99SC42

iTrader: (44)

No you have an IS300, its a little different ..I would just go standalone MS3 and be done with it.

Talk to Shaodome on here he maybe able to help you since you are in FL.

Ali SC3

iTrader: (10)

yeah for an is300 its different your stock ecu does a bunch of stuff the non vvti cannot so you would have to run 2 ecu's or something. this is not a guide for is300's unfortunately they are too different.

SCereal

iTrader: (4)

Sorry if it's been covered but quick wiring question. Going from a 97 to a 92 iirc aristo ecu, my maf power and grounds should now be 5v, yes? I can use those for my map and iat without having to splice into the tps? Same pins I hope...

Thx!

187

Ali I'm still having some issues with the tps. I have tried setting it probably 10 different ways in order to maintain a good normal idle. When I believe it is set and idling properly when you go back and restart it the next day from cold it will high idle and miss. Even when set it seems to be getting to much fuel across the board pretty much. I'm not sure if this has to do with the idle air screw not being where it would like to be or just needing to adjust the vpc.

Also the 02 sensor seems to be fighting at idle adding and taking fuel away. I can see the 02 voltage oscillating with the afr, but it never evens out which also seems odd. This also means it is oscillating while cruising.

Ali SC3

iTrader: (10)

If your car/engine harness is a 97 then the maf is 12V and you cannot use those wires for the 12v power and chassis ground as they are not the right ones for a map sensor. for a map sensor you will need the 5v sensor power from the tps as well as the sensor ground (different than chassis ground, actually goes to a pin on the ecu).

the signal wire from the stock maf you can reuse and move at the ecu connector like obd1 (the third wire you need for the map sensor). for the IAT you can reuse the maf wires as well for the IAT.

Of course instead of tapping into the tps sensor one could just run wire from the ecu and splice in there, but its easier to do it from the tps and I usually have my map sensor connected to the intake around there so its more convenient.


I would set the air screw as backed out as you can get it (So idle is as low as possible), make sure there is a little slack on the throttle cable, then I would turn the tps in the slot almost all the way in the direction that lets you set the base timing, as in where the tps % will be lowest. the ecu shouldn't have a major problem with that.
my o2 sensor usually oscillates like plus .5 or minus .5 around the right value on a good day, it never sits on the right values because its a narrowband o2 sensor.
if its oscillating more than 1 afr up and down though or the average is the wrong value then there could be a problem, I would check for exhaust leaks at the downpipe that can throw the numbers off as well, and also check vpc settings I have never used it before so can't really help with that one.

SCereal

iTrader: (4)

Glad I asked, I would have thought it would have pulled power from the ECU rather than the common circuit with chassis ground. TPS it is then.

Thank you!

Ali SC3

iTrader: (10)

yeah no problem. all 12V components on toyots's use the chassis or common ground.
the 5V components are sensors normally that are sensitive to small fluctuations and have their own sensor ground which is a pin on the ecu. the ecu is ultimately also grounded to the chassis/common ground, but the sensors are isolated by that separation of circuitry inside the ecu.

if you look at the 2jzgte diagrams for the map sensor, you will see on a gte harness the power and grounds for map and tps are actually spliced together, and go to the same 5v power pin and sensor ground pin on the ecu.

92-95 sc300 its easier cause the maf is 5v and all 5v uses sensor ground, so all the wires needed are right on the maf plug (if you dig deep into the 92-95 GE harness the tps and maf are spliced together for power and ground also). 96+ has to tap into tps or run 2 new wires.

187

my 02 voltage goes from like .06-.85 up and down constantly. The issue with moving the air screw way out is it puts a huge gap in the throttle response. I just reset it again today but with the same results i mentioned before.

I don't believe the vpc is contributing in any way after playing with it. I will take a look at the down pipe this weekend.

fried_rice

iTrader: (20)

I just completed a GTE ECU, Transmission and coils on a MKIV Supra NA-T. Fired up the first time and ran great. Drivability has improved 100%. Using the MAP-ECU 3, the MAP-ECU sucks with the GE ECU. Thanks for the info. This is also an easy way to convert to a GTE engine with less wiring.

I'm not sure if this is the proper way to set TPS, but this always works for me.

