Single turbo harness conversion grounding

[Mitchocalypse]

I'm in the process of cleaning up my harness for a single conversion + all emissions and idle controls delete. I've been following a write up I found, but now I'm at the last step which involves re-doing some of the grounds and there is a little bit of confusion because my harness is from a JDM car so there are some things that I already didn't have. Not to mention, the write up didn't include an idle air control delete which is where i'm getting thrown off.

Anyways, first question: There are 2 black and white wires that run through the rats nest (the grounds) that also meet back at a junction that also goes out to the idle air control plug. (4 way junction, 2 to rats nest, 1 to IAC, 1 back to ECU pinout). In the write up, they left the iac on so they had a section about re-grounding it properly. Obviously mine is gone now, as well as the 2 rats nest ones so i basically have this junction but none of the wires lead anywhere. Follow the single wire side of that junction, and it goes right back to the ecu pinout. Can I just remove this without affecting any other grounds? It doesn't connect anywhere else but I have no clue if there is some sort of circuitry in the ecu that requires this to go somewhere (electrical stuff is not my forté.)

If you need a picture of what i was trying to describe I can get one but its fairly straight forwards.


Second question, going with an aftermarket fuel rail, I will have no use for the fuel temp plug, so It's going to come off as well. 2 issues here,

1:there is a brown and black wire that leads to a junction going the thermostat housing plug as well as back to the ecu pinout (I think, I didn't check for any other stops on the way but i would assume that's it.) Can I just cut the brown and black wire near the junction and tape it back up, or will doing this mess with a ground anywhere?

2: I've heard of people using a power fc removing this fuel temp plug and having the exhaust temp light come on. People have suggested that instead of removing the 2 wires going back to the plug right back to their respective junction (for brown and black one) and ecu pinout (for the other one) that you should just put an equivalent resistor between the two and leave the rest of the wires alone.
I would like the wires entirely gone if possible but I don't want the light to always be on. Anyone have word about the truth behind this?

[TitaniumTT]

WHY WHY WHY WHY WHY WHY WHY do people remove the idle air control valve? I do not understand this? There is no performance benefit to doing it, theres no shortages of used TB's out there to get replacement parts from, you guys all understand what it's purpose is.... RIGHT?

[Mitchocalypse]

Originally Posted by TitaniumTT

WHY WHY WHY WHY WHY WHY WHY do people remove the idle air control valve? I do not understand this? There is no performance benefit to doing it, theres no shortages of used TB's out there to get replacement parts from, you guys all understand what it's purpose is.... RIGHT?

why?
same reason my a/c is out, my p/s is out, and tentatively the abs. To clean out the engine bay. Obviously you have to weigh out the pros and cons but for now I'll stick with deleting it. If not having it is causing issues, it's not a big deal for me to put it back on.

[TitaniumTT]

I took my a/c out because I personally don't like a/c, it doesn't get hot enough out here, and it's a great weight savings

I took my p/s out because I overworked he pump in an autox and it locked on me, plus the manula rack has a solid quill to it, but before when I properly depowered my powersteering rack, I welded the quill solid and got a lot better road feel

1st gen abs systems like the ones found in the RX's are horrible. Plus I put on a custom set of 12.2x1 rotors Wilwood calis in the REAR, and 13.25x1.25 rotors and 6 piston calis in the front.

Soooooo are you doing it for weight savings like the a/c system? Or for better road feel like removing the p/s and ABS systems? Explain to me how removing the IAC is anything like those.

Just say no to removing IAC.

[Mitchocalypse]

I'm deleting it to clean up the engine bay. And like I said if it causes problems I have 0 issues re-installing it. I'd like to try it without first though.

Regardless, any input on grounding or fuel temp sensor deletion?

[TitaniumTT]

Engine needs one good ground, give the starter it's own ground.

Cut the wire at the junction, clearly it's obvious the way sensors work that it won't effect anything

WHY DO YOU NOT WANT YOUR CAR TO IDLE PROPERLY?

Sense, it makes none to me. I would rather have an engine that had the ability to alter it's idle and maintain a steady one than have one less connector and one more blockoff plate.... But that's just me, call me an idiot for thinking idle is decently important on anything other than a race car

[Mitchocalypse]

I don't know how I've insinuated that you were an idiot. But anyways, I'm not here for a pissing match.

Thank you for the response relating to the original post.

[speedjunkie]

Brian, for the record, my car idles HORRIBLY with the ISC hooked up, but with it unhooked and idling just based on the throttle body settings, it idles fine. Just so you know lol. We've been trying to figure it out for the past year or two, and I've finally just given up and I'm running it blocked now. Well, the ISC is still there, but not hooked up, so it's my blockoff plate lol. I still have the connector, and once I feel like trying to fix it again, I may do that. But for now it's useless.

As for the ground, I didn't follow you very well I don't believe, but did you say the ground wires go through the ISC wiring? And you removed the ISC plug? If you did that, how are you going to add the ISC back in? When I stripped mine down to single turbo, I just unwrapped it completely and de-pinned them from where they connect to the ECU. I'm not sure if you're doing it this way, but it might make things easier, despite how long it takes.

[Mitchocalypse]

Originally Posted by speedjunkie

Brian, for the record, my car idles HORRIBLY with the ISC hooked up, but with it unhooked and idling just based on the throttle body settings, it idles fine. Just so you know lol. We've been trying to figure it out for the past year or two, and I've finally just given up and I'm running it blocked now. Well, the ISC is still there, but not hooked up, so it's my blockoff plate lol. I still have the connector, and once I feel like trying to fix it again, I may do that. But for now it's useless.

