2.5 V6 TDI A4 Avant Quattro swap project

[Nate_Grauvogel]

Nate... Although not that many people have gone this route to get a TDI converted car in the US, I think from a certain standpoint this project is not super extreme or crazy.

...

In short, I'd say that if you're interested, a project like this is worth looking into (I'm saying this now before it's all done). Don't pull your daily driver off the road and expect it to be done in four days, but if you've got the time, patience and resources, it's doable...

Caddy,

I never meant to imply that anyone who does a swap like this is crazy or demented... just hinting at the "outsider's" perspective - to us this is just R-n-R'ing one part for another, only on a grand scale. I think it's loads of fun.

I never had much experience with VWs (I worked as a general mechanic and saw lots of domestics in high school) until the time came to do a couple of repairs on our B4V that required peeling back some layers to get at the affected parts (radiator fan first, then heater core). Needless to say I was very impressed with the relative precision fit of these cars... I find working on them more precise, but more satisfying work overall.

Anyhow, I'm no stranger to big automotive projects... For now I'm just biding my time until I (ok... we) have the resources to pull off one of these awesome OEM+ conversions. For now I stay entertained finding little improvements I can afford, and dreaming about the big ones. My monthly eBay auto fun account is dried up at the moment - leather steering wheel for my Beetle.

Thanks for the updates. Keep up the good work!

Nate

 

[caddytd]

Nate...

I never meant to imply that anyone who does a swap like this is crazy or demented... just hinting at the "outsider's" perspective

I know... no offense taken. I was somewhat trying to situate the nature of the project in my own mind in regards to other comparable projects attempted by similar car nuts.

to us this is just R-n-R'ing one part for another, only on a grand scale. I think it's loads of fun.

Yeah...grand scale. I won't lie and say that it doesn't freak me out sometimes, especially when staring at all those wires.

Another update:

In order to get the harnesses out, I had to remove the carpet on the cabin floor. Last weekend, I removed the b-pillar trim and disconnected the wiring going into the doors. At that moment, I happened to compare the car's harness to the TDI harness and I believe I discovered that the donor (TDI) did not have power windows (!).

This was somewhat of a shock to me considering that pretty much ALL Audi's over here come with full options, but I'd imagine that you can order anything you want in Europe. It's still strange to think about a $38,000 car coming with crank windows but it appears that's the way this car was ordered.

Anyway, it took two of us to lift the carpet out. It's an impressive composite hulk of foam / sound deadening and carpet. Now's my chance to clean it all up. The PO mentioned that Audi did a heater core on the car at one point and you can see some minor stains up front (behind the dash area) from some coolant spills.



Here's a shot of the interior without carpet with some of the harnesses strung out to the different components.



Another one...



Last pic of the fuse panels. Check out the TDI panel...a lot less fuses. I'm hoping that's due to the nature of the engine's control system and not because the donor was stripped of options...



Lastly... I'd like to thank MOGolf for helping me out with the wiring diagrams. He was able to locate the V6 TDI wiring diagrams to steer me in the right direction while my copy of ELSA arrives.

The next step will be removing the entire harness, comparing them and "building" the TDI harness to have the options (radio / power windows) that I want...

 

[compu_85]

I bet someone yoinked the fuses... those little ones drive things like the ECU and interoir lights on my car.

 

[classen]

I'm jonesin' for more updates.
How's the conversion going?

 

[owr084]

I'm jonesin' for more updates.
How's the conversion going?

Same here! Find anything interesting yet? Lost tools, spare change, dead critters...

 

[caddytd]

Well... I've been busy with some family stuff (kid soccer games, etc), so I didn't get to spend as much time as I'd like on the car this weekend, but we're still working on sorting out the wiring.

Same here! Find anything interesting yet? Lost tools, spare change, dead critters...

Heh, heh... Yep, I found about 65 cents when I pulled up the carpet. The car is now making me money.

As we were working on the wiring, we did find some interesting things out about the donor car.

1. The donor didn't have cruise control. We were removing the harness for the ABS from the car and I noticed the wiring for the cruise vac pump wasn't there. I then looked at the turn signal / wiper stalks that came with the swap and saw that it didn't have cruise. Odd.

2. No headlight washers. For some reason, the donor didn't have the headlight washers in the bumpers. I can see it in the pics of the smashed donor, but for some reason it didn't occur to me until we traced the wiring on the windshield washer reservoir. This is kind of a bummer. That's a neat feature to have.

