Motronic 1.3 engine loom

GreatOldOne · #1 29th September 2012, 14:52

Hi chaps,

As you know, I'm embarking on an ECU upgrade from 1.0 to 1.3. I've just had the new loom out in the garden, trying to determine which bits are required and which aren't, and I seem to be hitting a mental block.

I don't suppose any of you have pics of your looms / and or notes on what is required?

I have all the bits I need (new trigger pulley, sensor, full loom with relays, ECU, coil, injector loom in plastic case & new Cyl1 spark lead with inductive pick up) - I'm just not relishing the retrofit for some reason.

Any pointers / advice would be gratefully received.

Ta

GOO

MartinClan · #2 29th September 2012, 19:37

Is not the loom for the engine and ECU complete in itself? It just needs a power feed to make it go. I can't remember a lot of detail so it couldn't have been that tricky. You are welcome to come and have a butchers at mine. At home mid afternoon tomorrow or any evening during the week.

Robin

GreatOldOne · #3 29th September 2012, 20:36

It is, I just need to work out what the other plugs on the ECU end do. I believe one is c136, which is for the air con... But the other 12 way plug is eluding me.

Plus I need to double check some modifications I did to the large round connector to get the water temp sender into the loom - make sure the pins assignments are the same.

peterux · #4 29th September 2012, 21:00

Oh dear, Jason, this is not like you with electrics?

If you lay the engine loom in like in this picture the connectors more or less fall to the right places.

Inlet coolant hoses fitted by marlinpeter, on Flickr

IIRC the two connectors just below and to the right of the diagnostic connector are for the crank sensor and the No.1 spark lead inductor.

In this picture below, you can see that I only made a few connections to the loom.(and I don't think I used them all?)
The thick wire with the separate in-line fuse is the fuel pump supply.

Fuses by marlinpeter, on Flickr

My ECU is mounted above the passengers feet,but the loom comes into the cockpit under the brake reservoir so I din't need to shorten it.

Heater and Engine Loom by marlinpeter, on Flickr

There is also a thick permanent live connection along the loom on the way to the ECU that goes to my fusable link. There must be ground connection somewhere but I don't recall where that is?

Does that help? Ask away if there is something specific that doesn't make sense.

...peter

Patrick · #5 29th September 2012, 21:14

Mines pretty much as Peter's picture shows. The only change I made to mine was extracting the cables for the coil so I could place it on the intake side.

Here's a pic of the loom before installation:

I don't have any better pics of it.

GreatOldOne · #6 30th September 2012, 11:28

Here's the plugs I'm having problems identifying:

12 pin plug, 10 pins connected. Comes out of the loom near the main rubber bung / grommet - might be C204?

4 pin plug, 2 pins connected - I think that this is C136, as the pins are connected to the ECU plug on pin 40 & 41, which according to the wiring PDF is the Air Con demand lines.

MartinClan · #7 30th September 2012, 12:57

I also had a couple of "spare" small plugs next to the main ECU plug. After trying to find out what they did I finally ignored them and just tied them up to the loom. And that's where they still are so couldn't have been important....

Robin

peterux · #8 30th September 2012, 19:38

Quote:

Originally Posted by MartinClan

I also had a couple of "spare" small plugs next to the main ECU plug. After trying to find out what they did I finally ignored them and just tied them up to the loom. And that's where they still are so couldn't have been important....

Robin

Ditto, just ignore anything not required. But I guess you know that

cabrioman · #9 1st October 2012, 17:15

Goo

If you pm me an email address I have a pin out diagram for the engine wiring harness round plug which identifies what does what and whats not needed.

John

GreatOldOne · #10 8th October 2012, 20:06

Right, I believe I've identified all of the plugs, and found the main power feed. In checking all the plugs back to the ECU connector, I've found that what appears to be my throttle position switch (TPS) is in this connector here:

Now, considering that all the TPS module I've seen, and the one I've got, is oblong and has three pins - and this is round and has 6 pins - I guess I'm missing something, right?

Patrick · #11 8th October 2012, 20:21

It reminds me of the plug that the injector loom plugs into under the manifold. Middle bottom plug in my photo further up the thread.

GreatOldOne · #12 8th October 2012, 20:30

No, it isn't - you can see that connector on the left in the background of my photo, sticking up from the main loom.

The left three pins on the round connector in the foreground are throttle closed, WOT and earth. The other three pins are connected, but I haven't determined what they are yet as I was told to put my toys away and come in for dinner.

GreatOldOne · #13 8th October 2012, 21:10

Hmmm. According to those in the know over on e30zone, it is indeed the TPS connector... But it's the TPS connector for an automatic car. It would appear that the loom I have has come from an auto donor. I'm guessing that I can discard the other three wires in that plug, and connect a three pin plug fro my old loom to the relevant cables.

Patrick · #14 8th October 2012, 21:15

aaah ok, never seen an auto loom before

peterux · #15 8th October 2012, 21:22

Quote:

Originally Posted by GreatOldOne

Hmmm. According to those in the know over on e30zone, it is indeed the TPS connector... But it's the TPS connector for an automatic car. It would appear that the loom I have has come from an auto donor. I'm guessing that I can discard the other three wires in that plug, and connect a three pin plug fro my old loom to the relevant cables.

Ahh... maybe that explains the other unidentified 12 pin oblong connector(near the ECU connector).
Maybe that connector went to the auto-gearbox ECU? (If they had them on e30's?)

GreatOldOne · #16 11th October 2012, 14:13

Peter gets the prize for guessing what the oblong connector is for! - I sat down and mapped it out with the multi tester.

The other three pins on the circular TPS connector terminate in the oblong plug, so I'm guessing that they send the throttle position to the autobox control unit via that plug. All the other pins in it are related to the auto box as well (kick down, lock up, park etc) bar the important one - the switching feed to the fuel pump relay.

So, I'll remove all the un-needed lines whilst I'm replacing all the cacky loom covering, wire on a three pin oblong plug from the old loom to serve as the TPS connector and then I can fit it all.

Patrick · #17 11th October 2012, 20:00

Glad you figured it out!

GreatOldOne · #18 25th October 2012, 18:06

She's alive again!!

What a faff though... You forget that a lot of the stuff on the engine went on so easily previously because it was out of the car. Try changing the crank pulley / trigger wheel whilst its in the car without turning the air blue. It can't be done!

Anyway - she's running ok, but still a little high on warm idle. I'm guessing I need to run around for a while so she can 'learn' what's what before I start fiddling again.

Patrick · #19 25th October 2012, 18:17

Yeahy nice one, ah yes the crank bolt, what an absolute **** or a job! I remeber it well and I had the engine out.

peterux · #20 26th October 2012, 13:29

Quote:

Originally Posted by GreatOldOne

She's alive again!!

What a faff though... You forget that a lot of the stuff on the engine went on so easily previously because it was out of the car. Try changing the crank pulley / trigger wheel whilst its in the car without turning the air blue. It can't be done!

Anyway - she's running ok, but still a little high on warm idle. I'm guessing I need to run around for a while so she can 'learn' what's what before I start fiddling again.

Glad you got it all running again.

Just another thought this morning, I wonder if you have a worn throttle body?
If air is leaking past the spindle or butterfly I'm guessing the ECU will assume it's a partial throttle opening and fuel accordingly.
It might be something you could swap with an ebay spare to check?

...peter