Aristo no fuel/start issue after trying supra ECU.
05-05-24, 10:08 AM
#1
Aristo no fuel/start issue after trying supra ECU.
This is kind of long but I've created a new issue trying to fix something else. I have a 95 sc300 auto with an 2jzgte vvti aristo swap using the aristo ECU. Everything was working fine but long story short the Air conditioning wont work in our cars properly because the aristo ECU lacking the AC request input that the supra ECU has. I sourced and tried to use a 2jzgte vvti ECU from an automatic mk4 supra. I was advised by others that the car should run but that there was a chance that the transmission might not be 100% because of small differences. I plugged the supra ECU and fired up the car. Everything seemed to function and run normally with no CEL. I put it in forward and reverse and it would go both ways. I realized when I went to test drive it that in park it would rev normally but in drive it was almost like in lag mode. It would accelerate VERY slowly trying to get to 2k RPMs. It would actually shift too but its like being in gear caused the engine to barely want to rev. When I put it in park it would rev again normally.
First off is there anything someone here could think of that would cause it to behave this way? The pin outs on the ECUs are almost exactly the same with very minor differences. I would love to get it working with this as it would allow me to have AC without basically going with a standalone, I wish it were that easy. It might run by using a manual transmission with that ECU, but I cant go that route anytime soon. These are the pin outs:
Supra: http://wilbo666.pbworks.com/w/page/5...ngine%20Wiring
Aristo: http://wilbo666.pbworks.com/w/page/4...ngine%20Wiring
So today I went to reinstall the Aristo ECU so I could at least drive the car, but when I went to start it the car would not turn over. It would crank like normal but It seems like I am not getting fuel. I could not hear the fuel pump prime like I could normally. Its a new Denso TT fuel pump from last year. I have the 12v mod done previously and I checked the 30 amp fuses as well as others under the hood and it looked fine. I rechecked the ecu plugs and noticed the ground for my HKS FCD had come apart from the tap on the harness. I'm not sure if it came lose this morning or previously but could that have something to do with it? I tried to put the supra ECU back in again but now it won't start with that ECU either with the same symptoms. Other than swapping the ECUs I didn't mess with anything else and I need to troubleshoot further.
First off is there anything someone here could think of that would cause it to behave this way? The pin outs on the ECUs are almost exactly the same with very minor differences. I would love to get it working with this as it would allow me to have AC without basically going with a standalone, I wish it were that easy. It might run by using a manual transmission with that ECU, but I cant go that route anytime soon. These are the pin outs:
Supra: http://wilbo666.pbworks.com/w/page/5...ngine%20Wiring
Aristo: http://wilbo666.pbworks.com/w/page/4...ngine%20Wiring
So today I went to reinstall the Aristo ECU so I could at least drive the car, but when I went to start it the car would not turn over. It would crank like normal but It seems like I am not getting fuel. I could not hear the fuel pump prime like I could normally. Its a new Denso TT fuel pump from last year. I have the 12v mod done previously and I checked the 30 amp fuses as well as others under the hood and it looked fine. I rechecked the ecu plugs and noticed the ground for my HKS FCD had come apart from the tap on the harness. I'm not sure if it came lose this morning or previously but could that have something to do with it? I tried to put the supra ECU back in again but now it won't start with that ECU either with the same symptoms. Other than swapping the ECUs I didn't mess with anything else and I need to troubleshoot further.
05-06-24, 10:26 AM
#2
The hks fcd absolutely needs a good ground, and I would never recommend installing them with wiretaps.
Get someone to install it correctly by stripping back the insulation on the tapped wire (loose blade carefully all around without cutting the wire inside), wrapping the new wire around the tapped wire, and even soldering it then wrapping it properly with heatshrink if you get to the pin end or tape it up securely with electrical tape.
The 2jzgte vvti uses a maf though so I am not sure how much having the fcd on the map sensor would affect how it drives, but loose connections are never good.
It could have been causing the ecu to go into a limp mode and probably the wiretap got loose when swapping out the ecus. that could be why it wasn't working right after the ecu swap.
Then when you swapped again the connection got even worse. hard to say without being there.
You should be able to use the a/c with a simple relay and your GS ecu. there is a thread on here, it just takes a relay and a few wires. Don't use wiretaps.
see post 70
https://www.clublexus.com/forums/per...problem-5.html
Get someone to install it correctly by stripping back the insulation on the tapped wire (loose blade carefully all around without cutting the wire inside), wrapping the new wire around the tapped wire, and even soldering it then wrapping it properly with heatshrink if you get to the pin end or tape it up securely with electrical tape.
The 2jzgte vvti uses a maf though so I am not sure how much having the fcd on the map sensor would affect how it drives, but loose connections are never good.
It could have been causing the ecu to go into a limp mode and probably the wiretap got loose when swapping out the ecus. that could be why it wasn't working right after the ecu swap.
Then when you swapped again the connection got even worse. hard to say without being there.
You should be able to use the a/c with a simple relay and your GS ecu. there is a thread on here, it just takes a relay and a few wires. Don't use wiretaps.
see post 70
https://www.clublexus.com/forums/per...problem-5.html
05-17-24, 04:33 PM
#4
So I still can’t get my car to run. I spoke to tweaked and they stated the CEL should be on with just the key turned to on. I have no CEL light to either ecu, which both just ran the car previously. Still no fuel pump priming with the 12v mod. They said this indicated possibly no power to the ecu.
I checked all the fuses in the kick panel as well as under the hood and everything looked good. I even replaced the main efi round fuse with no luck.
any ideas?
I checked all the fuses in the kick panel as well as under the hood and everything looked good. I even replaced the main efi round fuse with no luck.
any ideas?
Thread
Thread Starter
Forum
Replies
Last Post
Ali SC3
SC400 / 300 Classifieds
1
05-19-14 01:41 PM