2000 S4 MAF Problems

[EnvisionMore]

Well, this mess of a headache all started when i decided to install 3" catless downpipes. After installing the downpipes, my car was thrown into limp mode throwing the code 16486

P0102

Mass or Volume Air Flow Circ Low Input

I started by replacing the Bosch MAF since it was under warranty anyways, but it didn't help. I then decided to start tracing wires and found that the solid green wire had been unhooked from the MAF connector itself. I went to the VAST website and ordered a new Bosch connector trying to make things easier by just soldering a few wires. After clipping the wires from the original MAF connector, I noticed something like tin foil inside of the insulated wire holding the solid green and solid black wires in their own contained insulation if that makes sense.

I just disregarded thinking it was something left on my pair of cutters. I hooked up the wires exactly according to the pre-labeled wires from VAST. The MAF connector only had 4 wires - solid green, green/black, violet/gray, and green/yellow. On the other end coming from the ECU, it's all of those and then a 5th, which is the solid black wire. The wiring diagram says it's the ground wire, so I tried to ground it off to the frame in a few places, but it only makes me run super rich and misfire. When I twisted the solid black wire to the solid green and then connected it to the MAF connector, it doesn't misfire or run lean, but I'm still in limp mode due to the 16486 code.

If someone has some advice please feel free for suggestions! I'm probably just overlooking one thing, like the silver inside of insulation that the solid black wire goes to. I've added a picture of the wiring diagram to the bottom. The mass air flow is in the bottom right corner (G70).

[EuroxS4]

First things first,did you solder any wires together???If you did you gotta undo all of that.Reason being solder raises resistance in a circuit.Therefore could be part of the problem sicne the maf in reality just varies resistance and then the ecu interprets that into a reading.Thats why no one ever solders maf wires together.Even if you were to pick up a conversion kit for a boshc maf to a hitachi maf when goign from a abox to a mobx youll notice in the instruction they use crip connectors because they dont raise the resistance in the wires.So make sure thats all set.andwhat year car you got??s4??auto stick what year??which maf???

[EnvisionMore]

I have soldered, thank you for pointing that out. My main concern right now is the solid black wire, the ground. I will redo the connections with crimp connectors, but I still have no clue on what to do about the black wire. My car is a 2000 manual A-Box. I have ordered my hitachi conversion, but I need to know that my wiring is straight before I do anything.

Below I've attatched a picture showing how the black wire twisted with the solid green wire (signal wire) makes it run alright, but in limp mode. If I ground off the black wire it runs like shit.



Thank you for your advice so far!

[EuroxS4]

Ok the pin out for the maf is as follows:

Pin 1:empty no wires should be in the connector on pin 1.
Pin 2:Green/Yellow wire
Pin 3:Black/Green
Pin 4:Violet/Brown
Pin 5:Green.

Thats the pinout for the maf.The black wire which you hooked to the green wire shouldnt be connected.I have the wiring diagram up on my screen according to the diagram the black and green wires shouldnt be splcied together.If you look at the diagram and look to the left of the maf you have thick wires and a narrow line and black round circles where the wires meet that indicates a splice in the diagram but the black and green wire is not a round circle it simply means they are running next to each other.The silver foil you removed was most likely shielding to keep out interference between the wires.I could affect the way the maf behaves it could not.As stated i would disconnect the black wire from the green. and drive the car see how it behaves.

[aysix]

a properly soldered connection would offer lower resistance although twisting them should be better.

[EnvisionMore]

I have disconnected the black wire and left it alone, but it starts to misfire under boost and shoot a bunch of black smoke out the back while bucking due to being too rich. I'm out of ideas other than to unsolder and crimp connect them to see if the solder was messing with the resistance levels telling it to run a certain way with air/fuel ratio.

[skinnytirez]

I have a 2000 as well- used to have the exact same problems... upgrading/switching to the Hitachi was the best move i have ever made!
Buy the hitachi MAF & wiring harness from VAST & have J-fonz tune your car for it...

[EnvisionMore]

I have a 2000 as well- used to have the exact same problems... upgrading/switching to the Hitachi was the best move i have ever made!
Buy the hitachi MAF & wiring harness from VAST & have J-fonz tune your car for it...

I already have my conversion kit on the way from VAST, I figured might as well because M-box has all the tunes on nefarious motorsports.

[EuroxS4]

I dont mean to be a pain in the ass.But the only way that the hitachi maf is better is that its not prone to failure as much as the bosch conter part thats about it.But then again most of the bosch mafs i have seen fail is because people used a aftermarket air filter that was oiled.Then the oil transfers and stick to the maf eventually cuasing it to fail or read incorrectly.ITo be honest I prefer the Bosch over the hitachi just because I dont see any point to changing the maf and swapping the wiring around.Envision,I would try and check make sure the maf you have is good.And no need for a hitachi maf to run a mbox file.Theres a couple of mbox tunes with bosch maf tables in them so you can flash and use the stock bosch maf.Just a FYI just in case anyone was wondering.

[EnvisionMore]

I dont mean to be a pain in the ass.But the only way that the hitachi maf is better is that its not prone to failure as much as the bosch conter part thats about it.But then again most of the bosch mafs i have seen fail is because people used a aftermarket air filter that was oiled.Then the oil transfers and stick to the maf eventually cuasing it to fail or read incorrectly.ITo be honest I prefer the Bosch over the hitachi just because I dont see any point to changing the maf and swapping the wiring around.Envision,I would try and check make sure the maf you have is good.And no need for a hitachi maf to run a mbox file.Theres a couple of mbox tunes with bosch maf tables in them so you can flash and use the stock bosch maf.Just a FYI just in case anyone was wondering.

I haven't seen any tunes from nefarious that use the Bosch MAF and what not. I want to run an M-box to really compile and configure my own tune and what not. I've read that a lot less people have problems running the hitachi. I also switched due to the size of the MAF also. More volume = more power. I'm still trying to figure this headache out though. Bump if anyone knows anything more on this subject. Hopefully today my conversion will be the last of these stupid problems throwing me into limp mode :(

[EuroxS4]

The hitachi maf i believe is the same size as the bosch.the european rs4 only had a bosch maf installed in a bigger housing.I know there are a couple of tunes on the site that are for m box cars and have bosch maf tables patched into them so we can run these in a box car.Just have to reprogramm the cluster and your set.