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ETC reading

posted May 20, 2016 14:27:01 by u-johansson
I have done voltage check on a ETC and readings on 5 volt reference wire is 5 volt unplugged and 1,5 V cold and hot it is 450mv ground wire is 0,028V ground lead on multimeter is connected to battery ground. I guess it is voltage drop I am reading on the 5V reference wire and I guess the cold reading is to low and hot engine in spec.
The car is a Audi 100 1988 1,8 litre and problem is to much HC and sooty spark plugs.
New 02 sensor. It is a TBI Bosch type injection and has no MAP or MAF only TPS that calculate air intake. TPS has two pot and no glitch one is from 2-5V and second pot is 0-5V.
Question is if I am measured the ETC the right way and the problem is in the ETC.
[Last edited May 20, 2016 14:28:59]
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3 replies
Inge_Jeppesen said May 20, 2016 14:58:50
You have measured the right way. It would seem to high when cold. Should be closer to 4 volts. But since the ECT show normal when hot then the HC should also normal out when engine is warm. What are your other exhaust values?

Cold and warm.

u-johansson said May 20, 2016 16:05:57
I try to find the smog paper the car has been sitting for 2 years the test result on the smog test maybe in the trash. Bosch calls this fuel injection monojettronic.
[Last edited May 20, 2016 16:09:00]
u-johansson said May 21, 2016 07:24:57
I got the inspection paper from the owner and on old car there is only CO and CO is 8,3 and upper limit to pass is 3,5 (CO).
Checked the ETC and IAT this morning when the engine is cold and IAT inside throttle body was 2,6 V and ECT 2,5 V KOEO. The car has 2 more sensor on coolant but I guess this one must be the ECT because it match the IAT sensor when cold engine.
I upload the TPS waveform but the fix will be to change the hole throttle body since there is no parts to buy separately. The car starts fine cold and warm so I guess there is no leaking injector, to bad I did not measured the pulse width for the injector.
Engine oil and filter is new too.
[Last edited May 21, 2016 07:31:51]
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