Running rough at idle & smoking. Long read.

[MartinH]

Hi all. Major problem occured at the weekend with my 190E 2,6 Auto. Filled up with fuel (Unleaded) at my local garage, 200 yards down the road the car cut out at a junction but not before running on half it`s cylinders for about 15 seconds. I was unable to start it and consequently it was recovered to my mates garage.
We were able to start it first time when cold. But when it had warmed up it started to run like a bag of nails and was misfiring and smoking when revved.
We let it cool down again while we had several coffees and a think about it . Came to the conclusion that it could be contaminated fuel.
So, i drained the tank of £30 quids worth of Texacos finest. And put two gallons of fresh fuel in, from another garage. Started the engine and waited.
Gave it 10 minutes worth of warming up. It was revving at @1500RPM by this time and smoking very lightly. I blipped the throttle and the revs dropped back to @ 800RPM but still with a misfire. Hope your still with me here. I blipped the throttle and it stuttered briefly and then picked up. Ran it at 3000RPM for a few seconds and it sounded fine, but still smoking. Definately smoke, not condensation. Let the throttle up and it idled briefly and died.
Now the really puzzling bit. When we tried to restart it, it was almost as if the engine was hydraulicing. She`d turn over for two or three seconds then the starter would stall. I`ve left it at this stage for the time being.

A couple of other points. I haven`t changed the fuel filter yet. I think this might be a good idea. I also whipped the plugs out. They were greasy/dampish and black.

One other thing. There`s a dash light that comes on when the engine is running. It`s next but one to the left of the ABS warning lamp. There`s no symbol on it. Just a plain whitish/yellow window, Any ideas?? Are there any error codes that can be retrieved on the 190`s?

Any ideas/help would be appreciated.

 

[flagstaff]

this reminds me of a local newspaper story not so long back ... at an asda petrol station, several customers filled their cars from the unleaded pump but found they were getting diesel. is this an impossibility in your case?

 

[MartinH]

When i filled up the low fuel light had been on for about 5 - 10 miles. When idrained the fuel out it was definately petrol, However having said that. I poured a small amount onto a piece of metal plate and allowed it to evaporate. It appears to have left behind a small greasy patch. I would think it`s possible that there has been some cross contamination at some point before it went in my tank. I`ll be changing the fuel filter this weekend to see if that makes any difference.

We did wonder if there was a problem with the head gasket, But there`s no water loss. Oil pressure & water temp are ok. No oil in the water or vice versa.

 

[MartinH]

So many replies.

Come on guys. There must be someone out there thats au fait with the mighty 6 pot.

i`ve changed the fuel filter and put yet more fresh fuel in and added some injector cleaner. I`m still getting the white/orange warning light on the dash. The car starts first time from cold and idles at about 1800 rpm if left to it`s own devices. When i blip the throttle when it`s warmed up the revs drop back to @850rpm but the engine feels very lumpy. If i leave it to tick over it eventually dies after a minute or so. The exhaust is very smoky as if it`s overfueling badly.

My prognosis is that something is causing it to run really rich when warmed up. It`s probably doing it when cold but this may translate to the high revs.

Is there an easy way to disable the cold start. Or am i barking up the wrong tree.

HELP.....

 

[Stevie A]

There's no details about the light you mention in the MB manual I have for my 190E. It is a blank space.

Maybe there was dirt or something in the fuel you got and it has blocked up fuel delivery / injectors somewhere?

Change plugs for new. Check distributor and rotor. Check all hoses & breathers. Check OVP relay too as it can cause stalls and hard starts. That light could be possibly related to that.

Report back once you know more.

 

[flyingtech55]

Does your car have a cat?

 

[Jay Kilby]

1st the greasy patch left by your fuel will be the additives that are put in to replace the lead that has been removed.
2nd wet plugs are from over fueling

i would imagine our car is in "Limp" mode which means there is a fault somewere which is difficult to diagnose from you description. get it to a dealer or indy you seem to have checked the logical but i think it is not a fuel problem or delivery (spark plugs are wet)
i am not familiar with the engine but if it has old type distributor and rotor check them as well as leads check they all spark. look round the air filter box if it is sat on top of the engine if there are any pipes connected check them for leaks/breaks (Modern commonrail injection have seperate air box and use MAF sensors not vacum) if all is well take it to a dealer.
let us know if the car has a cat.

 

[flyingtech55]

i would imagine our car is in "Limp" mode which means there is a fault somewere which is difficult to diagnose from you description.

The car doesn't have a 'limp' mode as the injection system on these cars is basically a mechanical system with electronic 'trimming' of hte mixture. The trimming is normally driven by the output of the lamda sensor; hence my question asking if the car has a lamda sensor.

Gliderman

 

[Jay Kilby]

The car doesn't have a 'limp' mode as the injection system on these cars is basically a mechanical system with electronic 'trimming' of hte mixture. The trimming is normally driven by the output of the lamda sensor; hence my question asking if the car has a lamda sensor.

Gliderman

i stand corrected

 

[mike65]

My I suggest you put the question over at www.190revolution.net where there are a number of 2.6 owners.

Mike.

 

[MartinH]

OK. Thanks guys. All suggestions are appreciated. Mike, I`ll give them a whirl too. I found a cylindrical solenoid type doo dad under the air filter with two round pin connections. I disconnected this and the car ran a lot better. I imagine this must be part of the mixture control. Possibly controling the cold start injector? When reconnected at tick over the car cut out straight away. With the revs at about 1500 it increased the revs by about 200rpm. I`ll try anfd get a picture of it tomorrow.

Thanks again guys.

 

[Stevie A]

Martin - Give the part you mention a good clean or replace it. That part effects the timing / injection so would cause your fault. Clean in the throttle inlet area below the air filter housing in by the air entry part, but take great care to avoid damaging anything. the butterfly flap can be pushed down to allow some cleaning.

You have probably found the problem hopefully, otherwise the only other thing I could think of was a dodgy / dirty crank position sensor or other sensors (temp, TDC, airflow etc) that send info to the ecu for the injection timing.

 

[MartinH]

Thanks Stevie. It`s on the back burner at the minute as works takena turn for the worse (Or better) and i`m snowed under. Would cleaning it out with a proprietry carb cleaner be a good idea?