I came off the motorway to a slip road, slowing down to 20mph and about to turn when I saw smoke coming from my engine bay. Then all the lights on my dashboard (not just warning but all of them) starts blinking and without pressing the brakes, my car starts shutting down and coming to a halt. Good thing this wasn't on the motorway.

Popped the hood and smoke was coming from the left side (passenger side - am in the UK by the way). There was smell close to the alternator which I found out was melted tape that has been heated up. Left car to cool for 2hrs. Check the engine bay and nothing seemed out of the ordinary. Slide key in, turned on but not starting the car just yet. All seem good on the dash. Tried to start it but all it did was crank. Bought spark plugs and battery but it was the same result. Towed to mechanic, who said it was cat converter when I cranked it in his presence. Tow truck guy even sprayed something, cant remember the name but I think it was an oxygen spray into the air hose but still nothing

Before I start buying a new one and having him on it, just wanted to get a second opinion

  • Welcome to Motor Vehicle Maintenance & Repair! First of all, can you edit your question and put in the year/make/model/engine/transmission information for the vehicle in question? From your description, I don't hear anything you've said as pointing to the cat converter. The tow truck driver was probably spraying some kind of starting fluid in it to see if the problem was fuel (or lack there of) related. Jul 29, 2020 at 21:23
  • I agree with Paulster2 that nothing so far points to the cat. More diagnosis is needed; don't just go replacing (expensive!) parts. What's the make and model of the vehicle? If the car has an OBD port (most since the mid-90s do), get the codes read to see what the car thinks is wrong. Because it didn't fire when the tow truck guy sprayed whatever into the intake, I think the car has an electrical problem that's preventing the spark plugs from firing. Jul 29, 2020 at 21:32

1 Answer 1


The alternator must be tested. The melted tape suggests a short circuit, which likely fried the alternator. Check for exposed/corroded/damaged wires that could be the root cause of the short circuit before starting the car with any replacement alternator.

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