Dieseling for a second or two after turning it off

PIERREC

MEMBER
2002 OPEL CORSA
1.4L
4 CYL
2WD
MANUAL
94,000 MILES

Corsa B - Engine "runs on" (dieseling) for a second or two after switching it off. The car is old but in good condition with low mileage. Opel 1.4 4 cylinder multi-point fuel injection engine is as smooth as a song and pulls and accelerates well. In theory it should not run-on. I have done an "engine clean" with a decarbonizing agent, and have also used an injector cleaner.

I am at a loss what to do next.

1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

We need to start with checking the fuel pressure. It could be a leaking injector but if may only be leaking because the regulator is over pressurizing the system.

We don't have a manual on this vehicle as it is not offered here in the USA but the theory is the same.

Here is a guide that helps with checking pressure:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

The only way it can run on like you are saying for a second or two is if there is unburned fuel in the camber and it is hot enough to ignite it when it is compressed.

Can you get a video of this happening and we can confirm this is actually run on and not just the engine shutting down? Also, does it do it every time or only when it gets hot?

Let's start with this and we can go from there. Thanks