R32 Conversion Help/Advice - Mk4/Mk5 Loom differences, Mk5 ECU details, Loom splice

[Fanjita 1]

Hi all,

 

I know this has been covered in the 24v thread but I have decided to start my own thread in an effort to find any other help/advice.

 

Basically the story stands as follows, I bought the job lot for the MK5 engine with MK4 everything else, so loom, ecu, pedal, ancillaries, fuel rail etc etc.

 

Now I'm almost at the engine out point for my corrado ready to drop the new one in, but I appear to have hit a large barrier. According to both Stealth and SWICT, my setup will not work. It's down to the Mk4 engine producing a Cam position signal quite different to the Mk5, but this will not be immediately noticable.

 

The advice provided to me by both is either to: get a Mk4 head and swap it, or a Mk4 engine, or mk5 loom, pedal and ecu. As you might imagine both routes are bringing their own problems and cost and it's getting very difficult to carry on.

 

My first question for you knowledgable types, I have asked this already but as I said there may be others who haven't read my posts on the 24v thread.

 

-Vince has sent me the pinouts for the most common and recommended Mk5 ECU (PN ends in CP IIRC). Now both the ECU and pedal don't seem extremely difficult to source, although I haven't yet. Does anyone know if it's possible to adapt my MK4 loom to a Mk5 ECU? I can possibly source any plugs that are different from VAG directly, but I want to avoid spending huge amounts.

 

-I have tried to source what I need from eBay, breakers yards, and even by googling what I want or part numbers, to no avail yet. I've even had one breaker yard laugh at me! Any suggestions or know where I could source these parts? I know I have had an offer for an ECU (and appreciate it) but don't want to inconvenience you.

 

-Finally, If it is possible and I go ahead and adapt the Mk4 loom to work with the Mk5 gear, I may as well go the whole hog and do the loom conversion into my VR6 corrado myself. The guide is fantastic but the whole loom conversion is brushed over and getting someone else to do it is favoured by most, so does anyone have a guide or advice on exactly what I need to do?

 

I am in norwich, if there are any knowledgable types who are willing to help me with the car, I will offer what I can in return. I am hour building for becoming a commercial pilot, so anyone who helps me I will be glad to take for a flight (deadly serious, i fly a few times a week).

 

I have text Chris (the seller NormanCoal) to see if he knows something I don't but had no reply yet, I don't know if someone is able to ask him and see if he was aware of the problems and has done the necessary to prevent this?.

 

Please help me! I am really stumped.

 

---------- Post added at 2:10 PM ---------- Previous post was at 12:41 PM ----------

 

I've just realised FishWick has already answered one of these, sorry mate!

 

So the MK4 loom doesn't look much different to the Mk5? Any idea what part number I can use for the throttle pedal?

 

These pinouts should help, so now all I really need to find is a MK5 ecu and pedal!

[Kevin Bacon 5]

On balance, sourcing a MK4 head would appear to be the easiest option! But not cheap, because as well as the cost of the head, you also need to factor in another £150ish for the HG and head bolts. It does sound like the definitive fix though from what you've been told.

Did Vince also tell you the MK4 ECU is better for mapping? The MK5 still appears to be a bit of an unknown entity in tuning circles and there aren't many maps for it yet.

 

Did he say what the differences are between MK5 and MK4 heads? The cam trigger wheels are part of the VVT variators, so in theory just swapping those over should be all that's required if they are different, but I guess there must be some oil way differences or something otherwise they wouldn't suggest a different head.

 

Either way, I applaud this thread. In fact I was thinking of creating a 24V info thread myself, getting right down to the nitty gritty as it's such a grey area.

 

RE the MK4 loom, I forgot actually that the cam sensor wiring was a different colour when I compared it to Sam's (quicky1980) MK5 loom.

 

Still, it's doable. I took a MK4 loom, put it on a MK5 engine, had the pinouts for my ECU and just worked it out the old fashioned way with an end-to-end buzzer test.

 

I will assist in any way I can. I have a full version of VAG-COM and quite a lot of experience in wiring looms now!! Norwich isn't that far from me, I'm just outside Ipswich. Just the hateful A140 seperating us!

Edited May 23, 2012 by Kevin Bacon

[Fanjita 1]

Tell you what, it's Kev isn't it?

