1.3 Motronic Up-Grade & 2.7i How To

[jeffnhiscars]

Ive got a 1221 code which I believe to be caused by the 19lb 4 pintle injectors and a stock 525 ecu (since everythjing else is new). Is that something the ecu will learn or should I be thinking chip ?

[jeffnhiscars]

There you have it

thanks John

[ForcedFirebird]

Again, I did not have to splice those 2 wires (or any for that matter) to get my tach and fuel gauges to work. I wish I could confirm the donor year for my harness but obviously there's an exception to the splicing requirement. I do not have a separate injector harness if that helps narrow it down.

1987-only 325i (non-vert) donor engine harness would be a direct plug and play (edit: PnP on late 84 and up cars, earlier ones had the square c101) - that was the first year US got the 325i and the harness carried over. In 1988 when the coolant expansion tank moved etc, the engine harnesses changed. With your harness having the intergrated injector plugs, I would gather it's an 87 harness. The vert models are a little screwy since the chassis were sent out to be converted and were always a "year older" than the others. That's why you could get a 1992 vert in the e30 platform, but the e36 was a 2 and 4 doors - also why the verts kept the metal bumpers longer etc.

[jeffnhiscars]

Again, I did not have to splice those 2 wires (or any for that matter) to get my tach and fuel gauges to work. I wish I could confirm the donor year for my harness but obviously there's an exception to the splicing requirement. I do not have a separate injector harness if that helps narrow it down.

[ForcedFirebird]

Two 1 pin white connectors (brown and red wires) is your glove box light.

Flat 3 pin mini-spade connector, green is OBC drive away protection (ignition coil power lead), black is tech (which went through c101 on later cars), yellow is fuel economy gauge. If you want the fuel and tach to work, you will need to splice those wires into the harness bundle, or run wires to the c101.

The two black/white roundish plug 3 pin connectors that are clipped together are obsolete in the case of a swap.

One final thing to check is pin #20 in the c101 connector. If the chassis side is open, any engine harness can go in your chassis, peel the rubber boot off the back to see wires and if you have brown on one side and a color on the other, you will need to pull one side as early cars u8sed that for a ground, then some years it's missing, others it's a power. If yours mismatches and you turn the key, the body harness will start melting under your steering column.

[jeffnhiscars]

The car is buttoned up so I can't double check but that 3 wire connector goes to the cluster. Strictlyeta says you have tp jump 2 of those wires for the tach and econom gauge to function but ours was plug n play with zero splices.

ill add that on th first attempt to start I had no spark or fuel which was an obvious wiring issue. Turns out I had improperly connected a harness wire to the green/black which is 12v. Disconnected it and she started right up...and purred like a kitten. Loving the 731/272/1.3 combo. Best running M20 I've ever seen

[SterlingMetE30]

Can any one help with these plugs? 86 eta, and pretty sure the donor harness is from an 89.

Sent from my SM-G930T using Tapatalk

[SterlingMetE30]

Can any one help with these plugs? 86 eta, and pretty sure the donor harness is from an 89.

Sent from my SM-G930T using Tapatalk

[ForcedFirebird]

The VIN number the ECU is from is on the ECU case (if still intact). You can use the last 7 digits to see what it originally came from.

it's exactly the same. Just slightly different software - basically it has a speed limiter set to 125mph. There's no physical difference, advantage, or disadvantage to a 525 vs a 173.

Correct. Usually found in automatic cars for some reason. Not sure why BMW would speed limit the autos, but not manuals. Usually in the 80's and 90's cars were speed limited based on the tire speed rating that was sold with the car.

[nando]

it's exactly the same. Just slightly different software - basically it has a speed limiter set to 125mph. There's no physical difference, advantage, or disadvantage to a 525 vs a 173.

[Tainen]

Hello,

I have an ECU with the Bosch Motronic number: 0 261 200 525

Some searching makes me have more questions than answers. it does look like a motronic 1.3 system, but *everywhere* talks about the 153 vs 173 ECUs... is this 525 more rare or different in any way?

[Prizm]

I have verifyed the cps connecter buy checking continuity to ecu. Also verfiyed ohm change well cranking. Switched around connectors, to make sure. nothing. Verifyed all sensor grounds. Kinda stuck past geting replacment ecu.

[ForcedFirebird]

2.7 eta block with 885 head ecu wiring harnesses and all sensors for E to i swap

Just completed set up and cant get it ruining because i have no pulse to injectors. I have power to injectors, good fuel pressure. I have continuity from injectors to ecu on both banks. As well as continuity from cps with correct ohms. I also have spark.

I am thinking bad ecu but not 100% sure. Do you have any suggestions?

Thank you tz

Check to make sure the cylinder identification (sensor on #6 spark plug wire) and crank position sensors aren't swapped on the harness. They have the same 3 pin connector, and is a common mistake.

[Prizm]

2.7 eta block with 885 head ecu wiring harnesses and all sensors for E to i swap

Just completed set up and cant get it ruining because i have no pulse to injectors. I have power to injectors, good fuel pressure. I have continuity from injectors to ecu on both banks. As well as continuity from cps with correct ohms. I also have spark.

I am thinking bad ecu but not 100% sure. Do you have any suggestions?

Thank you tz

[jeffnhiscars]

A harness swap isn't too bad by itself, really. The A/C bracket needs to come off if you don't want to cut the oil pressure sensor wire, and the OEM CPS wire routing is kinda a pain unless you remove the water pump pulley at minimum (in the "i" setup).


Generally when we pull an engine at the shop, the ECU connector comes out of the firewall, the oil pan ground leaves the frame-rail, the C101 gets disconnected, and it all come as a unit.

Thanks for the input. We're changing the WP pulley anyway and the upper timing cover since the eta cover doesn't have holes for the wire conduit. We're not pulling the engine but it will be headless, which I assume is the best time to re and re the harness.