T4 Eurovan TDI, and syncro conversion from vr6

I have been working on converting this T4 from a vr6 to TDI. Currently i am building the wiring harness to be used on the TDI. I am looking for help with the ECU pin out. More specifically, where does pin 43 of the ECM go to? right now it is going to G1-9. From what i have read, it is supposed to be a single wire going to TV13 (vss signal). Where does TV13 get its signal from?

It may help if we knew what TDI ECU from what car, model year, platform, etc. you are trying to make work in your T4.

Because some TDIs just get the VSS signal across the CAN bus from the ABS controller, as it broadcasts a distilled signal obtained from averaging all four wheel speed sensors.

ECU part number 028 906 021 ek suggests it is from a 97' VW Seat Ibiza 1.9 TDI AFN. I am using an AFN TDI engine for the swap. I have been using Penbryn's wiring guide on the vwt4forum to build this harness. everything seems to match up except that one wire...so far.

I found an electrical schematic from a 97 Golf AHU. It shows pin 43 going to TV13 (blue single pin hub on back of fuse box) and it shows TV13 getting its signal from W-1 and W-1 is getting the signal from U2-2, that signal is originating from pin 7 of the golf instrument cluster. Now to see where this signal comes from on the 97 Eurovan........Looked it up, turns out the VR6 Eurovan also gets the speed signal from pin 7 to connector U2-2, then to W-1 and then TV13. Its plug and play. Just not sure why the harness i have has pin 43 going to G1-9. Must be different on the VW SEAT model.

Yeah, none of those cars were sold here, so I can't be of much help, sorry.

I do know that VAG us usually pretty consistent with that kind of stuff. And the later T4s would have been arranged in a similar manner to the A3, B4, and I would assume others of the same era.

The early T4s, like mine, are more akin to an A2. My '93 still has a speedo cable coming out of the diff housing.

Another question... I installed a wire from the alternator W terminal to connector G1-12....I also installed a 5 speed with syncro which allowed me to install the electronic 3 wire VSS pick-up in the transmission. Will these two signals but heads with each other?

Since you're talking about a Mk3 tdi I will share what I have with you, which I think is pretty accurate.

Pin 43 (of the 68 pin ECU) is VSS and goes to TV13 junction block. This is shared with at least one other connection that originates at W1 (harness W position 1) and internally in the fuse box connects to U2/2 and out as lilac wire to T28/7.

It's been a while since I've dug through the harness so the lilac color might be in error. The wire from W1 is blue / white though, that I am sure of.

You will need to find a suitable W harness or make the physical connection between the two blue / white wires some other way.

With TDI you don't need the W connection at the alternator, the ECU will calculate engine rpms with data from the crank position sensor and the needle lift sensor. How or what it does I don't know, but that's what I have read elsewhere.

EDIT: As for the PP comment about pin 43 going to G1/9 that would be in error. Mk3 (in the US) have no ECU wire running to harness G1/9 but the B4 Passat cars do, and that comes from pin 60 at the ECU which is the MIL.

Steve

In case it helps, the speed signal from the sender on the transmission goes straight to the cluster, which conditions the noisy signal in to a nice clean one. The cluster then outputs VSS to TV13 which is the junction box from which everything else is fed (ECU, cruise control, etc).

The W1 fusebox plus is where the speed signal comes in iirc. Steve is then spot on with para 2 above where it goes off to the cluster. The output from the cluster will come back in on one of the U connectors and then out to TV13 I think (its been a while!).

Not sure what would happen if you connect TV13 directly to the speed sensor without the cluster in between, as I've not tried it.

Since the thread title suggests that the conversion will also include the installation of Syncro drivetrain and suspension, I'm wondering if anyone knows how many 4WD T4s were produced globally. I'm intrigued with this exact swap, so it would be nice to know if there were enough produced initially to provide a sufficient donor pool for conversions.

Here's one I saw flying along on I-5 a few years ago: