Motronic 3.1

[Pug_101 0]

Just starting to fit a Bosch motronic 3.1 ecu to my 1993 std 1.9L GTi and would like a little help on a few points.

 

Having done some checking up on the conversion using the search and wiring diagrams I have decided the best route for me is to use the current loom fitted to the car and fit the new ecu to that in place of the old one as there are more wires in the current setup using motronic 1.3 than I think I will need with this new setup (i will be dropping the catalyst and AFM). The fact the engine bay loom is basically one piece including the lights, charging circuit etc has made me go this way for neatness and ease of install.

I am doing this now so at a later date I can run a Mi16 with this setup and hopefully in the mean time improve the cars running.

If there are an electricans or people with experience of this conversion could you help.

 

Is the 205 throttle pot a proper potentiometer or is it something else and if so how is it wired? I ask this as the wiring to this and the coolant temp sensor and mixure adjustment pot is somewhat different to the 205 setup.

 

Also will I need the Octane switch or can I use a resistor in it's place or just leave it out I aways try to use superunleaded? This is also part of the circuit above.

 

Found this on the web that may be of use to people

ECU Pin Outs

 

Thanks

[pug_ham 240 3 Cars]

I've got this system fitted to my car & so has Anthony (well to his skip) & the wiring isn't a hard job to do, even less wires than on an Mi loom.

 

The 205 standard TPS is purely a switch, open & closed. You'll need a proper throttle potentiometer for use with this loom.

 

I don't know if the ecu will fit your current loom with the pins in the right places for it to work & it won't have the wiring for the mixture poteniometer or inlet air temp sensor so I think it will be far easier to remove your current loom & fit this on in its place.

 

The ecu will need re-mapping to run an Mi properly as it has to much advance built in to run efficently & safely. You' run the risk of holing a piston iirc, AndyR ran his on it for a while but removed it before mapping for this reason after he spoke to Wayne at chipwizards about it.

 

What car has your donor loom & ecu come from? Judging by the mention of an octane switch I guess its from a ZX. I think when we wired this system in on NickR's car we left it out but I'm not positive about that.

 

I've posted the ecu pinout before but that explains it further if you don't have Autodata

 

Graham.

[Anthony 1,000]

Mine's using a mix of ZX Volcane ECU etc and a 405 SRi loom, and it was quite simple to wire up - the fact that I used a 405 SRi loom meant that it was very similar to doing a 405 sourced Mi16 loom in fact

 

The ZX Volcane loom looked easy enough to wire up, but I didn't really want the ECU in the engine bay, and to move it into the cabin with that loom would have taken alot of work.

[pug_ham 240 3 Cars]

I've got a ZX loom here for another forum member that I'm extending to keep the ecu in the normal 205 location.

 

If anything the ZX loom is harder to use but not by much.

 

Graham.

[Pug_101 0]

I've got this system fitted to my car & so has Anthony (well to his skip) & the wiring isn't a hard job to do, even less wires than on an Mi loom.

 

The 205 standard TPS is purely a switch, open & closed. You'll need a proper throttle potentiometer for use with this loom.

 

I don't know if the ecu will fit your current loom with the pins in the right places for it to work & it won't have the wiring for the mixture poteniometer or inlet air temp sensor so I think it will be far easier to remove your current loom & fit this on in its place.

 

The ecu will need re-mapping to run an Mi properly as it has to much advance built in to run efficently & safely. You' run the risk of holing a piston iirc, AndyR ran his on it for a while but removed it before mapping for this reason after he spoke to Wayne at chipwizards about it.

 

What car has your donor loom & ecu come from? Judging by the mention of an octane switch I guess its from a ZX. I think when we wired this system in on NickR's car we left it out but I'm not positive about that.

 

I've posted the ecu pinout before but that explains it further if you don't have Autodata

 

Graham.

 

No I don't have Autodata what is that exactly?

 

The donor is a BX (4x4) and I have the loom for this, but it does not contain any of the non engine electrics found under the bonnet so to use it would require quite a lot of work.

 

I have a Mi loom but have not looked at this yet, Is it basically the same as a 205 loom but with the different engine setup?

 

The module will not fit the current loom as the new one is a 2 row module and the 1.3 system a 3 row, but I have the ecu connector to change this around. Of the 22 wires I need for the new 3.1 system 14 are allready there ready to fit the correct sensors etc, 1 new wire to the rev counter will be needed and I need to pick a redundant wire in the loom for the extra ignition module trigger and the remaining wires are for the mixture poteniometer, inlet air temp sensor, TPS circuit which I havn't worked out yet.

 

What and where is the "injection matching resistor" as it matches up wire wise with the mixture poteniometer.

 

I have both the 1.3 & 3.1 pin out info.

 

Ok I need a throttle pot then, any going spare as the scrapies near me are rubbish. I will look anyway, I guess any citroen/Peugeot running 3.1 will have what I need?

