injectors stuck open?
03-13-13, 08:00 AM
#16
You can run 12V at idle on a higher volume pump than stock and not have that problem, half the turbo guys on here have some version of the 12v mod in place. the return line should take care of the extra pressure, meaning the injectors should inject the same unless you have a kinked return or some kind of super pump. make sure the fuel pressure regulator has a vac line on it.
Your problem is that injector not firing, try swapping injectors, or remove the clip off the injector, and then do the test with the light across the pins to remove the injector from the equation. If you have done that and the ecu is just not pulsing, I would take that pin out for that injector at the ecu, and with a multimeter do a continuity test, meaning you touch both ends of the wire and it beeps if the wire is good, if there is a disconnect in the harness, it won't bep meaning its broken somewhere. If thats the case simply run a new signal wire. if the continuity is good, its either the ecu or the injector if the other line is getting 12V.
A 2jz on 5 cylinders will still have power when you stomp it. it will be even better once you get #4 back.
Your problem is that injector not firing, try swapping injectors, or remove the clip off the injector, and then do the test with the light across the pins to remove the injector from the equation. If you have done that and the ecu is just not pulsing, I would take that pin out for that injector at the ecu, and with a multimeter do a continuity test, meaning you touch both ends of the wire and it beeps if the wire is good, if there is a disconnect in the harness, it won't bep meaning its broken somewhere. If thats the case simply run a new signal wire. if the continuity is good, its either the ecu or the injector if the other line is getting 12V.
A 2jz on 5 cylinders will still have power when you stomp it. it will be even better once you get #4 back.
Last edited by Ali SC3; 03-13-13 at 08:04 AM.
03-14-13, 12:26 AM
#17
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Thats good to know,[I will have more power] even before I go NA-T. Thanks for clearing that up for me. I checked for a pulse at the ecu, thus eleminating all wireing etc. and no pulse, so... I guess I'm looking for an ECU now. Thanks again, I kind of thought that was the case, but I hate buying parts until I'm sure I need them.
03-14-13, 08:29 AM
#18
No worries, we have all had our fair share of strange problems, It is less common to have an injector driver go out but it does happen from time to time, couldn't tell you why, but keep testing stuff and you will eventually find it.
Luckily these motors are so strong you can experiment quite a bit before you damage anything.
Luckily these motors are so strong you can experiment quite a bit before you damage anything.
03-14-13, 11:42 AM
#19
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Thanks again, I'm on it. I never thought of checking it without it hooked up to injecter. Good idea, I'll try it . Also i thought I could try finding what cly. fires just before #4 And temp. hookup between that trigger wire and #4. If it is the ecu, not injector it should run on all six. Even tho the fuel will be entering combustion chamber early for maximum epg hp etc, it should still fire. I'll post later with findings.
03-14-13, 12:39 PM
#20
you can only do that if you disconnect the other injector, or swap them to see if 4 starts working and the other one stops working.
If you try and make all 6 work, where 2 injectors are grounded through the same driver, I'm not sure that is going to do much but burn out another injector driver as firing 2 injectors in parallel is going to half the total resistance the ecu sees on the driver = not good.
now if they were low impedance injectors, and you had a mk3 resistor pack to temporarily hook up to those 2 injectors, you could hook up 2 injectors through that and test like that because the mk3 is designed for batch fire and has the right resistance to go with the low impedance injectors, but I am guessing you are running high impedance injectors like the stock ones, and you dont need to do all that stuff really you have already done the right diagnosis.
If the ecu is not pulsing ground and making your light flash when probing the 2 pins on number 4, and it does it on all the rest, it can only be the wire coming from the ecu has a short, or the ecu itself is shot.
If you try and make all 6 work, where 2 injectors are grounded through the same driver, I'm not sure that is going to do much but burn out another injector driver as firing 2 injectors in parallel is going to half the total resistance the ecu sees on the driver = not good.
now if they were low impedance injectors, and you had a mk3 resistor pack to temporarily hook up to those 2 injectors, you could hook up 2 injectors through that and test like that because the mk3 is designed for batch fire and has the right resistance to go with the low impedance injectors, but I am guessing you are running high impedance injectors like the stock ones, and you dont need to do all that stuff really you have already done the right diagnosis.
If the ecu is not pulsing ground and making your light flash when probing the 2 pins on number 4, and it does it on all the rest, it can only be the wire coming from the ecu has a short, or the ecu itself is shot.
03-15-13, 09:35 AM
#21
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W ell I tried that before I saw your last post. It crossed my mind that I could damage the ecu. But it is already damaged, I wanted to drive it while I wait for an ecu. Anyway I did it and it runs great! It is running rich, and it search's for idle speed sometimes, but strong. I need the fifth and the tenth vin numbers/letters from a 97 300sc so I van scan it and see whats up.I think any automatic car should be cool.
03-15-13, 12:59 PM
#22
Soarer13oy, did you fix your issue, I just realized there are 2 problems going on in here.
P00rbob, glad it worked temporarily, hopefully it doesnt mess anything up further. hopefully the ecu should fix it.
check that resistor make sure its got good resistance, which it shoudl if its working now, dont want to short out another ecu. those 2 cylinders are also probably getting a diff amount of fuel than the rest now, so don't push it too hard while its like that.
P00rbob, glad it worked temporarily, hopefully it doesnt mess anything up further. hopefully the ecu should fix it.
check that resistor make sure its got good resistance, which it shoudl if its working now, dont want to short out another ecu. those 2 cylinders are also probably getting a diff amount of fuel than the rest now, so don't push it too hard while its like that.