 

If i get hold of a Mk5 ECU with the pn Vince gave me (he said this is the best to use as he has a lot of experience and information on it) maybe we could look at this over a saturday? I'll obviously cover your fuel costs and keep you fed and watered! If you bring the r32, extra brownie points :).

 

So mk4 R32 pedal is a no-no for the Mk5 ECU, what pedal is best to use?

 

I really hope this is a goer, I know what you're saying about the head but this is a minter I can't deny, so I'd rather keep the engine intact. Plus just an ecu and pedal, would this not be the cheapest fix if it works, if we can get the loom to work?

[Kevin Bacon 5]

Yeah that's me :D

 

I was talking to Jon at Stealth today about my MK5 ECU conversion and he said the engine harness is the same on MK4 and MK5, save for a couple of plug and wire colour differences as we've already discussed. It's the car/pedal loom that's different apparently. So long as things are OK, end to end, then there's no reason why it won't work.

 

I use a 4Motion pedal mate, which is about £45+VAT from your friendly Robinsons Stealer :D We know this works because people have done R32 conversions into MK4s and the stock pedals have worked fine. The R32 pedal is a completely different plug and one that's hard to get hold of, so stick to the 4mo one.

 

Apparently the head differences are in the cams and VVT housings, so yeah, stick with the motor you've got!!

 

Yeah we can certainly lay the loom out on a Saturday and figure it all out. I don't think it will be a problem tbh.

Let me know when you've got your ECU and we'll pencil something in!

[Fanjita 1]

Kev,

 

From Sam's post in the 24v thread, he has pointed me towards 2 Audi ECUs. This ECU part number Vince gave me is not producing one to buy anywhere!

 

I was thinking I could just get me one of these Audi ECUs, do you think it would cause me any problems with the immo defeats? Or is it best to keep searching for a Mk5?

 

http://www.ebay.co.uk/itm/Audi-TT-Coupe-3-2-V6-Quattro-250PK-S-tronic-ECU-8j0-907-115N-/320901527586?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item4ab738b822#ht_517wt_1156

 

http://www.ebay.co.uk/itm/Audi-A3-8P-3-2-V6-Engine-Control-ECU-/130676211730?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item1e6ce8c012#ht_914wt_986

 

The two Sam Posted (thanks Sam).

[Kevin Bacon 5]

I don't know enough about the OE ECUs to be able to tell you for sure mate. Vince is definitely the man on that one I'm afraid!

[Fanjita 1]

I have just been looking through the wiring and checking the plugs over. The cam sensors (two grey plugs look to be at the end of each cam) don't appear to be the same fit as the plugs on my loom, how did you overcome this kev? Just order in the right plugs and wire them in?

[Fanjita 1]

Ok guys, spoke with SWICT, looks like the cam position sensor (although it doesnt change between marks) on some has a slightly different plug. To get it to work with my loom I will have to either change plugs or get the sensor with the right plug. The latter is easier.

[Kevin Bacon 5]

That isn't quite true fella. On my 2006 Audi BDB engine, I have a pair black cam sensors which are the same as the MK4's (BFH). On Heresites's 2007 MK5 BUB engine, he has a pair of smaller, grey cam sensors. Whether that is a cosmetic change I don't know, but I doubt it :D As you said, the cam sensor issue only reveals itself at high rpm, so you must therefore need the corresponding ECU to the sensors, or, swap the sensors to earlier ones. But I dunno....I have a hunch the trigger wheels on the cams are different as well.

[Fanjita 1]

Kev,

 

I've managed to get hold of the mk5 engine loom, but no ecu to fusebox loom! Still on the hunt for an ecu too, i can make a proper comparison and write up for others now I have both a MK5 and mk4 engine loom.

 

I was hoping still to get your help, I'm likely now to just do the loom work myself to get it working, it doesn't look that difficult!

 

I will let you know when I get the ecu then we can meet up to get this sorted?

Cheers

 

Sent from my GT-I9100 using Tapatalk 2

[Kevin Bacon 5]

Yep no worries mate :D

[Fanjita 1]

First observation,

 

The mk4 loom has the wrong connectors for the cam position sensors, and as this is the root of all problems with Mk4 management running on a Mk5 engine, this is not worth fiddling with to make fit. The sensors really need to stay as the Mk5 ones so the only option is to get the plugs swapped and check the pinouts, which is rather cumbersome. Really is looking best to stick with a Mk5 engine loom. No Mk5 fusebox loom yet so unable to compare this.

