CDTi Bosch MAF sensor - swap over the sensor, or change the whole assembly?
 

Hi chaps,

It's winter, and the dear old ZTT 2.0CDTi is sulking and wants some attention. Part of that is draining its battery overnight (I'll be checking the glow plug circuit shortly, as the car does not have factory sat nav - the battery is healthy and the alternator is putting out a good charge)...

...the other problem is a longer-term one, that of poor starting. I thought this might be the cam position sensor, but no, a new one didn't cure the problem. Argh. Putting a diagnostic on the car revealed that there was no MAF signal at all - kind of weird that the car still runs without the MIL illuminating...?

The MAF on the car is a Pierberg with a Rover Ron MAFAM. Sorry to say MAFAM fans, I haven't found this box to transform the car, and perhaps one reason is that the MAF has never provided the correct signal???

Cutting a long story short, I've decided to bite the bullet and buy a new Bosch MAF and disable the MAFAM and see how the car runs before doing anything else.

It's raining outside, so to reduce my exposure to the elements I am thinking of removing the Bosch sensor from the new MAF assembly and installing this in to the old one in the car, after removing the Pierberg.

Any reason not to do this? Should I replace the whole assembly? What do you chaps think?

Just having a look at the part. I can't see any reason not to change just the sensor - so this is what I'll do... and will post more soon :)

I have just changed the sensor in the past, no problems at all.

Did you notice the screws are 5 NOT 6 point torx security

sold here

http://www.amazon.co.uk/Silverhill-P...s=5+point+torx

or you may be able to remove the screws with a pair of long nosed pliers.


.

Thanks - yes I did. I have a set of these specifically for the purpose. Blooming annoyingly though, I now can not find them.... gggrrrrr!

Pierburgh
 

The purpose of the MAFAM is to allow you to match the Pierburgh Maf to your engine (mine was set at about 2.30). It is not a tuning box, just a substitute for the Bosch. Mine worked perfectly well for six years. Try unplugging the connector from your Maf and see how the car runs. It should be perfectly ok. Then try your new Maf and note any differences. You may well find that the only difference is improved MPG readings. Just change the sensor when you can remove the screws!

Mine is the tuning box - and was using the MAFAM to utilise the Pierberg MAF as Bosch was stupidly expensive back then. But I never did get the performance gains others found...

Still can't find the darn 5-point torx bits: we have had building work since I last used them, so they'll be squirreled away somewhere (I hope!)

Many of us released the screws with pliers (awkward) and then sawed a slot
across them for easy removal in the future.

Cheers chaps :D

Actually found the bits - hidden under my nose as it turned out! LOL Still, at least I got to tidy up the garage and start organising things that I've been meaning to do for ages!!!

New MAF fitted, the MAFAM removed and... no start. Flat battery. I thought that the battery was good, but even after charging, turning on the ignition dropped the potential across the terminals to 11v - which dropped further to 8v when attempting to crank. I suspect the battery is dead.

Predictably, the battery's warranty has just expired, so I'll have to stump up for a new one... and of course, I've missed the open hours at Eurocarparts :(

We need the car, so I suspect that we'll have to pay the extra premium and buy from Halfords tomorrow...

Will probably get the Yuasa 096. Dimensionally, it's a little taller (15mm) than the 100 Varta currently fitted - but a quick search on here suggests that most people find that it fits okay?

Yuasa 096: 80Ah 760A CCA Dimensions l:278; w:175; h:190mm

Rob

Before Halfords, try a local motor factors, you may get a better deal from them