 

Thanks

[pug_ham 240 3 Cars]

No I don't have Autodata what is that exactly?

Autodata

The donor is a BX (4x4) and I have the loom for this, but it does not contain any of the non engine electrics found under the bonnet so to use it would require quite a lot of work.

You don't need to change any of the 205 non engine electrics to fit any management system, all you need is the loom from the ecu to the injectors, switches or sensors associated with it & an ingnition switched feed or two along with the fuel pump wire.

 

Post the ecu number you have, I wasn't aware that the 4x4 BX's had this system fitted & its not mentioned in the BX Haynes manual. Best ecu to use is one from a ZX, like Anthony has. I had one on mine before it was mapped to my engine.

 

The injector matching (coding? ) resistor, I haven't got one on mine & I'm not sure exactly what it does. Maybe this is why my mixture pot doesn't have much effect. I'll have to look into it.

 

The best TPS is fitted to a Citroen ZX with MP3.1 as it has a similar throttle body to the 205 one but you also need a take off for the MAP sensor but this can be a T off the FPR vacuum line but the full ZX inlet with one is best imo. TPS's from a BX or 405 are a different bolt spacing to the 205 throttle body so you have to make an adaptor plate to fit them. Finding the right one can be quite a project though even with a decent scrappies nearby.

 

Graham.

[Pug_101 0]

ECU number

Bosch

0 261 200 206

 

Also have a second ECU which is a Lucas remanufactured one with the code:

0 261 200 119

Would you know what this is from also.

 

The loom i've got is around 7ft long and the modules designed to be inside the car. Also it has a seperate engine loom with a large round 23 pin connector (only 17 wired) to connect it to the rest of the loom.

 

What I would like is for the minimum amount of wiring under the bonnet so would rather not leave all the current wiring and add a new loom as well if possible.

Thanks

[inferno 1]

The loom and ecu you have is from a j reg BX GTi 4x4.

 

i can remove and post you the throttle pot, thats not a problem.

 

Your loom will be long enough to mount under the dash as it was under the seat in the bx.

 

if you feed your ecu plug and the two brown miltiplugs out through the bulkhead, untape the loom as far as you need to, ull see that the engine loom is seperate and u should be able to tape up the bx loom into the senser loom that remains, and end up with a very neet install. i find the strenthening tape in a self amalgamating tape pack for pipe repairs works really well as loom tape.

 

if theres anything else you find you need can u let me know by tomorow as the cars goin to my other workshop on sunday to be stripped of the running gear. could possibly post u a rev counter too, although im using that cars clocks myself, i have a xantia mp8 dash pack.

 

maybe the after sale support will make up for previous problems

 

BTW that multiplug with seperat engine loom part will replce the existing problamatic brown plug somewhere neer the thermo housing IIRC. id advise you do fit as i described above, using bx engine loom and the cars senser loom for gauges.

 

pm me if you need these bits, no extra cost as i did ask if there was anything else u need on saterday

Edited June 15, 2006 by inferno

[Pug_101 0]

The loom and ecu you have is from a j reg BX GTi 4x4.

 

i can remove and post you the throttle pot, thats not a problem.

 

Your loom will be long enough to mount under the dash as it was under the seat in the bx.

 

if you feed your ecu plug and the two brown miltiplugs out through the bulkhead, untape the loom as far as you need to, ull see that the engine loom is seperate and u should be able to tape up the bx loom into the senser loom that remains, and end up with a very neet install. i find the strenthening tape in a self amalgamating tape pack for pipe repairs works really well as loom tape.

 

if theres anything else you find you need can u let me know by tomorow as the cars goin to my other workshop on sunday to be stripped of the running gear. could possibly post u a rev counter too, although im using that cars clocks myself, i have a xantia mp8 dash pack.

 

maybe the after sale support will make up for previous problems

 

BTW that multiplug with seperat engine loom part will replce the existing problamatic brown plug somewhere neer the thermo housing IIRC. id advise you do fit as i described above, using bx engine loom and the cars senser loom for gauges.

 

pm me if you need these bits, no extra cost as i did ask if there was anything else u need on saterday

 

 

Thank you Tom.

Yes the above throttle pot would be helpful and also the octane switch what ever it is. I am guessing the other sensors have the same connections as the 205. Is the rev counter needed, if so i guess I need that too.

I totally agree with the pipe repair tape.

Will PM this message also.

Cheers

[inferno 1]

will post throttle pot asap, then u can decide on rev counter as explained in pm. i dont actually know where the octane resister is... does anybody have a pic? i certainly didnt take it off of that loom:S

[pug_ham 240 3 Cars]

Also have a second ECU which is a Lucas remanufactured one with the code:

0 261 200 119

Would you know what this is from also.

