EGT failure

[billman]

Hi, i have a problem there since my EGT in MT moves constantly from 0 to 1125 and then back again. Sensor seems fine on the multimeter and is new!

What can it be?

[mattias]

Disconnect the sensor and short the wires in the EGT input  connector at the ECU and make sure it reads room temperature. If it still misbehaves there is something either with the connector or within the ECU that is not alright.

[billman]

Sensor connected or not no change. With ignition on I see only 0 with engine running even with no sensor connected at all I see 0-1125-0-1125 etc

[mattias]

How about that short-circuit test? Just bridge  +/- on the input connector with a short piece of wire and tell us what you see.

[billman]

I did that and nothing changed! :-(

[[email protected]]

What you're exhibiting is consistent with an open circuit - could the wire be damaged?

[billman]

It was working, i did an engine swap (nothing changed at the ECU) i started it up and EGT is not working. I remove the sensor and install a new one (6mm) again no change. I checked both connectors and i see no fault there except the wire damage is inside.

[[email protected]]

It seems possible that the wire or the EGT chip is damaged then.
If the engine earths weren't 100% its possible that the EGT provided an earthing path.

[billman]

it was the mcp3208

[[email protected]]

How did it manage to hurt that?!?

[billman]

I have no clue. I first changed the ad and nothing happened. Then the other and it worked straight away.