The wiring is very simple, so I'm thinking of trying to get a TDI V6 washer reservoir (yes, they're different to allow for the twin intercoolers) for a car with that feature and then wiring it in with the normal washer circuit. We'll see.

3. Power windows? I know that the donor didn't have power rear windows at the very least, but I need to confirm that the fronts were power as well. Petr seems to remember they were power... Not a huge deal, really. I pulled apart the harness at the B-pillar and the window harness is separately wrapped from the others and should come out as a unit.

4. Bose stereo. The stereo in the donor was gone, so we didn't know what it had / didn't have, but the wiring is different from what's in the Avant right now. It's safe to assume the donor didn't have the full Bose system with the changer built in.

FWIW, we pulled off the rear panels in the rear and exposed the whole Bose amp / woofer system. Pretty neat setup. I've got pics, but forgot my camera. There's a little 5 or 6 inch woofer in the driver's rear along with the amps all built into a molded ABS plastic enclosure.

5. ABS: We made the decision to pull the ABS system wiring from the Avant in order to install all the wiring from the donor. From what I've seen in ETKA/ ELSA the ABS_should_be the same between the two cars, but I've also heard rumors that there might have been a larger brake setup in the rear of some of the Avants. Not sure yet. I'm crossing my fingers on that one.

Finally... I cleaned up and painted the rear subframe assembly with POR-15 to keep the corrosion at bay. I had never used POR-15 before, but I've got a new favorite paint... It goes on thick and leave a super tough finish. Seems almost like powder coat on surfaces that have pitting / corrosion. Wow.

More pics and updates soon...

 

[MOGolf]

Cruise is often an option in Europe. Few owners get the chance to use it. It can be added.

Headlight washers will require a different bumper too. SVTWEB would know all the details.

Several different sound system options in Europe, so who really knows what the donor had.

 

[caddytd]

Headlight washers will require a different bumper too. SVTWEB would know all the details.

Luckily, my car already has the washers in the bumper (I think all US models might have them standard). They normally come on when I hit the normal windshield washer switch, so I'll have to see if it'll be possible to "add" the wiring for the headlight washer pump in the same circuit.

Still working on the wiring. I removed the whole harness from the 30V car after spending quite some time trying to figure out how to remove everything correctly from the rear of the Avant. The trim / seatbelts / brackets and everything add some challenges.

I can say that right now all the wiring is out of the car with the exception of the main battery lead, the electric sunroof wires and the wiring to the windshield wipers. This is the mound before I pulled it out:



Don't worry... it's not that bad. The plugs / wiring harnesses are all pretty logical and distinctive.

For those of you following the process, note that practically EVERY part of the car must come apart to do this correctly... wheel well liners, headliner (antenna connection), trim, heater core box, carpet, etc. I think that SVTWeb remarked about this, but it didn't sink in with me until I got everything out.

BTW... here's that Bose speaker / amp box that I was talking about. It sits in the driver's rear "wagon" area and is completely modular. Three plugs, three bolts and it pops out.



The wiring near the rear hatch is very well thought out as well. There's plugs near in the rear body right before it goes into the hatch so you can simply unplug the rest of the harness. This is a great step forward from the older VW's that I normally deal with... snaggly look-alike wires that can't be removed easily.

The wiring part of the project is somewhat slow going and not too interesting, but we're pulling through and trying to keep the "fire" going. Once the wiring is sorted and in place, the actual engine / mechanicals install won't take that long by comparison.

 

[SVTWEB]

So far so good. I did far more planning on my conversion prior to the execution of the task, but it doesn't look like your in over your head yet.

A couple guiding points. Ensure that your harness is oriented correctly right to left. Take as many pictures of the existing if you can to assistin in installation of the new one. One of the key elements that I found on the wiring harness. The guides will line up perfect if you are installing it correctly. If you are off by +/- 15mm then you are installing something wrong.

If you get in a bind on any connectors, shoot a picture of them and make a post with all the pictures numbered. I can just about identify any connector that you will find.

 

[Early8Q]

Luckily, my car already has the washers in the bumper (I think all US models might have them standard). They normally come on when I hit the normal windshield washer switch....

FWIW My experience with a North American 2001 S4 Avant and the headlight washers was that they only engaged when the headlights were on. Meaning that if you hit the widshield washers with the lights off, the headlight washers did not activate. When the headlights were on, the windshield washers would activate the headlight washers as well. HTH

 

[caddytd]

FWIW My experience with a North American 2001 S4 Avant and the headlight washers was that they only engaged when the headlights were on.

