E30 M3 MAF conversion Help needed

[Robmann23]

Today I was helping my old man revert from a CSL style carbon airbox(this setup never ran right as we unfortunately could not find the Miller war chip tuning software) to an previous setup with with a standard shaped carbon plenum and MAF.

This setup had run previously but now after reverting wiring changes according to the instructions the car won't start.

The wiring for the MAF grabs 12v for the MAF reference input off another terminal on the ECU. All other wires from ECU to the MAF appear correct according to their descriptions.

When I measure across common and reference at the plug I get 12v (which the instructions say is correct), however when I measure across common and the other pins at the plug (MAF output signal and MAF air temp) I get roughly 12v too. According to the instructions I should get either 1v or 0.1v depending on sensor type.

So my question is does this mean the MAF itself is toast or is it something else?

The car cranks but it smells like it is dumping a huge amount of fuel in (maybe because the signal is at 12v when I think idle should be something like 1.5v?l

Any help would be greatly appreciated 👍

[kronus]

By MAF do you mean the stock flappy door AFM?

[Robmann23]

No so it used to have the flappy door AFM but has been converted to a MAF with a Miller performance kit.

The kit did work then he replaced it with a different one but he's now going back to it.

im wondering if the MAF is toast seeing as it reads 12v from common to all the other terminals?? Like possibly it has shorted out internally🤔

[TobyB]

If you unplug the MAF and meter the signal terminal going into the Miller box, does it still have 12v on it?
It should drop to 0v.
If you power the MAF, but leave the signal pin disconnected, does it output 12v? That would be
a definitive way to test the MAF. It should read low, and go up when you blow on it (seriously!)

I've worked with one Miller setup, and found it... obstrebperous....

t

[DesertBMW]

Miller MAF kit is a scam, it does not work. You must use the original barn down AFM, it is less restrictive anyway

[reelizmpro]

OP, so you are going from Miller MAF to Miller PnP Alpha N with WAR chip back to Miller MAF...is that right? TPS swapped back to stock ?

[TobyB]

Miller MAF kit is a scam, it does not work. You must use the original barn down AFM, it is less restrictive anyway

The version I worked on wasn't a scam, as such- it sort of tried to sort of work. Which at times was worse than not working at all.
As to restriction, the intake manifold's got the final word on flow, so from that aspect of things, it IS a bit of a scam, I guess. Until the AFM wears out.

These days, it'd be pretty easy to take a Ford MAF and an Arduino and set it up to first log the flapper and the MAF in series,
fake together a quick approximation of a transfer function, then swap the coding around to have the MAF output an AFM signal.
And then tune from there...
t
does it himself and... never... gets... around... to... finishing... it....

[Robmann23]

If you unplug the MAF and meter the signal terminal going into the Miller box, does it still have 12v on it?
It should drop to 0v.
If you power the MAF, but leave the signal pin disconnected, does it output 12v? That would be
a definitive way to test the MAF. It should read low, and go up when you blow on it (seriously!)

I've worked with one Miller setup, and found it... obstrebperous....

t

I'll be going round this weekend dto have another look at it so I'll give that a try

[Robmann23]

OP, so you are going from Miller MAF to Miller PnP Alpha N with WAR chip back to Miller MAF...is that right? TPS swapped back to stock ?

Yea basically but I think it was a Miller PNP carbon airbox with MAF and war chip. We still have that MAF, I tried to just plug that one in to see if the car would start with that plugged in and just kinda sitting on top of the motor but no luck. That MAF had a weird little circuit board in between the plug and the MAF itself. The little circuit board thing had 4 pins on the plug side (same as plug) but then only 3 pins on the MAF side so when it didn't work I just left it because god knows what that thing does haha

As far as the TPS Im not actually sure. I didn't do the the first to conversions with him but I'll definitely ask if anything was done with the TPS previously.