Citroen BX GTi 1.9 litre 16 Valve 87-89 Bosch Motronic ML4.1 0261200119

 

The throttle pot from the BX won't fit a 205 throttle body without an adaptor plate.

 

Rev counter is needed to have a working one, the current 205 one won't work from the ecu signal.

 

Graham.

[Pug_101 0]

I have made a start on replacing the loom as Inferno describes, but looks like the dash has to come out. I am correct on this.

Have stripped speedo pod out already and under steering wheel. Also metal plate in the way that is held on by unremovable spring clip

Someones been here brfore and made a right mess, Spare dash bits anyone?

[jackherer 543]

I have made a start on replacing the loom as Inferno describes, but looks like the dash has to come out. I am correct on this.

Have stripped speedo pod out already and under steering wheel. Also metal plate in the way that is held on by unremovable spring clip

 

I prefer to cut the ecu plug off the 8v loom and pull the wiring back through rather than remove the dash as I can never be bothered to put the dash back again...... obviously this ruins the 8v loom but thats hardly the end of the world. (edit: the sensor wires etc that you need to keep don't go through the bundle of wires I'm talking about cutting, its only the engine management stuff)

Edited June 16, 2006 by jackherer

[pug_ham 240 3 Cars]

The dash doesn't need to totally come out, just the main centre bolt & I think there are two 10mm nuts under the scuttle panel that also hold it in to remove so there is enough movement to get the ecu plug out & new one back in again.

 

Graham.

[inferno 1]

will the complete throttle body on the bx fit then? it is on the long manifold similar to but not an mi16 manifold, has 2 throttle butterflies...

 

ill take both bodies off and match them up tomorow. u had to take the dash pod out? arent the multiplugs tucked up in the kickwell?

[jackherer 543]

will the complete throttle body on the bx fit then? it is on the long manifold similar to but not an mi16 manifold, has 2 throttle butterflies...

 

ill take both bodies off and match them up tomorow.

 

the BX 8v TB has smaller diameter butterflies.

 

u had to take the dash pod out? arent the multiplugs tucked up in the kickwell?

 

yeah the multiplugs are by the heater matrix but theres a bundle of wires going over the steering column to the ECU plug that stops you being able to take the loom out easily.

[Pug_101 0]

Starting to think my idea of pining out the old loom and modifing it to suit the the new ECU wasn't such a bad idea after all, but I've started so I'll carry on with the loom removal way.

 

Havn't come across the two multiplugs yet, but like I said I cannot get this black steel plate from under the dashboard off and the ecu wiring is going over it.

 

No instrustions in the Haynes on how to take the dash off, Can I do it with out removing the centre Facia panal?

and it's just 3 bolts/nuts to move it enough Graham?

 

Cheers

[pug_ham 240 3 Cars]

I can't truly remember but I'm pretty sure the centre facia doesn't need to come off but the small triangle panel above the coin tray does to get access to the 10mm bolt in the centre of the dash. (needs an extention to reach it). The wipers have to come off to get the scuttle panel out for the other nuts under there, I think there are only two that need removing.

 

The black plate that the ecu mounts to is held up by spring clips that do come off, not easily but eventually they will work loose enough to allow the plate to drop enough to get the ecu connector over it. I tied some string to the connector for helping get the new plug back in.

 

The brown plugs will be near the heater matrix under the dash, not near the ecu.

 

Graham.

[Pug_101 0]

Ok I have the main loom complete inside the engine bay. Do I just seperate the brown plugs and there leads from the ecu connector and it's leads, thereby giving me 2 seperate looms?

Then discard the ecu loom and replace with the new 3.1 BX loom.

 

Thanks for the help so far guys, nearly there

[inferno 1]

yes pretty much

[pug_ham 240 3 Cars]

Yes, keeping the fuel pump wire (76) & 32a from the tachymetric relay seperate as you need these for the new loom.

 

Graham.

[Pug_101 0]

will post throttle pot asap, then u can decide on rev counter as explained in pm. i dont actually know where the octane resister is... does anybody have a pic? i certainly didnt take it off of that loom:S

 

Did a bit more work on this yesterday and i've noticed I have no injector connections with the new loom, looking at it I am guessing there should be a mini loom just for the injectors that plugs into the new loom, is these correct ?

Inferno do you still have this injector connections loom and that throttle pot ?

Cheers

[inferno 1]

i did give you the complete loom, including injector part, itll be the untidy bit with 2 earth crimps on it.

 

i do still have the TPS though as i though i read somewhere u found another! ill send it tuesday.

[Pug_101 0]

i did give you the complete loom, including injector part, itll be the untidy bit with 2 earth crimps on it.

 

i do still have the TPS though as i though i read somewhere u found another! ill send it tuesday.

 

 

Thanks Tom, did a lot of pin outing that day and must have got it wrong.

[Pug_101 0]

Still after a pot for the throttle.

Graham have you got the part number of the best fitting one please. I may have to this new.

Thanks