air has been metered at the MAF but the MAP sensor at the inlet isn't seeing the same amount of air.

[trevalvole]

uglymug said:

Bit of an update on the ongoing MAF sensor problem. Its still making itself known all the time while what I consider normal driving. So on the weekend I needed to drive to my local airport to drop of my BIL etc. Literally 5 mins into the journey it comes on. Now what I consider normal driving is changing down the gears and gently braking until you have to slow down or stop. It comes on when doing this. And driving down a hill where you just throttle off and let the car roll, after 10 seconds of doing this it comes on.

Fast forward to the journey home circa 50 miles. Instead of changing down the gears I take it out of gear and coast, either until I need to engage a gear or come to a stop. Done this at every opportunity and low and behold it didnt happen once. Just a mile from the house comes a long hill so kept it in 5th and throttle off letting it roll and 10secs later on it comes. ( did not touch the brake ) What the hecky peck is going on.Trying to get my head around this.

Any sugestions guys ..................

Presumably one difference between engine braking and coasting in neutral with the engine idling, is that when engine braking no fuel will be burnt, whereas when idling in neutral a small amount will be burnt to keep it idling?