01 V70 T5 MAF Question

[radial]

Hi Guys,

New to the forum today :)

Quick question... Had the engine management light come up during the week while me and the missus were in the Lake District, fortunately I had my laptop and OBDII Cable with me so code read with Scantool as P1171, looked to me to be related to MAF based on other discussions, so drove the car carefully for the last couple of days we were there, on the way home today things started getting VERY lumpy as if it was going to stall, but it didn't, this was only at low RPM and when stopped (at lights or traffic jams etc) while the car was moving at 60-70mph it felt fine with very occasional stutter.

Got home and pulled the MAF out and gave it a good clean through with some IPA, it is currently sitting drying off so haven't fitted it back yet.

My question is, if the MAF is knackered will this part do the job: http://tinyurl.com/3x5udu3 or is it just a little too cheap at £86, I notied the BOSCH part is £276 :eek:

Any advice would be greatly appreciated. :)

R.

PS: I guess I should also mention within the last 6k miles I've had ETM, Throttle Body and Pedal Sensor replaced and the last service 2k miles ago I had a turbo drain seal, and turbo drain gasket.

[princepugh]

If you've already got the light up you could try running without the MAF, see if the symptoms persist or not.

You can get the genuine Bosch MAF off ebay for a very good price if it proves the case you need one.

[radial]

Thanks princepugh, is it definitely safe to run with the MAF out? I hadn't considered trying this for fear of screwing something up..

R.

[princepugh]

Sorry, just been shouting at the TV.

What I meant to say is, plug the MAF sensor back into the air intake but leave the electrical connector out.

My understanding is that when the ECU sees no signal present from the MAF, it will run on safe 'tables'. It may well log another fault code but should enable you to eliminate or confirm the MAF from the symptoms you then experience.

Anybody willing/able to concur/confirm?

[radial]

HaHa yeah I've just been shouting at the TV too.. what a bunch of wallies!

I'll bung the MAF back in tomorrow without the connector in, should I reset the fault code first? and also would you recommend just leaving it to idle or take it for a spin?

Sorry for all the Q's but I'm fairly new to DIY on cars :)

Thanks for your help so far.

R.

[princepugh]

Clear the codes and see how if it can hold varying engine speeds at idle before taking for a test drive.

Don't plug/ un-plug it with the engine running.

[radial]

Clear the codes and see how if it can hold varying engine speeds at idle before taking for a test drive.

Don't plug/ un-plug it with the engine running.

Thanks dude, I'll give it a try tomorrow and post my results back :) Really appreciate the input!

R.

[radial]

Ok, put it back in and done as suggested, cleared code, started the car and ran with MAF connected for 15 mins idling (engine up to temp etc), ran a little better but not massively still a bit lumpy.. Next disconnected the lead from the sensor started it up and it was hideous! Coughed, spluttered and choked, then cut out after about 45 seconds. Plugged MAF back in and returned to okish but not great, so I am guessing there is a problem further down than the MAF now?

Here are the scantool readings before and after the clean of the MAF:

Before:
short fuel trim (bank 1): +0.8%
long fuel trim +25%
Airflow rate MAF 3.25g/s
O2 Sensor 2, Bank 1: 0.435v
O2 Sensor 1, Bank 1: 127.996 mA Eq ratio 0.999s

After:
short fuel trim (bank 1): +16.4% up to +18.8%
long fuel trim 0.0%
Airflow rate MAF 2.75g/s
O2 Sensor 2, Bank 1: 0.430v
O2 Sensor 1, Bank 1: 127.996 mA Eq ratio 0.999s

Any clues where I can go from here? Would it still be worth putting another MAF in to the car to see what happens?

Many thanks,

R.

[princepugh]

Not sure I can help you interpret the codes, however, it's definitely going to be worth checking the intake and charge pipes for leaks - best done via a smoke test if your local garage can do that?

You can check the obvious stuff - follow the pipe down from the airbox and see if the hoses are all on the vac tree properly - also worth checking that the IAT and MAP sensors are seated nicely on the ETM intake - thats the big charge pipe running behind the rad and in front of the engine. I'll take a pic later if I get chance.