Yes, you're correct. I thought about that after I posted the message. The headlights do indeed have to be switched to the on position on my other A4 for the headlight washers to work. I'll have to look again at the wiring diagrams.

So far I've separated the power window and stereo harnesses from both the original harness and the TDI harness. The TDI donor did indeed only have front power windows. The Bose harness came out fine and will be adapted into the TDI harness.

This process isn't really hard because we're not splicing wires, but it does take some time to lay everything out and remove the friction tape binding on the wire bundles.

I also removed the bulky in-car phone harness from the Avant's wiring as well. I don't see myself ever trying to hook up the old style Audi handset type cell phone system.

I also discovered that the central locking / alarm system is different on the donor than on my Avant, so I'll most likely be switching that wiring as well. The donor's system had less wires / pins on the plugs.

SVTWeb makes a good point about lining up the guides / attachment points. I took a lot of photos and even drew a diagram on how every harness lays in the car. Since this harness came from an Avant, all the wiring_should_lay into the car just fine.

 

[patrickc]

Can I make a suggestion?

How abt adding some sound insulation on the floorboards since you have the carpets out of the way? This comes out of my wishing that my car was better insulated against road and wind noise. Maybe you might wanna dynamat your doors while you're at it.

Just a suggestion...

 

[caddytd]

How abt adding some sound insulation on the floorboards since you have the carpets out of the way?

Not a bad idea. Kevin from DTR also suggested the same thing to me. He's got a product there that's similar to dynomat but costs less. The stereo shop next door uses it all the time.

The floor has_some sound insulation on it already, but there are many spots that are bare once you take the carpet up. The Audi is remarkably quiet as it is, but as Kevin points out, there's no better time to do it.

 

[Beta]

jc whitney sells asphalt based adhesive sound mats (like dynamat) for really cheap. I think they are about $30 for a ~3.5x2.5' sheet.

 

[SVTWEB]

I have found the the spray can version of Truck bedliner from Westley's works great for that purpose and can be unsed to fill voids that the mat versions do not.

 

[patrickc]

Are any of these dynamat replacement insulations available online to a canadian address?

Thanks!

 

[moondawg]

you mentioned the "cruise vac resevoir" connector missing from the donor car.....

The donor car being a TDI, my guess is that cruise is controlled entirely in the ECU. You can probably just enable it with VAG-COM.

someone feel free to correct me if I'm wrong.

moondawg

 

[BrokenArrow]

Came across this thread while idly searching google for 2.5 tdi stuff

Had no idea you guys didn't get diesels over there... seems most Audis and VWs i see on the motorways here in the UK are 1.9 TDi's.

Just wanted to wish you good luck, and let you know the end result will be well worth the effort when you pull it off. I got my 99 2.5 Quattro Avant back in October, have put 8 thousand miles on the clock in that time, and still manage to find an excuse to do a 20mile round trip 'just to drop a dvd back at the store'

Planning on a PSI powerbox soon to boost power, thinking about slightly larger wheels and stiffer suspension but not that fussed, as I like to keep things looking pretty stock
best sounding diesel ever too (well... except the v8s of course)

shame the front quarter got stoved in by a jcb telescopic loader the other week... took it well though - them build em tough!

i wish you well - I'll definitely follow this thread with interest

 

[caddytd]

Are any of these dynamat replacement insulations available online to a canadian address?

Kevin at DTR says that this is the stuff he's used in the past... It's called R-Blox and although the prices on the site look expensive, that's for a whole roll (aimed at installers, I'd imagine). I think DTR can get portions of a roll for my application. I'm considering it.

http://r-blox.com/indexrblox.html

Anyway... a minor update here...

I'm still working on the wiring for the car. It's taking some time. I originally was going to be using the entire chassis harness from the TDI donor, but I found out that after separating the power window harnesses, radio wiring and looking at the alarm system harnesses, it will be much easier to use the 30V (original). Long story.

Basically, the alarm / central locking system harness is signifigantly different between the two cars and after looking at what I had to remove, it made more sense to keep the 30V chassis harness. The other harness (ECU / cluster / climate control half of the harness) will, of course, come from the TDI.

If I had known this before, it would have saved me time, but it was useful in that I now am pretty familiar with most of the plugs and systems. Kind of like a crash course in that car's wiring...

