Eurovan VR6 to 2.5 TDi Swap

Joined
Nov 13, 2018
Location
Tempe, AZ
TDI
'15 Audi Q7 TDi, 01 Eurovan 2.5 TDi
Given how much this forum has helped me along the way, the least I can do is share what I learned (A LOT!) as I near the end of my swap on my 2001 EV. This project began with an incomplete van, as the original VR6 motor (AXK) and auto transmission were sold off by someone who never came through with the needed motor or trans to complete the swap.

Tip #1 - this process is much simplified if you start with a complete vehicle! (duh) - needless to say I needed a parts vehicle for many odds and ends that went missing with my original motor and trans.

I ended up sourcing a 2000 T4 from Germany, with the 88hp 2.5 TDi (AJT) and 02b manual trans. This turned out to be a short nose model, and with my 01 being a long nose, this did create a few problems (more on those later).

Tip #2 - if you have the option to use a donor of the same body style, definitely go for it. That being said, regardless of year/body style, the really critical points (motor mounts, engine bay space, etc.) are still identical.

Here's a couple pics of how things looked to get this swap started.

How I found my 01 EV -

https://drive.google.com/file/d/0B9cG_fnlvqETNVhONVRBM3BjWkQ4dHNidF9DdE1oSEowOWJJ/view?usp=sharing


Donor all loaded up for the drive home from Cali -

https://drive.google.com/file/d/0B9cG_fnlvqETTDh3RHZZZ1NIcDdoV3pYTDNPSDB3Ql85bDB3/view?usp=sharing
 
Joined
Nov 13, 2018
Location
Tempe, AZ
TDI
'15 Audi Q7 TDi, 01 Eurovan 2.5 TDi
I started with sound deadening, 80 mil on the floors and firewall (both sides), 50 mil on the doors - https://drive.google.com/open?id=1HXmstOkPzsXbsLa1U40WGR7Z-e-V9K7G

In the engine bay, there wasn't too much to clear out, it was more a matter of figuring out what I DIDN'T have in place to make this work

Because of the short nose/long nose mismatch, I had to source a few items that my van was missing -

1. Radiator and cooling fan assembly - these are NOT interchangeable between the two body styles.

2. A/C condenser and compressor - my donor, and to my knowledge most of the European market T4s of this age, did not have factory A/C -> You will need to source the A/C compressor bracket that bolts to the motor - at least on my AJT it did not come with it - pictured is the bracket installed -https://drive.google.com/open?id=1wcWGiPPBRB6VUuHaJt7cGqDf433r5pRq - luckily these brackets are the same on the North American market AAF motors - mine ended up coming off of a 93 Weekender - part number for the bracket is 074260887C, about $150 on Ebay.

--> Another note on the compressor - if you are going to use your VR6 compressor, you will need to change your pulley and magnetic clutch assembly - the 2.5 TDi V belt is 5 ribs, and will not align properly with the VR6 compressor. You COULD use a compressor from a NA market 5 cylinder (5 rib pulley), but you will have to modify your A/C line connections going in to the back of the compressor. I chose to swap pulleys - https://drive.google.com/open?id=12YUB1TnEIgh90KrBdtWXdl2s0cYjmRGo
https://drive.google.com/open?id=168tQr_vknwKeXHwhudvSKqjuvP8WoU7m
 
Joined
Nov 13, 2018
Location
Tempe, AZ
TDI
'15 Audi Q7 TDi, 01 Eurovan 2.5 TDi
I should've mentioned step #1 of this whole process should be driving your current gas tank down to near empty!! Or if you're like me, you can spend a bit of time siphoning the tank and finding somewhere to store 15 gallons of 91 octane! Once empty, the tank is pretty easy to drop - three cross braces, fuel lines and the evap system, and don't forget the screw tucked in behind the filler opening!

https://drive.google.com/file/d/10mvdNmkL4qNxMabqVQPZeFSJRKtdzJU5/view?usp=drivesdk

Most of the Eurovan diesel swap builds I read up on out there described drilling out the filler neck.

