Took the car out for a 1st run tonight to see what it could do. Was quite peppy and starts, runs fine. Took it out on a highway to see the spool and torque at higher RPM.... The engine will not go over 4000 RPM. Just seems to die out like someone cut the electrical power or fuel. I disconnected the battery when I got home, so I will have to take it out again and give the ECU a chance to store and check codes. If any of the gurus have any other suggestions, they would be greatly appreciated.
IJZ MK3 Swap stumbles at 4000 rpm
- Thread starter Heggy
- Start date
Took it out for another run, it just does not want to go. Seems at about 4000 RPM it just starts to be stopped or limited by something. Checked ECU codes, the light flashes as though all is normal...... I wonder if the CAT is plugged.... I guess I'll have to take the pipes off again : )
A friend suggested that the N/A fuel pump may not be able to supply enough pressure, the P/N are the same for aftermarket so I don't think that is the issue... Also he suggested that the pump resistor circuit may be energized. I guess I can check, but the ECU controls that, so I don't know why it would command the fuel pump relay to close at high RPM...?
A friend suggested that the N/A fuel pump may not be able to supply enough pressure, the P/N are the same for aftermarket so I don't think that is the issue... Also he suggested that the pump resistor circuit may be energized. I guess I can check, but the ECU controls that, so I don't know why it would command the fuel pump relay to close at high RPM...?
Na pumps are different.
7mgte had a fuel pump resistor. Try looking up the 12v mod.
Does the check engine light come on when it happens?
7mgte had a fuel pump resistor. Try looking up the 12v mod.
Does the check engine light come on when it happens?
If I look at Rock Auto, the pumps are the same. At least if I order one. I will check again and the resistor is something that is controlled by the ECU and just closes the fuel pump relay and routes the signal though a resistor. I will check the voltage and do the mod. No warning light, no codes. It seems to rev fine when not in gear.
http://www.cygnusx1.net/Supra/Library/EPC/291210/part.aspx?S=23220P the fuel pumps have different P/N's. The newer aftermarket pumps use the same P/N because they put the turbo pump in an N/A chassis now.
What are your plugs gapped to? What is the base timing set to?
Give us a run down of history for the car. Saying you got a 4k stumble with no added info is like pissing in the breeze. The more you give us, the better we can help you.
What are your plugs gapped to? What is the base timing set to?
Give us a run down of history for the car. Saying you got a 4k stumble with no added info is like pissing in the breeze. The more you give us, the better we can help you.
Sorry I guess there is little info:
Engine 1JZGTTE from ’90 JZA70 clip
Car MA70 ’87 N/A
Swapped, engine, ECU, tranny, driveshaft diff. Changed seals (front, rear, cam, valve, valve cover), clutch.
I did not check plug gap or timing as I did not change or adjust (checked condition of plugs during valve seal change, still serviceable).
The engine revved fine when I started it in the clip. It spools up when not in gear in the N/A.
Have not had time since yesterday to do any troubleshooting, will do some on Sat (next opportunity). I will do some voltage checks on the pump and I guess I may have to replace the pump if the voltage is good (i.e. not being dropped by the resistor). I may also check the CAT to make sure it is working OK.
Engine 1JZGTTE from ’90 JZA70 clip
Car MA70 ’87 N/A
Swapped, engine, ECU, tranny, driveshaft diff. Changed seals (front, rear, cam, valve, valve cover), clutch.
I did not check plug gap or timing as I did not change or adjust (checked condition of plugs during valve seal change, still serviceable).
The engine revved fine when I started it in the clip. It spools up when not in gear in the N/A.
Have not had time since yesterday to do any troubleshooting, will do some on Sat (next opportunity). I will do some voltage checks on the pump and I guess I may have to replace the pump if the voltage is good (i.e. not being dropped by the resistor). I may also check the CAT to make sure it is working OK.
Have not had much time to work on car lately, but I did try some things. Checked I/C connections, which were loose, tightened them all up. Checked fuel pump voltage, was 10 volts, took the connector off and bypassed the relay, now 14 volts. Still goes into limp mode at 4000. I'm beginning to think that it is wiring.
I still have some connections to do on my A/C and Hydro Fan is running at full speed. I've checked voltage and ground the rad temp sensor and hydraulic control on the pump, and all good. I noticed that there are wires that connect to the TPS, which I did not touch and are part of the harness. There are 2 wires that I'm not sure what to do with and it may be possible that this is causing the problem. There is a wire that goes to IH1 Pin 13 I'm not sure if it goes to LI PIN 8 to the AC amp...? And also the wire that shows going to the triple hi-lo press switch (looks like a normally open circuit so should not be a problem). These signals may impact the TPS and limit throttle for whatever reason.
I still have some connections to do on my A/C and Hydro Fan is running at full speed. I've checked voltage and ground the rad temp sensor and hydraulic control on the pump, and all good. I noticed that there are wires that connect to the TPS, which I did not touch and are part of the harness. There are 2 wires that I'm not sure what to do with and it may be possible that this is causing the problem. There is a wire that goes to IH1 Pin 13 I'm not sure if it goes to LI PIN 8 to the AC amp...? And also the wire that shows going to the triple hi-lo press switch (looks like a normally open circuit so should not be a problem). These signals may impact the TPS and limit throttle for whatever reason.
There are no codes and CEL does not come on. I am waiting for a boost press sensor to hopefully get my boost gauge working (It is clearing customs). Will be interesting to know whether there is boost or not. No AFR.
I just spent an hour looking thru posts on this site and there are quite a few similar problems and 2 exactly the same. Sad thing is there was no resolution posted 
http://www.supramania.com/forums/sh...-over-XXXX-Rpms/page2&highlight=1jz+limp+mode
http://www.supramania.com/forums/sh...-over-XXXX-Rpms/page2&highlight=1jz+limp+modeR154, Manual ECU. I really don't know if and when boost is coming in as there is no indication (yet). ]
When driving and fast or slow apply throttle, it zipps to 4000 and then just stays there. I've tried in the garage stationary and it seems to rev OK.
When driving and fast or slow apply throttle, it zipps to 4000 and then just stays there. I've tried in the garage stationary and it seems to rev OK.
Strange thing when I first start the car and accelerate, I can hear the turbo kick in a breath. It only does that the first time I start the car and go, after that it does not seem that the turbo(s) work. Is there something that controls them?
The twins run in parallel manually from the exhaust. You should get full boost before 4000 rpm with stock twins.
Which ECU and transmission are you running?
If your still running the NA exhaust it will restrict the 1J but you should still get boost.
Which ECU and transmission are you running?
If your still running the NA exhaust it will restrict the 1J but you should still get boost.
Standard ECU and R154. I decatted the CAT (thought it was blocked and it was not now it stinks) and although it is the stock exhaust (2.5") it should not stop the turbos from kicking in. How are the turbo's controlled? Is it mechanical or electronically controlled? It is kinda weird, first start up and they seem to come in, I can hear them pressurize the pipes and intercooler, after that they don't seem to work.....
now it stinks) and although it is the stock exhaust (2.5") it should not stop the turbos from kicking in. How are the turbo's controlled? Is it mechanical or electronically controlled? It is kinda weird, first start up and they seem to come in, I can hear them pressurize the pipes and intercooler, after that they don't seem to work.....Its possible they are damaged. You can at least check the play on the front turbo easily enough but to check the hot side blade condition the turbo has to come off. rear turbo is another story.
You can also remove the coupler at the throttle body and see how much pressure is coming out when you rev it up if you think there is no output.
You can also remove the coupler at the throttle body and see how much pressure is coming out when you rev it up if you think there is no output.