I basically get set up with both harnesses laying out in the bays at DTR and then consult the diagrams, compare wires / plugs / pins and sort through the differences. Almost everyone that sees me during this process groans that it looks impossible. It's really not.

Other details...
-Found some minor differences in the headlight harnesses (that's to be expected between Europe and US lights). Euro lights don't use the amber corner lights for "parking lights". I assume they have what I've heard called a "city" light that is wired to a bulb in the headlight housing for that purpose. I'll be running the US spec lights (at least in the short term), so I made changes to accomodate that.

-The TDI has an in tank fuel pump like the 30V, but also has additional fuel sender wiring (ELSA calls it "low fuel level sender") that goes to the tank. I think this is in addition to the sender that runs the fuel gauge. Perhaps this is used to tell the ECU/cluster when the car is low on fuel for other reasons. Others might have more information on that.

With any luck, I'll finish the harness in the next few days and start putting it back in along with the interior.

I know it seems like it's taking a long time, but I'm busy juggling family / work and other activities along with the TDI project. I should take a week vacation from work and really dig in. Forget the beach, right?

 

[bhtooefr]

Well, according to the Audi A8 4.0TDI review by Top Gear, Audi has (on that car, anyway) added a "bucking mechanism", such that when the car's very low on fuel, it starts bucking - but here's the thing. It'll start bucking long before it's out of fuel, and it artificially starts bucking, to make you freak out and think you're about to run out of fuel.

 

[v8volvo]

you mentioned the "cruise vac resevoir" connector missing from the donor car.....

The donor car being a TDI, my guess is that cruise is controlled entirely in the ECU. You can probably just enable it with VAG-COM.

someone feel free to correct me if I'm wrong.

moondawg

Exactly right...the TDI is drive-by-wire, so there is no throttle/fueling mechanism that could be actuated by a vacuum servo, which is what the cruise control used on the old gas engine to control speed. It would have drawn its vacuum from a "vacuum reservoir" such as that which you noticed was missing, so as not to make big changes in manifold pressure whenever it dumped vacuum to close the throttle.

On the TDI, the computer has complete control over fueling, so cruise control is just integrated into the ECU software, with no external componentry. Of course, it's now that way on VW gas cars, as well (everything is drive-by-wire these days). Much more elegant and precise way of dealing with it, anyway--the cruise on our TDI is completely seamless and smooth, and coordinated with transmission actions, unlike the system on our mechanical-throttle gasser Subaru.

 

[BrokenArrow]

-Found some minor differences in the headlight harnesses (that's to be expected between Europe and US lights). Euro lights don't use the amber corner lights for "parking lights". I assume they have what I've heard called a "city" light that is wired to a bulb in the headlight housing for that purpose. I'll be running the US spec lights (at least in the short term), so I made changes to accomodate that.

Sounds right - when leaving my parking lights on (by leaving the indicator stalk in one of the two on positions) it's a light in both the headlamp cluster, and rear light cluster on the relevant side that stays on, not the indicators.

 

[caddytd]

Update... more progress!

We've been making good progress on the car lately. All the harnesses are back in the car (modified 30V chassis harness with pwr windows and accessories plus the TDI cluster/ECU harness and reassembly has begun.

Last night Greg (another club member) and I managed to get the TDI pedal cluster installed along with the aluminum knee bar and console supports.

It went pretty well although we learned that it's more important than we imagined to install the different components_in_order. Certain bolts and wiring routings simply aren't possible if you put things back together in the wrong order.

I thought about taking photos of this stage of the process, but then thought that they'd be almost identical to the ones I took when I disassembled everythign in the first place...

Speaking of photos, the other thing that we learned is that the photos I took of the disassembly process are PURE GOLD. They're completely invaluable to the process. It's amazing how the initial removal of some items seems simple or intuitive only to be completely confounded with trying to reinstall it a few weeks later. Wow. The pictures bailed us out several times. Long live the digital photo.

I've also decided to take the advice of those who recommended adding some sound deadening material to the car. A car stereo shop is located just next to DTR, so I went over and talked to the owner about Dynomat (a product he uses and sells).

He ended up cutting me a deal on a full bulk box of Dynomat Extreme sheets (9 sheets) that I'll use for the floor / trunk area. It's definitely not the cheapest stuff, but apparently the difference is in the adhesive and quality.

The A4 is already a nice, quiet vehicle, but I'm looking forward to isolating even more of the noise. Adding this material should add approximately 20 pounds to the car.

