2jzgte77

So guys with limited time at home... I removed the resistor and soldered in a 14 ga wire. I plugged it in and nothing moves. So my next step is to check A-16 pin at the ecu 40 pin connector and see if the bw wire to pin29 has any issues. And I will check and see which wire from the small igniter pin goes to the ecu pin 16. Did I get it right this time ?

2jzgte77

Hi Ali ans Kahn Bro’s
i checked everything as you both said. The wiring is there. I junpered the manual tach and auto tach with the manual tach. The video I attached. The tach is doing a weird almost 180 degree sweep off

I don’t recal if I removed the needle to swap the face ?
Did I fk up the tach ?? Signal is there ...

guess I can’t load videos

2jzgte77

I got it to work !!!!!!!!! 10 friggin monthsssss!!!

both auto and manual work with the jumper mod !!!

the only thing now is the tach when cranked over sits at 2k. I think being a stand alone I need to alter the signal !!!!!

SO YOU CAN USE THE MANUAL TT TACH WITH THE JUMPER WIRE IN A NA TO TT CONVERSION

let me see if I can mess around with the AEM idle speed compared to what’s it pickin up on the laptop screen !!!!!!

KahnBB6

iTrader: (5)

^^ Excellent!! As discussed over text, you've got a clean, unimpeded signal to that MKV tach now. The problem may be either the voltage or type of pulsing/wave that your ECU outputs to it through your Supra's body plug II1-2 directly to that tach.

I would wager that if you had a stock MKIV TT ECU in the car your tach would be acting normally so it probably does have to do with some minor adjustment you'll need to do in your AEM Infinity ECU settings.

Aside, I am wondering if this inadvertently might be good info for SC owners who have swapped in GTE engines and are also running aftermarket ECUs like the AEM Infinity. It is entirely possible that given the tach circuits themselves are nearly the same in the SC's and MKIV NA's (not the circuit *boards* and physical wiring paths in the chassis) that an SC owner with a GTE engine swap and an Infinity ECU would also experience the same off-scale issue with their tachometer.... which requires a programming adjustment in the aftermarket ECU's settings for tach signal output.

Ali, I thought that would have been the case. Thank you for confirming my hunch

Yes, for the USDM market the 1998 Supra non-turbo got the same 2JZ-GE VVT-i that the 1998-2000 SC300 got. Just the same, that 1998 Supra non-turbo also came automatic-only for the final model year (funnily enough the 4.083 final drive ratio and Torsen LSD that were made standard from 1997 for the non-turbos stayed the same for the final 1998 model year. Previous to '97 it was 4.272:1 and usually open diff for the non-turbos. For 1998 the Supra Turbos stuck with the same Non-VVT-i engines from 1997 but they were by then sold as "49-state Federal Emission" cars not eligible for original brand new dealer sale in California regardless of a 1998 Turbo coming with an automatic or 6-speed).

In Japan they may have had a 2JZ-GE VVT-i Supra non-turbo with a 5-speed manual option but I am not sure. I'd guess it would have been an option in Japan to have a GE VVT-i with a 5-speed manual W58 + 4.083:1 diff in the "SZ" trim or with a V161 6-speed + 200mm 3.769:1 diff in the "SZ-R" trim. All the Japan-market MKIV Turbos were the "RZ" trim level and those got VVT-i from 1996 I believe.

But in the U.S. the Supra non-turbos basically mirrored the drivelines of the SC300's year for year with the exception of the NA 4.083:1 and 4.272:1 being offered differently in both cars depending on year and transmission type. And of course only the Supras got Torsen options in the USA.

Ali SC3

iTrader: (10)

Thanks for the detailed info, always a good read. I was not aware of that 98 n/a with the vvti and the 4.08 ratio. I wonder if they just reused the SC stuff sitting around that last year, I haven't driven the 4.27 ratio car but I always liked the balance of the 4.08 that the 5spd SC's come with.

2jzgte77

Just for my experimentation, i going to try a 1k ohm resistor or 2 in the line, to see if it helps, i think my wiring is getting 12 v to the tach, which actualy needs to be 5v
i will do a voltage test as soon as i get the chance, im also installing the clutch switch, since my 6 speed swap, i soldered the auto PNP wires 5 &6 to get it started, but it makes me uncomfortable to have it without the manual clutch switch, i will run those 2 PN switch wire to the clutch switch .

KahnBB6

iTrader: (5)

Just keep in mind that especially with the puller-type R154 and V160 transmissions both MKIV and SC owners alike tend to disable the clutch neutral safety switch as a means of preventing any potential crankwalk (the JZ rear crank thrust bearing has almost no oil buffer/lubrication at initial startup). Being able to start in neutral with no pressure applied to that rear thrust bearing from your clutch pretty much sidesteps this potential issue.

With your 420G 6-speed manual if you have a multi-plate clutch with a movement system or conversion system to pusher-type it may be a negligible issue but it’s still a good idea to disable the NSS or not have it at all.

I have my NSS disabled and just have made it a habit to check for and start in neutral now. I will also be switching to an aftermarket OS Giken push-type clutch soon which only adds additional safety measure (R154 puller-type transmission).

...

You may be correct about the tach signal needing to be only +5V from the ECU whereas the tach monitoring pin off the ignitor may be +12V. I’d still recommend using the wire originating from your ECU and the II1-29 Supra body plug pin but give the resistor(s) a try and see what happens. I’m at this point without alternative suggestions.

...

Ali, with time I have grown to appreciate Toyota’s decision to make a 2JZ-GE + W58 + 4.083:1 combination. I still feel that the 4.272:1 ratio is better for spirited mountain driving though. 4.083 always left me wanting going uphill in 2nd and 3rd with my W58 on the stock NA engine.

But I do think you’re onto something in that Toyota was normalizing the 4.083 ratio between the SC300 5-speed, Soarer 5-speed and Supra NA auto & manual in the later years.

It is more relaxed to drive with but at the expensive of optimum gearing for 8-10/10ths driving without boost.

2jzgte77

So gentlemen ...
this is all trial and error , I decided to splice open the igniter small connector and trace the wire. And as I cut it opened. I found out that there is NO pin#1 igniter wire leading to anywhere.

I ran a 16ga wire straight to pin #29 (big orange ) of the body harness which is supposed to lead another wire to the cluster /tach. This was after jumping a wire from the A16 pin on the ecu side to pin #29

second round like before I ran a wire from the igniter straight to the back of the tach IG- and it worked which I knew it would work from a few days ago

so now I’m wiring a new 16ga wire through the engine wiring harness and through the firewall to pin #29

i will solder 2-3 1k ohm resistor together , sharing wrapped and soldered in that line and see if it helps the signal to lower the voltage from the igniter
if it doesn’t change anything. I’ll just leave it or remove it

I’ll upload some photos later. Been on this for 4 hours lol

so everything should work once I’m done with it all

next I’ll be installing the backup camera and front camera just to be cool 😎

2jzgte77

Something weird happened since my last post

or I’m going crazy lol. While I disconnected the igniter plugs to run my wire to the body plug. Got it done and plugged it back in fire it up and it’s barley idleing !!
and when I step on the pedal to rev it up. It surely sounds like a misfire throughout the rpm range !!

so weird. Anyway thought I just put it out there ..
nothing else was unplugged or cut ... so weird
a misfire. I’m thinking maybe the igniter went bad ? Out of nowhere ? ...

UPDATE, look like my Igniter somehow went out... great !