15 replies to this topic

[Elephant]

Hello, not sure if this is my first post here or not, but I've been lurking in the darkness for a while now!

A little story to my question, I was discussing the E to I conversion with my friend on Sunday - saying how great it'd be if we found a 325i Auto in the scrappy to get bits off. We thought we'd go have a poke around as he thought there were a few BMWs there. Right at the back was a '90 325i Auto with 125,000 on the clocks completely untouched. Went to the front and asked if it came in running and how much they wanted for the bits. It was running and they wanted £200 for all this:

885 Head
Inlet manifold
Throttle body
AFM
Injectors
IAC
60-2 toothed pulley and sensor holder (sensor had poor wiring so will buy new)
173 ECU
GCU

And all the other little bits that go with it...

Then that night on eBay I found a 1.3 wiring loom from an '87 320i (at least it looks like a 1.3 loom!) for the grand price of £16 with postage.

So, with all that I should be almost ready to do the conversion once I've checked over everything - and at a bargin price!

But reading stuff on MyE28, I've discovered the E30s C101 connector to the fusebox is wired in differently to the harnesses that they have in the states as well as the wiring to turn the ECU on under the dash and the tacho.

Can anyone either tell me what wires need to go where or point me in the right direction?

Also, some sources suggest the Lambda sensor is different and needs to be changed. Is this true?

Any help is much appriciated as I'd like to get this going soon and with as little interruptions as possible as I need the car for Uni runs.

[bm0p700f]

Where are you. It would be a good idea to come down to sunny Suffolk and examine my car but if you are two far away then this might help.
e28---> 1987
Pin 1--------->Pin1.....To inst. cluster charging indicator lamp
Pin 2--------->Pin 2....To check control, static oil level sensor
Pin 4--------->Pin 4....To cluster, coolant temp signal
Pin 6--------->..............Not used with e30 FI (integrated idle control)
Pin 7--------->Pin 13..Fuel pump control
Pin 8--------->Pin 18..To starter, from ignition
Pin 10------->..............Not used on non-airbag cars? (would go to pin 20?)
Pin 12------->Pin 7.....12V to ign coil
Pin 13------->Pin 10...To check control, dynamic oil level sen.
Pin 14------->Pin 5.....To cluster, oil pressure warning lamp
Pin 15------->Pin 11...To cluster, SI reset
---------------->Pin 16...Unused
---------------->Pin 20...UnusedThe e30 harness also has a few extra wires coming through the C101 to support the additional features of Motronic 1.1/1.3:
Pin 12--->To inst. cluster for "Check Engine" light
Pin 6----->To a 15A fuse, hot in run or start, for the oxygen sensor heater relay.

The 02 sensor heater isn't critical, but you should splice it in. The check engine light can be helpful for troubleshooting but you would have to run wires to the cluster and install a "prizm" in the cluster from a 1988 528e with a "Check Engine" indicator. I'd just wrap it up in some electrical tape and tape it to the harness.

Thats most of the wiring. You still have the C103 to deal with in the glovebox. That connector carries the engine speed and fuel consumption signals to the cluster, the A/C-on signal to the ecu for idle control and most importantly a 12 volt signal to the ECU from the ignition switch that lets the ECU know its time to wake up. I'll add those splices to this thread when I have a chance to look them up.

This comes from mye28. I have checked this wiring scheme out against the ETM and all is good. I think my car is wired up this way but the garage that did the wiring had some trouble. I think they tried matching wire colours instead of pin numbers. May be it now wired up in the way turbodan originally posted. I have not checked. The one thing I know is the green 12V wire in the glove box from the C103 does not go to the ECU. It actually power my OBC correction module. So the ECU wakes up just fine without it.

I have also converted the car to an manual and fited a 3.46:1 final drive. I recomend going to these lengths to really wake the car up. So come on down to Suffolk have a look at how my car is wired up or have a play with turbodans wiring guide. I am sure you will have success.

[bm0p700f]

Oh I have replied to your mye28 pm as well with those questions.

[Elephant]

That makes more sense! From what I'd read, I had assumed the two looms were different - but if your garage had tried to match up the wires by colour then maybe that was the problem. I'll just hope for the best when I start cutting it all up!

