Fuel dilution consequences

[neo3]

Originally Posted By: Danh

I had the same thought, but I'm told that the on-board-diagnostics would detect a leak and nothing was noted by the dealer. A traditional "leak-down" test evidently isn't possible with the high pressure inherent in a DI engine. And no start-up flutters or "clouds of white smoke" (as my dealer told me to watch for).

What does DI have to do with a leak down test, which is purely a test of valve and piston sealing with the engine not running?

 

[Danh]

Originally Posted By: neo3
Originally Posted By: Danh

I had the same thought, but I'm told that the on-board-diagnostics would detect a leak and nothing was noted by the dealer. A traditional "leak-down" test evidently isn't possible with the high pressure inherent in a DI engine. And no start-up flutters or "clouds of white smoke" (as my dealer told me to watch for).

What does DI have to do with a leak down test, which is purely a test of valve and piston sealing with the engine not running?


This leak down test is looking for a loss of fuel pressure when the engine is off, which could mean a leaking fuel injector, not checking valves or rings.

 

[BrocLuno]

Why are you running Premium Gasoline? Is it called for? It usually delays flame propagation, and that's a bad thing here ...

I'd be running straight old Regular unless there is an engine ping/knock or something ... It burns the quickest and cleanest.

 

[HKPolice]

2 things:

1) The shearing of your oil is mostly due to the high pressure DI fuel pump added to the the K24 engine, it puts a ton of extra strain on the cams/timing chain on an engine that was not originally designed for DI.

2) The fuel dilution is mostly caused by low tension piston rings used to improve MPG. It is unlikely to be an injector or calibration issue.

If I were you, I'd try using a thick 5w30 or 0w40 if you want maximum protection. I think Honda has sacrificed long term reliability for max MPG which makes sense since these engines will still run long after the warranty has expired even with 5% fuel dilution & 6 cST oil.

 

[KL31]

Another option is to get a wideband O2 sensor installed with gauge. That will tell you the air fuel ratios. Be interesting to see if you are running rich at all.

You might even be able to buy an OBD2 scanner off Ebay and that may tell you real time AFR also. Not sure but worth the research. Something like that could be had for cheap and can link up to a smart phone app via blu tooth.

Also, I agree with BrocLuno on the fuel. Use regular if that's what the car was designed for. Regular burns more efficiently. Sure it's prone to detonation more, but that's because it burns more easily. Usually highly tuned cars, turbo, supercharged etc may use premium for safety. But it's a Honda CRV so I think you're more than safe in that department!

 

[bigt61]

Did you change the factory fill early? I'll bet the dilution is due to rings not fully seating, which takes longer with a quick switch to a full synthetic. It will go away in time if you're patient. It will go away faster if you do a run of SuperTech (or any other) 5w20 conventional for 5000 miles. I don't like changing out the FF early for this reason - my 2 cents.

 

[bulwnkl]

It seems you've said, OP, that the most recent sample when you ran premium fuel cut your dilution figure by 2/3. You said highway driving is the norm, so I discounted the fact that the latest was also highway miles.

Given the apparent drop in dilution by virtue of running higher octane, along with member badtlc's Mazda Skyactive UOA results (wherein we see that higher octane gasoline significantly reduces dilution in high-compression DI engines), does it make sense to buy all premium gas for a couple used oil analysis?

 

[Danh]

Originally Posted By: bigt61
Did you change the factory fill early? I'll bet the dilution is due to rings not fully seating, which takes longer with a quick switch to a full synthetic. It will go away in time if you're patient. It will go away faster if you do a run of SuperTech (or any other) 5w20 conventional for 5000 miles. I don't like changing out the FF early for this reason - my 2 cents.


Left the semi-syn factory fill in for about 5,500 miles. Not quite as long as Honda would like but a record long time for me.

 

[Danh]

Originally Posted By: bulwnkl
It seems you've said, OP, that the most recent sample when you ran premium fuel cut your dilution figure by 2/3. You said highway driving is the norm, so I discounted the fact that the latest was also highway miles.

Given the apparent drop in dilution by virtue of running higher octane, along with member badtlc's Mazda Skyactive used oil analysis results (wherein we see that higher octane gasoline significantly reduces dilution in high-compression DI engines), does it make sense to buy all premium gas for a couple used oil analysis?


That's the plan. Premium seems to have helped the fuel dilution issue as Badtlc noted with his Mazda and presumably for the same reason: reducing preignition and the consequent over fueling. I have a sample extractor and a 10 used oil analysis pack so I can experiment a bit.

 

[Danh]

Originally Posted By: KL31
Another option is to get a wideband O2 sensor installed with gauge. That will tell you the air fuel ratios. Be interesting to see if you are running rich at all.

You might even be able to buy an OBD2 scanner off Ebay and that may tell you real time AFR also. Not sure but worth the research. Something like that could be had for cheap and can link up to a smart phone app via blu tooth.

Also, I agree with BrocLuno on the fuel. Use regular if that's what the car was designed for. Regular burns more efficiently. Sure it's prone to detonation more, but that's because it burns more easily. Usually highly tuned cars, turbo, supercharged etc may use premium for safety. But it's a Honda CRV so I think you're more than safe in that department!


Premium seems to have helped the fuel dilution issue, not hurt it. Plus, Acuras use the same engine and recommend 91 octane fuel with a compression ratio only .5 higher. If 91+ octane is right for the Acuras, 87 seems marginal for the Honda. And, as others have noted, DI engines seem to deal with preignition by richening the mixture rather than retarding the timing, thus the theoretical influence on fuel dilution.