[1990 0]

I'm in excatly the same position James with mk5 engine and ancilliaies but Mk4 looms and ECU (Already immob defeated and modified to plug into my mk2 fusebox).

 

I have written down the mk4 and mk5 pin out and have them here side by side.

 

Mk4:

 

T121/pin115 is a Blue/Brown wire 1.0 it goes to pin 2 of the N205 Inlet can control valve 1

T121/pin120 is a Grey/Blue wire 1.0 it goes to pin 2 of the N318 Exhaust cam control valve 1

 

Mk5

 

T121/pin115 is a Purple/White wire 1.0 it goes to pin 2 of the N205 Inlet cam control valve 1

T121/pin120 is a Purple/Blue wire 1.0 it goes to pin 2 of the N318 Exhaust cam control valve 1

 

Based on that its just the plug thats a different size and the wires are different colours. I'm assuming the fact that the are still called N205 and N318 that they are the same sensor and that all the pin 1's are earths?

 

---------- Post added at 4:14 PM ---------- Previous post was at 4:00 PM ----------

 

Whats everyone else done with relay 100 for the secondry air pump?

[Fanjita 1]

AFAIK, keep it, the ECU looks for the load from the relay. If it doesn't believe the SAI pump is working it will revert to non-adaptive.

 

Just wire in the low current side. You can see the sensing loop on the wiring diagram I believe, might even be able to dummy it with a resistor.

[Fanjita 1]

Right,

 

About time I updated this:

 

MK4 engine loom - Appears too much hassle to make this work on the MK5 lump. The particular setup I had would not connect to my grey cam position sensors, the plugs were too small. Mk5 loom was acquired from a breaker for £70. If you do attempt to adapt the MK4 loom, get the cam sensors, but then you'll need to check each wire corresponds to the correct pin on the ecu plug, more trouble than its worth IMHO.

 

MK4 fusebox loom - This is doable, the MK5 seems like rocking horse s*@t to get hold of. Mark sucessfully adapted my MK4 loom to a MK5 by changing the plugs for the lambdas, and pedal. There are a couple of plugs that also are not needed on the Mk5 engine and these can be chopped.

 

Mk4 ECU - no point even trying to get this working, the internals of the ecu are very difficult to decifer, even if you do get the looms to connect to the MK5 engine, the cam position sensors will report in the wrong format. If there is no choice, the sprockets and possibly cams will need exchanging with a MK4s, a very long task indeed. For the BUB engine, the part numbers required are 022906032 CD or CE (manual or auto). Both will work regardless, you will just need some extra bits deleting from the auto's ecu and you will have a couple of errors from it.

 

DBW pedal - currently in limbo with this one, my pedal attempts so far have led with little success. Others have had success seemingly with pedals that I haven't. It seems each ecu might be different, but my advice is to just get the mk5 r32 pedal, don't take the risk of paying for anything that might not work. Part number 1k2721503N.

 

Lambda sensors - Find a year and get the right lambdas for that year of engine. There are so many different lambda sensors it can be difficult to find the correct one. Use this site http://www.meat-doria.com/ it's a godsend, just put the details in of the car your engine came from. You can find the year stamped on the side of the head. It will tell you what part numbers of lambda sensor will work with said engine. I have no reason to doubt this site, if anyone finds any inconsistencies let me know I will remove it.

 

I'll finish this when I get home!

Edited July 31, 2012 by Fanjita

[Narrdo 10]

Great thread currently looking at a MK5 bub setup and I’m not 100% sure on what loom I need obviously engine loom and ecu. Do I need all the interior wiring and fuse box to run the pedal? Or what

 

Thanks

[swiftkid 1]

There's a 200+ thread in the engine bay section along with a full DIY 24v conversion thread in the wiki. You need both sides of the ecu loom which should include pedal etc.

[Narrdo 10]

Thanks mate, I’ll check it out

[Kevin Bacon 5]

You will need a BUB pedal and both sides of the ECU harness. I wouldn't do this conversion again without a donor car to hand. Getting an engine from ebay with a missing or partial loom is a complete arse ache.

[Narrdo 10]

You will need a BUB pedal and both sides of the ECU harness. I wouldn't do this conversion again without a donor car to hand. Getting an engine from ebay with a missing or partial loom is a complete arse ache.

 

Yeah I’ve managed to get a full BUB wiring loom so that’s helpful.