LS swap folks. . What wire did you tap into on the ignition switch pigtail?

[pipernd]

I’ve had issues with my swap where I get a 0073/0100/0700 codes and intermittent hard starts. It’s been driving me nuts. I found some damaged trans harness wires that had been sitting against my exhaust and thought I had found the problem. Fixed those wires and nada.

I went to replace my ignition switch and saw that my harness red wire that requires 12v at Start and during Crank was spliced into the red/black wire off the ignition harness. I don’t trust AI but w/o me asking it told me that wire needed to be spliced into the black/yellow wire on the harness and that the red/black was the ACC wire and would drop to 0V during crank but that the black/yellow wire maintains 12v during crank.

I ran this by the tech guy at PSI and he suggested AI was wrong and that the truck wouldn’t start at all if the PSI red wire wasn’t wired correctly.

So. . . .AI doesn’t know what it’s talking about, right? I figure it doesn’t but I really hoped it did bc I’ve been told for months by PSI that i’m getting a voltage drop at crank that’s causing my ecu issues.

I’m about to go test the wiring but thought I’d post this now bc it was in my head.

 

[Lucky1386]

I am going to need this info soon as well. I feel like @dbbowen has it laid out on his engine swap thread but not entirely sure either.

 

[yotadude520]

I used one of these Bussman fuse taps for my trigger wire and put it in the ENGINE 20 Amp fuse in the fuse block inside the cab. Have had no issues with it since installing and you get the bonus of getting an easy ignition kill switch by just unplugging the fuse tap. That's the only fuse in the fuse box that had power when cranking.

https://www.autozone.com/p/bussmann-fuse-holder-bp-hhh-rp/32416?spps.s=2740&cmpid=LIA:US:EN:AD:ALO:GOO:TRS:SHO:OTE:GEN:NA:ALA:NA:NA:NA:NA:NA:NA:NA&gclsrc=aw.ds&gad_source=1&gad_campaignid=22356757832&gbraid=0AAAAADkcoVuAX6dXWjnzarY0Yj0tW4srQ&gclid=CjwKCAjwuanRBhBSEiwAY5y6V5gDZLW0_zdf9G0ziXRzfC7PLxkEFffBlYTR_2mAQmfOzL9H82FDIBoCUMEQAvD_BwE

 

[cruisermatt]

Both FJ60 and FJ62 have so many connectors in the engine bay on the LH fender that get left unused after a swap that have fused ignition switch power. What we do is simply plug into them since we mount the LS fuse block in the engine bay in that area anyways. One less wire to run into the cabin as well.
There is no reason to "Tap" or "splice" into a single wire on a 60 series when doing a conversion.

 

[Lead Head]

Isn't the IAT in the MAF? Sounds like you have problems with your MAF wiring.

 

[dbbowen]

Both FJ60 and FJ62 have so many connectors in the engine bay on the LH fender that get left unused after a swap that have fused ignition switch power. What we do is simply plug into them since we mount the LS fuse block in the engine bay in that area anyways. One less wire to run into the cabin as well.
There is no reason to "Tap" or "splice" into a single wire on a 60 series when doing a conversion.

My Painless harness was the same. I pulled from a wire under the dash close to the ignition switch, but like matt said theres tons of wires that are hot when the key is in the on position in the engine bay too.

 

[pipernd]

My Painless harness was the same. I pulled from a wire under the dash close to the ignition switch, but like matt said theres tons of wires that are hot when the key is in the on position in the engine bay too.

View attachment 4157404

I was completely wrong.

I tested the wire at the relay and it worked properly (12V only when key was in “on” or cranking). I was super confused so i reached out to PSI as well as the group who did my remote start/locks to see which wire was for what. Turns out all of the ‘foreign’ wires that are spliced into my various ignition switch pigtail wires are all from the remote start. The PSI wire is coming from somewhere else but is wired properly.

While that’s great, it doesn’t answer my question as to why I’m getting these issues. I have intermittent hard starts where it’ll click, almost turn over, click, click, click then turn over (or some semblance of that). It always turns over but still. . .it’s not starting as it should.

I’m also having CAN bus failures that impact a lot. It will put me into limp mode where I’m stuck in 3rd or 4th and it won’t shift and it won’t send any tach or mph info to the obd port for my cruise control to read rendering that dead.

I have re run my battery to body and battery to engine grounds with 2 gauge wire. I’ve cleaned and put in new signal wire connector on the starter. I’ve repaired 3 damaged trans plug wires that had been melted by the exhaust. The only thing I really haven’t done is re run the positive cable to the starter. Tomorrow I’m taking all the accessory wiring off the “stack” on my main positive terminal and moving them to a fuse box but I get the sense that’s just another move that won’t end up helping my CAN bus issues (or hard start). PSI thinks there’s a voltage drop somewhere in the ignition process that’s shutting the ECU off momentarily causing my issues but I’ve checked that and can’t find anything there either. Really frustrating.

