Guys I apologize for posting this in the wrong section but the brain power here can provide reliable information for sure.

I am trying to get my NA-t is300 up and running and had a couple pieces of a SRT kit to piece together a functioning kit...my problem is the intercooler piping. When I installed the piping the car would not start or drive, if you disconnect the maf it drives in limp mode but as soon as you plug the maf back in it dies! I figured it was an electrical issue so I whipped out the test light and tried to see if it was a poor grounding issue with the motor...I incidentally touched it to the piping and some how the piping has a ground signal (but its not in direct contact with anything).

Please help me before I lose my marbles and light this car on fire! The stock intake works just fine but as soon as I put the maf sensor into the SRT pipe and start it, it just takes a poop!

Is that intake supposed to work with the stock Is300 ecu? If it is I would try and reset the ecu so it can learn again, pull the EFI fuse or the battery cable for a few minutes.

Hey guys,

Making progress here. Almost all the hardware is installed on my na-t conversion and all that's left is some vacuum lines and stuff. Getting ready to start in in the electrical finally, a full year after getting a hold of the parts (damn!). One quick question regarding COP locations...where is cylinder 1? On the firewall or toward the radiator? Obviously everything would be reversed if my wiring, coils etc were set up incorrectly.

So ready for this thing to fire up!!!

Thanks!

Nice, 1 is at the front towards the radiator. When I did it with vvti coils I had a coil sitting on 2, 4, and 6. Then a plug wire from 6 to 1, a plug wire from 4 to 3, and a plug wire from 2 to 5 (companion cylinders).
This is also helpful when you go to set or check timing, this way there will be a plug wire going into 1 that you can just clip onto.

Right on, thanks Ali! I spelled a bunch of stuff out in post 3706 which I think is correct but totally forgot about that. That is a pretty important one lol. My brother in law is receiving all my charge piping and aluminum stuff to weld up today, along with the tail section of my exhaust. He already has the downpipe and midpipe to do work on. I'm leaving on vacation for a week Monday and hopefully it'll be done and ready by then. Crunch time!

Another question...given there are 2 o2 sensors on the manifold on my '92 sc300, is the signal wire going to b48 the one closer to the firewall, or closer to the radiator? I'm assuming that is critical.

Use multimeter set to continuity and answer your own question

At this point I can't pull the ECU to figure it out as it is jammed into a carport. I am trying to get all the underhood wiring done and prepped so once it is out of the carport I can just put the wires through the firewall and it'll be all ready.

On another front, where did you guys run the wires through the firewall? Factory location somewhere or drill and grommet closer?

Thanks!

I really don't know which one it is I did what Vrank said. Do you have an afr gauge? if you don't see it swinging around 14.5 afr a few minutes after start, then you got the wrong one.

might be overthinking it a bit, there is no wrong way to run wires unless you run them where they will short out or catch on fire.
Passenger side the first time I ran extra wires I ran it through the factory harness spot, just made a small hole in the rubber accordian part on the main harness and used a coat hanger to get the wires through.
A cleaner solution would be to unwrap the main harness and rewrap it after adding the wires you need and removing the wires you do not; but this is a pretty time consuming task.

Drivers side there is the spot that everyone uses for running power wires for amplifiers etc.. search and find it.

Part of the fun of na-t is the setup and learning how to do the stuff, and you should have at least an afr gauge and a boost gauge so you will learn to notice when the o2 sensor is not working, or you have a boost leak etc..

I already have an aftermarket amp and power cable, so I am sure I can just feed the wires for the o2 sensor and boost gauge through that, along with my new power wire for the fuel pump. Passenger side I will run the b53, 54, and 71 wires. No problem beeping out the factory o2 sensor wire...I'm a test tech so I'm well versed in multimeter, etc...I just thought I saw it somewhere in here at one point so I figured I'd ask. Once I figure it out I'll post up. Can't wait to get back into it, but I gotta finish building the swingset for the kiddos first. Damn adulting.

Thanks!

someone did post it at one point, but with how much variations I have read about with everyone trying to do the same mod who really knows.
the important stuff is the map sensor, the ignitor/coils, and ecu. the car should start and run with those unless you are too large on injector size.
The o2 sensor won't come into play for a few minutes after startup, especially the first time you start it up so I wouldn't even worry about it at this point.
get it started and set/verify the timing, then see what else is happening. air fuel will change as timing is changed too, so if it is off a bunch, reset the ecu after you have gotten the distributor in the correct spot.

I'm finishing up the harness for the ignition coils today, and will be moving on to the through-firewall stuff tomorrow. Pretty sure I only have 5 spare pins here. Will it hurt anything if I beep out the harness and remove the ECU side pin for the 5th wire from the stock igniter that isn't moved to the new igniter harness? I think it's white with a blue stripe, if that rings a bell. That way I can cut that one off at the ECU side and have the 6th pin I need, if it won't affect anything else.

Something odd...I have a '92 sc300 non-vvti and pin b71 already had a wire there, a brown one with a white stripe. According to the logic in this thread, that location should be empty since its a trigger for heater wire for a 4 wire setup, which this doesn't have. Am I missing something, or should I be splicing into it? I already did but can just cut it if need be. Otherwise done! Thanks!

EDIT: Also, reporting back on the o2 sensor...the front o2 sensor closest to the radiator was the one plugged into B48 on my '92.

Hey guys,

Quick question. How many 1997 non-VVTi GE guys have gotten this mod to work?

Is the the only drawback to the 1997 being that it’s OBDII, and it will show check engine lights due to emissions and it being more picky?

Reason for my question is I love the newer 97+ body, but don’t want to add more of a headache with making the OBDII system happy.

Any guy’s successfully used a OBDI USDM 6spd Supra ECU? I’m assuming because the US ecu’s are MAF sensor based it adds more variables but it would be tuned for stock 550’s. I believe the MAPECU was the best solution for tuning this ecu with a piggyback.

I think that wire runs to the stock coil which is on the passenger side, it does not run to the ecu.
you can reuse your other o2 sensor signal wire once you figure out which one it is, some people repurpose it for electronic boost control etc.. but you can reuse is as long as you disconnect at the ecu also.
Just get a hold of some more wires or someone on here may have some extras if you only need a few. I'll see if I can find some in my parts bin.

You car probably has heated o2 sensors before then, alot of CALI and some Federal models had them depending on year etc.. so you just need to confirm you are using the right plug in the engine bay and the signal wire is going to the right spot.
You know that is the case if your o2 sensor has a 3-4 wire square connector. If you have a single wire connector you don't have heated wires from the factory and you should add those then. the other 2-3 wires are just power and ground wires depending on year of ecu.

People had misfires on this setup but I never personally ran it. I would say if you can use the MAF and 550's and seal up all the IC piping, recirculate bov etc... it would probably run well enough.
Map ecu adds in alot more variables and is hard to tune, so while in theory it would be helpful, I think for most people it would be more of a hassle then setting up the piping for recirculate.

I might be doing this in a few months if I can get my 2jz back together, I decided to go non vvti on it at first so I can have obd2 and will be using one of those ecu's.
I was going to be vvti with an aristo vvti ecu but I may have to be able to plug in now and the is300 ecu immobilizer is a hassle to bypass.
Also that cylinder head turned out to have valve issues, so non vvti it is at least initially.