I tried popping the reducing collar off of my tank, and that was a no go. Before grabbing my drill, I had another gas tank from the parts van and tried it, and sure enough the collar popped right off with minimal resistance. No idea why the difference, but I'd recommend trying it before drilling. Perhaps somebody out there can weigh in on why the difference between two identical fuel tanks?

https://drive.google.com/file/d/1OHvBoODLtm10Ds-X8q7u_wmYfAPC33qO/view?usp=drivesdk

From there I needed to remove the in tank fuel sender - remove the fuel lines and harness, use some elbow grease to loosen the cap, and once inside it just took a 1/4 turn to remove the whole unit.

https://drive.google.com/file/d/1vE7mWiDHIcFITKlskwdPTFmDHPQRGeW7/view?usp=drivesdk

Once out, you will notice there is a mounting plate upon which the gas unit sits, but which your diesel fuel sender will not need. Talking to some other folks, they just put their sender right on top of the base without issue, so that's what I did. I ended up sourcing the model specific diesel fuel sender on Ebay. I can say, having run the motor now with only a couple gallons of fuel in the tank, there hasn't been any issues with fuel pickup (but I definitely don't have as much margin for running low on diesel).
 
Joined
Nov 13, 2018
Location
Tempe, AZ
TDI
'15 Audi Q7 TDi, 01 Eurovan 2.5 TDi
Next, getting the motor disconnected and ready for it's temporary home on the engine stand.

https://drive.google.com/file/d/1Kw7HPnGUY7HN2bK2gkdgLbJXnEWe7nPb/view?usp=drivesdk

Being a total rookie, I took a lot of unnecessary pictures documenting the connections at the motor, as these are few and fairly intuitive, and I did not take near enough of the wiring at the fuse panel itself. My advice to those new to wiring like myself, take your time labeling and documenting that wiring! This came back to haunt me later in the process.

Motor pulled -

https://drive.google.com/file/d/1xAG7PmFyjuFMjKuxLDXRAy3BgQu4xuAm/view?usp=drivesdk

You can see the rear portion of the downpipe was plasma torched off - I saw this and ordered a downpipe from the UK, so as not to be hung up with that later in the process, which ended up being unnecessary - when I got the TDi downpipe, I found that the TDi flange is just SLIGHTLY larger than the VR6 flange, so I have to sleeve the exhaust anyways.

https://drive.google.com/file/d/1kHEOy1OOmJScRfO_onEZiZBT5OAJrxqg/view?usp=drivesdk
 

Zeitgeist

Veteran Member
Joined
Nov 10, 2004
Location
Cascadia
TDI
'04 Variant and Vanagon mTDI
Does anyone know the differences between the various 2.5 TDI engines found in the T4? I assume between the 88hp and 150hp models, the pumps, injectors, ECU tuning and turbos are different, which implies that it might be possible to upgrade a lower output engine.
 

mogly

Veteran Member
Joined
May 27, 2003
Location
Sarnia, ON, Canada
TDI
MKIV TDI + B5.5V AVF/01E
I'm more familiar with the ACV and AXG. 102 and 151 hp units. The 88hp unit is not intercooled but besides that I'm not sure of hardware differences. The 102 is intercooled (up top) and a k14 wg turbo. The 151 has a vnt22, larger injectors, different ECU and large FMIC.

There is also a 102hp VNT unit. These came in long nose vans and had the same FMIC set up as the 151s but assuming smaller turbo.
 
Joined
Nov 13, 2018
Location
Tempe, AZ
TDI
'15 Audi Q7 TDi, 01 Eurovan 2.5 TDi
Correct Zeitgeist - to get an AJT (also the AYY) modified to achieve the same performance as the ACV/AUF/AXL (102 hp), only requires the intercooler, ECU tune, and injectors. Gearing is also different between the two setups, I haven't driven mine enough to know if there's a need (yet) to modify my trans.
 
Joined
Nov 13, 2018
Location
Tempe, AZ
TDI
'15 Audi Q7 TDi, 01 Eurovan 2.5 TDi
Just wanted to post a few more pitfalls to look out for if you're attempting a similar swap, I have been hung up on some injection timing issues lately so I haven't had time to post.