 

[Lead Head]

I was completely wrong.

I tested the wire at the relay and it worked properly (12V only when key was in “on” or cranking). I was super confused so i reached out to PSI as well as the group who did my remote start/locks to see which wire was for what. Turns out all of the ‘foreign’ wires that are spliced into my various ignition switch pigtail wires are all from the remote start. The PSI wire is coming from somewhere else but is wired properly.

While that’s great, it doesn’t answer my question as to why I’m getting these issues. I have intermittent hard starts where it’ll click, almost turn over, click, click, click then turn over (or some semblance of that). It always turns over but still. . .it’s not starting as it should.

I’m also having CAN bus failures that impact a lot. It will put me into limp mode where I’m stuck in 3rd or 4th and it won’t shift and it won’t send any tach or mph info to the obd port for my cruise control to read rendering that dead.

I have re run my battery to body and battery to engine grounds with 2 gauge wire. I’ve cleaned and put in new signal wire connector on the starter. I’ve repaired 3 damaged trans plug wires that had been melted by the exhaust. The only thing I really haven’t done is re run the positive cable to the starter. Tomorrow I’m taking all the accessory wiring off the “stack” on my main positive terminal and moving them to a fuse box but I get the sense that’s just another move that won’t end up helping my CAN bus issues (or hard start). PSI thinks there’s a voltage drop somewhere in the ignition process that’s shutting the ECU off momentarily causing my issues but I’ve checked that and can’t find anything there either. Really frustrating.

That 100% of the time is either a severe voltage voltage drop on your starter wiring (either positive or ground) or a failing battery. You need to start with the heavy gauge wires, and the battery. It's pointless to try and do any other diagnostics until you investigate these two things.

 

[tmxmotorsports]

I was completely wrong.

I tested the wire at the relay and it worked properly (12V only when key was in “on” or cranking). I was super confused so i reached out to PSI as well as the group who did my remote start/locks to see which wire was for what. Turns out all of the ‘foreign’ wires that are spliced into my various ignition switch pigtail wires are all from the remote start. The PSI wire is coming from somewhere else but is wired properly.

While that’s great, it doesn’t answer my question as to why I’m getting these issues. I have intermittent hard starts where it’ll click, almost turn over, click, click, click then turn over (or some semblance of that). It always turns over but still. . .it’s not starting as it should.

I’m also having CAN bus failures that impact a lot. It will put me into limp mode where I’m stuck in 3rd or 4th and it won’t shift and it won’t send any tach or mph info to the obd port for my cruise control to read rendering that dead.

I have re run my battery to body and battery to engine grounds with 2 gauge wire. I’ve cleaned and put in new signal wire connector on the starter. I’ve repaired 3 damaged trans plug wires that had been melted by the exhaust. The only thing I really haven’t done is re run the positive cable to the starter. Tomorrow I’m taking all the accessory wiring off the “stack” on my main positive terminal and moving them to a fuse box but I get the sense that’s just another move that won’t end up helping my CAN bus issues (or hard start). PSI thinks there’s a voltage drop somewhere in the ignition process that’s shutting the ECU off momentarily causing my issues but I’ve checked that and can’t find anything there either. Really frustrating.

Sounds like you need to take it to a ls swap shop. Do you know who did your swap? And how long has the swap been done? And yes for a remote start system you have to tie into alot of wires at the ignition switch. Does it start well with the remote start? I've installed thousands of these remote starts i was the shop Forman for a high end car audio shop in va Beach va for years we also did dealership work for Chevrolet toyota and honda.

 

[pipernd]

That 100% of the time is either a severe voltage voltage drop on your starter wiring (either positive or ground) or a failing battery. You need to start with the heavy gauge wires, and the battery. It's pointless to try and do any other diagnostics until you investigate these two things.

I increased the gauge on my battery to engine ground to a 2gauge and I’m planning on swapping out the heavy positive main from the battery to the starter as well. We’ll see then i guess. . .so frusrating.

 

[Lucky1386]

You will get it as long as you don't give up. Focus on the most basic easy items working your way up to the more complicated items.

 

[cruisermatt]

I was completely wrong.

I tested the wire at the relay and it worked properly (12V only when key was in “on” or cranking). I was super confused so i reached out to PSI as well as the group who did my remote start/locks to see which wire was for what. Turns out all of the ‘foreign’ wires that are spliced into my various ignition switch pigtail wires are all from the remote start. The PSI wire is coming from somewhere else but is wired properly.

