Fuel dilution = wear? Always?

[wemay]

Does fuel dilution always constitute higher wear? Could this dilution have been taken into consideration by recent d.i. auto manufacturers and relegated as a non-issue if rcomd'd oci is followed? I don't see why so many of them are moving towards d.i. if this weren't the case.

 

[JHZR2]

It's not like they don't know about it... Certainly design attributes can be adjusted. And look at it another way - even with fuel, the oils aren't going way far out of grade. So with oils like 0w-16 coming along, in all likelihood, a 30wt with some fuel will have the same or better film strength.

 

[wemay]

Originally Posted By: JHZR2
It's not like they don't know about it... Certainly design attributes can be adjusted. And look at it another way - even with fuel, the oils aren't going way far out of grade. So with oils like 0w-16 coming along, in all likelihood, a 30wt with some fuel will have the same or better film strength.


Very true.

 

[Russell]

I have also wondered about the potential effects re fuel dilution. I have beed advised that oOld BMWs with the M50 engine tend to run a bit rich,especially on cold starts due to leaky injectors etc. This is one reason I tend to change oil/filter every 3,500 miles.

 

[Merkava_4]

There shouldn't be any fuel dilution in a modern fuel injected car. The computer is constantly monitoring the fuel trim numbers and if the fuel trim is too rich, it'll set a diagnostic trouble code and the check engine light will come on.

 

[OVERKILL]

Originally Posted By: Merkava_4
There shouldn't be any fuel dilution in a modern fuel injected car. The computer is constantly monitoring the fuel trim numbers and if the fuel trim is too rich, it'll set a diagnostic trouble code and the check engine light will come on.


Oh, it happens. To warm up the cats, fuel is dumped. And many cars have rich WOT maps to deal with high compression and to ward off detonation.

Once they warm up and are in closed loop, generally injected engines run nice and clean. But that doesn't change that fuel has already made its way into the oil during the warm-up event for example. And if the vehicle doesn't see periods of long highway drives with the oil at temp, that fuel is never flashed off.

 

[Russell]

Originally Posted By: Merkava_4
There shouldn't be any fuel dilution in a modern fuel injected car. The computer is constantly monitoring the fuel trim numbers and if the fuel trim is too rich, it'll set a diagnostic trouble code and the check engine light will come on.


In my case this is a 1995 BMW with 233,000 miles and original injectors. Cold starts is my concern. BTW, no codes

 

[Clevy]

Originally Posted By: Merkava_4
There shouldn't be any fuel dilution in a modern fuel injected car. The computer is constantly monitoring the fuel trim numbers and if the fuel trim is too rich, it'll set a diagnostic trouble code and the check engine light will come on.


Not quite.
At start up the ecu runs the engine very rich to light up the catalytic converters so they are at operating temp as soon as possible. And at start up the pistons aren't tight in the bores yet so fuel inevitably ends up in the crankcase.
That's why vehicles that only run for short periods end up with fuel in the oil. It never gets the chance to evaporate out. Which why short trippers are always recommended here to get out on the highway regularly to get the oil hot for an extended period.
My charger never smells like fuel in the oil. Every time it gets started it runs at least 40 miles and often 80 which is a round trip to the city and back.
I suggest reading as much as you post. You'd know this stuff and wouldn't pass out incorrect info.

 

[Clevy]

Originally Posted By: OVERKILL
Originally Posted By: Merkava_4
There shouldn't be any fuel dilution in a modern fuel injected car. The computer is constantly monitoring the fuel trim numbers and if the fuel trim is too rich, it'll set a diagnostic trouble code and the check engine light will come on.


Oh, it happens. To warm up the cats, fuel is dumped. And many cars have rich WOT maps to deal with high compression and to ward off detonation.

Once they warm up and are in closed loop, generally injected engines run nice and clean. But that doesn't change that fuel has already made its way into the oil during the warm-up event for example. And if the vehicle doesn't see periods of long highway drives with the oil at temp, that fuel is never flashed off.



What is it they say about great minds?
I posted almost identically,in different words of course.

 

[Merkava_4]

Originally Posted By: OVERKILL
Originally Posted By: Merkava_4
There shouldn't be any fuel dilution in a modern fuel injected car. The computer is constantly monitoring the fuel trim numbers and if the fuel trim is too rich, it'll set a diagnostic trouble code and the check engine light will come on.


Oh, it happens. To warm up the cats, fuel is dumped. And many cars have rich WOT maps to deal with high compression and to ward off detonation.

Once they warm up and are in closed loop, generally injected engines run nice and clean. But that doesn't change that fuel has already made its way into the oil during the warm-up event for example. And if the vehicle doesn't see periods of long highway drives with the oil at temp, that fuel is never flashed off.


On my GM product, there's a secondary air injection system to warm up the catalytic converter.

 

[Ducman]

Originally Posted By: Merkava_4
Originally Posted By: OVERKILL
Originally Posted By: Merkava_4
There shouldn't be any fuel dilution in a modern fuel injected car. The computer is constantly monitoring the fuel trim numbers and if the fuel trim is too rich, it'll set a diagnostic trouble code and the check engine light will come on.


