Harness Wiring Questions -- avoiding splices?

[firemist32]

Hello I am new here and Gerard from Kroon recommended I come with questions. I am installing a new Kroon as well after a small (thankfully) electrical fire that required a new main harness and new battery and ground wires. I am almost done installing but I have a Lindsey racing MAP sensor that I am trying to wire in. It says to attach the DME to pin 28 solid brown wire on the original and new wire harness. However I am trying to grab it about 1/2 up the floor and not cut near the DME and I am seeing 2 solid brown wires. One is a little thicker than the other. Kroons instructions do not mention 2 solid brown wires. Any ideas? Please see photo if it attaches correctly

brown_wires

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[Tom]

Hello I am new here and Gerard from Kroon recommended I come with questions. I am installing a new Kroon as well after a small (thankfully) electrical fire that required a new main harness and new battery and ground wires. I am almost done installing but I have a Lindsey racing MAP sensor that I am trying to wire in. It says to attach the DME to pin 28 solid brown wire on the original and new wire harness. However I am trying to grab it about 1/2 up the floor and not cut near the DME and I am seeing 2 solid brown wires. One is a little thicker than the other. Kroons instructions do not mention 2 solid brown wires. Any ideas? Please see photo if it attaches correctlyIMG_0378.jpg

Follow those wires to their ends and then use a multimeter to see which wire goes to DME 28. If you aren't set up to do that, let me know and I'll check mine. Seems a shame to cut into a new Kroon harness though. Do you need to tap into the brown wire and leave it connected, or do you need to cut it completely and feed the MAP sensor to DME28? Might be a better way to do it without cutting/spicing anything....

[mwc951]

Get a F9T DME...
MAP is plug & play.

[Tom]

Get a F9T DME...
MAP is plug & play.

I actually just got one, with OBD. It came with 2 wire pigtails, which Joe says are to connect optional external sensors, such as wideband, MAP, and fuel pressure. Are those just used for logging signals, or can the F9T DME do something with them? Also, if you happen to have the pin-outs for those pigtails, I'd appreciate it.

[firemist32]

Follow those wires to their ends and then use a multimeter to see which wire goes to DME 28. If you aren't set up to do that, let me know and I'll check mine. Seems a shame to cut into a new Kroon harness though. Do you need to tap into the brown wire and leave it connected, or do you need to cut it completely and feed the MAP sensor to DME28? Might be a better way to do it without cutting/spicing anything....

Yes I need to cut the wire and one wire to go to the map sensor from the DME side and now the dead side of that wire goes to a different wire of the MAP. If you know another way I am all ears. I am also supposed to T-Tap the blue-green wire. See photo from Lindsey instructions below where they call the Brown wire Black but it's for sure brown on my old harness and this new one.

Lastly someone below mentioned the Focus 9 DME which I have but its the original Turbo version. Its before he got fancy and offered the ODB port / extra wires etc so not sure mine can do that

lindsey_screenshot

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[firemist32]

Get a F9T DME...
MAP is plug & play.

How would this work since the Lindsey Map sensor looks for the Vacuum line coming off the manifold as pictured above in my other reply

[Tom]

Follow those wires to their ends and then use a multimeter to see which wire goes to DME 28. If you aren't set up to do that, let me know and I'll check mine. Seems a shame to cut into a new Kroon harness though. Do you need to tap into the brown wire and leave it connected, or do you need to cut it completely and feed the MAP sensor to DME28? Might be a better way to do it without cutting/spicing anything....

Yes I need to cut the wire and one wire to go to the map sensor from the DME side and now the dead side of that wire goes to a different wire of the MAP. If you know another way I am all ears. I am also supposed to T-Tap the blue-green wire. See photo from Lindsey instructions below where they call the Brown wire Black but it's for sure brown on my old harness and this new one.

Lastly someone below mentioned the Focus 9 DME which I have but its the original Turbo version. Its before he got fancy and offered the ODB port / extra wires etc so not sure mine can do that
Screenshot.jpg

Ah, now I know what you are up to. Vitesse Racing was the first to repurpose the circuit on DME28 for use as a MAP input, and then Rogue followed suit. In both cases, you needed to clip a resistor on the DME board too, though that may or may not be necessary with the Ftech DME, since it was Rogue-friendly from the start. Which Lindsey product are you installing?

On the factory harness, that brown wire on DME28 gets crush-welded to other ground wires (inside the rubber snorkel where you can't see it) and together they go to the smaller of the two bellhousing grounds. So, my original suggestion of using a multimeter to find the other end won't really work. DME28 will ohm out to the small bellhousing ground, but that won't tell you which brown wire you are after in the bundle. Are you sure that other bigger brown wire doesn't have a yellow stripe on it? The bigger brown wires all have yellow stripes on my harness(es) and they all get crush-welded together and become the bigger of the two bellhousing grounds.

The best way to confirm you have the correct wire is to remove the screw on the end of the main DME connector and slide the cover off. You will need to remove the zip tie holding the rubber boot on the end, and roll the boot back too. You can just use a new zip tie once you're done. See pictures below. With the cover off, you can see where the brown wire comes out of 28, then physically trace it back into the harness. You can push and pull on it a little if your view is blocked, and see which wire in the harness moves. That way you know for sure which wire is correct. It may be the small one in your picture, but I'd hate to cut it and then learn the DME side does not ohm out to DME28.