While that’s great, it doesn’t answer my question as to why I’m getting these issues. I have intermittent hard starts where it’ll click, almost turn over, click, click, click then turn over (or some semblance of that). It always turns over but still. . .it’s not starting as it should.

I’m also having CAN bus failures that impact a lot. It will put me into limp mode where I’m stuck in 3rd or 4th and it won’t shift and it won’t send any tach or mph info to the obd port for my cruise control to read rendering that dead.

I have re run my battery to body and battery to engine grounds with 2 gauge wire. I’ve cleaned and put in new signal wire connector on the starter. I’ve repaired 3 damaged trans plug wires that had been melted by the exhaust. The only thing I really haven’t done is re run the positive cable to the starter. Tomorrow I’m taking all the accessory wiring off the “stack” on my main positive terminal and moving them to a fuse box but I get the sense that’s just another move that won’t end up helping my CAN bus issues (or hard start). PSI thinks there’s a voltage drop somewhere in the ignition process that’s shutting the ECU off momentarily causing my issues but I’ve checked that and can’t find anything there either. Really frustrating.

We always add a relay to the starter circuit on these swaps here. I've found the Toyota wiring can barely cary enough current to get the GM starter solenoids to activate. If you look at the starter solenoid wire on any GM V8 vehicle it is always like a 12awg wire.

We use a starter relay from HZJ 70 series (OEM Toyota and rated for engine heat, it is mounted in the engine bay in the 70 series) and mount it on the firewall and wire the orignal starter solenoid wire to the, and get the power for the relay from the positive battery lug on the starter. Do this and you won't have another problem.

Sorry to hear your swap has been such a hassle Mike, I am really bummed for you

 

[pipernd]

OK, after playing with this for hours it appears that my S wire is either bad or has disconnected somewhere between the ignition switch and starter.

That said, when probing around I found a 2nd wire in the engine bay, right next to the S wire, that also only provides 12V when the key is in the “start” position. I tapped into that wire and ran it to the starter solenoid and. . . Voila. . It’s never started so well. So. . . Anyone know what this wire runs to? In this pic you can see the mystery wire, a white wire that’s coming from the firewall that is spliced to a black/white wire. I spliced into that run w/ the blue tapper and yellow wire to the starter solenoid. The white wire w/ black tape (that’s 2 wires spliced together too) is the original S wire to the starter solenoid. There’s no power getting to that wire from the firewall forward.

So. . . Any guesses? I’m going to see if this gets power when the vehicle is in Drive to test whether this line passes through the NSS. If it works properly any reason I can’t just tap into this guy permanently for starting?

 

[tmxmotorsports]

Are you leaving that connection like that?

 

[pipernd]

Are you leaving that connection like that?

Haha. .no, that’s just a set up to test the wire i was using so I could, by myself, turn the key to “start” and have a multimeter on the wire. The yellow wire i have tapped into was just a jumper wire to test the wires in that bundle.

 

[Lead Head]

According to the workshop manual I have, there is only one wire coming out of the ignition switch for Start - a black/white wire. This wire then goes down to the neutral switch, where it turns into a Black/Red wire and then goes to the starter. So a white wire coming out of the firewall is not original, and who knows what it does or where it goes.

 

[pipernd]

According to the workshop manual I have, there is only one wire coming out of the ignition switch for Start - a black/white wire. This wire then goes down to the neutral switch, where it turns into a Black/Red wire and then goes to the starter. So a white wire coming out of the firewall is not original, and who knows what it does or where it goes.

thanks! at the ignition switch itself i have 2 wires steady 12v and 2 that are 12v when in “start”. this is 1 of the 2 obviously i just dont know where it goes. nonetheless i have a good wire for the starter solenoid which is what i was looking for. just wish i knew what was what but im not a mechanic nor a electrician!

 

[Lead Head]

thanks! at the ignition switch itself i have 2 wires steady 12v and 2 that are 12v when in “start”. this is 1 of the 2 obviously i just dont know where it goes. nonetheless i have a good wire for the starter solenoid which is what i was looking for. just wish i knew what was what but im not a mechanic nor a electrician!

According to this, there should be 6 wires at the ignition switch. Black, Black-Green, Blue-Red, Black-Yellow, Black-White, and Black-Blue. The only wire that should be "hot" when turned to "Start" is the Black-White wire.

 

[pipernd]

According to this, there should be 6 wires at the ignition switch. Black, Black-Green, Blue-Red, Black-Yellow, Black-White, and Black-Blue. The only wire that should be "hot" when turned to "Start" is the Black-White wire.

what’s it say re 12v constant?!i have 2. i have 2 12v start too.

 

[tmxmotorsports]

i would trace the wiring that goes through the fire wall and see what going on before going any further.