3.3TT Creating True Plug-N-Play JB4 Harness (w/Fuel Wires)

ecko04

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This is for if you’re looking to clean up your engine bay and get rid of the Posi-Taps. I have a tendency to over tighten Posi-Taps which weakens the plastic housing and always makes me second-guess whether the wires are making contact. Due to that issue, I felt it best to get ride of that weak link and create a true plug-n-play solution


This is only for the 3.3TT. I haven’t confirmed fitment for the 2.0.

Pickup two LSU 4.9 extension harnesses, 6” or 12” are more than sufficient.

I ordered mine from here:

Home Bosch 6 way LSU 4.9 Extension Harness

You can also pick them up from here:

12 LSU 4.9 Bosch NTK Air Fuel O2 Sensor Extension Harness Cable LSU4.9 AEM AFR | eBay

Or if you want to go full DIY and create your own extension harness you can pickup the connectors here:

BOSH LSU 4.9 CONNECTOR + seals and terminals | eBay

From there you’ll want to splice and solder a wire lead to the harness or you can splice and solder the black fuel wires from the JB4 directly to the extension harness.

The red signal wire from the o2 sensors corresponds with this position from the plug. The red signal wire position is the same for both o2 sensors.



Simply pull back a bit of the wire sheath, tap that wire location, solder, tape, and heat shrink. Pull the sheath back over the wires to cover them. Plug the harness ends in, ensure they snap/click into place.

Do the same for the other side.

That’s it. You now have a fully plug and play JB4 and a system that’s fully removable with no traces of install.

Next up may be a DIY on replacing the fittings, check valves, worm gear clamps, and vacuum lines the ADD W1 catch with -8AN and -6AN braided hoses, spring clamps, and AN hose finishers.

--EDIT--

I did a little research, I can basically make the harnesses for existing JB4 customers for the cost of the extension harnesses themselves + shipping.

What the end user will get is:

- x2 extension cables with PNP connectors
- x2 solder sleeve heat connectors

What the end user will need to do, aside from connecting the extension cables, is to take the single wire coming from each extension cable and the fuel wire from the JB4 and twist them together. Next, you'll take the supplied solder heat sleeve and slide it over the wires you just twisted together ensuring the solder joint is in the middle of the wire. Next, you'll take a lighter and heat the solder joint and the silicone ends to create a soldered joint and waterproof seal.

It will take you longer to read the paragraph above than to complete the steps.

I would go with solder sleeves because it's far more likely for an end user to have access to a lighter, or a gas stove, than a soldering iron. And given that I can strip back a part of the wire that needs to be exposed before shipping, the end user will not need a stripping tool.

If you fast forward this video to 2:47 -
- it is basically what I described above.

Just think of one wire as the JB4 fuel wire and the other being the attached wire coming from the o2 extension harness. Once the solder is melted, you have a complete PNP harness, no posi-taps needed.
 

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MrSmoofy

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For some reason, this isn't clear what you're saying.

Are you soldering the fuel wires to the extension cable and then just plugging the extension cable in between the car's current connection so that you're not taping/splicing the cars wire?

I guess a picture here of the finished work would make it more clear. Either way, I like the idea of not having to tap the car's wires and makes it easier to remove and put back in during any dealer service.
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Terry@BMS

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MrSmoofy

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Looks fine to me. If there is demand we'll look in to making similar extension harnesses for guys who want them. :)
You can put me on the list of people that would rather have a plug and play situation instead of a wiretap. No rush for me though saving up to purchase.
 

Terry@BMS

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I already told our team to source the connectors. :)
 

Kamauxx

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Looks fine to me. If there is demand we'll look in to making similar extension harnesses for guys who want them. :)
People on the G70 forum have been discussing this for a few weeks. Might want to reach out to them as well.
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ecko04

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Here are some pics.

Unfortunately I didn’t take any while I was wiring everything.

It’s pretty much just an extension cable and you’re plugging it in-line while wiring in the o2 sensor wire to the extension leaving your o2 sensor wires unmolested, creating a true plug-n-play solution, and ridding yourself of those plastic Posi-Taps.

At a minimum, I recommend solder and electrical tape. To take it a step further I’d add heat shrink.
 

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turboAWD

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Looks fine to me. If there is demand we'll look in to making similar extension harnesses for guys who want them. :)
I'll be buying jb4 soon - I'm TOTALLY down for a 100% plug-and-play / unplug with no harness modification solution. Bring it on - the wire taps are the ONLY slight hesitation I've had about buying a jb4. Sure, I know how to make the above cable, but I don't want to spend the time. $15-20 in parts, $50 for labor + packaging? $75 accessory? I'm totally there..

Speaking of which - how reversible is the WMI kit?
 

ecko04

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I'll be buying jb4 soon - I'm TOTALLY down for a 100% plug-and-play / unplug with no harness modification solution. Bring it on - the wire taps are the ONLY slight hesitation I've had about buying a jb4. Sure, I know how to make the above cable, but I don't want to spend the time. $15-20 in parts, $50 for labor + packaging? $75 accessory? I'm totally there..

Speaking of which - how reversible is the WMI kit?
It’ll probably be closer to $80-90. Cost of the two extension cables alone are $35-40/each and you still have 10 mins of work afterwards.

If they’re doing them in house it’s connectors, wires, terminals, seals, and labor.
 

turboAWD

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It’ll probably be closer to $80-90. Cost of the two extension cables alone are $35-40/each and you still have 10 mins of work afterwards.

If they’re doing them in house it’s connectors, wires, terminals, seals, and labor.
I was trying to not over-price it for other people's sake.. Personally, I'd pay $100-125 for a ready-made Burger cable..
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ecko04

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I was trying to not over-price it for other people's sake.. Personally, I'd pay $100-125 for a ready-made Burger cable..
I totally understand.

I hope that the Posi-Tap option remains the default and the harness will be offered as an upgrade at the time of ordering.

And another option can be provided for those who already have the Posi-taps.

Hopefully it can remain inclusive and within the financial reach of owners.
 

ecko04

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I did a little research, I can basically make the harnesses for existing JB4 customers for the cost of the harnesses themselves + shipping.

What the end user will get is:

- x2 extension cables with PNP connectors
- x2 solder sleeve heat connectors

What the end user will need to do, aside from connecting the extension cables, is to take the single wire coming from each extension cable and the fuel wire from the JB4 and twist them together. Next, you'll take the supplied solder heat sleeve and slide it over the wires you just twisted together ensuring the solder joint is in the middle of the wire. Next, you'll take a lighter and heat the solder joint and the silicone ends to create a soldered joint and waterproof seal.

It will take you longer to read the paragraph above than to complete the steps.

I would go with solder sleeves because it's far more likely for an end user to have access to a lighter, or a gas stove, than a soldering iron. And given that I can strip back a part of the wire that needs to be exposed before shipping, the end user will not need a stripping tool.

If you fast forward this video to 2:47 -
- it is basically what I described above.

Just think of one wire as the JB4 fuel wire and the other being the attached wire coming from the o2 extension harness. Once the solder is melted, you have a complete PNP harness, no posi-taps needed.
 
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