1JZ Idle issues - weird ISCV behaviour.

[Aether]

Okies, just got back in from checking the T13 piggyback harness and need to clear up some confusion I had...sorry if I led down the garden path...

It seems the T13 harness is only intercepting the signals for the injector, ignition and map/airflow sensor pins. These are hardwired to go through the EMU first and then onto the ECU. The speed signal wire is currently set to go directly to the ECU, but is able to be intercepted to go to the EMU first and then onto the ECU. Every other signal goes directly from the connector to the ECU and is not being intercepted by the EMU. The length of the wiring added to these pins is very short, less than 15cm, so don't think it would be causing any changes in resistance that would affect it. I noticed that the EMU has only one earth wire going to it, which is currently connect to E (Ground), the ECU also has another pin being E# (Sensor Ground), no sure which one of these I should be using as the earth for the EMU.

Pic below of the harness and how it is wired up:

[bk_]

Two things remain:
* what does Emanage software report for ECT,IAT,MAP,TPS(% or voltage)? Do the numbers look ok?
* Toyota OEM ECU error codes

Right now we don't know what the OEM ECU thinks is happening.

Many many years ago, I custom-made a Toyota OBD1 reader/LCD display unit. This might help?

[Aether]

Hey, sorry for the late reply, but haven't had much time to work on the car...got out for a few minutes tonight to do some quick checks to make sure ECU is getting sensor data (with EMU T13 plug and play harness connected), ambient temp approx 25 degrees Celsius:

- Continuity from CTS sensor wires to ECU - Confirmed.
- Resistance of CTS Sensor terminals with connector unplugged - 1.988kohms.
- Resistance of CTS pins using THW and E2 (Sensor Ground) - 1.156kohms.

- Continuity from IAT sensor wires to ECU.
- Resistance of IAT sensor terminals with connector unplugged - 2.045kohms.
- Resistance of ECU pins using THA and E2 (Sensor Ground) - 1.173kohms.

I currently have the Throttle Body of so can't capture any logs from the EMU to see what it reads for the IAT/THW/MAP/TPS, but I remember looking at the logs from a few months back when I had the idle issue and they seemed to be ok...as soon as the TB is back on I will get some further logs and post here.

I know there is the diagnostic test on the ECU that can be run, but it only does ECT/EFI/ABS/TRC/SUS and I think one more...is the ECU able to show errors for things like CTS and IAT Sensors?

Awesome ODB-1 reader you made, was that a kit purchased from somewhere or personally made...at the end of the day I would gather that the EMU would see exactly what the ECU would be seeing seeming, so would have those details in the logs?

[Aether]

Just worked out the diagnostics as well, not sure if they are valid or not, so will need to get the TB back in, reset the ECU and take it fr a drive and see what the diagnostics show...

[bk_]

2000 ohms sounds about right for 25C (20C: 2300 ohms, 30C: 1650 ohms)

error code 22 - water temp sensor circuit failure
error code 24 - intake temp sensor circuit failure
error code 41 - TPS circuit failure
error code 47 - TPS switch failure(??)

Another thing - usually this happens on the JZA70/JZX81 ECUs more than the JZZ30/JZX90 - have you checked capacitors on the PCB for leakage or failure?

I built the OBD-1 reader as a once-off project. I didn't reverse engineer the flags - so I wouldn't know if it had flags for CTS/IAT or not.

[Aether]

Hey bk_, just got the throttle body back in and ran the diagnostics test...got the following errors:

ABS 71,72,73,74,75,76,77,78
SUS 21,22,51
TRC 49,24,48

A lot of sensor errors, I read somewhere last night that if the ECU sensor ground is faulty, you can get multiple sensor errors like I have above, is that true?
I believe the ABS errors are due to the car not being driven...and read that they can be ignored.

As confirmed all sensors have connectivity to the ECU and resistances are in the post prior. Also when I changed the CAT, I had to remove the old sensor which connects to it, and just left it tied away under the car...is this a problem?

Also in regards to the ECU Caps, I have two ECUs, one stock and one where I have had the Caps already changed...

Thanks,

[Aether]

UPDATE: reset the ECU, checked the diagnostics, following errors were recorded:

ABS 71,72,73,74,75,76,77,78
SUS 21,22,51
TRC OK

Went for a 5 min drive around the block, came back and the only errors recorded were:

SUS 21,22

ABS OK
TRC OK

Noticed thou that the car is not holding idle at all now, take the foot of the accelerator and it stalls. Adjusted the TPS today and everything is in SPEC...

