Modifying ECU for Miller MAF (vs. connector)

[tig]

I have a project going to put a Miller MAF in Vlad; mostly as a test exercise to determine how well they work.

I don't want to modify the ECU connector to do so:

https://www.millerperformancecars.com/f ... %20III.pdf

I have a spare 059 ECU that I would like to dedicate to this and would rather modify it than the connector.

I want to be able to swap out the MAF and ECU easily.

Does anyone know if it's possible to modify the ECU and if so, what specific traces I would tweak on the PCB?

[RDAvena]

Why not make a short pigtail using a male plastic connector off of a dead AFM and a female AFM connector. Modify the wring between the two.

AFM Male side connects to the stock AFM wiring harness and the female end supplies the correct switched wiring to the MAF.

This eliminates trying to put jumpers or cut traces on the stock ECU board.

[tig]

Why not make a short pigtail using a male plastic connector off of a dead AFM and a female AFM connector. Modify the wring between the two.

AFM Male side connects to the stock AFM wiring harness and the female end supplies the correct switched wiring to the MAF.

This eliminates trying to put jumpers or cut traces on the stock ECU board.

Interesting idea. If this were possible, why didn't Miller just design the MAF this way to begin with and put the wire mods at the MAF plug instead of forcing customers to modify the ECU plug?

[RDAvena]

Interesting idea. If this were possible, why didn't Miller just design the MAF this way to begin with and put the wire mods at the MAF plug instead of forcing customers to modify the ECU plug?

On the Aluminum bodied MAF it uses the F150 Lightning MAF module and the BMW wiring did not translate exactly to the pins on the MAF. Newer ones use the later round plug for the plastic MAFs. It is never an actual "plug and play" unless it comes from BMW.

But at least with this workaround you will have the least invasive of modifications.

[tig]

Interesting idea. If this were possible, why didn't Miller just design the MAF this way to begin with and put the wire mods at the MAF plug instead of forcing customers to modify the ECU plug?

On the Aluminum bodied MAF it uses the F150 Lightning MAF module and the BMW wiring did not translate exactly to the pins on the MAF. Newer ones use the later round plug for the plastic MAFs. It is never an actual "plug and play" unless it comes from BMW.

But at least with this workaround you will have the least invasive of modifications.

On page 9 of the PDF linked above are the instructions for modifying the ECU connector:

Code: Select all

1. Locate the following pins (make note of which color each pin is): 
a. Pin 35 (Red/Blue) 
b. Pin 9 (Grey/White) 
 
2. Take the Grey/White wire and cut the connector pin off. Take the Grey/White 
wire and create a „T‟ soldering it into the wire coming out of pin 35. The below 
picture illustrates this step. Note, your Tee’ing the portion of pin 9 that leads to 
the engine bay. 

Pin 9 is reference output. This Gray/White wire goes to pin 3 of the AFM (page 1360-11). This mod disconnects that wire from the ECU.

Pin 35 is power (hot in run or start). The Red/blue (RD/BU in the ETM) wire goes to pin 87 on the main relay via G102 (Page 1360-9). After the mod this 12V+ still goes to pin 35, but ALSO goes to Pin 3 of the AFM/MAF.

What you are suggesting is another way of doing this mod is to put a connector between the existing AFM plug and the MAF that ties in 12V hot in run or start into Pin 3.

Right?

[RDAvena]

I did not modify the ECU connector. I did everything at the AFM connector. Same color wires. This is why I commented on making the pigtail.

[Dinan e28]

What about the pictures of my jumped ecu, I sent you last year?
It doesn't get any easier then that.

[tig]

What about the pictures of my jumped ecu, I sent you last year?
It doesn't get any easier then that.

I forgot. I'll go look again.

[tig]

Well, Dinan e28, was not able to get me pics of how he modified his ECU, but I trusted that it was possible and decided to just do it.

Step 0: Verify the 24 pin 059 ECU that Kohler sold me actually works. Installed it in Vlad and it ran fine.

Step 1: Verify that my understanding was correct that the mod involves disconnecting Pin 9 (reference sensor) from the ECU and having that same wire (white/gray) carry 12V to the MAF.

Step 2: Crack open the ECU and poke around.



Step 3: Decide which way to hack the thing.

Option 1: Do it on the leads to the connector. Snip #9 and run a wire from the snipped #9 to the somewhat hidden #35.



Option 2: Do it on the back side of the board, soldering a wire onto where #35 and #9 connect, cutting the wire trace on the ECU board for #9.



I chose Option 2. Either way if I screw up the ECU is toast and either way, once done the ECU is never going back. Only down side of Option #2 is that someone looking at the board from above will never see that it's been modified. Too bad. Maybe I'll put a sticky note in there.

Step 3: Mad soldering skillz with less mad wire trace cutting skillz:



Step 5: (Optional, only if you have a broken Miller chip from Kholer, and you trust that it actually, really is a Miller MAF chip...because Kohler never screws up). Soldier the pin that is broken directly to the socket. (!!)





Step 6: Put the case back together and label it. I considered putting the URL to this thread on it :-)





Step 7: Walk back up to the garage, plug it in, and cross your fingers.

If you don't hear from me in the next few hours, call 911 please.

[wkohler]

Why didn't you just solder the included map pin to the chip?

[tig]

Why didn't you just solder the included map pin to the chip?