As for the ground, I didn't follow you very well I don't believe, but did you say the ground wires go through the ISC wiring? And you removed the ISC plug? If you did that, how are you going to add the ISC back in? When I stripped mine down to single turbo, I just unwrapped it completely and de-pinned them from where they connect to the ECU. I'm not sure if you're doing it this way, but it might make things easier, despite how long it takes.

Yes I've stripped everything down and was de-pinnin them from the plugs that go into the ecu. If I need to hook the ISC back up I will just plug the pins right back in and run the wires back through.

Here is a picture of the grounding wire. There were a few junctions but everything from them is removed. It's just a stray wire leading into an ecu Pinout. Since its a ground I'm just not sure if I should just de pin it or solder it back into another ground.
Pic:

[TitaniumTT]

Originally Posted by speedjunkie

Brian, for the record, my car idles HORRIBLY with the ISC hooked up, but with it unhooked and idling just based on the throttle body settings, it idles fine. Just so you know lol. We've been trying to figure it out for the past year or two, and I've finally just given up and I'm running it blocked now. Well, the ISC is still there, but not hooked up, so it's my blockoff plate lol. I still have the connector, and once I feel like trying to fix it again, I may do that. But for now it's useless.

That's because PFC. Run any other aftermkt ECU and it'll run just fine once setup properly.

The 13B-RE turbo FB in the shop now that I installed a Haltech PS1000 on idles PERFECTLY @ 850rpm all day everyday. and it ramps up when cold, and does everything it should do.

[Garfinkles Motor Works]

If your car is highly modified the PFC computer will not learn to idle using the ISC .but you can get a car to idle by setting the computer ,timming and throttle body settings correctly .My car would to idle with the ISC hooked up if the AC was running .If the AC was turned off then the ISC did not control the idle .Steve Kan was staying at my house years ago and he disconnected mine and told me the car would not learn to use the ISC .To get a computer to learn to idle the car needs to idle for 15 -20 minutes with the ISC clean and pluged in .

[speedjunkie]

Originally Posted by Mitchocalypse

Yes I've stripped everything down and was de-pinnin them from the plugs that go into the ecu. If I need to hook the ISC back up I will just plug the pins right back in and run the wires back through.

Here is a picture of the grounding wire. There were a few junctions but everything from them is removed. It's just a stray wire leading into an ecu Pinout. Since its a ground I'm just not sure if I should just de pin it or solder it back into another ground.
Pic:

Hmmm, not sure on that one. I left the ISC connector in, but apparently I can get rid of it now lol.

Originally Posted by TitaniumTT

That's because PFC. Run any other aftermkt ECU and it'll run just fine once setup properly.

The 13B-RE turbo FB in the shop now that I installed a Haltech PS1000 on idles PERFECTLY @ 850rpm all day everyday. and it ramps up when cold, and does everything it should do.

Yeah that's pretty much what we've concluded too. But I really like my LED commander!!! lol And also my homemade commander mount that looks like it's floating lol.

Originally Posted by Garfinkles Motor Works

If your car is highly modified the PFC computer will not learn to idle using the ISC .but you can get a car to idle by setting the computer ,timming and throttle body settings correctly .My car would to idle with the ISC hooked up if the AC was running .If the AC was turned off then the ISC did not control the idle .Steve Kan was staying at my house years ago and he disconnected mine and told me the car would not learn to use the ISC .To get a computer to learn to idle the car needs to idle for 15 -20 minutes with the ISC clean and pluged in .

I'm pretty sure my tb settings are correct, other than the bleed air screw because everything is modified. Not sure about timing and all that though. Maybe I'll try it again sometime lol.

Mine would run OK sometimes, but then when I'd return to idle it would act hunt, stop, then hunt again sometimes. It was weird.

Sorry to hijack your thread, Mitch. lol

[Mitchocalypse]

Originally Posted by speedjunkie

Hmmm, not sure on that one. I left the ISC connector in, but apparently I can get rid of it now lol.



Yeah that's pretty much what we've concluded too. But I really like my LED commander!!! lol And also my homemade commander mount that looks like it's floating lol.



I'm pretty sure my tb settings are correct, other than the bleed air screw because everything is modified. Not sure about timing and all that though. Maybe I'll try it again sometime lol.

Mine would run OK sometimes, but then when I'd return to idle it would act hunt, stop, then hunt again sometimes. It was weird.

Sorry to hijack your thread, Mitch. lol

no worries!
Do you remember what you did with the ISC ground at all? because it is the same one. Worst case I just do whatever you've done but bypassing the ISC plug. I assume you've soldered it somewhere?

[C. Ludwig]

Have you realized yet that the black/white wires are not grounds but are, in fact, switched 12V+?

[Mitchocalypse]

Originally Posted by C. Ludwig

Have you realized yet that the black/white wires are not grounds but are, in fact, switched 12V+?

I was sort of suspecting them of not being grounds because they don't actually ground anywhere lol.

Switched 12v+ .. is that basically like a key on ignition source? And if so i could remove that whole wire because it isn't required anymore.

-I really hate electrical stuff. The only reason I attempted this in the first place is because i had (what I initially thought) clear write up. I guess it was also a good chance to learn the harness a lot better and to redo the loom but when it comes to circuitry i'm just turned right off.

I think thats everything then. This really cleaned up the harness.