CHT Sensor - Chalky substance

[mray2686]

Been having an issue with my '86 3.2 after running for long periods of time. Symptoms would be loss of power, surging, and backfire intermittently.

Over the past few months I've replaced DME relay, plugs, ignition wires, distributor cap, rotor and speed & reference sensors. Thought the issue was solved until it happened again 5-6 hrs. into a rally. DME was sent off and came back with a clean bill of health.

Fast forward to today, after more research I was left with a CHT sensor and coil still not touched. I've replaced the CHT sensor, mine I believe was original as it was a single wire unit. What interested me was the head of the removed sensor. It has this chalky like substance to it. Wondering if that possibly was the failure point or if that is normal after pulling from the car.

Either way, car started up and ran great for the test drive this morning. I need to get more time and miles on the car to ensure it doesn't happen again before the fall rally drives get started. Coil next on the list if the issue persists, but hoping that is not the case given how hard it is to find good coils these days.

Curious if you've seen something like this before?

[dannobee]

It's anti-seize. It's not your problem. The thermistor is inside the case.

Normal resistance at room temperature is around 1500 ohms, and the hotter she gets, the less resistance she has. Check there, first.

[dannobee]

One more thing, there's a bulletin to update the single wire sensor to the sensor with two wires, for a better path to ground.

[john walker's workshop]

The old single wire unit grounds to the head, so any crap on the threads isn't good.

[mray2686]

Yep, new unit is dual wire. Plug and play, hopefully takes care of my issue.