View Full Version : Maf sensor

02-11-2013, 11:00 AM
Hey guys i have recently purchased an 97 audi a4 it has the 1.8t aeb motor in it. When i bought the car there was no maf sensor on so i called the dealership and gave them the vin# off of the car to get a new one. I installed it and plugged it in and the car runs like complete shit and is really rich but when i unplug the maf its driveable. Do you guys have any suggestions??

02-11-2013, 11:03 AM
Fault codes. Check them.

Chances are it's a massive air leak.

02-11-2013, 11:12 AM
There are no fault codes and the exhaust manifold had a leak and i just put a new one on. It has a big turbo on it with a fmic and it does have a tune on it but idk which one because the guy who i had starting to work on it went outta business

02-11-2013, 11:35 AM

You might need a bigger cap to fit your intake if you have a big turbo. The bent piece of pvc in this DIY is unnecessary but you get idea. This is how I did mine but there are other ways.

02-11-2013, 11:45 AM
Thanks i already tested it for leaks and there were none this is why im stumped

02-11-2013, 12:06 PM
Thanks i already tested it for leaks and there were none this is why im stumped

Ah I thought you were saying you had an exhaust leak but never checked otherwise.

What kind of tune and whats the pcv system setup look like?

02-11-2013, 12:07 PM
Does it have a CEL when the maf is unplugged? This could be a case of someone running a mafless tune...

02-11-2013, 12:13 PM
Im not sure of the tune i cant get ahold of the guy who worked on my car....and there is no cel when maf is unplugged

02-11-2013, 12:20 PM
I'd bet it's a mafless tune. Not a great idea on m5/non wideband me7.5, but it's often done nonetheless.

Post over on nefmoto.com if you have any questions about tuning. If you could go without your ecu for a couple days I could take a look at the tune, but that's not an option for most people.

02-11-2013, 12:27 PM
Okay im gunna see if i can get ahold of the guy again to see wat tune is on it but ill let you know thanks!!

02-11-2013, 12:39 PM
If it was a mafless tune would it start cutting out after 10lbs of boost cuz the last time i had it to the garage he said it needed the maf sensor hooked up to run but the exhaust manifold had to be done first and that is now done and it still doesnt run with maf hooked up could it possibly be the wrong maf sensor

02-12-2013, 06:39 AM
You might need a bigger MAF housing. I just did it to my '97 AEB and it made a world of difference on my k04. Basically you'll need just the housing from a vr6 of our generation. I accidentally bought an '01 TT MAF and had to hack up the housing to fit my stock sensor. By the way, it's best to use the stock MAF sensor with the upgraded housing. No need to wire in a newer sensor.

Hopefully that's all it is. Good luck!

02-12-2013, 10:15 AM
Thanks ill have to try that

02-12-2013, 10:38 AM
The size of the maf sensor is built into the tune. Swapping in a larger sensor will likely make things worse. YOU NEED TO KNOW WHAT THE CAR IS TUNED FOR!!!!!!

If there is no check engine light or codes without the maf connected, and your car has many aftermarket parts, I'd be it's a mafless tune. Get a proper tune and go from there.

02-16-2013, 02:51 PM
The tune is a united motorsports tune and i rechecked the codes and there is one for the boost pressure control valve open

Mad Cow
02-16-2013, 03:22 PM
How does a mafless tune work for M5.x? There's no wideband O2 or MAP sensor, how else will it calculate load? Unless it just uses throttle position, but I can't see that ever running properly.

02-16-2013, 04:27 PM
^It doesn't.

OP, find out what that tune calls for and run the proper MAF that it requires. But what you really need to do is find out what the PO previously did to the vehicle. There are ways to add WB to the AEB, so you need to find out if he did that or not. Basically, find out what is going on with your vehicle. For example, see what ECU you are running. And you can do something like send that ECU to UM to see what tune is really on it.

Edit: What turbo do you have? If you look on the UM website, it tells you what MAF and injectors is used for certain application. If injectors and fpr match what is on their site, there is a good 85+% chance you will need the MAF that is listed also.


02-18-2013, 05:37 AM
Okay does my pcv valve need to be hooked up to my intake cuz its not...

02-18-2013, 05:43 AM
If you mean your prv aka pancake valve, then yes. If not, then you should basically have a huge intake leak on your turbo inlet on the port the prv is supposed to be.

02-18-2013, 10:18 AM
Where exactly is that located

02-18-2013, 10:26 AM
Would plug directly into your turbo inlet pipe.

02-18-2013, 10:54 AM
There is a custom air intake put on and there is no lines or anything running to its just the filter and the tube to the turbo

02-18-2013, 10:55 AM
And the maf sensor is in between them

02-18-2013, 11:09 AM
How many wires are coming out of the o2 sensor?

Sent from my iPad using Tapatalk HD

02-18-2013, 11:21 AM
If you have the stock turbo inlet or a silicone one that resembles it then the port will be on there. The green arrow is pointing to where it should go.


02-18-2013, 05:09 PM
I dont have that

02-18-2013, 05:24 PM
What do you have? Take a pic.

02-18-2013, 08:25 PM
I will this weekend im a truck driver so i wont be home till friday but ill post a pic then

02-21-2013, 03:43 PM
PO had a oil catch can installed but there is only a line running into it and none coming off of it could this part of the reason???

02-21-2013, 04:29 PM
Read post #17

02-21-2013, 04:42 PM
I found out the tune is stage 2 from UM

02-21-2013, 04:51 PM
Take a pic and tell post exactly what your setup is. People would post and actually help if you posted more info. You are leaving us guessing as to what is actually done to your vehicle. For example, what TIP are you running? And if the PO was running a catch can, where is it? Pics!!!

02-23-2013, 10:19 AM
How do i put pics up here from my phone??