1.Set idle with Idle screw, I usually set to about 1000RPM off the tach, or 700-800+ through piggy-back when warm. I've found that many SC300 gauges do not read correctly. When reading 700RPM many times it's actually idling at 500 and fighting to stay alive.
2.Set TPS ohm via TSRM

A lot of times the lower idle causes dying when coming to a stop and poor idling, on the manual cars especially, if you think you're at 700 and really at 500 dipping down when the clutch is released.

Ali SC3

iTrader: (10)

that is not a problem, there is supposed to be a small gap in the response, that is the ecu sensing you come off the idl pin. it shouldn't be huge but it can be felt especially after a reset and then it starts to go away. when you set the tps on the edge that the response is perfect, sometimes it will read over the edge and you get your problem.

set it with a little gap in the response, and after the first couple times the ecu sees you rev the car up it should remove some of the gap in the response after it learns what the values are. if you keep setting it where it can't learn it wont work right in all places.

yeah you could convert to a gte engine with a single turbo without a whole lot of fuss. some pigtails will need to be lengthened/rerouted etc.. but its doable.

good news on it working right. did you hook up all the wiring for the gte trans? working wouthout codes. pretty neat and yeah the map ecu 3 should work great on the gte ecu. I have a map ecu 1 on mine and its pretty neat to play around with.

fried_rice

iTrader: (20)

Yes, the GTE Aristo Transmission works great. Somone along the line did some very weird things to the supra and that was the main reason for the conversion. The GE transmission kick down cable which normally goes to the stock intake manifold was tied open so it would never go into O/D.

We wanted stock drivability and better HP capability down the road, without spending a ton on parts and engine management. The auto transmission can't be controlled very well with stand-alone ecu's without spending big money.

The OEM kick down switch now works perfectly, only the few plugs on the transmission itself were added. I had the 3 Bolt flange welded to the stock driveshaft and made an extension for the shifter linkage.

$125 for the transmission and $100 for the driveshaft, now the stock auto transmission is bumped from 350RWHP to 450-500RWHP stock.

The new MAP-ECU-3 is great. They just came out with flex-fuel and WIFI IPhone/IPad gauges. I've been using MAP-ECU with good success for 10 years. I have a MAP-ECU-2 on our SC running 1000cc injectors and E85, stock fuel lines to a driftmotion rail, Walbro 400. We've got to 23psi and around 600RWHP through an R154, with fuel left. Borrowed the GTE IACV for the Supra, so it's down at the moment. Going to see how far we can push the setup, as we have about $700 in the fuel system.

I like to push the limits of stock like configurations, when done right, they work very well for drivability and keeping cost down.

Ali SC3

iTrader: (10)

you have any wiring tips on those extra plugs for the gte auto trans.
I haven't done it nor do I plan to (manual trans for life over here) but several people have asked.
glad its working out for you yeah if you borrow gte parts its a win win as the cost is down and the reliability is up.

trd4life

I'm also in the same boat I've done the tt ecu mod and now have added a tt auto trans. I'm looking for the pigtails needed and hopefully some wiring tips. Great job btw!

fried_rice

iTrader: (20)

My good friend did the wiring while I was finishing up everything else. He does a ton of GTE swap harnesses and had the extra transmission clips laying around. I'll send him a link to this and see if he'll post more detailed info.

The only thing I can post now is the plugs I believe needed to be added, some circled plugs may be the same, You'll have to look at both transmissions and read the Pinouts for both GE vs GTE. One thing to note is the GTE VVTI transmissions are different and require a lot more wiring.

For the driveshaft, I believe the SC400 driveshaft should be bolt in without modification for SC's. For a Supra I had the GE flange cut off and the Aristo flange welded and balanced.

Here's some pics to give you an idea of what clips you'll need, circled in red. If you have friends with GTE manual swaps, go cut their auto clips off .

fried_rice

iTrader: (20)

I also forgot to answer the question of throwing codes. The car was not throwing any codes related to the GTE conversion. The FFIM had an Accufab TB which had the TPS replaced, no oxygen sensors, and for some reason a code for MAF.

So O2,TPS and MAF codes, which all could be easily fixed, but did not seem to effect performance or drivability. The car needs more things addressed so we're waiting to address those in the future