Wow that's funny ^^^ I was just writting a new thread today on how to get the teach working in a 97 cluster lol.. I had mine completely apart too.. Only problem I had is that when 're installing the back cover my grounding screw for the Temp gauge stripped out and caused my temp gauge to not work.. Took my a good minute to figure out.

 

Alright guys I have a challenge for all you electrical gurus out there doing this mod on an OBDII car.

I have officially and successfully completed the Aristo TT-ECU Mod on my 97 SC300 Auto.. Everything is perfect so far.. Base timing at 8°, 14.7:1 ratio, idle at 811-880 RPM fully warm, O2 sensor in and working, and all the goodies to go with.

Now the problem, when I finally go to drive the car for the first time, it blows the 30 amp EFI fuse and dies in the street. All systems seem to be working perfectly fine except the flashing O/D Light, but think I have narrowed it down this far..

The auto trans is not the problem, originally I thought it was blowing because I put it into "R" or"D".. Turns out that this isn't the case, I found out that it is only blowing the fuse when I turn the steering wheel. I can watch the headlights flicker and dim just before it blows, meaning when the idle up for the power steering pump kicks in, it over powers the circuit and pops the 30 amp fuse.. Question is why?

As far as I can see there is only the EFI fuse and EFI Relay on the circuit so how is it over loading? Another little tip is I have had the car idling for over 20 mins tonight and it never blew or died, but as soon as I turned the wheel it popped the fuse

 

Could there be a wire dangling down and binding into something when turning the wheels? Or a wire being grounded somewhere?

Jack up the front of the car, then try the same scenario without any load on the power steering rack and see if it does it. If it does it in the air I would be willing to bet something mechanical moving is pinching a wire or grounding out somewhere.

 

Harness up in the wheel well is fully intact? I don't know if you're lowered but that's a common issue with that harness getting chewed up.

Can you "save" it? if you turn the wheel slightly and it starts to flicker can you straighten it out and it not blow?

 

wow nice write up, had no idea it so buried in there for the 97 cluster.

Good to hear its running well Aswilley but def not good on the blowing the fuse part.
never heard that one before, when you turn the wheel it pops the efi fuse?
were you able to free rev it without turning the wheel?
flashing overdrive is just the fault code for the torque converter lockup not working.

2 things come to mind, are you using a tt fuel pump on the n/a fuel ecu, that could be overloading it and as soon as it exceeds the amps of the EFI fuse it will blow that fuse. 12V mod or a proper 12v relay triggered off the stock fuel ecu would fix this. turning the wheel raises the electrical load, so it could be just enough to do it.
removing the fuel pump from the EFI circuit by using a relay would give the EFI circuit back the overhead it needs to run everything, and the relay off the EFI circtui will keep the fuel pump operating like stock with the safety shutoff but will keep it at 12V on its own dedicated circuit.

next thing is obscure but since you mentioned turning the wheel, I think some of the SC's have an electrical connection on the steering rack on the drivers side (I think certain autos), maybe try disconnecting it if you have that on your car. I know on my rack its just an empty connector sitting there nothing runs to it on my 5 spd. could be causing mixed signals if they are different between the 2 chassis and you have that function.
I have also bypassed the plastic idle up switch, really didn't notice much difference after it was gone, but doubt that is part of the problem.

other thing could be an o2 sensor or other wiring shorting out as they are all on the EFI fuse.
coil power should come from EFI fuse but shouldn't be the problem if it was running at idle unless the system is overloaded by the above denso pump. usually a walboro won't do it, but everyones fuel pump ecu is in a different state some like it some don't.

 

Alright so here are the last hints before I start trying to diag some more..
The Car will run fine, free rev fine and start and drive forward and backwards perfectly, as well as "L" and "2" gears (well within the 10 feet I had to test it lol)


Car is on stock 1997 N/A fuel pump

@ The Aristo ECU I have removed pin A8 for OD2 because it is not used on the Aristo.

