MAF and performance question

[sc0rpius]

Hi, I changed my MAF with a genuine bosch one about 4 months ago. Before and after the change it ran a bit faster with the MAF disconnected.

Now I just disconnected the MAF and tried the car, damn theres alot of difference. Feels totally different. And in the engine I can hear some kind of hissing/leaking kinda sound coming from the back of the engine when the car is turned off after a run.

Air leak or do all cars run faster with there MAF off?

[mountie66]

Hi, I changed my MAF with a genuine bosch one about 4 months ago. Before and after the change it ran a bit faster with the MAF disconnected.

Now I just disconnected the MAF and tried the car, damn theres alot of difference. Feels totally different. And in the engine I can hear some kind of hissing/leaking kinda sound coming from the back of the engine when the car is turned off after a run.

Air leak or do all cars run faster with there MAF off?

Don't make a habit of running it off!! they will run a bit better but your fueling will be off and ecu will try to correct it... as for air leak check all the air breather pipes there is a y pipe that is known to be a problem as a matter of fact all the rubber pipes corrode..

[pauldazzle]

I bought an A3 Quattro about a year ago, it was ECU-Evolution remapped with a Turbosmart DV fitted. I'd owned 3 Revo'd mkiv Golfs in the past & was stunned at how much quicker the A3 felt, but a few days after buying it noticed that the MAF was unplugged so I plugged it back in, but it was completely dead, the car wouldn't even idle. Fitted a new VAG MAF & the car was definitely slower. :'(

Hissing sound on turn off sounds like you've got a leaking vacuum or boost pipe. There are several of these pipes that split. The one that goes into the top of the DV often splits & can be hard to spot. The 2 small braided pipes to the right of the inlet manual also fail.

Edited 13 October, 2010 by pauldazzle

[rwbaldwin]

Hi, I changed my MAF with a genuine bosch one about 4 months ago. Before and after the change it ran a bit faster with the MAF disconnected.

Now I just disconnected the MAF and tried the car, damn theres alot of difference. Feels totally different. And in the engine I can hear some kind of hissing/leaking kinda sound coming from the back of the engine when the car is turned off after a run.

Air leak or do all cars run faster with there MAF off?

No.

If you have unmetered air entering the engine or are leaking metered air, then it is quite possible that it will run better on the default map. Assuming the MAF is good, then it means that you probably have a boost leek.

Edited 13 October, 2010 by rwbaldwin

[sc0rpius]

No.

If you have unmetered air entering the engine or are leaking metered air, then it is quite possible that it will run better on the default map. Assuming the MAF is good, then it means that you probably have a boost leek.

Yeah, I have a number of small problems with this car. Is there a Skoda or VAG specialist in Birmingham that someone can recommend? Don't want to give it to a backstreet.

[pauldazzle]

Awsome in Manchester have a very good reputation, & are VAG specialists. http://www.awesome-gti.co.uk/

[Guest westallc]

no it wont run faster

when unplugged it returns the ecu to a default setup. so if the car is mapped it will return the car to below standard power so less than 180bhp

if remaped the car should feel so so much better with maf then plugged back in so maf is deffo at fault

p.s its not uncommon for new mafs to be dead out of the box

[sc0rpius]

Car is standard not mapped. So £75 for another MAF and it could be knackered aswell...

How do I know for sure this one is knackered? Just feel like running with it off all the time...

[JohnBoyMinster]

I wouldn't run with it off all the time, you need to take care of your car! Whey out £75 for a new MAF and run with it conneted - if you want more power do it properly and get a re-map - it will pay in the long run!

[mbames]

Car is standard not mapped. So £75 for another MAF and it could be knackered aswell...

How do I know for sure this one is knackered? Just feel like running with it off all the time...

a scan with vagcom and check the MAF readings should give you a good indication if the MAF is totally borked. Compare the readings between your old and new ones..... Or post the figures on here, and I am sure someone else with a good/working MAF will confirm if they look good.