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Limp mode

posted 8 Sep 2012, 16:05 by Robert Crane   [ updated 8 Sep 2012, 16:07 ]
Took the vehicle out again today with plans for a similar run as last week when the non starting issues emerged. That ended up being a user error so it would be interesting to see what happened today.

Pull over, open the filler cap, fueled without issue. Started feeling good that perhaps this would be the first day without "issues" but that euphoria was soon dashed. A matter of moments after getting back onto the road the "1/4 Slow Down" light started to flicker again. Surely not? It seemed to follow it usual sequence of flickering, going on and then disappearing from the dash. However, this time the power did not return and the car suffered dramatic power loss as it went into "limp mode". My understanding is that in this mode cylinders 1-4 get shut down to prevent the catalytic convert from overheating. That leaves you running on only cylinders 5-8.

That 50% loss of power makes a big difference to the performance of the car and you need to adjust the way you drive it accordingly. My thoughts were the issue would resolve itself as it had in past but unfortunately I was wrong. The loss of power continued driving along the freeway. Ok, time to turn around and head back home with my tail between my legs again.

After parking the vehicle I checked the engine to see if there were any signs of overheating, especially around the catalytic converters but there was none. That doesn't mean they aren't the problem but you get the feeling that it is a faulty thermocouple sensor. I suppose I could have stopped the car, turned the engine off, waited a little while and then fired it back up to see if the car would come out of limp mode but my biggest fear was not being able to get it home again so continuing on seemed the best option.

Oh what fun!
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