Next, I received some replacement parts from Petr a while back to take care of the damage from shipment. Here's a shot of the passenger side section of the intake manifold.

http://www.hostdub.com/veeman_album16:intake_2

The ports on the head are facing straight up, so this piece is installed on end (opposite to the photo).

The dividers in the ports kind of struck me as odd. I imagine they cast those dividers in there either for strength or possibly for port flow characteristics. Perhaps that material creates a subtle port velocity increase or causes a "tumble" in the intake air. Not sure on that.

Here's another shot...Short little runners off the plenum.

http://www.hostdub.com/veeman_album16:intake_1

Good progress so far. The wiring is making more sense to us now and I think we've rounded a crucial bend in the project...

 

[jnecr]

20lbs for the dynamat doesn't sound bad at all, it should definitely make the car quieter...

 

[caddytd]

I worked more on the car this weekend. I had a minor moment of drama when working on the relay panels and I noticed that the OBD II plug (designated as T16) appeared to be absent in the TDI harness.

In the US models, it's in the lower portion of the dash to the left of the steering wheel (just next to the hood release lever). On the 30V harness, the plug was in that position, but not on the TDI harness. There weren't any cut wires or anything, so I wondered if the donor actually came with the diagnostic plug...

I did some searching on the diagrams and the wires heading to T16 all said that the diagnostic plug was in the rear of the center console. I'd seen a block off plate in that location on my other A4 (1.8T), but figured that all most newer cars had the plug in the dash.

Anyway, I checked it out on the TDI harness and sure enough, the OBD II diagnostic plug was indeed wrapped up with the parking brake switch harness. The center console has a spot for the plug. All is good.

I also found that I'm going to have to resplice the glow plug power leads. There are two 8/10 gauge wires that go to massive fuses (50-60 amp) in the relay panel and those had been cut in the donor harness.

Petr's crew didn't really have a choice but to cut those wires due to the way they tie into the engine side harness. That wiring is all one section and doesn't unplug. Not a huge deal. I'm most likely going to solder the connections to ensure a good connection.

I'll be resplicing those heavy wires, then putting all the relay panels back into place permanently.

My plan is to get all the wiring hooked up, then start testing accessory systems (power windows / alarm / HVAC / radio / door locks) before reinstalling the major portions of the dash and carpet.

After that's done, it should be engine time...

 

[Action Jackson]

My friend tdimeister brought me to this post. The work done thus far is very impresive indeed. I would love to swap a V6 diesel into a torsen wagon. Here in Canada however there were few VAG offerings of torsen wagons before 2001. Therefore the purchase price of the project car gets a bit steep. Most 2001+ Passat 4Mo and Audi A4 avants sell for well over $15,000 CAD.

I have toyed with the idea of an older model A8 (1998-1999) V8 diesel swap. Now that would be fun. Alas these are all just dreams. No money exists for any project let alone getting into a newer car. My B3 gasser will just have to keep me going for now. But I live for these projects. Great work, and thank you for sharing!

 

[bhtooefr]

Wait, you have a B3 gasser?

Hmm...

1.9 turbo diesel? Especially seeing as you're in Canada...

 

[Action Jackson]

Dont tempt me . Tdimeister says it himself, he's a bad influence to my pocket book.

In all fairness, the wagon's days are numbered. I've driven the B3 platform for nearly 10 years and am starting to desire some change.

 

[caddytd]

More progress...I finished up the wiring in the back of the car, then plugged as many things in as I could for some tests. I'm happy to report that I connected the battery and the following systems are up and running as they should:

High / Low headlights
Turn signals / hazards
Wipers
HVAC head/ blowers (pretty neat to see the flappers/valves all actuate, btw)
All four power windows
Interior lights

I didn't try the stereo (didn't have the code with me) or the rear wiper, but I'd imagine they're both fine. Progress. Sweet.

There's only one plug on the passenger side front connection point that doesn't match it's plug on the 30V harness. Couldn't find it in the diagrams, but I have to look again.

It's good to see the car starting to come to life once again... Now I'll be mainly working at putting the dash back and the interior components back in, then it's onto the engine.

I also just ordered new shocks/springs for the Avant. After some consideration, I went with the Bilstein Sport / H&R Sport springs combo. Should be a little over an inch lower and a bit firmer over the worn out stock sport suspension. That should be here this week. Can't wait to drive this thing.

 

[Action Jackson]

Where can I find information on the power modifications for the 2.5 V6 TDI?