Throttle no reset, Lambda control and poor running
Discussion
I thought I share the findings with my LHD conversion Tuscan Mk 1 running on a later ECU (three connectors) and 4-wire Lambda.
Before putting the body back on I had all the wiring installed to check the engine out carefully, mainly for leaks or other issues which might appear when using an unknown engine bought years ago out of an accident damaged car.
After fuel pressure checks shown all normal values at around 3,5 bar I tried starting it and hey, it fired straight away, running for some minutes and than started with poor running. Throttle balancing was managed in time but the throttle position sensors showed high numbers and wouldnˋt reset with EvoOli‘s tool. Checking for the 5 Volt Feed at TPS and resistance values all seemed normal but running was really bad with misfires and it needed some throttle opening now to stop it from stalling.
Being a bit confused I went to this forum and found no real answer but the hint for the Lambda earthing modification. Checking with the Voltmeter the wiring of the earthing in the engine loom of the Lambda sensors revealed they were not connected to earth as suggested by the Speed 6 engine wiring loom but to the ECU Pin called SigRtn. Resistance of the Lambda heater was measured at 6.4Ohm so current around 2 Amps per sensor seemed quite a high load for this single thin wire which should ground also all the sensor signal paths.
Disconnecting the Lambda made the TPS work again, reset no issue any longer and engine recovered to smooth running.
Now to the Lambda mod, pretty simple as described: just cut the heater (!) grounds and connect them up to a good earthing point, I did choose a stud on the chassis. Another start and everything was working perfectly fine.
So thanks to the guys here supporting with this useful information, the Lambda mod seems to be a must....although my Tamora is still good without. I will measure the heater resistance on this car, the only idea I have is the replacement sensors I am using on my project are simply drawing much more current. Will see and let you know.
Before putting the body back on I had all the wiring installed to check the engine out carefully, mainly for leaks or other issues which might appear when using an unknown engine bought years ago out of an accident damaged car.
After fuel pressure checks shown all normal values at around 3,5 bar I tried starting it and hey, it fired straight away, running for some minutes and than started with poor running. Throttle balancing was managed in time but the throttle position sensors showed high numbers and wouldnˋt reset with EvoOli‘s tool. Checking for the 5 Volt Feed at TPS and resistance values all seemed normal but running was really bad with misfires and it needed some throttle opening now to stop it from stalling.
Being a bit confused I went to this forum and found no real answer but the hint for the Lambda earthing modification. Checking with the Voltmeter the wiring of the earthing in the engine loom of the Lambda sensors revealed they were not connected to earth as suggested by the Speed 6 engine wiring loom but to the ECU Pin called SigRtn. Resistance of the Lambda heater was measured at 6.4Ohm so current around 2 Amps per sensor seemed quite a high load for this single thin wire which should ground also all the sensor signal paths.
Disconnecting the Lambda made the TPS work again, reset no issue any longer and engine recovered to smooth running.
Now to the Lambda mod, pretty simple as described: just cut the heater (!) grounds and connect them up to a good earthing point, I did choose a stud on the chassis. Another start and everything was working perfectly fine.
So thanks to the guys here supporting with this useful information, the Lambda mod seems to be a must....although my Tamora is still good without. I will measure the heater resistance on this car, the only idea I have is the replacement sensors I am using on my project are simply drawing much more current. Will see and let you know.
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