Because I didn't think it would hold. And I needed to pin something to my wall.

I'm back from my test drive. It worked! I rock.



Throttle response is definitely sharper. Butt dyno didn't notice a huge change (I had the OEM 059 chip in right before). I did notice that the Miller chip raises the redline just like the Conforti chip does. I really don't like that.

Friday I go to the dyno and do runs with all three setups.

[ahab]

Miller will also repair your chip for a nominal fee if you send it to them. AMHIK. I think it was $30.

[Brad D.]

Friday I go to the dyno and do runs with all three setups.

I am anxious to see the results. What type of dyno are you running on?

[wkohler]

Miller will also repair your chip for a nominal fee if you send it to them. AMHIK. I think it was $30.

Given they're the ones that sent me a virtually broken chip and charged me $70 for shipping despite my original request of a 24-pin chip. I wouldn't pay them $30 to repair it. When I got that chip there were more than ten bent legs. I got it in the ECU, but when the fuel pump died on I-8 in 130° temps I was grasping at straws so I swapped it to another ECU. It broke when I swapped it back to return the borrowed ECU. I guess it couldn't handle the pressure on that leg. I think if you look underneath the legs, there's a glob of solder somewhere on the chip like it was already "repaired."

[ahab]

Ouch. I'll agree that service is not one of their strong suits.

[tig]

Friday I go to the dyno and do runs with all three setups.

I am anxious to see the results. What type of dyno are you running on?

See http://www.carbconn.com/

[Dinan e28]

CEK Sorry I wasn't able to open my ecu and get picks to you again. I also couldn't find the copy of the picks I took in the first place. We did it the same way you did. Did you get any custom tunes for your motor?

[tig]

I'm going do to the same thing now to a 179 ECU for my B35. I really much prefer this technique of modifying the ECU versus mucking with the wiring harness. It makes it far easier to swap the MAF out and put the AFM back in for testing and diagnostics. ECUs are relatively cheap and a 179 MAF chip will only go in a 179 ECU so they might as well be put together permanently.

I'm going to be getting a WAR chip and this mod will also work for that.

To recap what the mod is really about:

The MAF requires 12V where the AFM required -5V called the 'reference output'. On both the B34 & B35 the wire is gray/white and goes to pin 3 of the AFM. On the 059 ECU the reference output is at pin 9.

On the 179 ECU the reference output is at pin 12. So for the 179 ECU we need to make it so pin 12 is connected to 12V instead of -5V.

We know that pin 37 of the 179 ECU is 12V from the main relay, so we'll find that on the board and figure out how to route it to pin 12.

Here's the ECU that's been tested and known good in Vlad along with the Miller chip.



Open up to see how it differs from an 059. Much more modern. One board. Much tighter traces...


The red probe is pointing to in 37 and the black to pin 12. Note there's no obvious way to cut a trace from Pin 12 to 'snip' it like there was on the 059 ECU.


The solution is to snip the actual post within the connector, bend it up and soldier the wire directly to it. I chose to run the wire through the front between the connector and PCB.


The other end gets soldiered to where pin 37 meets the PCB.


And we're done.


I might have time tomorrow to swap the MAF and test it before I start the drive to 5erWest. We'll see...

[sansibar]

Hy,
I just want to know how to snip pin n°12,because my standard tools are just too big to access ? Did you test the modded 179 ECU with the MAF and does it work properly with the connection 37>12?
thanks

rob

[tig]

Hy,
I just want to know how to snip pin n°12,because my standard tools are just too big to access ? Did you test the modded 179 ECU with the MAF and does it work properly with the connection 37>12?
thanks

rob

I used a wire cutter with a pointy tip that could reach through. You could also use a tiny file to cut through it.

Yes I tested it and it works great. Ive driven some 20k miles and it's been great. I also have a WAR chip installed since doing this mod.

[athayer187]

Hy,
I just want to know how to snip pin n°12,because my standard tools are just too big to access ? Did you test the modded 179 ECU with the MAF and does it work properly with the connection 37>12?
thanks

rob

I used a wire cutter with a pointy tip that could reach through. You could also use a tiny file to cut through it.

Yes I tested it and it works great. Ive driven some 20k miles and it's been great. I also have a WAR chip installed since doing this mod.

I can vouch for this mod too - small pointy cutters are the way to get in there (I bent the adjacent pins outward slightly to make more room).

[sansibar]

great, I will this method, thanks

rob

[sansibar]

So, i did the mod on the ECU in last december, and today the weather was fine to take her out, but the engine only cranks and does not fire :-(
switched back to the AFM and stock ECU and all was fine. What I didn't do last year was to check if the engine was firing with he spare ECU, unfortunately, because I think the spare ECU is not working correctly which I hope.
Is there any way the I can test the ECU myself, but I don't think so.

rob

[tig]

So, i did the mod on the ECU in last december, and today the weather was fine to take her out, but the engine only cranks and does not fire :-(
switched back to the AFM and stock ECU and all was fine. What I didn't do last year was to check if the engine was firing with he spare ECU, unfortunately, because I think the spare ECU is not working correctly which I hope.
Is there any way the I can test the ECU myself, but I don't think so.

rob

Not that I'm aware of. I'd re-check your work (soldiering etc...).

[sansibar]

I think I found the mistake :-) will try next week