Car pulls back

[Damolamov70]

Hi guys.
I have just fitted an aftermarket air filter to my v70t5. now when I accelerate slowly it pulls back at about 80 in 5th if I accelerate hard it just keeps going, but if I ease it up it hits 80 then slowly drops back to 70
Any ideas
Thanks in advance

[Santa]

Getting any shuddering?

Does it work ok with the original air filter back on?

Make and model of filter?

Did you disturb the MAF?

[Damolamov70]

Yes it shudders and ye the maf did get moved but nothing major and I don't no what make the air filter is as my mate had it from an old car
Don't no if it works with the original as haven't been on a road that allows a nice cruising since

[Santa]

Just seems strange its at speed rather than at revs. I assume it doesn't happen at around the 3k mark in all gears?

[LeeT5]

Hi guys.
I have just fitted an aftermarket air filter to my v70t5. now when I accelerate slowly it pulls back at about 80 in 5th if I accelerate hard it just keeps going, but if I ease it up it hits 80 then slowly drops back to 70
Any ideas
Thanks in advance

Firstly, :welcome: and I hope you introduced yourself?

Secondly, there may be several reasons for this. More likely, the OE filter was masking an underlying fault (which is often the case with any modification that is meant to improve engine performance).

A cotton or sponge filter increases airflow by about 50% (40% if oiled). Assuming you did not diagnose any faults using diagnostics beforehand nor did you reset adaptations on the car, then my guess is your MAF was sailing close to it's upper limits and increasing airflow suddenly has caused the MAF to go outside it's limits and therefore, the ECU is taking control and "adjusting" the car as best it can to safer levels. This is why you're experiencing 'surging', even at 80 mph.
My car did exactly the same thing at motorway speeds when I had a boost leak!

Assuming you're MAF is OK then the car is clearly trying to allow for another fault.

You could try the following; Remove the MAF and clean it using MAF cleaner or Contact cleaner. Do not use Carb cleaner as it leaves residue. If you have VIDA, change the adaptation also, although this is not necessary for a MAF.
Remove the ETM (throttle housing) and give it a good clean with Carb cleaner. You'll be shocked at the difference this can make!

If the car continues to behave the way it is then you have an air leak or a boost leak (same difference).

DO NOT oil the filter. As it's a second hand filter, if it's been oiled then you either need to clean it using degreaser, rinse and air dry or discard and buy a new filter.

NB: Popular to some people's belief, after market filters and induction units cause running issues. Fact is, they don't because they are 'pre' MAF and therefore not metered.
The issues always arise from after market filters etc because of an underlying issue not previously detected using a stock setup or by oiling the filter too much.

TOP TIP! - Don't oil your filter....it contaminates the MAF sensor and causes it to not meter the air correctly.

CHECK: you don't have any split vac hoses, split or cracked Intercooler (very common), dirty MAF sensor.
Further diagnosis can only really be attained by using a Mityvac and by having the car 'smoke leak detected'.

I spent months trying to find various boost leaks, all were very hard to find. In the end I had to get help from my local dealer for a smoke leak test (found and fixed two major leaks - not obvious to human ear or eye) and invested £80 in a Mityvac to find the other 3 leaks which the dealer couldn't find. One was a hair line crack in a boost pipe to my boost gauge (undetectable to naked eye), the other two were leaking one way valves. However, once sorted your car will be transformed. ME7.01 is very good at masking faults and if you just use the naked eye, you'll be there for ever!

[Damolamov70]

It's at 3000 in 5th gear but not sure about other gears it doesn't seem to but maybe I just don't notice it
sorry for not introducing my self I am Damien and I have a v70 t5 2001
I have ordered a new maf and will clean the filter just incase it was oiled.
I have changed the crank sensor and boost pressure sensors for new because the diagnostics said they were no good. If that doesn't work I will check for cracks in the boost pipes.
Thanks for all the help I will keep you guys informed.

[Biff]

If it were me basiclly mate I'd carry out a stage 0. If you search stage 0 in the search bar it will come up with a pinned thread (I cant do it off my phone to cut the link). This should get you somewhere near & rule out any faults that need ironing out before tuning.
For the price it will cost its well worth changing the vac pipes, I uprated mine with top quality samco for under £20.
My old R had a non genuine maf on it, no codes showing & I chased the fault for a while. In the end it was shown on the diagnostic software that the maf wasn't reading correctly so I'd reccomend a genuine bosch maf.
Dont want you making same mistakes as mine had.
Welcome by the way.

[abdul]

Any link to a mityvac

[LeeT5]

Google.

Make sure you get the one that does pressure and vacuum.

[Damolamov70]

Hi guys finally the new maf arrived fitted in seconds lol car is all good now cheers for all your very sound advice and I will be looking in to what you suggested lee when I get some time to my self
Cheers again

[LeeT5]

Any link to a mityvac

http://www.ebay.co.uk/itm/Mityvac-MV8500-Dual-Vacuum-and-pressure-Pump-Brake-Bleeding-Metal-Pump-Kit-/311259175203?pt=LH_DefaultDomain_3&hash=item48787e1923