Oh, it happens. To warm up the cats, fuel is dumped. And many cars have rich WOT maps to deal with high compression and to ward off detonation.

Once they warm up and are in closed loop, generally injected engines run nice and clean. But that doesn't change that fuel has already made its way into the oil during the warm-up event for example. And if the vehicle doesn't see periods of long highway drives with the oil at temp, that fuel is never flashed off.


On my GM product, there's a secondary air injection system to warm up the catalytic converter.



That's not what Air Injection does.
Air Injection is designed to more effectively burn the excess fuel "before" it gets to the Cats.

 

[INDYMAC]

There are some relevant points about fuels dilute in this article:
http://www.thermal-lube.com/Publications/In-Line,%20Continuous%20Monitoring%20of%20Fuel%20Dilution%20in%20Motor%20Oils%20by%20Fourier%20Transform.pdf

 

[Shannow]

If you give the fuel a viscosity of (say for example, as I can't find a number) 0.1cst...or even lower. The widman calculator can't take "zero" as the viscosity of a constituent, but will take 0.00000001 cst

Choose it as (say) 2% "blend" int eh oil of your choice, and see the resultant viscosity.

Then see if that gives you enough comfort to accept dilution in your chosen lube, bearing in mind that it's only one of the parameters that upset oil over time.

I can't say that this is a valid technique, but it's accepted for mixing hydrocarbons.

I don't believe that fuel dilution automatically equals wear...

at least in this PCMO forum.

dilution with alky, vege oil etc. do other stuff than thin the oil down.

It used to be a technique to get aircraft started in cold weather, and apparently boiled off as they got hot.

 

[Zaedock]

Originally Posted By: Ducman
Originally Posted By: OVERKILL
On my GM product, there's a secondary air injection system to warm up the catalytic converter.



That's not what Air Injection does.
Air Injection is designed to more effectively burn the excess fuel "before" it gets to the Cats.


You are both right, depending on the system.

 

[OVERKILL]

Originally Posted By: Ducman
Originally Posted By: Merkava_4
Originally Posted By: OVERKILL
Originally Posted By: Merkava_4
There shouldn't be any fuel dilution in a modern fuel injected car. The computer is constantly monitoring the fuel trim numbers and if the fuel trim is too rich, it'll set a diagnostic trouble code and the check engine light will come on.


Oh, it happens. To warm up the cats, fuel is dumped. And many cars have rich WOT maps to deal with high compression and to ward off detonation.

Once they warm up and are in closed loop, generally injected engines run nice and clean. But that doesn't change that fuel has already made its way into the oil during the warm-up event for example. And if the vehicle doesn't see periods of long highway drives with the oil at temp, that fuel is never flashed off.


On my GM product, there's a secondary air injection system to warm up the catalytic converter.



That's not what Air Injection does.
Air Injection is designed to more effectively burn the excess fuel "before" it gets to the Cats.


Exactly. Pre-cat air injection is designed to lean-out the overly rich exhaust exiting the engine, making it hotter, so it can more quickly light-off the cats.

 

[m6pwr]

Originally Posted By: OVERKILL
Originally Posted By: Merkava_4
There shouldn't be any fuel dilution in a modern fuel injected car. The computer is constantly monitoring the fuel trim numbers and if the fuel trim is too rich, it'll set a diagnostic trouble code and the check engine light will come on.


Oh, it happens. To warm up the cats, fuel is dumped. And many cars have rich WOT maps to deal with high compression and to ward off detonation.

Once they warm up and are in closed loop, generally injected engines run nice and clean. But that doesn't change that fuel has already made its way into the oil during the warm-up event for example. And if the vehicle doesn't see periods of long highway drives with the oil at temp, that fuel is never flashed off.


I've often wondered if this is why BMW deliberately runs such relatively hot oil temps of 250 degrees in its gdi turbo engines - - to boil off some of the fuel dilution.

 

[KB2008X]

Manufacturers are going forward with Direct Injection because of the increasing demands for higher fuel mileage, from both the marketplace and governmental pressures. This push will continue regardless of whether DI leads to increased fuel dilution of engine oil, or not. Oils are always improving anyhow, to accommodate today's and tomorrow's engine operating conditions, and no doubt fuel dilution issues will continue to be a focus point for oil producers.

Whether DI will cause more fuel dilution, or whether fuel dilution automatically equals increased wear, is going to vary depending upon each individual application of that technology and that engine's operating conditions. And only time will tell.

Auto manufacturers can test this technology relentlessly in the lab and on the road, and I'm sure they have, but nothing can match the DI test that is ongoing right now. Several million vehicles running DI engines for a few years will be the ultimate test. Some manufacturers will pass that test with flying colors, and some will not, and who passes and fails won't necessarily be who we'd expect.

In the meantime, if I had a DI engine I would be inclined to use caution and change the oil on the severe use OCI schedule until I was completely satisfied that it was unnecessary.

DI is the next step in fuel delivery and in time I expect we'll see it in almost all daily driver type vehicles. As a late-adopter I'm looking forward to sitting back and observing how DI technology impacts engine life and what adjustments will be made. Pull up a chair, this is going to be interesting.