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vwhammer Sun Mar 07, 2021 7:10 pm

Just getting into the wiring on my OBD2 ABA swap and figured I would start a thread where I might be able to ask questions as I move along in the process.

For starters, I was laying everything out that I currently have and came across a simple two wire harness that I can't sort out where it goes.

It has female flat connectors at one end and male flat connectors at the other end in a two position housing.

The wires are brown/green and white.





I assume that the two position connector went to the harness that ran to the stock ECU and, since that is long gone at this stage, that explains why I can't sort out where it plugs in.

My initial thought is that it ran to the fuel pump.

I searched pretty hard in the Bentley but can't find any brown wire with a green stripe connected to a fuel pump.

I also assume, since my new ABA harness has provisions for the fuel pump, that I can toss this piece in the scrap bin.

We know what they say about assumptions but am I on the right track here?

hardway Sun Mar 07, 2021 7:17 pm

That is the fuel pump harness. The two female spade connectors with the boots go to the pump. The plastic gang plug goes through the right front bulkhead to the engine bay harness.

vwhammer Mon Mar 08, 2021 9:18 am

OK so that confirms my thoughts on the fuel pump wiring.

I have a couple more questions about some other wires but I will have to get home to get pics before I post all that.

Well maybe someone already knows the answer to one of my questions.

I had my main harness built by Dave at TDC shop.
He does a good job at labeling everything.
I found a wire (don't recall what color) that says "trigger" on it and is not terminated.
Anyone know what that might go to.

I feel like if it went to a switched 12v source or a relay of some sort he would have either labeled it as such or already run it.

dkoesyncro Mon Mar 08, 2021 1:46 pm

I'd guess he's referring to the VSS, but I'm not positive? Rogertj is also doing an ABA and I gave him my Bentley. He's been posting Q's lately, might be of some help- good guy!

The actual trigger wheel is a shielded and insulated sensor but....??

vwhammer Mon Mar 08, 2021 3:25 pm

Hmmm I am not certain that is the answer.
For the record this is the "trigger" wire I am talking about.

It appears to be red with a light blue or gray stripe
It goes to pin 40 on the main ECU connector.
A Bentley would probably sort this out in short order but I got 99 Bentleys and a MK3 ain't one.

In other news I came across these connectors as well and can't find a place for them.



looks like they could go to the alternator but there are no connections on there for them.
I have not actually tired to find these yet in my van Bentley so I am gonna give that a shot.


Seems like a beefey wire for one of the connectors so it must carry some juice

dkoesyncro Mon Mar 08, 2021 6:34 pm

On a whim here, I have a euro Bentley that has the ABA with in the pages. The wire colors don't match but pinning out. Pin 40 from the ECU lands at the #2 terminal of the throttle position sensor G69

The other harness could be alternator but maybe even starter?

erste Mon Mar 08, 2021 6:49 pm

dkoesyncro wrote: On a whim here, I have a euro Bentley that has the ABA with in the pages. The wire colors don't match but pinning out. Pin 40 from the ECU lands at the #2 terminal of the throttle position sensor G69

Yeah, that's what's listed here:
http://www.a2resource.com/electrical/management/motronicvr6aba.html
Pin 40 ABA OBD2 is throttle position sensor signal 1 (Red/Blue)

My mk3 bentley is in the van, but that page is usually a pretty accurate reference.

vwhammer Mon Mar 08, 2021 6:51 pm

OK I think the 2 black connectors originally went to the starter but now am not certain if they still need to go there or how they need to be connected.

I must be overlooking it in the Bentley but I am not finding the smaller red/white wire anywhere.

This also gets more confusing because I am running the TDI starter which has a totally different connection so I need to sort out what wire goes to that

dkoesyncro Mon Mar 08, 2021 7:00 pm

Well scratching the memory bank, red/wht wires are found at the heated oxygen sensor and relay.

Karl sold pigtails for his TDI starter adapter and I think "thatvwbusguy" sold them to?

vwhammer Mon Mar 08, 2021 7:05 pm

erste wrote: dkoesyncro wrote: On a whim here, I have a euro Bentley that has the ABA with in the pages. The wire colors don't match but pinning out. Pin 40 from the ECU lands at the #2 terminal of the throttle position sensor G69

Yeah, that's what's listed here:
http://www.a2resource.com/electrical/management/motronicvr6aba.html
Pin 40 ABA OBD2 is throttle position sensor signal 1 (Red/Blue)

My mk3 bentley is in the van, but that page is usually a pretty accurate reference.

