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20vt conversion wiring question


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#1 pauldoubleyou

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Posted 05 June 2017 - 11:22 AM

Right so bit of an strange question. 

 

I'm in the throws of doing a 20vt Lupo. When it comes to the wiring, is it better to run the old Lupo engine loom to the 1.8t ECU, then splice what i need to the 20vt engine.. 

 

Or better to run the 1.8t engine loom to a 1.8t ECU, and then splice.. what? Plugs for indicators, lights etc? Will the interior side just plug right in?

 

I dont want to run standalone.



#2 natedogg

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Posted 06 June 2017 - 12:30 PM

i think your better off splicing the mk4 1.8t loom to suit the lupo fusebox.

 

I sent both of my looms to ACR (Andy Outhwaite) on the recommendation of Old Man Bam and he did any excellent job.


Edited by natedogg, 06 June 2017 - 12:30 PM.


#3 Banmenow

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Posted 06 June 2017 - 01:55 PM

Splice it
Use rubjonny on here. Top top work may be waiting list but so worth it

#4 Luke mk3

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Posted 06 June 2017 - 04:02 PM

1.8t has two ecu plug's, small one is engine side large one is dash side.

The engine side stuff stays the same pretty much. The dash side needs to be spliced into the Lupo fusebox engine compartment plugs.

Probably save yourself the hassle and get someone else to do it if you don't understand!

#5 pauldoubleyou

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Posted 07 June 2017 - 02:24 PM

Thanks for the replies guys. No I totally understand, and am competent, but it was just that one stupid question that has ensured I stay in the right direction. There not a lot of data on the Lupo conversion but there is a lot on G1/G2 (diferent wiring altogether, simpler) and also a few great writeups on T4s (none of which are anything like the lupo but the premise is there).

 

Ill work it off the wiring diagrams but it also means ill be pulling the dash.. I thought there might be a chance I could avoid it.



#6 rubjonny

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Posted 12 June 2017 - 01:43 PM

you dont have to pull the dash (i dont think?) just remove the polo loom complete.

 

when I made a polo loom what I did was strip the polo wiring loom, then split off all the wires from the sensors etc back to the ecu plugs. I de-pinned all the wires out of the ecu plugs that went to the fusebox, and swapped them into the 20v ecu large plug. Had to add in post-cat wiring iirc, no biggy and change the pre-cat to wideband plus add the MAF plug in there as it was a 1.6 with map sensor instead.

 

Then I added the T14a plug for the main 20v sensor harness, so the mk4 loom dropped in without any modification. this saved a herll of a lot of effort, plus means if theres ever an issue with the loom in future the customer could just swap in another sensor harness and plgu it in.

 

It helped that the original polo engine was also dbw, as all the ecu pins are the same type just had to figure out the order. He even retained the polo throttle actuator and it worked fine once the pinout was worked out for it as its a bit different to the MK4 later throttle pedal unit.



#7 pauldoubleyou

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Posted 19 June 2017 - 07:55 AM

That was my original thinking. Ive heard that Andy at ACR will do it but its like £400, which sounds ridiculous. 

 

Ive stripped the loom right back to the wiring now and from what i can see the smaller ECU plug is where most of the engine sensor wiring goes into. My intention was to do just that, just repin the 1.8t engine loom into that ECU plug then plug it into the 1.8t ECU. 

 

But.. it seems too simple. 

 

Soon as i can get hold of a copy of the wiring diagram for the Lupo and the Octavia that is. 



#8 rubjonny

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Posted 19 June 2017 - 08:06 AM

have a look in my signature, you'll probably find what you need. if not, just ask ;)

 

as you say most of the 20v wiring is in the wee plug, so easiest way is use that complete and power it up thru the t10a/t14a. You need to ID all the dash feeds in the lupo loom as well as the ecu power & trigger feeds etc then wire them to the correct place on the T14a and big ecu plug. 

 

you can either choose to splice the 20v wires to the lupo ends, or if it has the right plug on it for the 20v ecu you can do what I did which was to de-pin the ecu plugs on the original loom car entirely then ID what does what. figure out the matching pins for the 20v loom and re-insert them. Doing it this way I didnt even have to strip the loom tape off completely, just a small section near the ecu down towards the engine.

 

if it is a DBW ecu, this is the pinout for the remote type actuator if you need it:

33-4
34-6
35-1
36-3
72-5
73-2

 

this may help you figuring out the 20v loom as well:
http://clubgti.com/s...read.php?267196



#9 pauldoubleyou

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Posted 19 June 2017 - 11:20 AM

Superstar. 

 

I stripped back the loom from the bay yesterday (not the 20v engine loom with the injectors etc on it) just to see whats what. I mistakenly thought i could just pull the old engine loom out completely but theres all sorts of peripheral crap from the Lupo on that loom. 

 

I need to get hold of the ECU pinouts really for the Lupo before i commit to snipping and other stuff. 

 

With having to splice the dash / fusebox side - is it more sensible to have the dash off then? 

 

Really appreciate your replies - do you do plug and play looms? If so could you PM me a price? Its Lupo 1.0 to AUQ.


Edited by pauldoubleyou, 19 June 2017 - 11:21 AM.


#10 rubjonny

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Posted 19 June 2017 - 11:38 AM

yeah EVERYTHING in the lupo bay is wired in 1 great lump, but it will come out with enough effort. but if you're happy to work in the engine bay you can just leave it in there to do your wiring work. this gives an idea of what you're dealing with:
http://www.ebay.co.uk/itm/222517899658

 

looking at that it does seem to go along under the dash for a bit, not sure how accessible things are underneath or if the dash does actually have to come out? luckily for me the customer took care of all that side and just sent me his loom in a big box to deal with :lol:

 

as I say I didnt splice anything at all to the inside, all the feeds I needed were on the polo ecu plugs. So I de-pinned all the wires from the fusebox side out the polo ecu and re-pinned in the right place for a 20v :)  then all I had to do was add a couple more wires for the wideband lambda and replace the 4 pin plgu with a 6 pin, add the MAF wiring in out of a donor 20v then add the T14 plug in the right place to suit the 20v sensor harness. as it was a DBW i also added the ecu relay box, rather than trying to run a decent permanent live from the fusebox to it instead I added a feed to it from the polo battery box. its a while ago now but I probably re-used the SAI relay power wire as thats went to the mk4 battery box so had the right end on etc, told the guy to fit it in and use a 15a fuse in his battery box same as the 20v has inside the car on the live feed.

whats the year and engine code on the lupo? if not sure let me know the ecu part number

I do plug n play looms yes, but my list is properly backed up I'm afraid 8 months at least I recon :(



#11 pauldoubleyou

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Posted 20 June 2017 - 09:47 AM

These replies are gold, cant thank you enough. 

 

Im just going to pull the dash to be honest, its almost off. It will at least help me to get into the wiring between the ECU and the internal loom / fusebox - and i need it off to get to the pedal box.

 

I didnt expect the loom in the bay to be quite so much like a snakes wedding. There are individual wires that go from the engine side loom into the internal fusebox, and some that go to the smaller ECU plug but all looped into each other for some reason. 

 

Ill get a decent pinout removal kit and match them up I think. 

 

Is ETKA the best place to get ECU plug pinouts for the Octavia and the Lupo?

 

Lupo is a 2000 1.0 AUC i think. I can clarify on the ECU.



#12 rubjonny

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Posted 21 June 2017 - 08:35 AM

the joined wires you mention are probably for things like fuel relay power, perm live, ignition etc which are tapped into from several places.

 

ETKA is for parts, if you want diagrams its ElsaWin you need. which I have ;)

 

look in my signature link for 6x0aucecu.pdf, that should cover what you need. The octavia loom will probably be the same as the equivalent code VW/Audi ecu loom, see my sig and my wiring guide above.

 

the bad news is its not a DBW type ecu with a 80 pin ecu plug, so all the pins are different. you'll have to cut the wires off the old ecu then tap to the new one. The good news is as long as the wires are thin enough you dont need a terminal tool to remove the old pins or to crimp new wires into the DBW ecu terminals. Slide out the purple retaining tab on the end then the pin holders pop out. Pull the rubber seals back then use a pick tool to release the tab for the wire you need to work on, cut the wire off and pull it out and bin the pin. Swap over one of the many spare pins VW thoughtfully left for you in the empty positions then use something suitably blunt to push the new wire into the pin jaws. You'll see what I mean! If you've ever terminated a/BT type phone socket you'll know the score.

 

or just cut n splice where necessary, whatever works. just be sure to stagger your joints so they dont bulk out the loom or rub thru



#13 pauldoubleyou

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Posted 21 June 2017 - 11:22 AM

Owe you a pint somewhere down the line. 

 

I had looked through that google drive in the past too, but hadnt spotted that pdf was relevant. Think ive got a copy of ElsaWin somewhere from when I had a bad VAG habit.

 

Right, going to crack on and give it a go and ill stop hassling you! Thanks buddy.



#14 Rawr_32

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Posted 21 June 2017 - 12:02 PM

the joined wires you mention are probably for things like fuel relay power, perm live, ignition etc which are tapped into from several places.

ETKA is for parts, if you want diagrams its ElsaWin you need. which I have ;)

look in my signature link for 6x0aucecu.pdf, that should cover what you need. The octavia loom will probably be the same as the equivalent code VW/Audi ecu loom, see my sig and my wiring guide above.

the bad news is its not a DBW type ecu with a 80 pin ecu plug, so all the pins are different. you'll have to cut the wires off the old ecu then tap to the new one. The good news is as long as the wires are thin enough you dont need a terminal tool to remove the old pins or to crimp new wires into the DBW ecu terminals. Slide out the purple retaining tab on the end then the pin holders pop out. Pull the rubber seals back then use a pick tool to release the tab for the wire you need to work on, cut the wire off and pull it out and bin the pin. Swap over one of the many spare pins VW thoughtfully left for you in the empty positions then use something suitably blunt to push the new wire into the pin jaws. You'll see what I mean! If you've ever terminated a/BT type phone socket you'll know the score.

or just cut n splice where necessary, whatever works. just be sure to stagger your joints so they dont bulk out the loom or rub thru


Completely unrelated but I've tried sending you a pm Johnny bug it's just coming back with an array error?

#15 rubjonny

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Posted 21 June 2017 - 01:13 PM

just had a look and my PM box is full! best have a word with the admin team tho as it should just say that to you, rather than put up some kind of random message? deleted some old pms :)