engine lumpy when started after heavy rain overnight

[bobincharente]

The engine is lumpy when started after heavy rain, it has happened twice in the last 6 months. If it was a petrol it feels like a spark plug was not firing.
The problem goes away after revving the engine to about 3,000 rpm a couple of times and is then OK. Has anyone any ideas as to what would cause this ?

Thanks in advance
Bob

 

[LostKiwi]

Sounds like condensation is getting somewhere perhaps. Incidentally you're about an hour east of our French house.

 

[ioweddie]

Give the leads a dose of WD40 where they clip into the spark plugs

 

[Wighty]

I wonder if when the engine is dry and trouble free , spraying it all with something like acf50 or similar to lock any future water out ?

 

[Frontstep]

My diesel runs better when its raining, apart from very obvious leak of water into something I would look elsewhere for the lumpy start.

 

[umblecumbuz]

Give the leads a dose of WD40 where they clip into the spark plugs

Bit difficult with a diesel.
Sounds either like damp on the electrics or water getting into the air intake. Both remote, but the scant symptoms you've described point that way.

 

[Oldspanners]

Check that all the drains from around the front of the windscreen/wiper arm/bonnet hinge area are clear as these get easily bocked with leaves etc. and can overflow into the fuse box on some models and cause havoc. They should run clear and easily allowing no build up of water you may need to take a bit of time and probe them gently to unblock completely.
With the rain we been having lately it won't take much to restrict the flow.

 

[ioweddie]

Bit difficult with a diesel.
Sounds either like damp on the electrics or water getting into the air intake. Both remote, but the scant symptoms you've described point that way.

Ooooops! Misread the post I thought it was petrol Sorry!

 

[bobincharente]

Update - Problem solved

As it is not raining today I have investigated the problem and found that the drain in the centre of the windscreen was almost completely blocked by an insects nest underneath the grill. Spent 30 minutes poking the grill out with a nail then reverse flushed the pipe and a mass of paper-like bits came out. All ok now water runs away quickly.

Thanks for everyone's suggestions

Bob

 

[Oldspanners]

Update - Problem solved

As it is not raining today I have investigated the problem and found that the drain in the centre of the windscreen was almost completely blocked by an insects nest underneath the grill. Spent 30 minutes poking the grill out with a nail then reverse flushed the pipe and a mass of paper-like bits came out. All ok now water runs away quickly.

Thanks for everyone's suggestions

Bob

Check around where the water overflowed into because the electrics will have got water where they are not supposed to and it will need to be dried properly and cleaned otherwise you are just storing up problems for later when corrosion sets in.