[radial]

Thanks for your help so far, I'll go check the pipes again in a min (when the gailforce wind dies down!) :)

Pics would be greatly appreciated.

[radial]

Right, I've just had a quick look at the pipes and everything seems ok, but if you can send some pics that might be good as I probably missed something :)

[princepugh]

Here's a pic of the IAT and MAP sensor, they sit on the charge pipe leading to the ETM, which leads to the intake manifold at the front of the engine. If they're not clipped in and sealed properly you'll get a pretty rough idle. I'd avoid actually removing them as the plastic clips can get brittle over the years!

I'd also check the intercooler hose clamps, one on the other end of the ETM charge pipe, the other on the end of the charge pipe coming over the top of the engine.

[radial]

Thanks for the help Princepugh... well further to the story, I took the car in to my local garage on Tuesday, they diagnosed the fault as the O2 sensor and replaced it using my RAC warranty.

I picked the car up Wednesday morning and took it for a 10 mile drive, problem came back and worsened, the car felt awful, engine management light started flashing so I went back home and code read it, and it was misfiring in cylinder 2.. AARRGGHH, so took it back and they have replaced the coil (again under my RAC warranty).

Picked it up this afternoon and went for another drive, just about to pull in to my drive engine management light came up again.. code read it and it's the same sodding code as before P1171.

I'm at a loss... how can a garage not diagnose this properly, my warranty compay are gonna have a fit if they see another claim going in :(

Don't spose anyone has a spare MAF (2001 V70 T5) they could lend me for a couple of days do they? I'd rather give that a go myself than take the car back in so soon. Everything seems like it is seated properly, and I can't feel any holes in pipes etc, but I can't vacuum test as I don't have the kit to do so.

All the best.

R.

[princepugh]

Where u based fella?

[radial]

I'm in Welwyn Garden City, Hertfordshire

[princepugh]

Check your Private Messages

[The Flying Moose]

Thanks for the help Princepugh... well further to the story, I took the car in to my local garage on Tuesday, they diagnosed the fault as the O2 sensor and replaced it using my RAC warranty.

I picked the car up Wednesday morning and took it for a 10 mile drive, problem came back and worsened, the car felt awful, engine management light started flashing so I went back home and code read it, and it was misfiring in cylinder 2.. AARRGGHH, so took it back and they have replaced the coil (again under my RAC warranty).

Picked it up this afternoon and went for another drive, just about to pull in to my drive engine management light came up again.. code read it and it's the same sodding code as before P1171.

I'm at a loss... how can a garage not diagnose this properly, my warranty compay are gonna have a fit if they see another claim going in :(

Don't spose anyone has a spare MAF (2001 V70 T5) they could lend me for a couple of days do they? I'd rather give that a go myself than take the car back in so soon. Everything seems like it is seated properly, and I can't feel any holes in pipes etc, but I can't vacuum test as I don't have the kit to do so.

All the best.

R.

I dont have a spare MAF and dont know how helpful you will find this information. BUT, if you have ran the car with the MAF sensor unplugged and it was worse then you problem is 95% sure not the MAF sensor. When removed if the MAF sensor is faulty the engine will run noticeably smoother.

[radial]

Good point V70ETS, thank you for the input... I will try tomorrow with it unplugged as it's had the O2 sensor and a coil done so I'll see how it runs without the MAF.. never occured to me to try that again today, duh!

princepugh has very generously offered to loan me his spare to check that as well so hopefully I can find some light at the end of this very very annoying tunnel :)

Many thanks once again,

R.

[cornclose]

I got a new MAF for mine last year from GSF Parts and it was £150 ish. It's a Genuine Bosch item.

[jdavis]

I got a new MAF for mine last year from GSF Parts and it was £150 ish. It's a Genuine Bosch item.

I recently got quoted £165 from GSF for a Bosch Maf for my ME7 T5 so it'l probably be about right.

[radial]

I recently got quoted £165 from GSF for a Bosch Maf for my ME7 T5 so it'l probably be about right.

Thanks for that :)