If you want to avoid cutting into the new Kroon harness, you can just pull the pin and brown wire out of the main connector, and insert your own pin/wire in its place. You'd then connect the map sensor signal (green) to the wire you just added, and connect the map sensor ground (black) to either the wire you just removed from the harness or to any solid chassis ground. Probably easier to use a different ground and just bundle up the original brown wire in the harness where its terminal can't touch anything. The pins are all Junior Timer pins, so you can read up on how to extract those and were to get new one here:

viewtopic.php?t=565

If you tell me more about the blue/green wire you need to tap into, there may be a way to avoid cutting/tapping into it too, such as adding an extra wire to wherever it terminates. Is that the AFM temp signal?


This is why you can't really trace the brown wires with a multimeter -- they are all connected together...

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[firemist32]

If you tell me more about the blue/green wire you need to tap into, there may be a way to avoid cutting/tapping into it too, such as adding an extra wire to wherever it terminates. Is that the AFM temp signal?

Were you able to see my picture from Lindsey above? Before my car fire this was all working fine and the original wires were cut on the wire harness but I like the idea of not cutting them. Lindsey says the blue/green wire is a 5v wire that connects to the red wire. Not sure what function that blue/green wire normally has in the car. The MAP sensor is part of a MAF kit the Lindsey sells that I am running with an upgraded turbo etc. Also I assume the F9 DME doesn't need anything clipped because it was working fine and uses a 28 pin Lindsey chip in there as well

I am not following you on pulling out wire at pin 28, but if I did that and bought a new pin I could conceivably crimp the brown wire with the green wire from the MAP and push them both into pin 28.

The "cut side" of the brown wire connects to the black in the MAP and is presumably a dead wire that point right? Like not even connected to a ground. Sorry my knowledge on all of this is so low. I appreciate the help Tom

[Tom]

If you tell me more about the blue/green wire you need to tap into, there may be a way to avoid cutting/tapping into it too, such as adding an extra wire to wherever it terminates. Is that the AFM temp signal?

Were you able to see my picture from Lindsey above? Before my car fire this was all working fine and the original wires were cut on the wire harness but I like the idea of not cutting them. Lindsey says the blue/green wire is a 5v wire that connects to the red wire. Not sure what function that blue/green wire normally has in the car. The MAP sensor is part of a MAF kit the Lindsey sells that I am running with an upgraded turbo etc. Also I assume the F9 DME doesn't need anything clipped because it was working fine and uses a 28 pin Lindsey chip in there as well

I am not following you on pulling out wire at pin 28, but if I did that and bought a new pin I could conceivably crimp the brown wire with the green wire from the MAP and push them both into pin 28.

The "cut side" of the brown wire connects to the black in the MAP and is presumably a dead wire that point right? Like not even connected to a ground. Sorry my knowledge on all of this is so low. I appreciate the help Tom

I'll try to do a quick video later today to better explain what I mean about pulling out pin 28 to avoid cutting it. The brown wire currently in the harness is connected to ground at the bell housing, so when you pull that pin out of DME28, the wire will still be grounded. But I'll show later why it might not be the best/easiest way to supply ground to the map sensor.

On the blue/green wire, I wasn't sure if that was related to the MAP connections, since Lindsey's chart seems to have different colors (black instead of brown; and green/yellow instead of blue/green). Not sure if those are just errors or if the chart refers to a different model or what, but on an 86 Turbo, those wires are brown for DME28 and blue/green for DME9. The blue green wire supplies 5 volts to the AFM. For whatever reason, LR is using a MAP sensor that runs off 5 volts, so they are trying to use pin 9 (blue/green) as an electrical outlet for the MAP sensor. That's going to be a harder wire to avoid tapping into -- possible, but not quite as easy/elegant as Pin 28. I'd ask Lindsey if they have a 12v MAP sensor with the same output scale. If they are using GM sensors, there should be one, just a matter of finding it. That way you could use any 12v power source and not need to cut into your brand new ($$) harness! If LR can't help, post the part number of the MAP sensor they supplied and maybe we can find a 12v equivalent. Alternatively, you could add your own little 5v voltage regulator, or wire in a 2-pin JPT connector, or tap into 5 volts inside the DME itself, to avoid cutting/tapping. Or you could just tap the wire as LR suggests, if you aren't too troubled about molesting your perfect harness. Happy to help you sort that out, if you are motivated not to cut/tap.

[firemist32]

If you tell me more about the blue/green wire you need to tap into, there may be a way to avoid cutting/tapping into it too, such as adding an extra wire to wherever it terminates. Is that the AFM temp signal?

I'll try to do a quick video later today to better explain what I mean about pulling out pin 28 to avoid cutting it. The brown wire currently in the harness is connected to ground at the bell housing, so when you pull that pin out of DME28, the wire will still be grounded. But I'll show later why it might not be the best/easiest way to supply ground to the map sensor.

On the blue/green wire, I wasn't sure if that was related to the MAP connections, since Lindsey's chart seems to have different colors (black instead of brown; and green/yellow instead of blue/green). Not sure if those are just errors or if the chart refers to a different model or what, but on an 86 Turbo, those wires are brown for DME28 and blue/green for DME9.

I just talked to Lindsey they are not aware of a 12v option and they acquired from Rogue Tuning and the original link with better installation instructions and purpose is here http://roguetuning.com/map_sensor_installation

If you can think of something to not cut or tap let me know I am all ears. Thanks