ECU mystery (B35)

[Theotherotter]

When I was taking the lower dash apart as part of replacing the heater valve on my E12, I found a surprise in the glove box.

My car has an M30B35 / 265 swap out of a 1989 635CSi. ECU is # 0 261 200 179, which according to my reference (https://prepa205gti.wordpress.com/wp-co ... homaso.pdf) matches a 1989-94 Motronic 1.3 B35, so no surprises. But I found a chip in the glove box - # 1 267 356 460 - which from the same reference is the stock chip for that ECU. Which suggests that I have....who knows what running in the ECU. Naturally, I'm curious to find out.

1)What should I be careful with if I try to undo the harness connector? I'll just go ahead and ask how to do it.

2)How do I open the ECU housing to see what's in there? It appears that the flat panel (top in vehicle) is just held in place with folded-over tabs but perhaps there's more that I can't see.

[kojo96]

When I was taking the lower dash apart as part of replacing the heater valve on my E12, I found a surprise in the glove box.

My car has an M30B35 / 265 swap out of a 1989 635CSi. ECU is # 0 261 200 179, which according to my reference (https://prepa205gti.wordpress.com/wp-co ... homaso.pdf) matches a 1989-94 Motronic 1.3 B35, so no surprises. But I found a chip in the glove box - # 1 267 356 460 - which from the same reference is the stock chip for that ECU. Which suggests that I have....who knows what running in the ECU. Naturally, I'm curious to find out.

1)What should I be careful with if I try to undo the harness connector? I'll just go ahead and ask how to do it.

It's easy, there's a lock tab at the back, push it back and lift the connector up and out from the rear. It has a plastic positioning tab at the front and it needs to be cleared to remove.

2)How do I open the ECU housing to see what's in there? It appears that the flat panel (top in vehicle) is just held in place with folded-over tabs but perhaps there's more that I can't see.

Pry the tabs up, the top will lift off. The screws on the bottom secure the PC board, it's a single board, much more advanced than the 059 ecu.

[Theotherotter]

OK, I’ve got the ECU out and the top off - and I still have no idea what chip is in it because it’s under a plastic cover. How do I remove this?

https://imgur.com/a/motronic-1-3-red-la ... cu-8WRxcnu

[kojo96]

OK, I’ve got the ECU out and the top off - and I still have no idea what chip is in it because it’s under a plastic cover. How do I remove this?

https://imgur.com/a/motronic-1-3-red-la ... cu-8WRxcnu

It pops off, looks like an aftermarket/performance chip in there.

[Theotherotter]

Edit: I got the cover off, and it’s a Miller Performance chip. Label says ‘179 G3’

Can anyone tell me about these? There’s no info on this (obviously an older product) on their web site. The engine swap was done about ten years ago and I assume the ECU was chipped then, too.

[kojo96]

Edit: I got the cover off, and it’s a Miller Performance chip. Label says ‘179 G3’

Can anyone tell me about these? There’s no info on this (obviously an older product) on their web site. The engine swap was done about ten years ago and I assume the ECU was chipped then, too.

Mind putting an image of the chip here, I have one amd want to compare to what was in yiur ecu. Thanks

[Theotherotter]

Sure:

https://imgur.com/a/miller-performance- ... 34-PS2JOYP

Sorry, I seem completely incapable of getting the correct version of an Imgur link to put the photo directly into the post.

[Mike W.]

[kojo96]

Sure:

https://imgur.com/a/miller-performance- ... 34-PS2JOYP

Sorry, I seem completely incapable of getting the correct version of an Imgur link to put the photo directly into the post.

[Theotherotter]

I think I'm going to assume this is basically similar to a Dinan chip. I wrote them to ask, but based on some of the things I've read about them I'm not sure I'll get a response.

[ahab]

This is the "stock" Miller MAF chip, as opposed to their W.A.R chip. It compliments the AFM replacement they sell as a kit called the Miller MAF conversion. Check under your hood and above the valve cover you should have a smooth plastic tube with a flat connector going to it instead of a cast aluminum thing with a formed black plastic cover. Google search will fill this out for you.

[Theotherotter]

Taking a look confirmed what I suspected, which is that my car has the stock intake. I googles that Miller intake and was certain my car didn’t have it.

[kojo96]

Taking a look confirmed what I suspected, which is that my car has the stock intake. I googles that Miller intake and was certain my car didn’t have it.

It's not the intake ^ was talking about. It was the MAF... Google MAF vs AFM, report back.

[Theotherotter]

I know - I’m familiar with different methods of air and fuel metering. I meant the entire intake tract downstream of the air box (I have a K&N), but I just did not google enough. Googled enough to get a bunch of stock E34s and there’s an obvious flapper box (I’m surprised, since even my LH Saab SPG uses a hot wire airflow meter) and mine doesn’t have it.

[kojo96]

I know - I’m familiar with different methods of air and fuel metering. I meant the entire intake tract downstream of the air box (I have a K&N), but I just did not google enough. Googled enough to get a bunch of stock E34s and there’s an obvious flapper box (I’m surprised, since even my LH Saab SPG uses a hot wire airflow meter) and mine doesn’t have it.

You have a Miller Performance chip for the 179 ECU, similar to all the aftermarket chips. The MAF chip won't run a car using a AFM, and visa versa.

[Theotherotter]

Do you know whether this chip is tuned for 91+ octane, or for 87?

[kojo96]

Do you know whether this chip is tuned for 91+ octane, or for 87?

Doubtful it's for 87 pump gas but I've run 89 and 91, couldn't feel any difference and never had an issue with detonation.