Hmm ok but my engine harness already has the plug that goes to the throttle body so I am curious where the extra wire might go.

Maybe I should contact TDC and see what he says.

Man am I glad I did not try to tackle the main harness wiring on this myself.
Maybe I would have a better understanding of it when it was all said and done but I don't think I have the attention span for this sort of stuff.

I struggled enough just sorting out the wiring on my auto to 5 speed swap in my MK4 Jetta. Got it eventually but was glad to be done with it.

It also does not help that all this stuff has been apart for more than 2 years so I don't remember how any of it came apart.

vwhammer Fri Mar 12, 2021 3:59 pm

Ok so, after talking with Dave at TDC shop, I know what the red and blue "trigger" wire does.

More or less it needs to be a keyed on 12v source that does not shut off when cranking and stays on after the car is started.
It actually powers up the ECU.
That might make nice wire to add some security functions into.

Anyway I am still not sure what to do with the two black connectors that I think went to the starter.

Also for anyone that has done the TDI starter swap what wire did you run to the single plug on the back of the starter?
I know that it is suppose to be the starter signal wire and I could easily run a wire to it but if there is a wire already in the harness that I can use, which I assume there is, then I would rather do that.

Vanagon Nut Sat Mar 13, 2021 11:18 am

Hi.

edit: if your Vanagon has an automatic transmission, the two black connectors you show may involve wiring to the neutral safety switch circuit.

I haven't looked at the images but some thoughts:

- the 50 wire to starter should be present in the Vanagon harness. Both my ABA's use a "cheap" vw mk3 type starter + Mullendore adaptor and pre made 50 connector. Very reliable so far.

- there might be relevant wiring diagram images here in the gallery

- re: blue/red wire. I would suggest not tying anything else into it.

The Vanagon Bentley wiring diagrams show that as key is turned from ignition on (15) to engage starter (50 position), positive remains on the 15 circuit thus in your case, allows positive to continue uninterrupted along the blue/red wire to ECU. This allows ECU to do things like pulse injectors while cranking starter.

I'm sure TDI labelled this but there is also a wire in ECU harness that connects to B+. This wire brings a constant source of positive to ECU which allows it to maintain certain settings, keep DTC's stored, etc.

Neil.

vwhammer Sat Mar 13, 2021 7:30 pm

I believe you are correct with the neutral safety switch stuff.

Found the wiring in the Bentley and that looks like what I am dealing with.

I think I have the starter stuff sorted.

Just have to figure out how to wire up my alternator as I have a kind of universal high output unit but I should be able to sort that out on the venders website.

Moving along.

Vanagon Nut Sat Mar 13, 2021 9:02 pm

Looks great! I'll have a look at your build thread but looks like a forced air induction of some kind? Very interesting to see where parts are located.

Neil.

vwhammer Sat Mar 13, 2021 9:04 pm

Nope just an NA set up.
I have a bunch of stuff torn apart to make it easier to run wiring for the injectors and such.

Vanagon Nut Sat Mar 13, 2021 9:16 pm

oh ok. I thought that was a fan on an intercooler in front of stock black junction box.

vwhammer Sat Mar 13, 2021 9:16 pm

Oh thats the fan for my trans cooler

Vanagon Nut Sat Mar 13, 2021 9:18 pm

Ah, right. That was my other thought. I like that air cleaner location. Looks like the Ford Mustang type. Will air cleaner interface to Vanagon snorkel elbow?

vwhammer Sat Mar 13, 2021 9:23 pm

Yes it is the V8 mustang box with its own little snoot on it.
I used an aluminum coupler to connect the snoot to a piece of brake cooling duct that runs up the pillar and connects to the stock van snorkel intake that is just behind the the vent.

Vanagon Nut Sat Mar 13, 2021 9:30 pm

ok cool. Yeah, I didn't use the stock snorkel elbow. As you know, it has water drain hole. I used spring reinforced bilge pump type hose to connect air cleaner to Vanagon snorkel. In heavy rain, a fair amount of water would seep in at join to snorkel. Comedy of errors but even though I squeezed the hose to a sort of oval shape, it didn't seal well.

Neil.



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