1.3 Motronic Up-Grade & 2.7i How To

[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]

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]

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]

There you have it

thanks John

[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 ?

[ForcedFirebird]

Could be. 1221 is for oxygen sensor out of range, or relay fault. Might go away once the ECU trims the fuel, but honestly there's no reason to use 19lb - specially with ca stock chip. I've been able to get 180+whp with the stock 14lb injectors and FPR...

[jeffnhiscars]

I picked up the fresh 19s when I was gathering parts and planned to throw in a chip once I got her sorted. Ive been idling quite a bit while working on the AC so suspect that may have triggered the 1221. Does the code clear itself after x amount of time or do I need to reset the ecu and see if it comes back ?

[ForcedFirebird]

The M1.3 actually has a memory that uses LTFT, so don't disconnect power to it or it will run worse until the ECU re-learns that it has way oversized injectors.

In the interim, you could always use the ETA 2.5 bar fuel regulator. That will bring the effective fuel delivery down to 17lb - closer to stock, and will make the ECU much happier. Right now it's trying to correct 26% of injector difference, the 2.5bar regulator will bring that closer to ~17%.

[Camper Van Someren]

Long story short, I just bought a car with an i motor, but the previous motor added a bunch of eta pulleys and sensors and stuff so he could run an eta ecu. More info here if you’re curious: https://www.r3vlimited.com/board/for...ter-pump-issue

I have a few questions about converting it back to an i ecu. I read all 500 posts, plus used the search feature, couldn’t find answers to these:

1) Is there any way to tell the i and eta pump and crank pulleys apart so I know which type is currently on the car?

2) I’m currently doing a timing belt and when I put it back together, I’d like to put an i harmonic balancer and crank pulley on it but continue running it with an eta ecu for a while. Problem is my car already has a CPS there that was reading the non-toothed balancer. I know the primary cps reads the flywheel - the manual says this one on the front is for diagnostics only. Question is, can I put the i balancer on and either leave the diagnostic CPS or just disconnect it? Will that affect the way it runs?

3) noob question: I’ve read on here that one i part I’ll need to switch is the “air fuel module” but I’m not familiar with this. The more I read, it seems that the AFM is just the black box on top of the MAF sensor and these parts are swapped together. Is this true?

[nando]

the eta doesn't have a toothed wheel on the front hub, that's a pretty obvious giveaway.

I'd just disconnect the front CPS if it's not needed.

E30s don't have a MAF sensor. You need the AFM that matches the proper version of motronic - the one for an Eta will not work with Motronic 1.3.

[Camper Van Someren]

the eta doesn't have a toothed wheel on the front hub, that's a pretty obvious giveaway.

I'd just disconnect the front CPS if it's not needed.

E30s don't have a MAF sensor. You need the AFM that matches the proper version of motronic - the one for an Eta will not work with Motronic 1.3.

Thanks Nando!

1) I know it currently has the eta harmonic balancer (non-toothed - that is easy) but the prior owner mixed and matched other pulleys and I’m wondering about the actual pulley on the crankshaft and water pump. I have read that these have different diameters - does anybody know the exact dimensions, or any identifying marks, so I can see whether I have the pulleys from the i or eta?

2) I hope that (redundant) front CPS isn’t needed, but has anybody run an eta motor without one?
Edit - found on bimmerforums: “An additional TDC sensor is located on the front of the crank for diagnostic purposes and is not used by the computer.”

3) I’m trying to figure out what the AFM looks like and where it is located so I can pull it in a junkyard. It’s probably just different terminology, but when I searched realoem there was nothing called an Air Fuel Module or anything close. There was a Volume Air Flow Sensor. Ditto when I google AFM, I keep getting MAF or something similar:
Edit: more info from e30zone re: AFM vs MAF. They say the AFM stands for Air Flow Meter. Is this the same as the Air Fuel Module mentioned in post 1 of this thread?

[nando]

It's an Air Flow Meter. it's basically a metal flap with a spring and a potentiometer in a box that converts how far the door is open to an air flow value. it can't measure mass, or pressure, so it's not a MAF or a MAP - but it's not surprising that those descriptions are wrong because people don't know how it works. lots of 1980's cars that had Bosch fuel injection use the AFM (Porsche, VW, etc).

It was never called a "module" in the past, although maybe some people are calling it that now.

[Camper Van Someren]

My car came with a spare fuel rail and injectors with part# 0280150941. These appear to be Ford injectors - 14.3ohm resistance, 14lb flow rate.

I have heard of people using Ford injectors with the 325i but when I search this part # on E30 websites I get nothing.

Would these be ok to use with the 325i ecu?

[ASEHugo]

I’m almost done with my 2.7i build in my early model ‘86 325es, but I was curious where you guys put the ground cables that usually live on the top of the passenger strut tower? Early models don’t have the stud, so what do you guys do to overcome that?
Thanks!

[ForcedFirebird]

There's a 6mm threaded hole in the battery tray, worked for me.