Wiring - I really overcomplicated this, but in the end it's pretty straightforward as long as you're labeling everything you need.

From the Eurovan I pulled the TCM and its wiring, ECM, engine control harness, instrument cluster and left everything else intact.

From the T4 you will need the ECM (which you will need to do an immo delete on), engine control harness, instrument cluster, as well as the 103 and 109 relays from the fuse panel -

https://drive.google.com/file/d/1gNdcWWGkt_T3WW81BxyCxx9ihr0GLuNf/view?usp=sharing

On the pedal assembly, I opted to just move the clutch pedal assembly and line over to the existing unit on the Eurovan - the EV brake booster is identical to the T4, including the bracket to support the clutch pedal and cylinder - apparently the brackets fail over time, but lucky me my bracket is brand spankin new...

https://drive.google.com/file/d/1hb7S6R07oTApVbk14FGUXo4y3xwrSwEP/view?usp=sharing

As well the brake/clutch fluid reservoir is identical - just nip off the end of the stubbed line on the reservoir to hook up your clutch line. This pic is of the T4 reservoir prior to moving the clutch.

https://drive.google.com/file/d/19zbmP6xtO3fjdvV3LTGQda3DUjLjWziq/view?usp=sharing

I made a CRITICAL rookie mistake prior to separating the trans from the motor - I didn't set TDC on the motor using the flywheel marks before disassembly. This...was...stupid. Luckily finding TDC on cylinder is much like the 4 cylinder TDis here in the US - cam lobes up -

https://drive.google.com/file/d/115QCJ0nNAvSgvWFT9xMTyb7TWGvsY49k/view?usp=sharing

Timing belts fitted without too much trouble (once TDC was established!) - the 2.5s use both an idler pulley and tensioner on the IP side - the idler pulley on the right is what gets manipulated in order to advance or retard injection timing.

https://drive.google.com/file/d/10I_qMvNy8ejLEDDLwBvkEEU4fBNxpKIQ/view?usp=sharing

Before the trans goes back on...some cleaning was needed - this was POST cleaning :eek:

https://drive.google.com/file/d/1Il-omS2_ik9I2Yh2h7Y64V9H_AY3Q4id/view?usp=sharing

New rear main seal is in order...
https://drive.google.com/file/d/1JgN0ihf7rc-E-fL5gplrnTJQ9rnZ4HXY/view?usp=sharing

Time for the new DMF - I read up and down about DMF vs SMF on T4s, but the my concern about dampening vs potential DMF failure won out, so I went dual mass..

https://drive.google.com/file/d/1c-t-xYYWVKQ2kkBWy3I9dzs85ZStxAl5/view?usp=sharing
 
Joined
Nov 13, 2018
Location
Tempe, AZ
TDI
'15 Audi Q7 TDi, 01 Eurovan 2.5 TDi
The swap still isn't 100% complete, but here's a few more pics and steps leading closer to where I am now.
I have a wiring issue that I think is common to a couple fault codes I'm throwing - I attached the VCDS fault log in case anyone has some advice! As well, my injection timing is still off, I'm going to replace these stanadyne injectors that are commonly problematic around 100k km, but I also think the injection timing is being affected by the engine coolant temp fault. You'll also notice the brake switch and ABS control module coding faults - still haven't resolved those either, I'll update on this as I get it resolved.

