Sudden temporary loss of engine power


#1

Hi, I searched for this problem on the internet but couldn’t find exactly the same situation so I thought I’d ask it here.

The situation is: while driving on the highway, the engine suddenly lost acceleration. The engine was still making engine sounds, electronics were on. It just couldn’t pull the 120kmph I was driving, the RPM slowly went down (with the gas pedal to the floor) and the car decelerated to 100-90 in 5-10 seconds and then I pulled over.

After 5-10 minutes waiting, I tried driving again and the car drove fine, went to 120kmph and beyond, as usual. But then 15 minutes later, the same thing happened. After waiting, it drove fine.

Other details:

  • car is diesel from 2006. Last maintenance was 10k km ago.
  • I drove through a very heavy rain right before it first happened.
  • A few month back, when it was colder, there would be thick white and stinky clouds coming from the exhaust when the engine was started from cold state. Those would disappear in a couple of minutes.
  • sometimes when I turn the key to start the car, it makes a strange, “zippy” noise and doesn’t start. On the next try it does.

What do you think it can be? I’ve read about clogged air filters and exhaust (there is no smell, I can’t even see smoke when I start the car), ignition problems, fuel pump problems. Could the rain have had anything to do with it?


#2

Your fourth bullet point sounds like a failing overrunning clutch within the starter. You could either proactively replace the starter now, or wait until it fails completely, at which point the car won’t start. I’ll leave your other questions to those that have more experience with diesels than I do ( which is almost everyone ).


#3

The loss of power, I’m guessing OP’s speculation is correct, some sort of exhaust restriction. Cat, muffler, bent exhaust pipe, etc. There’s stuff inside failing mufflers and cats that can move around, so they work fine for a while, then later shift & move into a position where they are clogging the exhaust stream. Sometimes a shop can simply remove the pre-cat O2 sensor as a test (if your diesel engine uses one), which allows the exhaust gasses a new path to exit. If that solves the problem, major clue.


#4

The only thing you’ve told us about the car is that it is a 2004 diesel maintained 10km ago. What make and model of vehicle? Which diesel engine? How many miles on it?


#5

the smoke when cold and it being a diesel makes me think your glow plugs are shot. If your glow plugs are shot, that will make for extended crank times when cold- wearing out your starter which could explain the “zippy” noise.
Could be multiple things going on here, but we’re going to need more info on our car to make any kind of guess.