Need a quick answer, if possible! Neutral Safety Switch bypass an auto, but manually converted with JDM Auto Turbo ECU

the t3d

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It's an odd situation, but I have just bypassed the Theft Deterrent ECU, and wanted to make sure the Neutral Safety Switch is properly bypassed as well. The car was an Auto originally, but I converted to manual. I got an turbo pre-89 harness, as mine is an 87. The harness was from a manual. I have the JDM Auto ecu, as all of the EGR stuff is removed and blocked. When I converted the car to manual. I removed all of the harness wiring that went with it, so that black-blue and white-black wiring that should be jumpered to bypass the switch is not on the car anymore. I thoroughly looked for where the connector from the chassis harness, but cannot find that anywhere. So my question is can I jump 12v from the IGN SW wire at the ECU to this NSW wire so that it can read the switch is closed? Or is best to use a constant battery voltage wire at the ECU that is not dependent on the ignition power? It would just see that the switch is closed all the time essentially, right? That seems to make the most sense, and I am about to do it, but I just need to make sure that this sense. It does on paper, but I just want to make sure I am not missing something. Thank you!
 

the t3d

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I'm not qualified to answer, but it's an interesting problem. Please post your resolution. I'd like to understand better :) Good luck!
Me too lol. I have these wiring diagrams all printed out and laminated, so it seems to make sense, but yeah I will definitely share the resulting outcome if someone chimes in to confirm.
 

debrucer

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58 views and no answers possibly means I'm not the only person not qualified to answer :(

Have you tried FB anywhere? Too much detail here for FB, but maybe we can drive traffic to your post? Where else have you looked for an answer? There is an ECU Master forum here, you might look there to see if you can find somebody to talk to about it.


I've re-read your post and it appears to me that either way would work. I can't imagine why the check would be needed with the switch off.

That said, I'm still skeptical about recommending poking around not knowing. I just know that I am going to have similar problems and issues over the next six or seven months... or my car will never run again. I've looked at the groups I know are useful, but I don't see too many places to ask such question.

Update: @the t3d Send a PM to @shaeff. He is one of the long-time operators here and was last on February 3rd this year :)
 
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the t3d

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58 views and no answers possibly means I'm not the only person not qualified to answer :(

Have you tried FB anywhere? Too much detail here for FB, but maybe we can drive traffic to your post? Where else have you looked for an answer? There is an ECU Master forum here, you might look there to see if you can find somebody to talk to about it.


I've re-read your post and it appears to me that either way would work. I can't imagine why the check would be needed with the switch off.

That said, I'm still skeptical about recommending poking around not knowing. I just know that I am going to have similar problems and issues over the next six or seven months... or my car will never run again. I've looked at the groups I know are useful, but I don't see too many places to ask such question.

Update: @the t3d Send a PM to @shaeff. He is one of the long-time operators here and was last on February 3rd this year :)
Damn dude. I appreciate the effort a lot. I just try and think of it as the ECU would, and that it is straight up looking for a voltage signal of 12 volts at that pin, which then allows the following preprogrammed ignition and starting processes to happen. So I think tomorrow I may just jumper it and see what happens.

Maaaaybe I'll make a post to FB, but we'll see. Thanks again though. Regardless, I'll let you know what happens. I also bypassed the theft deterrent system that affects the starter properly, so I'm hoping that is no longer an issue as well.
 
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Dave 1jz

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Normally you connect the black/blue starter wire to the NSW black/white. Toyota originally did a jumper close to the gearbox to go from auto to manual.

It must be added that this is for manual chassis with a auto ECU.
 
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the t3d

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Normally you connect the black/blue starter wire to the NSW black/white. Toyota originally did a jumper close to the gearbox to go from auto to manual.

It must be added that this is for manual chassis with a auto ECU.
Correct. As mine was an automatic before and now has a turbo manual harness, the color of the wire at the ECU is black and yellow, which is the clutch start switch wire. My hypothesis is to jumper either constant or ignition sourced battery voltage to that pin so it reads as if the clutch or neutral switch is complete. I'm just deciding on constant or ignition power at this point.
 

suprarx7nut

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I think what matters is getting the behavior listed in the link below. I fought with this on my GTE-swapped 90 or my manual swapped 88. It was not as simple as I expected.


1581959182257.png
 
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the t3d

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So how did you end up doing it? My ECU is an automatic JDM, was yours and auto as well?
And if I'm reading that correct, then an AUTO ECU is looking for a voltage only IF the car is NOT in park or neutral. So if I'm currently not seeing voltage at that pin with key ON, then it's already reading it "jumped". I gotta confirm this with my 87 TSRM.

*Edit: those voltage specs you highlighted are at the G- pin at the ECU for the CPS. That seems to serve as a reference signal rather than an input like the neutral switch. Could be used as another way to check if it thinks the car is in P or N though. Why is this so simple but difficult? Lol I'm just trying to mimic what jumpering the NSW would do, but without the harness.
 
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suprarx7nut

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And if I'm reading that correct, then an AUTO ECU is looking for a voltage only IF the car is NOT in park or neutral. So if I'm currently not seeing voltage at that pin with key ON, then it's already reading it "jumped". I gotta confirm this with my 87 TSRM.

*Edit: those voltage specs you highlighted are at the G- pin at the ECU for the CPS. That seems to serve as a reference signal rather than an input like the neutral switch. Could be used as another way to check if it thinks the car is in P or N though. Why is this so simple but difficult? Lol I'm just trying to mimic what jumpering the NSW would do, but without the harness.
I think you need to mimic the harness. instead of trying to get the ECU what it wants, just run the wiring exactly as the TEWD shows.

I don't recall exactly what I ended up doing and that was before I started recording most my tasks. I think there was a connector with pins that needed re-arranging, but i might be mixing up projects. I've had a few mk3s with varying combinations of NA/turbo and USA/JDM ecus.

When in doubt, follow the TEWD to a tee. Don't try to modify the wiring (or anything, really) until you fully understand exactly how it works. That's a boring approach, but a lot less frustrating in the end.
 
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the t3d

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I think you need to mimic the harness. instead of trying to get the ECU what it wants, just run the wiring exactly as the TEWD shows.

I don't recall exactly what I ended up doing and that was before I started recording most my tasks. I think there was a connector with pins that needed re-arranging, but i might be mixing up projects. I've had a few mk3s with varying combinations of NA/turbo and USA/JDM ecus.

When in doubt, follow the TEWD to a tee. Don't try to modify the wiring (or anything, really) until you fully understand exactly how it works. That's a boring approach, but a lot less frustrating in the end.
That's great advice, and after doing more digging and acquiring more resources, I think I figured out how to go about it. I'll do a little write soon and post it up. Thank you for the help!
 
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