By the way, the CTS is new, although it was not a genuine Toyota but an aftermarket one which was advertised as being the one for the Soarer.

[Aether]

Just measured temp sensor resistance at ECU after a 20 min drive and the resistance measured between THW and E2 is 155 ohms ~ 90 degrees...so it seems as thou the resistance is correct from the CTS sensor and is reaching the ECU.

Changed the ECU with another one I have, checked error codes, exactly the same error codes as above...grrrrr...any ideas?

[dumbass]

For fk sake throw the emanage in the fking bin
I've never seen one work properly for longer than afew weeks

Anyway with all those codes seems like u have a sensor ground issues

Disconnect battery for five minutes then reconnect then road test
Then recheck codes again
If they come up the same check sensor ground

[bk_]

fail safe condition:
DTC 22: THW fixed at 80C
DTC 24: THA fixed at 20C

No idea about DTC codes 51, 48, 49.

What's the engine from? you haven't said. it could be 1992 JZX90.. Or could be 1997 JZX100 or even JZZ30.

How is the wiring done? Engine transplant?

[Aether]

Heard that the emanage is not the best but ain't in a position to spend big bucks on a new aftermarket computer and have it go through the tuner's again...maybe in the future...

bt_, engine is from a Toyota Soarer JZZ30, engine came out of the car for respray and went back in as is, no wiring mods were done apart from the aftermarket EMU.

The TRC errors are now gone, no 48,49,24 error codes anymore, so it seems the THA and TPS/TRC are all fine now...don't think it is the Sensor Ground no more, as the TPS/TRC/MAP/THA/THW all run off the same sensor ground and they seem to be working fine now...

Only 21,22,51 exist, interesting thing I found is:

51 Switch Condition Signal

3 sec. or more after engine starts, with closed throttle position switch OFF (IDL1).
Park/neutral position switch: OF (Shift position in "R", "D", "2", or "L" position)
A/C switch ON.

Seems as thou error 51 has something to do with the IDL signal...I am sourcing another throttle body tomorrow with all sensors set from factory...see if that makes any difference to Error 51, as for CTS sensor error I have no idea. Looking at temp graphs for the sensor, the resistance changes which indicates to me that the sensor is working fine, but you are right in that it seems to be in a fail safe mode at 80C, error code 21 is for:

21 Main Heated Oxygen Sensor Signal

Main heated oxygen sensor signal voltage is reduced to between 0.35V and 0.70V for 60 sec. under condition

a) ~ (d). (2 trip detection logic)

a). Engine coolant temp.: Between 80° C (176°F) and 95°C (203°F)
b). Engine speed: 1,500 rpm or more
c). Load driving (EX. A/T in overdrive (5th for M/T), A/C ON, Flat road, 50 mph <80 km/h>)
d). Main heated oxygen sensor signal voltage: Alternating above and below 0.45 V.

[bk_]

TRC? You have a TRC throttle body?

I dont remember JZZ30 coming out with TRC from factory.

[Aether]

Sure do, pic attached

20131204_232216.jpg

[Aether]

Update: Took my ECUs to another guys house and tried them in his car and no error codes where returned...we did not start the car thou, just plugged the ECU in and turned the ignition on in diagnostics mode...and let the test run.

Placed the ECU back into my car, and checked voltages on the ECU pins with the loom connected:

VCC-E2 = 4.94V

IDL1-E2 = 0.6V fully closed
IDL1-E2 = 12.7V fully open

IDL2-E2 = 0.6V fully open
IDL2-E2 = 12.7V fully closed

VTA1-E2 = .6V fully closed
VTA1-E2 = 3.6V fully open

VTA2-E2 = .6V fully open
VTA2-E2 = 3.6V fully closed

THA-E2 = 1.12V @90C approx

WTH-E2 = 0.3V @90C approx

All the voltages above match exactly what is in the troubleshooting guide for the 1JZ...this is just doing my head in...the ECU is seeing what it is meant to be seeing, so why the hell is it failing to cold start and still throwing error codes 21 & 22...?

All test were done with E2 (Sensor Ground), so the ECU ground is not the issue...it seems.

[Daddio]

err...how will the ecu obtain any codes without a start and run? Doesn't the TSRM suggests a 2 trip detection logic?