[ahab]

You may not have the MAF, but that chip is for the G3 version of the MAF kit. G3 being for Gen 3 MAFs which are the first plastic body Miller MAFs. Someone broke up the kit and you got the chip. It's tuned for high octane.

https://www.millerperformancecars.com/s ... ler-detail

You have a Miller Performance chip for the 179 ECU, similar to all the aftermarket chips. The MAF chip won't run a car using a AFM, and visa versa.

Are you sure about that? I don't believe Miller sold standalone chips, they came with the MAF kits. I could certainly be wrong but I've been using their kit on my 535 since the group buy here 12 or whatever years ago. I also have a Gen 3 on my M5 with a W.A.R chip but I don't recall ever seeing the regular chip available on its own. I am slightly surprised the car will run with only the chip, but by Gen 3 you didn't need to modify your wiring harness so it's not completely out of the question. How well would be the issue.

[kojo96]

You may not have the MAF, but that chip is for the G3 version of the MAF kit. G3 being for Gen 3 MAFs which are the first plastic body Miller MAFs. Someone broke up the kit and you got the chip. It's tuned for high octane.

https://www.millerperformancecars.com/s ... ler-detail

You have a Miller Performance chip for the 179 ECU, similar to all the aftermarket chips. The MAF chip won't run a car using a AFM, and visa versa.

Are you sure about that? I don't believe Miller sold standalone chips, they came with the MAF kits. I could certainly be wrong but I've been using their kit on my 535 since the group buy here 12 or whatever years ago. I also have a Gen 3 on my M5 with a W.A.R chip but I don't recall ever seeing the regular chip available on its own. I am slightly surprised the car will run with only the chip, but by Gen 3 you didn't need to modify your wiring harness so it's not completely out of the question. How well would be the issue.

Confusing it is... I had a Gen 3 (aluminum tube/Ford lightning MAF sensor) in my 88 535i. I had to modify the wiring, but did what CEK did in modifying the ECU.
The modified ECU with the Miller MAF chip would not run my car with the AFM. I tried running the Dinan chipped 059 with the MAF sensor and it would not run the car.
From what I understand, the MAF system runs on a different Voltage signal to the ECU.

[ahab]

Ok, yep, you’re right about the harness. I had forgotten that the Gen3 DID need a wiring change. Gen 1 was visible in the engine bay but Gen 3 was done at the ECU connector, at least that’s how I did mine anyway. Pretty sure that’s how you were supposed to do it.

Perhaps I’ve forgotten about the chips too! I honestly don’t remember them selling standalone chips, and they certainly aren’t selling them now, but clearly I’m not remembering all the details here.

[Theotherotter]

So my car does indeed have the MAF kit. Thanks for all the help understanding what I have. There is German text on the molded plastic of the intake tube, and I wonder what the part comes from. It is similar to, but not the same as, what is in the link you gave. I'll try to attach a photo in the next post. Do you know the part number or particular application for the MAF? (You mention Ford Lightning, so I'm guessing some prior generation of F150 Lightning?) It's good info to have. My 911 runs on a Megasquirt and uses things like an E30 TPS, a Jeep Cherokee IACV, Crown Vic plug wires, Ford V6 EDIS coil pack, Accel off the shelf injectors, but I have part numbers for everything in my files. The Miller setup was probably added when the B35/5-speed swap was done in 2010 (per the BAR sticker in the door jamb). Before I knew I had it, once I looked up what a stock B35 ran on I was using 87 in it to no apparent ill effect (it's nice to have *one* car that uses cheap fuel), but have been using 89 since then.

You may not have the MAF, but that chip is for the G3 version of the MAF kit. G3 being for Gen 3 MAFs which are the first plastic body Miller MAFs. Someone broke up the kit and you got the chip. It's tuned for high octane.

https://www.millerperformancecars.com/s ... ler-detail


Are you sure about that? I don't believe Miller sold standalone chips, they came with the MAF kits. I could certainly be wrong but I've been using their kit on my 535 since the group buy here 12 or whatever years ago. I also have a Gen 3 on my M5 with a W.A.R chip but I don't recall ever seeing the regular chip available on its own. I am slightly surprised the car will run with only the chip, but by Gen 3 you didn't need to modify your wiring harness so it's not completely out of the question. How well would be the issue.

Confusing it is... I had a Gen 3 (aluminum tube/Ford lightning MAF sensor) in my 88 535i. I had to modify the wiring, but did what CEK did in modifying the ECU.
The modified ECU with the Miller MAF chip would not run my car with the AFM. I tried running the Dinan chipped 059 with the MAF sensor and it would not run the car.
From what I understand, the MAF system runs on a different Voltage signal to the ECU.

[Theotherotter]

Edit: JFC why can I never get the correct Imgur link to
embed the image??

https://imgur.com/hbDuEp8

[ahab]

Yep, Definitely a MAF. I don't think Miller offered the MAF kit as early as 2010, and most certainly not the Gen 3 but my memory of such things has already proven rickety at best. Hopefully kojo96 can answer your questions.

Is that Kastanienrot or Ruby? Just able to see a glimpse of the paint in your photo. Don't ask me why you're having trouble with linking photo but I'm going to blame it on the site. It's weird here. How about some pics of the whole car?

[Theotherotter]

The original color is Bordeaux Red, but when it was repainted it was in a slightly brighter red. It may be another BMW red, but I'm not sure what it is. The difference is obvious when you look at the A surface metal and the engine compartment with the hood open. It was a very good paint job, and all the jambs were done and it looks like the glass came out, too. I've got plenty of pictures but don't want to deal with imgur again so here's a link to one from the weekend before last at the PVGP:

[ahab]

Looks like Verona perhaps. Great looking car.