 

[Danh]

Originally Posted By: HKPolice
2 things:

1) The shearing of your oil is mostly due to the high pressure DI fuel pump added to the the K24 engine, it puts a ton of extra strain on the cams/timing chain on an engine that was not originally designed for DI.

2) The fuel dilution is mostly caused by low tension piston rings used to improve MPG. It is unlikely to be an injector or calibration issue.

If I were you, I'd try using a thick 5w30 or 0w40 if you want maximum protection. I think Honda has sacrificed long term reliability for max MPG which makes sense since these engines will still run long after the warranty has expired even with 5% fuel dilution & 6 cST oil.


You may be right about viscosity. The dilemma is preserving the warranty - I know Honda would have to "prove" a higher viscosity caused engine damage, but it would be a huge, long hassle and Honda's pool of experts is a lot deeper than mine.

 

[HKPolice]

Originally Posted By: Danh
Originally Posted By: HKPolice
2 things:

1) The shearing of your oil is mostly due to the high pressure DI fuel pump added to the the K24 engine, it puts a ton of extra strain on the cams/timing chain on an engine that was not originally designed for DI.

2) The fuel dilution is mostly caused by low tension piston rings used to improve MPG. It is unlikely to be an injector or calibration issue.

If I were you, I'd try using a thick 5w30 or 0w40 if you want maximum protection. I think Honda has sacrificed long term reliability for max MPG which makes sense since these engines will still run long after the warranty has expired even with 5% fuel dilution & 6 cST oil.


You may be right about viscosity. The dilemma is preserving the warranty - I know Honda would have to "prove" a higher viscosity caused engine damage, but it would be a huge, long hassle and Honda's pool of experts is a lot deeper than mine.


I haven't heard of anyone being denied warranty work because of thicker oil. AFAIK, Honda still specs 5w30 for this engine in other countries where 0w20 isn't readily available especially in South Asia where 20w50 & 10w40 are still common.

Anyways, if you use a 0w30 or 5w30 the fuel dilution & shearing will bring viscosity into 0w20 range, there will be no way for Honda to tell that it was a virgin 30 weight.

 

[BrocLuno]

Exactly

 

[bluesubie]

In the event of a Powertrain Warranty claim, wouldn't Honda just ask for oil receipts?

 

[HKPolice]

Originally Posted By: bluesubie
In the event of a Powertrain Warranty claim, wouldn't Honda just ask for oil receipts?


AFAIK they won't do that unless they find sludge in the engine or other signs of neglected maintenance.

 

[Danh]

Originally Posted By: bigt61
Did you change the factory fill early? I'll bet the dilution is due to rings not fully seating, which takes longer with a quick switch to a full synthetic. It will go away in time if you're patient. It will go away faster if you do a run of SuperTech (or any other) 5w20 conventional for 5000 miles. I don't like changing out the FF early for this reason - my 2 cents.


The car has no measurable oil consumption so I assumed that meant the rings were well-seated. Is this faulty logic in the context of fuel dilution? Thanks.

 

[HKPolice]

Originally Posted By: Danh
Originally Posted By: bigt61
Did you change the factory fill early? I'll bet the dilution is due to rings not fully seating, which takes longer with a quick switch to a full synthetic. It will go away in time if you're patient. It will go away faster if you do a run of SuperTech (or any other) 5w20 conventional for 5000 miles. I don't like changing out the FF early for this reason - my 2 cents.


The car has no measurable oil consumption so I assumed that meant the rings were well-seated. Is this faulty logic in the context of fuel dilution? Thanks.


Old wives tale. Why would Honda use 0w20 synthetic as factory fill if it affected ring seating? Oil consumption is the biggest symptom of unseated rings because it is not scraping away excess oil from the combustion chamber. Fuel dilution is due to low tension piston rings, it's even part of Honda CRV's press release: http://www.hondanews.com/releases/2015-honda-cr-v-powertrain

Quote:
Reduced friction: Offset cylinder, piston rings, accessory belt, etc.


This isn't the first time Honda has used low tension rings, it first appeared in the Fit: http://www.thecarconnection.com/news/1080516_2015-honda-fit-powertrain-preview-drive

Quote:
Honda's Earth Dreams initiative for lower fuel consumption, and in addition to direct injection it employs a high-tumble port, low-tension piston rings

 

[kschachn]

How was the fuel dilution measured? Directly via GC or FTIR?

 

[Danh]

Originally Posted By: kschachn
How was the fuel dilution measured? Directly via GC or FTIR?


It was Polaris, so GC. On my first UOA with this car, Blackstone said things were great and dilution was
For those using Polaris, if you see "GC" next to dilution amounts it mean the value came from (surprise!) gas chromatography. If you see "Estimated" it means Polaris thought viscosity was high enough to not warrant a GC test and a value was imputed. The %s I mention here are all Polaris GC.

 

[kschachn]

Originally Posted By: Danh
Originally Posted By: kschachn
How was the fuel dilution measured? Directly via GC or FTIR?

It was Polaris, so GC. On my first UOA with this car, Blackstone said things were great and dilution was
For those using Polaris, if you see "GC" next to dilution amounts it mean the value came from (surprise!) gas chromatography. If you see "Estimated" it means Polaris thought viscosity was high enough to not warrant a GC test and a value was imputed. The %s I mention here are all Polaris GC.


That's good to know, the way Blackstone does it isn't direct and I don't trust their numbers.