Could you have your original rebuilt? Relentless Motorsports in TX does a good job I've heard.

I know you mentioned the coil but have you replaced the ignitor? Mine was running rough and the ignitor helped. You'll have to buy used, I don't think you'll find a new one. Have you cleaned, adjusted your IACV? Same for your TPS. Do you know what CEL error code you're getting?

 

I tried 2 ECU's and the 3rd one finally worked for me, if you're not getting the CEL at all, it's 99% of the time an ECU issue. If you're positive its getting fuel, spark and compression then you can be sure its the ECU.

Sounds like you tried the fuses but to be sure, you can test them by swapping the EFI1 with the Starter or Fog light relay and seeing if its working, they're the same. If you still don't get a CEL with those swapped, you'll need to replace the ECU.

Note: Since you have a manual Supra, you can use an SC300 ECU Auto or Manual, doesn't matter either way. They are plug and play and are far more common/cheaper.

 

so i got it to idle and code throwing now is 21 27 28 and they are all o2 sensors related. I replaced walker o2 sensors non heated, 1 wire since mine takes one wire and federal. model of sensors are walker 250 - 21050 , i tried resetting by taking out the efi then taking off battery terminal and repluggin and the code is still there. I am only down to two things either the sensors arent compatible or ecu is bad. Both ecus i switched, the cel will not go off. The remanuefarture ecu kept flasshing cel rapidly and the other throws up code 21 27 28.

 

I am looking for a bay area mechanic supra specialist. I am located in san jose , California in the south bay.
I have a 1994 toyota supra na, manual 5 speed, 2jz ge non vvti, my car is federal version. 3 months ago it had hard time starting and died out on me twice at red light and i had to turn it off and start it a few time for it to starts. It began harder and harder to starts and sometime no cranks, and i had to switch the key a few time for it to fully crank and starts. SO I REPLACED starter and it fix the problems and it cranks , i replaced MAF sensor and the it fixed the idles and i was able to drive it again for another month.

(the previous owner told me he had the ecu solder and repair) side note:
Another symptom appeared to happen, the check engine light started to flicker on and off and the car sometime dies out and begins hard to starts (this cant be the starter because the car is cranking) While this happens, the check engine lights flickers off and on , and it eventually stayed on. I ignored and drove it, what happens is one day i drove home and the engine felt like it was misfiring and it rumbles but i drove home fine on freeway at high miles. However when I came home, it does not start and crank, and just shuts off.

After this incident , it had the whole car replaced with parts as i thought it needed a tune up and maintenance anyways. I replaced spark plugs, spark wires, distributer, and its rotors, did timing for distributer, changed timing belt, waterpump, oil pump, fuel filter, and checked fuel pump pressure and it is good, i replaced fuel regulator.

Currently now, the car cranks and starts and holds idles, but it is idling very unstable and feels like it is going to die, and WHENEVER I TAP on the gas pedal or pressed all the way, it bogs our without any acceleration and power and it dies out or it the idling will become unstable and the engine will shake and dies out. So i checked for vacuum leaks and theres none, i had the tps replaced had it at a position where the idle is best, i clean out the maf again, iginition coil, and none of this helps.

Since the previous owner told me the ecu has been replaced before, i then assumed it was the ecu, i replaced two used ecu but i do not know if they are federal or california, and will any of these differences affect the ecu not to turn the check engine light on, or is the check engine light off, or ecu is just not compatible. I have an od1 scanner (actron elite auto scanner) (i also know the supra has its own blinking code just by counting the check engine light) however the scanner isnt picking up any check engine light, and so i am assuming the ECU IS BAD, because wether the check engine light off (if the light bulb is burnt) then the ecu should still throw a code unless it isnt getting power or burnt fuse). Now to test if it has power , i unhook ecu and the car does not start just crank. With ecu the car cranks and idles just poorly, it dies out or idles unstable when i tap on the gas pedal.

- I also replaced fuel pump relay, and checked efi fuse and they are all good.

My question is DO I need to buy a federal ecu since my car is a federal not california car, and do i need to get it programmed. I check some site says its plug and play , and no need for program but this link tells me they need to program and have vin number. The two ecu i bought it off same model and they are used one is from a 98 na and one is from a 94 na and manual.

https://www.fs1inc.com/89661-14590-1993-toyota-supra-3-0l-ecm-engine-computer-pcm-ecu-programmed-plug-play.html

I do not want to change the fuel regulator as i doubt this is the main concern, because there isnt a check engine light , and maybe there isnt signal to the ecu. I DO not or have any experiences with IT or wiring issur diagnosis. I am thinking to replace a brand new ecu from the link above. HOwever i would appriciate it if anyone refers me to the right mechanic in the bay area as it could just be an ignition fuse. I do not know if the ecu for my year supra if it has a ecu fuse or relay and if it does where is its location. Does this has to do anything with my ignition switch fuse, as i do not know if we have an ignition fuse?

PLease any help, it has been 4 months and my baby supra is sitting here, and i really need your help. Is there anyone mobile to come take a look and we can work out a payment because I am at my dead end. I want to have it check on wiring and fuses before ordering $1200 ecu which might not work.

My name is Nate, and my phone is 6695886747

i have attached the oem ecu in the vehicle which is number 79, the two ecu i replaced tested but did not change the symptom are the remanufacture and one with number 86. They all have the same model number and from na 2jz ge manual supra.

is there anyone who can show me step by step how to test if there is power coming to the ecu, or can anyone help me out if they are in the bay and work on supra. I can have my car tow to your place or shop.

Regardlmg the check engine light not coming on /flickering - I had the same issue. I disassembled the dash to access the circuit board. And I press up on the harness that connects to the circuit board turned the key to acc (dash lights come on) & check engine lite came on !! Let go of the harness & check engine light would go out. This was also affecting ABS light as well. Again I press up harness oil, ABS & check engine light came on, let go ABS & check engine light turn off My mechanic placed foam material under the harness & it’s been working ever since. And regarding car not starting I had a similar issue, it was the fuel pump ecu, it was malfunctioning (located rear (hatch) corner panel on left side) new fuel ecu $350.
Lastly regarding a mechanic, I live in Scotts Valley & my mechanic is located in Campbell, his shop is amazing & he is a brilliant mechanic. He is well known throughout the Bay Area & specializes exotic cars & race cars.
I’ve owned my 93 Supra for 24years, motor & tranny are original / stock. And because of my mechanic my Supra is immaculate, it looks & drives like the day I purchased it. I’m not sure if my mechanic is accepting new clients however I will ask and I will contact you either way.

 

Here’s a pic of my Supra

 

Here’s a pic of my 93 Supra

 

It's the ecu...send it to Josh at relentless instead of throwing parts at it. Electrical issues are usually one thing and much simpler then people think..and in the supras case these ecus caps seem to expire on 95% of the cars due to age.

 

Thanks for the reply. Will be looking up Josh @ Relentless hopefully he will help me out & repair my ecu.