@ the ECU I have swapped the Bank 2 O2 sensor to pins B71 and B48 so the connector would reach at the sensor and the sensor would work.. (common ground w/ B1 so should be fine)

@ Bank 1 O2 sensor - Completely Disconnected... BUT!! I have the heater wire tapped for a switched 12v signal for the Trans cooler Temp sensor to turn on the fan on the cooler.

@ Bank 3 O2 Sensor - Completely disconnected inside the car

YES... Ali SC3 it does have a grey 2 pin connector on the Rack I believe it is for the PPS ECU and controls the solenoid valve. So yes this is what I wanted to disconnect next to see if it is overloading due to excessive resistance in the solenoid,

This is as far as I have gotten before work.. Hope this helps a little more. I am tracing the schematic today to help eliminate any possible causes too so I'll let you know how that goes ..Thanks for all the great input guys.. I will lift it up tonight and see if unloaded it still pops the fuse.

 

While Aaron is troubleshooting that, I wanted to revisit the torque converter lockup issue. From what I can tell and forgive me if this is what you tried, Ali, but the GE ECU sends 12V OUT to the transmission out pin 80.8 to enable the lockup. The GTE ecu GROUNDS pin 80.14 to do the same. So I'd think all we need to do is when GTE 80.14 goes to ground, we need to send a 12V+ down the line. (moving the pin of course). The noid is grounded inside the transmission so hopefully just a matter of energizing that circuit when required.

Is that what you were trying to do with the Reed relay like the AC fix? My electronics skills are limited to the basics so I dont know how the reed relays work. Once my car is moving again i may test this with a switch to see if i can get the convertor to lock up manually. If that works then we just have to engineer a way to get the ECU to do it.

 

I am not sure you want to tap the o2 heater wire for anything, as on the JDM ecu there is only 1 o2 sensor, so it might not be getting the right signal. I would test it first or just disconnect temporarily to see if that is affecting anything.

yeah that clip has something to do with PPS, but not all cars have it. like my 5 speed does not have anything connected there. I would just remove it as a test it could be the signals for that are going to pins on the ecu that are not meant for that on the jdm ecu.

just a thought really not sure why you would have that problem never heard of it before but its a toyota it can't be that hard to figure out, sure you will get it here shortly, if I think of somehting new then I will let you know, its definitely not the fuel pump then if its the stocker.

This is what I thought at first, then I realized that the TT ecu does not simply send 12v down the line instead of ground. The TT ecu sends a pulse-width modulated signal, meaning it alternates between zero and ground many times a second, and depending on how fast its switching between the 2, the sensor on the trans will lock up, or it won't. this is why the relay did not work because the relay will not reliably trigger off a PWM signal. you could wire up a switch to the GE solenoid and it would lock up when grounded, but as to get the GTE ecu to do it that is a larger problem.

its sort of like our mafs where the hotwire puts out a voltage, and out karman maf's put out a frequency at a specific voltage. the ecu looks at the frequency to determine what to do.

I have seen someone make a circuit for this on a 5vz, I just have no interest in doing it because the trans is not worth the trouble involved and I am not a vendor looking to make money off such a circuit.

one way to do it you would need a programmable IC device, and to use a GE lockup with a GTE ecu, you would set it to detect the pulsewidth from the GTE ecu, and depending on the puslewidth it would then ouptut ground to the GE solenoid when desired to close it. There are off the shelf circuits that may come close to doing this, just never bothered to do it, but what I wrote above is exactly what you would need to do.

another way to do it you can use a simple low pass filter to produce an analog ouptut voltage according to a PWM signal, but that would just give us 2 voltages on the other side.
http://www.instructables.com/id/****...WM-to-Voltage/

you still need something to say 1 of those voltages I will ground the solenoid, and the other one I won't do anything. maybe a type of threshold comparator circuit could do that without involving the more complicated programmable IC device as said above, where above a certain compared voltage it can ground the solenoid, possibly via a relay. basically one output would be compared to the input showing zero difference, and the other would produce an actual voltage difference (and a relay could then turn that into a ground to activate the solenoid).
The IC option above you can essentially program to do most of these things in software but there is usually some lag time and it has to start up, vs the simple circuits will be working right away.

figuring out the circuit would be neat so others can just plug and play it, but its a bit involved as you see.
I would try and search for similar circuits online and see if you can borrow some ideas to get something going.

hope that helps, also you can just install a gte valvebody onto the GE trans, or simply upgrade to a GTE trans. if someone wants to work on it, I can help them but I dont want to go through all the hassle to still have people blow automatic transmissions left and right. itll only buy you so much time.

