Is running rich too bad ?

[NICAT]

Hi.
i see light black smoke at higher RPMs, (over 4000 rpm),
Have it diagnosed several times, but no one can find the exact reason,
I am not experiencing significant increase in fuel consumption. And performance is fine.
I am not driving the car daily. may be 300km at a month.
My question is, is running rich too bad ?
I already make some research, some saying that, if engine is running rich, the exess fuel will be washing the oil film in the cylinder wall, thus causing faster ring and cylinder wall wear. (won't the fuel will evaporate as soon as it reaches the cylinder wall ?)
As far as i know turbocharged engines are also running rich, does this mean , it is not such a bad ?
Regards.
BMW E60, M54 Engine

 

[Trav]

Any idea what the fuel trims are?

 

[NICAT]

Originally Posted by Trav
Any idea what the fuel trims are?


Hi.
i know that, to get help here, i should provide results of diagnosis, but unfortunately i do not have any.

I have already ordered cable, and DIS V57 software, will try to diagnose it myself, and get full details.
regards.

 

[Tman220]

what makes you think this is even a problem? Lots of engines will blow visible smoke when they hit fuel enrichment close to wide open throttle, especially performance engines. Does this car still have cats? because if it doesn't that will amplify this possible none issue even more.

 

[Emanuel]

I do think running rich is bad, I have a carburated Fiat Uno that´s running rich, I have done blotter spot test and I can see clear signs of fuel dilution of the oil, this thins out the oil and wears down it´s additives

 

[R18Civic]

Only bad thing is too rich can ruin the cat.

 

[clinebarger]

Originally Posted by Trav
Any idea what the fuel trims are?



Just to expand on this.....

If the black smoke is at Wide Open Throttle only, Fuel trims will not be affected as most vehicles drop out of closed loop & run solely on the PE (power enrichment) & VE (volumetric efficiency) tables in the calibration.

 

[Trav]

I think this one may use 2 upstream wide bands which IIRC remain in control at WOT. Fuel quality may be an issue in the county the OP is in. Effect of AF monitor? Dirty MAF?

 

[Lolvoguy]

Originally Posted by Hemispheres
Only bad thing is too rich can ruin the cat.

But not the engine?

interesting. Please explain.

 

[Audios]

Is the check engine light on? Its possible the cat isnt getting up to temp often enough with only 300km a month driving. Maybe a good high rpm ride would help get the cat up to temp and burn stuff off. Possible crankcase vent failing too, but it depends on what faults are shown.
In terms of running rich, the cat and O2s are usually what takes a beating from all the carbon and low combustion temps. Besides washing down the rings, if combustion chamber temps dont get hot enough there will be issues with carbon, soot, unburned fuel etc. Long term yes it will ruin an engine, but Id guess wed be talking 10k miles or more.

 

[FCD]

Yes running rich is bad, you can create bore wash in extreme cases which cleans the oil from the cylinder walls.
In less extreme cases it will still dilute the oil, causing a loss of viscosity and it strips away the Zinc / Moly tribofilms , again accelerating wear.

 

[The motor guy]

I see tons of late model cars smoke now. Especially the eco boost engines. I've seen camaros do it too after a hard pull. You can smell the heat going through the cats too.

 

[Tman220]

Originally Posted by motor_oil_madman
I see tons of late model cars smoke now. Especially the eco boost engines. I've seen camaros do it too after a hard pull. You can smell the heat going through the cats too.

I agree and have witnessed this myself. Its funny people are condemning the engine already too, when we havn't even established if this isn't 100% normal operation.

First of all, if the engine blows a little black smoke at WOT and still runs strong you have ZERO worries of washing down the cylinders. At high RPM the point of washing cylinders down is still far richer than when it starts running like crap because its pig rich.

 

[eljefino]

Originally Posted by Tman220

First of all, if the engine blows a little black smoke at WOT and still runs strong you have ZERO worries of washing down the cylinders. At high RPM the point of washing cylinders down is still far richer than when it starts running like crap because its pig rich.


If your car's warmed up good then yeah the gas won't condense on your cylinder walls, it'll get burned up and turned into soot.

Some cars will dump lots of fuel at high RPM and load just to cool off the combustion chamber to cut detonation.