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Motronic MP3.1 wiring diagram and more

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welshpug

on the 8v 205 and the zx & bx the IAT is a different type screwed into a boss moulded into the intake hose, the type you have pictured is the 106/306 type that fits the Solex throttle body, the plug is the same and I believe the scaling of the sensor is the same.

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pug_ham
On 1/12/2022 at 7:42 PM, Gavin Waddell said:

So now i need to find a 106xsi wiring diagram and a bxgti one. He also stated fitting a lambda .

BX GTI uses the same ecu as the 405 SRi so you be able to follow the diagram for that which is on here somewhere iirc.

 

The BX wouldn't have a double relay but the two separate relays like the 405.

 

I don't think the 106 ecu plug wiring differs that much to the ZX one but I'll get some screen shots from autodata in the next few days & add them in a reply.

 

I know the ecu from a S1 106 Rallye fits the 405 & ZX loom as I have one somewhere.

 

g

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Gavin Waddell

Thanks for that Graham, that clears this up a bit. I will use the 405 wiring  diagram to check the ecu outputs and make sure that every thing is where it should be and also maybe wire in a lambda. When i was reading Josh's old posts he said he had some trouble with the co2 pot. 

And then once you upload the 106 diagram i will be able to check the double realy wiring.

 

Thanks again.

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Gavin Waddell

Hello Graham

 

Where you able to find the 106 wiring diagram?

 

 

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pug_ham
7 hours ago, Gavin Waddell said:

Hello Graham

 

Where you able to find the 106 wiring diagram?

 

 

Sorry Gavin, it had slipped my mind.

 

I'll try to get it done one day this week & post the screen shots up asap.

 

g

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pug_ham

Finally got a screen shot of the autodata ecu wiring diagram;

 

 

 

106_1.4XSi_mp3.1.JPG.4bd0528b35b493562a0275737ea02cb5.JPG

 

Let me know if you need the codes for the parts & I'll make a note of the others.

 

T7; Coil

B147; TPS

R9; Throttle body heater

Y3; Injectors

 

g

 

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Gavin Waddell

Hello Graham

 

Haven't been on for a while,

other life projects.

 

Thanks for the diagram.

Going to be a pain but could i get the codes for the other componets so that i can double check every thing.

 

Thanks Gavin

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pug_ham

Hi Gavin,

 

Ok, I'll try to get some time on my laptop with autodata on in the next week or so & gather the component codes.

 

g

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Gavin Waddell

No stress, when you have time.

 

Thanks again.

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Gavin Waddell

Graham, what 106 engine managment did you get the info from? 

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Gavin Waddell

TU5J2/Z

TU2J2/Z

?

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pug_ham

A phase 1 106 1.4 XSi, TU3FJ2 (K6B) on Motronic MP3.1.

 

Key to the diagram I posted previously;

 

30; battery positive.

K46; injection double relay.
T1; coil.
R9; intake manifold heater.
15; ign switch.
F7; fuse.
Y99; idle air control valve.
Y3; injectors.
A52; ignition amp.
P7; tacho.
X1; data link connector.
H63; mil.
B147; tps.
R62; co adjustment resistor.
B25; IAT.
B24; ect.
B75; cas sensor.
M12; fuel pump.

 

g

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Gavin Waddell

Cool, thanks for that Graham.

 

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Gavin Waddell

Hello every one

 

im still working on this project just making time for it.

i went through the ecu pins for a zx ecu to see if my loom was correct and all was in order (which make sense as it came out of a running car).

i then decided to look at the double relay wires and thee weer a few discrepancies which i would need some advice on:

 

Just to make sure i used a ZX and 106 wiring diagram for reference.

 

so here it is

Double Relay discrepancies

 

1: On the ZX diagram the double relay pin 5 is for injectors , but on mine the wire is cut   But the injectors are wired to pin 11 on the DR

2: I have a wire running from pin 6 that goes to a 2 pole plug which im guessing is the SAD, the only thing is that the other plug wire goes to a ring terminal? would this be for power? or run to the starter as per one of the other mp3.1 threads to get the sad working.

3; Pin 11 is a thick wire that has been cut, on the ZX diagram it should run to the battery and pin 18 of the ecu. instead pin 18 of the ecu is connected to pin 15 of the DR.

 

Here or my thoughts on all of the above:

1: leave as be as it should work as is.

2: im stumped on how the SAD should be connected?

3: Re pin the wire and run a new wire to the black distribution block?

 

thanks in advance

 

Gavin

 

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pug_ham
On 8/24/2022 at 5:26 PM, Gavin Waddell said:

Double Relay discrepancies

 

1: On the ZX diagram the double relay pin 5 is for injectors , but on mine the wire is cut   But the injectors are wired to pin 11 on the DR

2: I have a wire running from pin 6 that goes to a 2 pole plug which im guessing is the SAD, the only thing is that the other plug wire goes to a ring terminal? would this be for power? or run to the starter as per one of the other mp3.1 threads to get the sad working.

3; Pin 11 is a thick wire that has been cut, on the ZX diagram it should run to the battery and pin 18 of the ecu. instead pin 18 of the ecu is connected to pin 15 of the DR.

The Inlet Air temp sensor also runs a plug that looks the same fitting as the SAD but that is fed from pin 6 on the ecu not the double relay from looking at the ZX diagram although on the 106 diagram I have, it runs from pin 6 on the relay (I can't make it out on the ZX diagram I have to hand) and it basically runs through the IAT to earth which could explain the ring terminal.

 

Also, on the 106 diagram, pin 5 runs to the coilpack.

 

Pin 11 is from the battery positive to the double relay, looking at my diagram, it is linked to pin 15 & the ecu pin 18 so that's ok imo.

 

I need to get my laptop with autodata here so i can have a better look at the diagrams on there because I'm trying to work from a bad scan of the haynes manual atm.

 

g

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CitrAX

Excellent information behind links posted in this topic, thank you.

It allowed me  to do some troubleshooting on my newly acquired 1992 Citroen AX GTI 1.4 running on Bosch Motronic MP 3.1. Or actually “not running” currently haha.

Maybe someone can help identify this problem.

Car doesn’t start, has no power to the fuel pump or coils.

I have traced the problem to the fuel pump control circuit between Motronic pin #20 and fuel pump relay #10.

I am getting ignition voltage to this circuit with key ON.

Circuit is supposed to be ground trigger to activate second half of the relay which provides battery voltage to the fuel pump and coils.

I tested all functions of the double relay and they all work as shown in the diagram.

The wire between relay and ECU is not shorted to anything else in between.

But apparently the ECU never switches to ground at terminal #20 so no power to the pump or coils.

Is it possible the ECU is not providing fuel pump control signal for some intended reason? Like no RPM signal for example? I tested the RPM sensor and it appears to be generating AC signal. 

Or does this sound like mosfet failure inside the ECU?

I tried jumping relay terminals #1 and #9 to power pretending to be the relay working properly but car still doesn’t get spark making me wonder if this ECU has failed internally.

What say you?

If mod thinks this should be a separate topic let me know and I'll erase and repost, thanks.  

image001.jpg

Edited by CitrAX

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CitrAX

Follow up: problem was bad cranshaft sensor.

Without tachiometric signal Motronic MP 3.1 control unit doesn't provide ground for secondary portion of the fuel pump relay, thus no fuel pump or coil power. 

Thank again for posting these diagrams it allowed me to repair my car. 

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welshpug

I had missed this but as I was reading your post I was thinking crank sensor, as it primed fine, it meant the circuit and ecu function was fine.

 

  I don't know why exactly but the TU engine seems far more prone to crank sensor failure than XU.

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