I was watching Dr 914s walkaround of a D Jet 2.0 motor, and he makes a comment that the Cylinder Head Temp sensor causes a lot of problems, and can get wonky.

Is it possible for one to test out fine (2750 ohms) and then act bad? I have a strange syndrome where the car was running fine, but developed a rich syndrome very suddenly. Haven't had a chance to check it again, but it was almost new.

TIA

Rob

Yes. They don't have good stress relief. Intermittent shorting between lead and ground is possible. Likewise because of lack of stress relief, it's possible to have the copper conductor break, and result in an intermittent open which will lead to rich condition.

but in 12 years of having a d-jet car i have see the suddenly or even intermittently rich issue tied to a MPS issue more than a bad CHT

recheck the MPS,

Phil

MPS freshly rebuilt professionally

@Robson51 Absolutely! I was just a victim to this heinous crime. $20 part can ruin an otherwise wonderful car I was randomly going VERY rich and huge bogging issues. Tested fine then tested WAY off spec the next time. Easy to test but test a few times.

Might check the CHT wire to the ECU also. Do you have a known good MAP to cross check? Or carry an ohm meter to check the sensor output next time it gives up the Ghost. These type headaches are why I converted to water cooled. GL

I had one go out intermittently. usually if it goes "open" the engine will quit. The ECU needs to see some resistance.
Mine went rich because I was running a 1 k parallel resistor, so it was reading as if it was still cold. But better than sticking me on the highway, made it home and put a new one in.

I gave up water pumpers due to coolant leakage.