 

Oh the lockup is a PWM... yeah nuts to that, you're right it's not worth it. I'll pull the bulb so the flashing OD light doesn't annoy me until I go stand alone and 4l80.

Thanks for all the info!

 

yeah the gte uses PWM. It was years ahead of its time. the next cars to recieve it were in 96 when obd2 came out, but obd1 2jzgte ecu's had it. one of the reasons why I say its a better ecu, the logic they use in it is more advanced than the n/a one. I wonder that the is300 auto uses, maybe you can put one of those in but seriously everyone needs to manual swap or gte auto swap.

maybe there is a simpler way to control the lockup, like from other makes and models could be like a simple controller you can put on there for it since the GE trans uses the most simple form of turning it on and off. or just have it lockup when in 4th gear but I am sure something would probably go wrong with that also.

I did a google search for "transmission lockup controller" and found a ton of devices for GM's etc, one of them has to work the same way, lol.

 

I should have clarified better Ali.. Origanlly the 02 sensor was plugged into Bank 1 at the front of the engine below the Dizzy (the right spot for the ECU to pick up) but I did not want to add wire to my sensor to get it to reach the downpipe, so instead I just swapped the pins at the ECU for bank 2 O2 and HTR.. So I could plug it into the factory connector location just under the throttle body and get the correct signal at the ECU to make it happy.. So the connector for bank 1as it sits, is not used, or is dead now.. That is why I tapped the heater wire at bank 1 to signal the fan on.. It is not interfearing with ECU signals at all to my knowledge

 

I went to crank my NA-T and got nothing yet. I'm running a JDM Aristo ecu. I followed this and Hi-PSI's build as well I could LOL. The car cranks but wont start. I've done the 12v fuel pump mod, TT ecu, Map sensor and ds61 ignitor. Still the stock dizzy. I hear the FP running and theres fuel in the line. I also checked for spark at plug one and it was good. Im re-checking my harness for anything unplugged but I'm pretty stumped

Aristo auto ECU
500cc injectors
borg warner S366
TT headgasket
XSpower exhaust mani + FFIM with added ports
Aeromotive 340 fuel pump

So it cranks but wont start now. Sounds like it wants to but wont turn over.


Thanks,
Jeri

 

Ok I see, just verify that the wire you tapped to is still working as a switched 12V wire. I guess you moved the signal wire and the ground for the heater at the ecu, and the plugs have 12v switched on them so that should have worked. I used to use the old stock coil power wire for switched 12V but should work fine.
I had a brain fart and forgot that its the ground that the ecu triggers, so even though it only has 1 o2 sensor heater trigger, both plugs should have live switched 12V for the heater from the way the GE harness is setup.

double check the ignition wiring but my hunch is you have a bad map sensor. usually its the bad map sensor that causes a no start or a rough start and immediate stall. check the check engine light for codes if you are throwing a 31 its 100% your map sensor or wiring.

 

Thanks Ali, that definitely worked. My pins werent seated enough in the ecu. As soon as i did that it fired up. But it barely idles. Fell flat after needing full throttle to keep it putting the way it was. But progress for sure!

 

that is progress, now its getting a signal. where did you connect the map sensor too?
if you connected it to one of the ports on the top of the throttle body it wont work right, those are for emissions only.

I am sure I sound like a broken record to those who have been reading this thread for a while but tee it off the fuel pressure regulator for optimal results. those should be the only 2 things on that vacuum nipple.
you do have the 500cc injectors but it should start and idle ok. having to floor it all the way down tells me that the map sensor is giving a wrong signal now, but at least you have the signal.