Car is blowing out a lot of smoke and stalling out. Why is the car doing this?

Asked by Jun 07, 2012 at 07:03 PM about the 1978 Datsun 280Z

Question type: Maintenance & Repair

I have a 1978 Datsun 280Z.  The car was running fine and perfect and one day it stalled on me and would not start back up.  I changed the fuel pump and the fuel filter.  The car now starts, but is blowing out a lot of smoke and it smells like fuel.  If I drive it, it stalls and will not pass 10 miles per hour along with a cloud of smoke behind me that looks like I am fumigating.  What could be the problem and how do I fix this.

5 Answers


what color is the smoke? White=coolant (head gasket or craked something) Blue=oil (valve seals/piston rings) black/brown=running rich

6 people found this helpful.

sounds like it is dumping too much fuel. focus on the thigns that affect air/fuel mixture

ECU controls rich/lean. ECU gets info from water temp sending unit. Some blocks have an additional block temp sending unit (same part, 2 different locations). Also check you air control unit that sits on top of engine toward drivers side and has an air hose connecting the front and rear of it.


I had the exact same symptom. Found that the Water Temperature Sensor failed with an open circuit. When this sensor fails it tells the ECU to add more fuel because it thinks the engine it is super cold such as 30 degrees. To test, with engine off I removed the elect connection and jump the connector with a paper clip. This tells the ECU that the engine is warm and does not need any extra fuel. I then attempted to start car, it fired up and ran perfectly. I shut off engine and replaced the fault sensor. Car is now running great!

3 people found this helpful.

Paper clip test worked for me. Z smoked and barely ran, I jumped the water temperature circuit in the illustration and hallelujah! No smoke and running fine.

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