Friday,28,December,2018,10:01:07:30156
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 10 x64
VCDS Version: 18.9.0.2 (x64) HEX-V2 CB: 0.4436.4
Data version: 20180927 DS296.0
www.Ross-Tech.com
VIN: WV2MB47001H118692 License Plate:
Mileage: 154040km-95716mi Repair Order:
Chassis Type: 70 (7D - VW Transporter/Multivan (1996 > 2004))
Scan: 01 02 03 08 15 17 18 19 22 25 35 37 56
VIN: WV2MB47001H118692 Mileage: 154040km-95716miles
-------------------------------------------------------------------------------
Address 01: Engine Labels: Redir Fail!
Part No: 074 906 018 B
Component: 2,5l R5 EDC 0000SG 2519
Coding: 00002
Shop #: WSC 25900
VCID: 15773D8EBC96CA6F5D3-4B7A
3 Faults Found:
18062 - Please check DTC Memory of Instrument Cluster
P1654 - 35-10 - - Intermittent
17664 - Engine Coolant Temp Sensor (G62)
P1256 - 35-10 - Open or Short to Plus - Intermittent
16955 - Brake Switch (F)
P0571 - 35-00 - Implausible Signal
Readiness: N/A
-------------------------------------------------------------------------------
Address 03: ABS Brakes Labels: 7D0-907-379.lbl
Part No: 7D0 907 379 D
Component: ESP 5.3 T4 FRONT V26
Coding: 06912
Shop #: WSC 25428
VCID: 323DE6122D383D57581-5160
4 Faults Found:
00526 - Brake Light Switch (F)
36-00 - Open Circuit
01203 - Electrical Connection between ABS and Instrument Cluster
31-00 - Open or Short to Ground
18256 - Please check DTC Memory of Engine Controller
P1848 - 35-00 -
01044 - Control Module Incorrectly Coded
35-00 - -
-------------------------------------------------------------------------------
Address 08: Auto HVAC Labels: None
Part No: 7D0 907 040
Component: CLIMATRONIC 0003
Coding: 00032
Shop #: WSC 02743
VCID: 5F9B5FA60E2AC03FC7F-25A6
2 Faults Found:
00799 - Coolant Temperature Sensor (G110)
30-00 - Open or Short to Plus
00792 - A/C Pressure Switch (F129)
35-00 - -
-------------------------------------------------------------------------------
Address 15: Airbags Labels: 1J0-909-60x-VW3.lbl
Part No: 1J0 909 603 BM
Component: AIRBAG VW3 - V04
Coding: 16973
Shop #: WSC 02743
VCID: 75B71D0E9CD66A6FBD3-4B5C
No fault code found.
-------------------------------------------------------------------------------
Address 17: Instruments Labels: 7D0-920-xxx-17.lbl
Part No: 7D0 920 803 B
Component: T4-KOMBIINSTR. VDO V25
Coding: 01151
Shop #: WSC 00186
VCID: 2313135662C2A4DFA37-513C
2 Faults Found:
01039 - Coolant Temperature Sensor (G2)
30-10 - Open or Short to Plus - Intermittent
00562 - Sensor for Oil Level/Temperature (G266)
30-00 - Open or Short to Plus
-------------------------------------------------------------------------------
Address 19: CAN Gateway Labels: 6N0-909-901-19.lbl
Part No: 6N0 909 901
Component: Gateway K<->CAN 0001
Coding: 00000
Shop #: WSC 00000
VCID: 70B92C1AE3B44F476E5-513C
1 Fault Found:
01044 - Control Module Incorrectly Coded
35-00 - -
-------------------------------------------------------------------------------
Address 25: Immobilizer Labels: 6X0-953-257.lbl
Part No: 6X0 953 257
Component: IMMO 0008
Coding: 00001
Shop #: WSC 40301
VCID: 7DA7052EA4E6322FF53-4B3C
WV2MB47001H118692 VWZ1Z0A1207766
No fault code found.
-------------------------------------------------------------------------------
Address 35: Centr. Locks Labels: 7D0-959-800.lbl
Part No: 7D0 959 800 C
Component: Funksteuergerát 0001
Coding: 00001
Shop #: WSC 02743
VCID: 2D07F56E340662AF053-4B1E
No fault code found.
End----(Elapsed Time: 02:32, VBatt start/end: 12.2V/12.2V. VIgn 0.0V)-----
-
Before I moved the motor in, I did a refresh on the linkage - the balls were dry rotted and cracked, and I figured I'd never have better access than right now -
https://drive.google.com/open?id=1dfxSgtIXEX5K-4TfzNnZ28bWIMePXg5S
Motor bolted right up, no need for motor mount mods like some other swaps require - just the two mounts up front on driver/psgr side, and the pendulum mount towards the rear.
https://drive.google.com/open?id=1GEkUVGcbWS3-ZqSlgiduX7mj7LeVYHy0
