P2 R Bosch maf

[Markyb]

Trying to chase a hunting issue, and looking back through what my car has had, a maf isn't one of them, does anyone know of the cheapest place to get a brand new maf from, without the housing would be ideal, ipd has them at 142.95 dollars plus postage and import when it gets here.
Thinking some basic stage 0 stuff might be in order

[expolicev70t5]

Ive just got full Bosch MAF from parts for Volvo online about £250 this was with vat and housing

[Tim Williams]

If you check your ignition timing first that might point you in the right direction. Less than 8 degrees BTDC and you will have an air leak after the ETM. The most common cause are the one way valves that Lee can advise on. Air leaks will cause hunting at idle, loss of performance and possible MAF codes. Most P2.5 and R's I see with MAF codes are caused by other parts.

[LeeT5]

...also, before you go shelling out on a new MAF, get some proper cleaning spray for MAF's (Contact cleaner is not really man enough) and definitely don't use Carb cleaner, it will melt plastic!!

Give it a good clean then see how the car reacts. 9/10 I clean at the roadside have a dramatic effect on idling and general performance and ultimately most idling and rough running issues.
Rough idle is generally caused by the MAF readings going out of spec and the ECM making adjustments to suit.

I paid £90 for a brand new, sealed with hologram Bosch box from Europe. If it doesn't have the hologram on a yellow Bosch box it ain't OE!

[Markyb]

I probably have some codes stored that I need to get read to see if they point at anything, Was hoping for Tim to look at it back in Feb for a service and mot but you must have been mega busy couldn't get hold of you. The cbv has been swapped and that seemed to make it run better as boost builds, but still not running same top end pre downpipe installation, just frustrating the hell out of me along with the hunting idle. Had liners shimmed late August and it's been doing it since, replaced vac lines to tcv, I still want to get the intercooler done, get rid of the Rica and get hold of the proper tme exhaust to finish it off

[LeeT5]

I agree with Tim in that I also believe you have an air leak or boost leak (depending on where it it). Ultimately, a leak is a leak and it will make the car hunt and you will get MAF fault codes, especially ECM 6805.

The two - one way valves that Tim is referring to caused me 6 months of grief and a 2 psi loss in boost.
I advise you have a smoke leak test and replace the two valves as these will not be detected on the smoke leak test.

If you diagnose methodically you'll sus out the problem easily, if you don't, then I don't envy the long road ahead.

[LeeT5]

I probably have some codes stored that I need to get read to see if they point at anything, Was hoping for Tim to look at it back in Feb for a service and mot but you must have been mega busy couldn't get hold of you. The cbv has been swapped and that seemed to make it run better as boost builds, but still not running same top end pre downpipe installation, just frustrating the hell out of me along with the hunting idle. Had liners shimmed late August and it's been doing it since, replaced vac lines to tcv, I still want to get the intercooler done, get rid of the Rica and get hold of the proper tme exhaust to finish it off

To clarify, if you see a MAF code, it does not mean you have a faulty MAF.
Use of VIDA diagnostics and fault description will help you.

[Markyb]

Ok I will sack this idea off for now and see if I can hold of Tim, as until I can get it off the road myself for a useful length of time, all I can really do is swap a few obvious parts out, and don't have my own access to vida, nor would I know where to start with doing a smoke test.

Thanks

[Tim Williams]

Message sent to book in.

[Markyb]

Problem found after no useful codes stored, vvt solenoid giving strange readings, and possibly exhaust pulley may need doing in the future. Car is pulling very very well through mid to top end again. Super thanks to Tim for being patient, with me insisting it felt down on power. Bugger all air leaks, and a couple of one way valves and a bit of piping replaced for extra piece of mind, and a stray oil leak solved to! Bring on the intercooler!!!!!!

[LeeT5]

Problem found after no useful codes stored, vvt solenoid giving strange readings, and possibly exhaust pulley may need doing in the future. Car is pulling very very well through mid to top end again. Super thanks to Tim for being patient, with me insisting it felt down on power. Bugger all air leaks, and a couple of one way valves and a bit of piping replaced for extra piece of mind, and a stray oil leak solved to! Bring on the intercooler!!!!!!

Referring to your first post - Its just goes to show how, if codes are interrogated incorrectly or symptoms not investigated methodically, you may have wasted a couple of hundred pounds on a MAF you didn't need!

Glad you got it sorted.

[Ettienne]

Mine had a similar issue it was the vac lines under on the inlet manifold and the associated with the one way valves (valve were OK) replaced it all with silicon been fine since, Iirc ones an odd size 8mm to 10mm