1.3 Motronic Up-Grade & 2.7i How To

[Regnar75]

if its any consolation i have the flat top pistons and an 885 head (full motronic 1.3 swap) and i love it. i am putting a new clutch in at the moment, but plan on getting a dyno test to see what its at. even if its not on par with a nice 325i its still a massive improvement over the ETA

[Andy.B]

if its any consolation i have the flat top pistons and an 885 head (full motronic 1.3 swap) and i love it. i am putting a new clutch in at the moment, but plan on getting a dyno test to see what its at. even if its not on par with a nice 325i its still a massive improvement over the ETA

I just wrapped up my flat top piston 2.7i build. With a 274 cam, chip, intake, and 3.25 diff, the car pulls much harder than my gf's stock (chipped) 325i with a freshly rebuilt top end, and a million times harder than the eta did (which had the same intake and diff).

[Regnar75]

id love to get a cam.

[Chilezen]

What is the difference between B25 and B27 block? Is it just the throw of the crank that produces the greater displacement?

[whitebulat22]

Block is exactly the same and it is just the 3 mm crank difference that adds the displacement.

[Regnar75]

^ actually in this sticky there are mentioned a few differences in the blocks

http://www.r3vlimited.com/board/showthread.php?t=285315&page=2

but i dont think its anything to really concern yourself with. just for the knowledge

[jayuuey]

I read through the thread but didnt really find what i was looking for. Can someone please break down how to splice in the oil level sensor, oil pressure, o2 sensor? Pics, wire colors, etc would help a lot.

I have an 87e and harness from 87i.

Thanks in advance.

[Regnar75]

^ i wish i could be help when it comes to the oil level sensor, and oil pressure, but i just used the 325i oil pressure sensor that matched my harness, and didnt hook up oil level. the O2 sensor on the other hand i can help a bit. theres two types of o2 sensors, theres a 3 wire and a 4 wire....instead of typing im just going to paste what i already put in this thread.
-O2 sensor, I used the 3 wire one that I had stock spliced it into a 1.3 female connector I grabbed from junkyard. Using e exhaust the I connector/o2 sensor will not reach without extending anyway. Look inside connector and find #1 mate that with #2 on the female connector. #2 with #3 and #3 with #4 respectively. Connector #1 on female end (grey wire) I didn't hook up, no issues yet.

i put a bunch of notes on little issues i had on that one post, its on page 22 here. post #324.

but if your going to use the I exhaust, just get a new O2 sensor, its a wear item anyway and you wont need to splice anything to get it to fit, but the I sensor is too short to reach the o2 location on the e exhaust so if your sticking with the e exhaust, grab an I o2 sensor from junkyard and cut the plug off (the one that plugs into your harness) splice o2 sensor (NOT HARNESS) to match the connector (stated in my post) and use that. or buy an I o2 sensor and just extend the wires to reach the o2 bung

[Andy.B]

I read through the thread but didnt really find what i was looking for. Can someone please break down how to splice in the oil level sensor, oil pressure, o2 sensor? Pics, wire colors, etc would help a lot.

I have an 87e and harness from 87i.

Thanks in advance.

I just did this swap, and also used an 87 I harness in my 87 e. It is the easiest possible combination, because you shouldn't have to cut and splice anything. Your current oil level sensor will plug into the 87 i harness. You need a new o2 sensor anyway, so just buy the right one (the small 4 wire plug, not the larger screw type plug). And for the oil pressure sensor, they are cheap enough to just buy a new one ( about $10).

And since you are using the same year harness, you don't even have to splice anything under the dashboard. Just plug in the 3 wire c104 from the motronic harness to the body harness and you're all set.
(This only applies to the 87 325i harness in an eta AFAIk).

[jayuuey]

Thanks for the last two posts.

Andy,
do you have a picture of your engine harness on the ecu plug end? Im wondering if i actually have an 87i harness or not. Mine has a 3 wire plug (2 wires in one section and 1 wire in another. Does that sound right?

I just did this swap, and also used an 87 I harness in my 87 e. It is the easiest possible combination, because you shouldn't have to cut and splice anything. Your current oil level sensor will plug into the 87 i harness. You need a new o2 sensor anyway, so just buy the right one (the small 4 wire plug, not the larger screw type plug). And for the oil pressure sensor, they are cheap enough to just buy a new one ( about $10).

And since you are using the same year harness, you don't even have to splice anything under the dashboard. Just plug in the 3 wire c104 from the motronic harness to the body harness and you're all set.
(This only applies to the 87 325i harness in an eta AFAIk).

[Swanny]

You'd know right away if you had a late model harness since there'd be a removable connector for the injector harness. The 87 had a goofy 3 plug wire that i believe went to the tack and obc that was on the glove box side of things. I'm trying to hunt down the differences between the harnesses myself since my body harness is an 87 and the engine harness is an 89.

[Maad325]

well most of the wires are color coded. you only really need to hook up the yellow/black start input wire, the green ignition wire and the black/green unloader to get it to start. what you need is the bmw etm wiring diagrams to find out which pins are which. you should be able to find them in the forums though.. search c101

Where did you hook up these wires? I just finished my swap and it's currently getting no spark.

Sent from my SM-N900V using Tapatalk

[StereoInstaller1]

You'd know right away if you had a late model harness since there'd be a removable connector for the injector harness. The 87 had a goofy 3 plug wire that i believe went to the tack and obc that was on the glove box side of things. I'm trying to hunt down the differences between the harnesses myself since my body harness is an 87 and the engine harness is an 89.

I did a write up on how to fix that, been a couple years tho, so it's buried.

[Swanny]

I did a write up on how to fix that, been a couple years tho, so it's buried.

Yeah i saw it when doing research on the swap. Will dig around and repost.

[Panda_kRz]

Hey guys, sorry didn't want to go through the whole thread looking for a simple answer, but if a 1987 325(e) comes with a 15 pin connector up front, it is a 1.0 motronic, correct? Also is there a DIY/guide for swapping the 1.0 to 1.1/1.3? The first page didn't really specific on how to do so, thanks.