1JZ SC300 will not rev past 2000 rpm STILL!
10-30-13, 06:15 AM
#62
Lead Lap
Thread Starter
So we checked everything over again. MAP and Ignitor connectors look fine. Mike is saying the engine harness needs to be replaced. I am reluctant to do so because he pulled it apart and checked it over and said everything looked fine. He Ohm tested it as well. So far I have spent almost 2 grand throwing parts at the problem, enough to buy a new engine. The only thing we have not replaced is the engine and the engine harness.
He wants me to buy a brand new harness from Tweak'd performance but two things make me nervous.
1. he said he is 50% sure its the harness. $1,000 is a lot for 50% certainty.
2. I wouldn't mind spending $1,000 on a brand new harness but I don't know specifically if the harness is 100% new.
So I sent Tweak'd this email. Hopefully they get back to me.
If anyone has dealt with this company or their product please tell me what you think. Also if anyone has anything they think could be the problem aside from the harness shout it out before I spend $1,000 on a 50/50!!
He wants me to buy a brand new harness from Tweak'd performance but two things make me nervous.
1. he said he is 50% sure its the harness. $1,000 is a lot for 50% certainty.
2. I wouldn't mind spending $1,000 on a brand new harness but I don't know specifically if the harness is 100% new.
So I sent Tweak'd this email. Hopefully they get back to me.
Hi, I'm trying to determine if I need to buy a brand new engine harness from you. At this point I have tried everything but replacing the harness. I have a 92 SC300 oem 5 speed with a 1JZ pulled from a manual soarer. Both are 1992. I had the swap running and driving for a year when I crashed and had to re-shell. After I got the swap running in the new shell a wire in the body harness was damaged and arched on some metal in the wheel well. From then on the engine would not rev over 2,000 RPM.
I bought another running and driving 92 SC300 OEM 5 speed and put the engine in with the same issues. So I took it to a shop and they took the harness apart and checked over the wires and ohmed them as well. They told me it was fine and continued to trouble shoot. 8 months and quite a lot of money and parts later they think it's the harness.
This is a list of new parts we have tried:
1. ECU x3
2. Injectors
3. Fuel rail
4. FPR x3
5. Fuel Pump x2
6. Fuel Filter
7. Igniter
8. Timing checked twice
9. New timing belt tensioner
10. Coil packs
11. Spark plugs
12. Fuel
13. Crank Sensor
14. Knock Sensors
15. Cam sensors
16. Coolant temp sensor (ecu)
17. spot welded crank trigger wheel
18. Coil pack connecters
19. Fuel Dampener Bypass
20. Fuel Pump ECU x3
21. Fuel Pump bypass 12v constant modification
22. Ice Cream
At this point the only thing we have not changed is the wiring harness. The car will not rev above 2,000 rpm, the fuel pump runs as long as the battery is connected, we have double checked and triple checked pinouts to make sure the wiring is correct (even though it has not changed since the engine last ran successfully), and the engine floods. Let me know your thoughts please. I am just afraid to spend $1,000 without being sure that this is the issue especially after spending so much money already.
I bought another running and driving 92 SC300 OEM 5 speed and put the engine in with the same issues. So I took it to a shop and they took the harness apart and checked over the wires and ohmed them as well. They told me it was fine and continued to trouble shoot. 8 months and quite a lot of money and parts later they think it's the harness.
This is a list of new parts we have tried:
1. ECU x3
2. Injectors
3. Fuel rail
4. FPR x3
5. Fuel Pump x2
6. Fuel Filter
7. Igniter
8. Timing checked twice
9. New timing belt tensioner
10. Coil packs
11. Spark plugs
12. Fuel
13. Crank Sensor
14. Knock Sensors
15. Cam sensors
16. Coolant temp sensor (ecu)
17. spot welded crank trigger wheel
18. Coil pack connecters
19. Fuel Dampener Bypass
20. Fuel Pump ECU x3
21. Fuel Pump bypass 12v constant modification
22. Ice Cream
At this point the only thing we have not changed is the wiring harness. The car will not rev above 2,000 rpm, the fuel pump runs as long as the battery is connected, we have double checked and triple checked pinouts to make sure the wiring is correct (even though it has not changed since the engine last ran successfully), and the engine floods. Let me know your thoughts please. I am just afraid to spend $1,000 without being sure that this is the issue especially after spending so much money already.
Last edited by OBEEWON; 10-30-13 at 06:21 AM.
10-30-13, 10:12 PM
#64
1000.00?? Wow the price of his harness has definitely gone up! He built a harness for my brother's 1jz mk3 a few years ago for 600.00 bucks. He does great work, excellent actually. But the few times that my brother dealt with him, he was a ****.
11-18-13, 01:16 PM
#67
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11-20-13, 11:31 AM
#69
Lead Lap
Thread Starter
SO!!!! I sent the harness out to Tweaked Performance. They took it apart and checked it thoroughly aaaannnndd.....
They found nothing wrong with it.
They suggested we eliminate the traction control wiring altogether though. In other news I lent my ECU to another shop who was trouble shooting a 1JZ car and my ECU solved their issue (they were having the same issues as me). I’m 100% lost.
They found nothing wrong with it.
They suggested we eliminate the traction control wiring altogether though. In other news I lent my ECU to another shop who was trouble shooting a 1JZ car and my ECU solved their issue (they were having the same issues as me). I’m 100% lost.
11-20-13, 11:43 AM
#70
Awwwww man. I was hoping they would get you straight. Have you tried adding a dedicated ground (or two) from engine to chassis? Did you sand the harness ground points on the intake?
Also, you can pop your drivers side valve cover and verify that the cam triggers are still intact and not broken off. Check the air gaps on the crank, and both cam sensors to be sure there is nothing creating an excessive gap.
Sorry you still have no resolution on this man.
Also, you can pop your drivers side valve cover and verify that the cam triggers are still intact and not broken off. Check the air gaps on the crank, and both cam sensors to be sure there is nothing creating an excessive gap.
Sorry you still have no resolution on this man.
11-21-13, 06:10 AM
#72
Lead Lap
Thread Starter
Awwwww man. I was hoping they would get you straight. Have you tried adding a dedicated ground (or two) from engine to chassis? Did you sand the harness ground points on the intake?
Also, you can pop your drivers side valve cover and verify that the cam triggers are still intact and not broken off. Check the air gaps on the crank, and both cam sensors to be sure there is nothing creating an excessive gap.
Sorry you still have no resolution on this man.
Also, you can pop your drivers side valve cover and verify that the cam triggers are still intact and not broken off. Check the air gaps on the crank, and both cam sensors to be sure there is nothing creating an excessive gap.
Sorry you still have no resolution on this man.
Last I saw it was still flooding. We unplugged injectors one at a time which is how we found two leaky ones. Swapped them all out and it ran ok for a bit then back to floody.
11-21-13, 07:37 AM
#73
thats definitely not right. maybe check the injectors again, its possible something is making them go bad. possibly a bad injector resistor box? I wonder if those have ever gone bad on anyone before. maybe hit the resistor box with a multimeter and check the resistance of all 6 resistors.
11-21-13, 09:07 AM
#74
No resistor box on 1jzs unless he added one to run Low-Z injectors. Obeewon, the air gap I am talking about is the distance between the cam/crank sensors and the trigger itself. In the case of the crank, it is the star wheel. On the cam sensors, there are little "****" on the cam that pass by the sensors to trigger them. Make sure the **** are still on the cams and in good shape. Although it is very unlikely, maybe one was damaged and you are losing that cam trigger signal.
Hehe..I said ****
Hehe..I said ****