I was on a short test drive in my '91 Civic DX (stock DPFI, auto trans) when the CEL light came on and a few moments later and the engine progressively began to loose power whith the temperature gauge rising. I limped the car home and there was considerable smoke coming from the engine compartment, so I left the hood open to allow it cool down. The ECU is throwing code 4. I have recently replaced the water pump and timing belt, as well as valve stem seals and related parts to repair a blown head gasket. There is no evidence of coolant loss nor smoke emanating from the exhaust. I drove the car well over 50 miles on my first test drive, a couple of days ago, and the engine ran fine. The Haynes manual says code 4 applies to the crank angle sensor which, I assume, is in the distributor?

As usual, your comments, observations and suggestions are greatly appreciated.

 

yep that sensor is inside the distributor. when mine died i also saw smoke come up from under the hood. i'd bet it's the dizzy.