Water in petrol?

[TheJim]

My 2l 190e has been acting up. This time it has been cutting out on me.
It runs fine most of the time but then it will go through a phase of running really badly and then cutting out. Sometimes it starts straight afterwards. sometimes you have to leave it a while.

This behaviour has only started in the last couple of weeks, since I filled up at a particular petrol station. I don't think it could be crap in the fuel as it would block and then refuse to start wouldn't it? Someone suggested it might be water in the petrol.

Any thoughts?

n.b. The fuel filter and air filter are new and the fuel pump seems to be healthy. The plugs might be up for renewal.

 

[tom7035]

Is it only around engine tickover speeds the problem occurs or at higher revs?

 

[turnipsock]

Did this happen at the same time as the fuel and air filter were replaced.

I would run the car until the tank is nearly empty and fill up with petrol from a decent station. (You could alway run it till empty and fill up out of a can) that would eleminate the dodgy fuel scenario.

 

[TheJim]

It can start hunting at any revs, the filters were replaced about 3000 miles ago.

I have been chatting to some chaps about this, they have recommended trying injector cleaner. The thought being that the detergent will allow the water and petrol to mix and therefore pass through the engine with the next tank of petrol.

I have bought some STP stuff this morning, I shall try it tonight.

Any other thoughts?

 

[tom7035]

My thoughts were along the lines of Injector Cleaner if the fault was apparent just around tickover speeds. Maybe also a good idea to clean out the throttle body around the butterfly valve first, before adding the cleaner.

 

[Parrot of Doom]

I had a similar problem years ago in a Ford Galaxy, VAG Tdi engine. Dodgy fuel bought in Spain, every 50 miles or so the engine would lose power and crawl to a stop. We had to undo the fuel lines to each cylinder and crank the engine (simple job, just one spanner needed), spit the crappy fuel out, and away she'd go for another 50 miles. We just kept doing that until the dodgy fuel had been diluted out of the tank.

 

[TheJim]

Well, touch wood it seems to be going OK at the moment. Rather than cutting out it is just running a bit sluggishly all the time- presumably that means the water or whatever is being burnt steadily and is leaving the system mixed with the fuel rather than coming out in fits and spurts. I have racked up about 50 miles so far..........