Also, in your PM you said do not use a big bore Throttle body? What is classed as big bore? I have the one off the 2.5i and was planning on using that.

Another question, if you were to skim the head by say 0.025" then the timing would be out by 1 degree; and if you gain 1 or 2HP through skimming the head, then this would be countered by cam being out, right? I don't want to get into the expense of having having vernier pulleys either, so would it still be worth it? I know you can use offset woodruff keys to get the timing correct but I'm not sure its worth it if there's very little to be gained.

Again, thanks for the help.

[Elephant]

Last thought - the 02 sensor on the E28, is it heated and should the plug match that of the loom?

[bm0p700f]

I don't use an O2 sensor and my car runs just fine. U.K E28's don't have an O2 sensor anyway. As for the big bore TB I mean a bored out 325i TB. That is too big when keeping the stock AFM. The AFM outlet is smaller than the BBTB inlet so the air flow sows down then it it speeds up entering the inlet mani. This robs power. The stock 325i TB is a good match for the stock AFM.

If you skim the head by what you sugest you will not need a vernier pulley. As you will bump the compression ratio from 9.35:1 to 9.93:1 I hope you will gain more than 1-2 hp. The gains from the CR bump will be noticeable through the rev range and will result in more low end torque. Fuel economy should be improved too. Milling the head should retard cam timing and thus give you a bit more top end power and the expense of low down power.

If you know the diameter of the cam gear then the ammount of retard is = arctan(ammount of mill/radius of cam gear).

It will not be out by much and you can no doubt just fit the the head with no issues.

[Elephant]

Ok, that's great. I was wandering where the 02 sensor was - guess this is the trouble with reading a mainly American based forum!! Thank you for your help, I think I'm ready to get this conversion happening once I pick up a few more things - mainly gaskets!

[Elephant]

Bringing up the old thread again, so it's all in one place. Saves a bit of confusion and searching for others!!

I bought a wiring loom from a 87 320i and have finally got round to trying to establish which of the 5 pins on the C104 connector does what (I wasn't sure which was which so tested both black (2 wires) and white (3 wires) blocks). StrictlyEta.net say that pins 6 (RPM output) 32 (fuel consumption output) and 38 (12v ECU power) go to this connector and need to be bridged/spliced.

However, I have found that the pins from the C104 on my loom from the white block go to pins 33, 42 and a relay whilst the black block goes to pins 41 and 40 of the ECU

Obviously Strictly Eta is an american site, but I would've thought the pins would remain the same. At a guess I would say that the pin that goes to the relay is the ECU power, but what about the rest?! I guess that is the main difference.

I believe I'm correct in saying that they are the same looms and apparently almost the same ECU!

Other than that any idea why there are these differences? I'm a little worried it may not work when I go to start it after the conversion.

Also, where's a good place to find out the info regarding the wiring?

[bm0p700f]

Also the way the E30 wires up is completley different to the way the E28 wires up.

"However, I have found that the pins from the C104 on my loom from the white block go to pins 33, 42 and a relay whilst the black block goes to pins 41 and 40 of the ECU" No, no and no again, well I really don't understand what .

The wiring is as my previous post. If you are really worried come up to suffolk one weekend and we can examine the wiring in my car and generate a list, as it works you can just copy this. You could also use the ETM which is what I did to confirm the wiring guide I have copied from my28.com.
I hope the loom came from a motronic equipped 320i. Also what are the last three digits on your ECU. I hope they are not 164, 153 or something other than 173 or 179.

[Elephant]

This is strange, BMWFans.info has differing information regardless dates, E30s and engine looms - but in essence I probably have a different loom and need to get one from a 325i, last thing I want is a car that won't start! I think the pins on the ECU plug are in a different combination on the '87 320i to the '90 325i loom, and thus may not work with my '90 325i ECU (or I am a little silly and need to think more!).

I'm sure the C101 connections you have posted are correct, but the C104 seem to be quite different. I'll have to do a bit more investigating.

The ECU is from a 325i and is a 173, and the rest of the parts I have are from the same car (apart from the pulse generator).

Thanks for the help again!!