There were a few modifications I had to make in regards to the intercooler - firstly I ended up with an intercooler that is wired for the 2 pin sensor + air temp sensor vs the 4 pin sensor seen in the later model T4s. My motor and ecu is wired for the 4 pin sensor, so I ended up placing the sensor inline in the intercooler hose -
https://drive.google.com/open?id=1SS-U9arXo2CHTmfgRjk8eVImizvoTl9z
2 pin sensor still in place with the temp sensor port plugged (since this function is integrated in to the 4 pin sensor) -
https://drive.google.com/open?id=1ABc9LgkTt3Nz9Gu7y6pY5Pkt15l3S-Af
Also, the T4 TDi is equipped with a coolant reservoir/N75 bracked integrated in to the firewall - I ended up mounting the reservoir to my rad (like all the VR6 EVs are set up), and mounted the N75 to the underside of the intercooler bracket. I may try welding that bracket in to the firewall eventually, since the coolant hoses don't quite have the factory look...
https://drive.google.com/open?id=1Ez6shGGIkrbR4sFBwE-WWYeItcchqkqi
T4 bracket -
https://drive.google.com/open?id=1lJTAbHjz5NnjpQkJ6hGR92cDxor-ftfQ
New home for the N75 on the Eurovan -
https://drive.google.com/open?id=1CfK64ZazKK1v-3Lnw5InrRSO-pVk0kX-
On an earlier post I mentioned the rad/coolant line compatibility issue - because of the short nose/long nose mismatch between donor and recipient, the secondary water pump doesn't quite sit in a "factory position" - sourcing some long nose coolant hoses would remedy the situation, since these short nose hoses don't quite reach the rear of the bumper frame assembly -
https://drive.google.com/open?id=1JhDOpaYwh36xksLDnFsxjGp_T81KQXkc
https://drive.google.com/open?id=1A-2A9_VMQ7PGW6P2Vqa0fZtGFU4myNbN
About a 1000 miles in to the swap so far, and no issues with coolant leaks arising from running setup, though.
There's only a handful of wiring connections to make on the motor itself, most of the work with wiring came in routing it through the firewall, and finding homes for everything around the fuse panel (the connections TO the fuse panel itself were fairly intuitive). I will address the wiring mistakes I made perhaps in a later post.
After a couple runs around the block with the motor, I was having a no start issue -
https://drive.google.com/open?id=1bc_UaeNsRlA_01yeu7_IbsJX_v_nc94c
So I found that ALL of the bolts mounting the starter to the trans had backed out slightly, which ended up causing one of the flanges on the starter itself to crack, so off to the interwebs I went to buy a new starter. Luckily no damage to the flywheel, and upon installation she started right up.
This just speaks to the importance again of double and triple checking all your bolts!!! I loctited and torqued to spec every bolt I removed, and despite that, these still loosened only after a few miles of driving.
 

TdiEurovanUS

New member
Joined
Oct 25, 2022
Location
Delaware
TDI
Eurovan
Interested anyone know where one would get parts to support an install like this, axles/cv joints, oil filters, fuel filter, water pump, timing and fuel pump belts.....
 

d24tdi

Veteran Member
Joined
Jan 6, 2019
Location
MT
TDI
96 B4V
brickwerks.co.uk is excellent and has fast US shipping.

spareto.com ships to the US.

German or UK (etc) ebay is always there too. And a few of the folks who sell conversion kits for the T4 TDI swaps (like QGAP in CA) also stock service parts for the engines. Timing sets, etc.

Not too big of a deal, unless you are broke down in the middle of nowhere and need a part ASAP, as no small town FLAPS will have anything on the shelf of course so everything must be shipped.
 

TdiEurovanUS

New member
Joined
Oct 25, 2022
Location
Delaware
TDI
Eurovan
d24tdi Thank you will take note and give them a try. Using as a cross country trip machine so will see. I have a cv talking back on right turns so will see who has some.......thank you
 
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