03-15-13, 07:54 PM
#23
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Ok, I got the 97 sc300 obd2 VIN and put it in the snapon code reader, and it says no comunication. It wants me to plug into a nine or thirteen [I can't remember for sure] plug behind left kick panel. Of caurse I don't have this connecter. does anyone know what I can do to retreave my codes? I'm thinking I may have to go to supra forums because this is more of a supra issue. Of caurse all of you guys have said connecters. But if anyone has a clue I'm all ears lol thanks.
03-15-13, 08:31 PM
#24
edit** its normally under the steering column on the left, but on some cars its somewhere else like with the fuses.
I have never had an odb2 SC so I cant tell you but it should be the standard one not the toyota one.
you don't need a fancy reader, just go to an autozone or something or get a cheap one online.
shouldn't have to enter vin numbers either.
I have never had an odb2 SC so I cant tell you but it should be the standard one not the toyota one.
you don't need a fancy reader, just go to an autozone or something or get a cheap one online.
shouldn't have to enter vin numbers either.
Last edited by Ali SC3; 03-15-13 at 08:42 PM.
03-15-13, 11:39 PM
#25
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Maybe I havent been clear, I have a 86.5 supra I swaped a 2jz out of a 97 sc300. I put the ecu and harness from sc into supra, but didn't get that plug. I put the standard under dash code reader plug in but have been unable to get codes.
03-16-13, 12:31 PM
#26
oh i see whats going on, maybe start a new thread with all the details.
you aren't going to be pulling a whole lot of codes then.
maybe its just the wire for the number 4 injector, you can take the pin out of the socket at the ecu and tie it to ground, and repeat your light test at the injector. if it doesn't light up its the wire that may have been damaged in the swap somehow. this is the same as the continuity test on the multimeter, except you touch 2 ends of the same wire and it beeps if its good. if the wire is good then the ecu is suspect. you could always use an older generation ecu, and then you can connect the body wire for your old check engine light, and get the codes that way. you would have to change the maf though at the least. If you are planning on going turbo just do the tt ecu mod instead of getting another stock ecu.
you aren't going to be pulling a whole lot of codes then.
maybe its just the wire for the number 4 injector, you can take the pin out of the socket at the ecu and tie it to ground, and repeat your light test at the injector. if it doesn't light up its the wire that may have been damaged in the swap somehow. this is the same as the continuity test on the multimeter, except you touch 2 ends of the same wire and it beeps if its good. if the wire is good then the ecu is suspect. you could always use an older generation ecu, and then you can connect the body wire for your old check engine light, and get the codes that way. you would have to change the maf though at the least. If you are planning on going turbo just do the tt ecu mod instead of getting another stock ecu.
03-19-13, 09:57 AM
#28
you can pick them up in the classifieds here or on SF.
Aristo ecu's are generally the least expensive around $100, you will need a map sensor usually ~60-80 used, and an air temp sensor (generic is fine about $20), and ds62 ignitor (usually $30), and coil packs (vary from $40 for mk3 coils to $150 for vvti coils). also you will need 440cc inejctors or 550cc if you need the extra fuel. the 440's are generally good up to a bar of boost.
check out my tt ecu mod. IF you are going turbo there is no reason not to you basically need the injectors and better coils anyways. plus since you have a mk3, you don't have to mess with all that odb2 nonsense.
https://www.clublexus.com/forums/sc-...t-ecu-mod.html
the aristo ecu should blink out the cel codes even in a mk3 but you may have to wire the CEL wire from your mk3 body plug to the cel wire on your odb2 harness if you havent done that. also not 100% sure on the differences between an odb2 harness and the odb1 harness pin wise but I think they are very similar.
Aristo ecu's are generally the least expensive around $100, you will need a map sensor usually ~60-80 used, and an air temp sensor (generic is fine about $20), and ds62 ignitor (usually $30), and coil packs (vary from $40 for mk3 coils to $150 for vvti coils). also you will need 440cc inejctors or 550cc if you need the extra fuel. the 440's are generally good up to a bar of boost.
check out my tt ecu mod. IF you are going turbo there is no reason not to you basically need the injectors and better coils anyways. plus since you have a mk3, you don't have to mess with all that odb2 nonsense.
https://www.clublexus.com/forums/sc-...t-ecu-mod.html
the aristo ecu should blink out the cel codes even in a mk3 but you may have to wire the CEL wire from your mk3 body plug to the cel wire on your odb2 harness if you havent done that. also not 100% sure on the differences between an odb2 harness and the odb1 harness pin wise but I think they are very similar.
03-22-13, 08:33 PM
#29
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Thank you I hadnt thought could get the TT ecu now. Can I run that 2jzge no-t? Of coarse I will go turbo once I get the money together. but it runs pretty good now and I love to drive it.I
03-23-13, 01:48 PM
#30
TT ecu will run without a turbo, but if its running good for now then just enjoy it till you are ready and have the parts collected. I would get a replacement stock ecu then before something else bad happens if its the ecu thats bad, as you can always sell it later.
did you ever check that the wire from the ecu to the injector is still good?
take the pin out at the ecu and ground it, then go to the injector connector and then do the light test.
If you have a multi-meter, you can just touch the pin at the ecu with one lead, and then the ground pin on the injector connector with the other pin and it will beep if the wire is good on continuity mode.
You need to do this test, because if its the wire thats bad no amount of ecu's are going to fix the problem.
did you ever check that the wire from the ecu to the injector is still good?
take the pin out at the ecu and ground it, then go to the injector connector and then do the light test.
If you have a multi-meter, you can just touch the pin at the ecu with one lead, and then the ground pin on the injector connector with the other pin and it will beep if the wire is good on continuity mode.
You need to do this test, because if its the wire thats bad no amount of ecu's are going to fix the problem.
Last edited by Ali SC3; 03-23-13 at 01:51 PM.