[Elephant]

Just to clarify, there are two different looms fitted to the E30 320i. First is one dating from '89-'91 and is the one that's also used on the 325i from '88 to '91 - this is the one needed. Then there is a second loom, which I think I have, which was fitted to the 320i '86-'91 and 323i but only the RH auto and LH manual (no dates). Seems a little strange they overlap in dates so widely but I think it'll be easier to try to get the loom off the 325i I got the rest from.

I'm not sure of the differences between the two, but the ECU connections would appear to be one of them! The ETMs I have found are all US spec cars which don't include the 320i, so are a bit useless with my loom. Plus if 5 pins are different on my loom for the ECU I bet more are!!!

Out of interest if the 320i loom I have wasn't from a Motronic equipped car then would the ECU plug still be the same? This might explain the differences - I didn't know that they came fitted with anything else.

[Elephant]

Went to scrappy today to check out the 325i wiring loom and it looks exactly the same (surprise!). I'm gonna try to check as many of the C101 connections as possible to make sure they match up, I guess even if the pins on the ECU Plug are different they should still match up with my ECU. The ETMs are all American, and the looms and ECUs are different to European models. I'll post my findings when I get around to checking it out!!

[bm0p700f]

The ETM for US spec car are valid, they really are. You need a motronic 1.1/1.3 loom froma post '88 325i or 320i. Motronic 1.1 was introduced on E30's in Septemebr 1987 I belive with motronic 1.3 coming in during 1988 sometime. You will need a motronic 1,3 ECU from an E30 325i/320i (post 1988) or E34 520i/525i. Your ECU plug should be a 3 row 55 pin affair. Make sure you get the right ECU or you will not be able to get a chip to run the engine. I recomend getting a rolling road remap done by gunni @motorworx or Ant @ A-tech or Paul Sheppard @ motorworx.

As for the connector behind the glove box simply pull present fuel rate wire and tach signal wire from the motronic 1.3 loom before it goes through the circular c101 and sent it up through the firewall and join it to the matching wires there (there's only three of them). Thats it.

E28 L jet/motronic 17 pin c101 fuse box side.

Pin 1 D+ (alternator)
Pin 4 Temp guage
Pin 6 pin15 diagnostic port.
Pin 7 Fuel pump
Pin 8 Starter + ignition control unit
Pin 10 airbag (not used)
Pin 12 15u (coil)
Pin 14 Oil pressure
Pin 15 service indicator
Other pins not used unless you have a check control eqipped car.

Compare this to the pitcure attached.

[Elephant]

I have the 55pin ECU connector, which would Motronic 1.1 and 1.3; the loom is from an '87 320i with a large diagnostic port.

"As for the connector behind the glove box simply pull present fuel rate wire and tach signal wire from the motronic 1.3 loom before it goes through the circular c101 and sent it up through the firewall and join it to the matching wires there (there's only three of them). Thats it."

I don't quite understand what you mean by this, I thought the ECU power, Fuel rate and Tach signal is sent through the C104. Do you mean I need to match up these wires with my C103?

The only reason I want to check the C101 connections on the E30 harness is because the C104 connections appear to go to the wrong pins on the ECU and other parts of the loom may also be different. Unless of course my loom is not a Motronic 1.1/1.3 one, but then I would expect the ECU plug to be different if this was the case!

[bm0p700f]

I really don't know what the c104 is, also the c104 in an E30 does not exist in an E28 in the same form. As for the three wire plug behind the glove box do what I have described. The tach is pin 9 and is a black wire on the E30 circular C101 so pull that wire. The present fuel rate is a white black wire and is pin 14 on the E30 C101 (not the speedometer signal wire has the jpeg I posted says).
These two wires in an E30 pass through the C101 and through the main loom to the cluster but in an E28 they do not go through the C101 but through the connector behind the glove box. So pull these wires and re-route.

If you have an OBC your mpg figures will be out so the only way around this is buy the OBC correction module from http://www.seattlecircuits.com with a chip with a +/-60% range. This module works very well.

[Elephant]

Ah right, I got it all wrong!!! Thanks for sticking with me and explaining it again. I didn't realise that the tach and econogauge wires went through the E30s C101.

Thanks again for the help, much appreciated.