2JZGE Na-T TT Ecu Mod
03-13-14, 03:17 PM
#1459
this is a good deal for a used harness right here in the classifieds, its cut but has all the pieces.
https://www.clublexus.com/forums/sc4...-2j-parts.html
https://www.clublexus.com/forums/sc4...-2j-parts.html
03-14-14, 02:46 PM
#1463
I think you could be the first if you hurry! 
Your SC is part of the 120 club so it def wouldn't be good if it didn't work out.
The mod does work though its not really different than wiring a USDM odb2 gte swap into an SC chassis which does work, difference here is you don't need any of the extra turbo vsv's and a few of the GTE sensors spots need extending to GE locations so instead of removing that stuff and moving sensors, we are choosing to add a few ignition wires to the ge harness that are missing.
Really you could use either harness for the mod, but obviously an odb2 gte harness for a SC chassis is not a regular off the shelf harness, its basically a swap harness. So it comes down to doing the wiring correctly, so if you are going to do it make sure you know what is what on the diagrams and your ecu plug, or you could maybe bite the bullet and get a custom harness made, call them up and tell them you want all the vvti ignitor and coil wires added to your ge harness, and you want it set up for a map and IAT, and they should be able to handle that but they usually want a spare harness to merge so it could get costly quick, also they may not even want to do it for vvti coils, they may want to just do it for gte coils and if you don't have a FFIM then you will have to rewire anyways, but good news is all the wires are there plus 3 extras so its just a matter of repinning and tying off wires at the ecu.
As you see that gets costly and lengthy using a gte harness anyways, so that is why I never really thought about mentioning it before. On another note I have heard of a ODB2 USDM GTE Swap in a ODB2 tacoma with everything working wired by I want to say tweak, so I would think its much easier in the SC chassis we are lucky since we use the GE harness you don't have to touch a body plug.
If we did then you would have to read and do the rest of Gerrb's thread and you would want to really set some time aside for absorbing all that.
I am going to look into some of the steps I have and try and cut out the unecessary ones like checking the distributor grounds and stuff. look for an update in the following weeks.
Your SC is part of the 120 club so it def wouldn't be good if it didn't work out.
The mod does work though its not really different than wiring a USDM odb2 gte swap into an SC chassis which does work, difference here is you don't need any of the extra turbo vsv's and a few of the GTE sensors spots need extending to GE locations so instead of removing that stuff and moving sensors, we are choosing to add a few ignition wires to the ge harness that are missing.
Really you could use either harness for the mod, but obviously an odb2 gte harness for a SC chassis is not a regular off the shelf harness, its basically a swap harness. So it comes down to doing the wiring correctly, so if you are going to do it make sure you know what is what on the diagrams and your ecu plug, or you could maybe bite the bullet and get a custom harness made, call them up and tell them you want all the vvti ignitor and coil wires added to your ge harness, and you want it set up for a map and IAT, and they should be able to handle that but they usually want a spare harness to merge so it could get costly quick, also they may not even want to do it for vvti coils, they may want to just do it for gte coils and if you don't have a FFIM then you will have to rewire anyways, but good news is all the wires are there plus 3 extras so its just a matter of repinning and tying off wires at the ecu.
As you see that gets costly and lengthy using a gte harness anyways, so that is why I never really thought about mentioning it before. On another note I have heard of a ODB2 USDM GTE Swap in a ODB2 tacoma with everything working wired by I want to say tweak, so I would think its much easier in the SC chassis we are lucky since we use the GE harness you don't have to touch a body plug.
If we did then you would have to read and do the rest of Gerrb's thread and you would want to really set some time aside for absorbing all that.
I am going to look into some of the steps I have and try and cut out the unecessary ones like checking the distributor grounds and stuff. look for an update in the following weeks.
Last edited by Ali SC3; 03-14-14 at 02:54 PM.
03-16-14, 12:46 AM
#1464
@Ali SC3 - Will do. I am not doing this mod or anything until the end of this coming summer or the following christmas break. For now Chem and Neuro courses are all I care about(school school school). The research for my NA-T project is a side thing that gives me a break from books which works because cars are my hobby/passion.
Just wanted to shout out to you Ali for all the help and R&D.
Just wanted to shout out to you Ali for all the help and R&D.
03-17-14, 02:10 PM
#1465
For ODB2 if you are manual then I would go ahead and find a 6 speed ecu or you will have to deal with the possibility of auto trans codes popping up when doing the tt ecu mod on obd2.
on obd1 the trans codes come up by blinking the overdrive light, but manual odb1 don't even have overdrive lights so there is no need to worry about it. ODB2 though I want to say the trans solenoid codes show up on the scanner as a regular type of code but you may or may not fail for transmission codes alone, I think some places its only engine/emissions codes.
on obd1 the trans codes come up by blinking the overdrive light, but manual odb1 don't even have overdrive lights so there is no need to worry about it. ODB2 though I want to say the trans solenoid codes show up on the scanner as a regular type of code but you may or may not fail for transmission codes alone, I think some places its only engine/emissions codes.
03-18-14, 08:40 AM
#1467
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how about using a 97-01 aristo gte auto trans with an obd1 tt ecu mod'd SC? thats the only option i can think of that hasnt been discussed yet 
my guess is that itd work but without checking the wiring im not one to say.
my guess is that itd work but without checking the wiring im not one to say.
03-18-14, 09:26 AM
#1468
Yeah you can always swap a gte auto trans in there, and you can use the 92-96 ones also the gte got the more electronic trans early on, but you would need to run the missing wires for the pressure control and rewire a few things as some sensors on the gte get switched power or ground from the ecu and on the ge its the opposite for some reason... not all of them just a few, this would be just a matter or flipping the pins though so not a big deal. I have the diagram may have posted it somewhere but it wouldn't be that hard to wire up or you can just copy the wires from a gte harness or borrow them from a gte harness.
Well if you are auto and obd2 want to get rid of all the codes then yes ideally you would want to change to a gte trans, odb1 its not as big of a deal cause it just blinks the over drive light and what doesn't work stock is the torque converter lockup, you need to rewire as I mentioned. I should probably update it on the main thread somewhere but its hard to confirm since I don't have an auto car. maybe even an Is300 trans may be electronic enough but power wise I would go with the gte trans they are easy to come by for very cheap, and a solid upgrade if you are going na-t and want to keep the auto, it will handle the power much better than the stock auto.
Well if you are auto and obd2 want to get rid of all the codes then yes ideally you would want to change to a gte trans, odb1 its not as big of a deal cause it just blinks the over drive light and what doesn't work stock is the torque converter lockup, you need to rewire as I mentioned. I should probably update it on the main thread somewhere but its hard to confirm since I don't have an auto car. maybe even an Is300 trans may be electronic enough but power wise I would go with the gte trans they are easy to come by for very cheap, and a solid upgrade if you are going na-t and want to keep the auto, it will handle the power much better than the stock auto.
03-21-14, 10:33 AM
#1470
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Wooooo!! Got a call from my shop yesterday and my sc is running! They said it ran pretty well for the 20 secs they had it on. Said they just have to clean up the wiring and set the timing, and test drive it. Oh and they still gotta jump the resistor on the cluster for the tach. But other than that I should be good to go. I'll post again when I pick it up and drive it. I am so excited!!