I beg to differ.

If engine oil can seep past a valve stem seal into the port, and then drip into the chamber, then it is entirely possible that petrol in the pressurized intake stream can certainly weep up the valve stem into the engine oil. Remember that the intake side is often under tremendous pressure compared to the crankcase pressure and the intake is always wet with petrol. Stock boost pressures >20 PSIG while crankcase pressure is what <20 inches of water? So it's certainly possible.

How much petrol flow is there? That's a different question but it appears to be something worth investigating.

Unfortunately valve stem seals work exactly backwards from what we want them to do: When they're new - and we want them to leak oil into the stem/guide wear path for run-in and cooling - they seal very well. And when they're older - after we have a nicely run-in guide and stem that doesn't need as much oil - they leak more. Sigh.

 

^I can see your point, but I highly doubt that that's occuring here. No one is seeing any oil consumption, and if the fuel dilution issue were caused by leaking valve seals that were allowing fuel to get into the oil supply, we would also be seeing oil get past the valve seals and into the combustion chamber causing consumption. I still lean towards leaking injectors, because if they are leaking constantly, then even perfectly good valve seals would have a hard time keeping fuel out with a highly pressurized intake stream that is filled with fuel constantly, rather than being timed correctly with the intake valve opening. I guess now after thinking about it, the fuel can get into the oil this way as well, and it's not just the rings. Two entry points, but the same culprit: leaky injectors. In any case, we will know soon enough because I have an appointment with my dealer on thursday to have the issue documented. Mitsu will decide what they want to do, and we'll go from there.

 

Let's not forget that the AFRs must be contributing to the dilution. Any time you can *see* unburnt fuel exiting your exhaust, there's simply way too much in the chamber. Now, there may indeed be other contributing factors, but I'm thinking AFR is still a big culprit here.

I can't wait to see the results of a tuned car (I think I read yours has a stock tune, STi2). There may be some dilution still, but if it stays <= 2% over 3k miles, I'm not sure I'll be concerned about it anymore.

 

I dont see the dealer or Mitsu doing anything about it. They will simply sit tight and hope for cars to have failures after their warranty has expired or find reasons not warranty a engine failure if it happens with in warranty. Like I said before look what they have done to us on our transmissions.....nothing. Legal action and time is the only way anything will get done on these issues.

 

Where or what is the TSB# that people keep referring too? My TSB list shows nothing under lubrication or fuel.

 

I just sent my first oil sample for analysis (1,009 miles) and will be sending another right after the 2,000 mile mark. These will be followed by yet another sample after I get a tune to lean out the AFR (after 3k-3600 miles). I'll check out the trend based on the analysis reports, of course this process is going to take me another month to complete.

Since this is such a predominant problem, I hope as many people will follow oil analysis, and share with the rest of us results (maybe someone can consolidate the reports so it's available public), and we individually can present these to our dealers (or even Mitsubishi), to validate our concerns, wheteher its a mechanical (leaking injectors, etc.,) or software problem (AFR tune too rich)...

I for one will share my results, only reason why I'm thinking out loud is if others have already had oil analysis, they need to share results like STiEVO has.

BTW, Bob (OilDoc), is a great guy to deal with, I ordered a few analysis kits, and I'm sure he'll be along for the ride to help us out...

 

Hey guys, I just want to give my sincere appreciation for all you who went out of your way to send testing samples to the labs so we all can remedy the issue.

Thanks!!

 

I have said the exact same thing in earlier posts, but the main point to keep in mind is that even though rich a/f ratios will contribute to the issue, there is no way that it could cause that substantial of an amount of fuel dilution in my oil on it's own. Keep in mind, though, that it is very possible and highly likely that my case is worse than average, because another member on the stock tune showed a 2.4% fuel dilution after 2500 miles, while my results came back at a whopping 4.1% after only 1950 miles. The only way to know if you have an issue is to do oil analysis. These are expensive cars that have tons of little problems because A: it's made by mitsubishi and they have terrible quality control, and B: it's a first year car and a complicated one at that.

 

I should be getting my results any day. I will post asap.

 

Can some one please direct me to the TSB on this? I cannot find it in my system. As an EVO X owner and I didn't want to spill the beans, but I'm the warranty administrator for my Dealership. I would like to get the to bottom of this. It is the first time I have heard of it. We have only sold 3 or 4 EVOs this year.

 

I see that Oil Doc has had his account disabled for some reason. Oil Doc, if you happen to get reinstated send me a PM. My car goes to the dealership tomorrow and I'm going to have them save some oil for me to have analyzed.

EDIT: It looks like we're going to start to get more results soon, so I whipped up a quick MS Excel document so we can organize the data a little bit. I filled out what we know about Q15H's MR, and I used his analysis results image as a template to make data entry easy (So thanks Q15H!). Don't feel obligated to use it, but I thought it'd be nice to have a standard set of data from those who have gotten their results.

 

+1
If you are talking bout a TSB to do oil changes @ 3k and not 5k. There isn't one. Just word of mouth from someone on the boards.

 

Thanks and, yes, we need to get as many results as possible and organize them into a presentable form like a spreadsheet.
To Andrew (Drew 84) regarding the TSB on oil dilution: I do not think there is one. The only word from Mitsu that is related to this issue is, I believe, in the owners manual (or a TSB?) saying not to rev the engine until it reaches normal operating temperatures otherwise fuel will enter the engine oil. This occurs presumably as a result of a sufficient "gap" between the rings and cylinder wall such that fuel will "bleed" through the rings if boost is applied. While this is expected probably in every forced induction engine, it is the level of addition that is of concern. So one of the potential sources of the fuel other than faulty injectors and high A/F ratios after warmup due to the "OEM tune" is drivers not adhering to this Mitsu recommendation. I am not trying to suggest this is THE source of the problem; just trying to anticipate a possible Mitsu response to fuel dilution namely, "Driver Error". So we need to be prepared for this type of response (ie, it is our fault) if we cannot document the source(s) of this fuel intrusion.

Later, Ken

 

Well early on in this thread, this OILDOC guy made it sound like Mitsu had released a TSB on the fuel in the oil. Which, I find this fascinating. I have a brand new car, I don't want to see it ruined. I also had the car flashed for the latest ECU updates before I picked it up. So for the sake of science. At 1,000 miles I will have my oil changed and sent out. Right now I have a faint fuel smell but I believe that is because the car is brand new(281 miles on it), the rings have not seated yet, and I have not seen temps rise above 32degrees for the week I have owned the car. I have a very good relationship with my DPSM and maybe if I can substantiate some first hand evidence. I can find a solution or some information. I have the ability to submit quality control reports to Mitsu engineering. We did that with Outlander rear door windows coming off the track. Now they have a TSB to repair it.

 

Mine goes in for its 5k mile change tomorrow. I also still have an uncontaminated sample of its original 4.5k mile oil change. I think I'm going to send them both in, provided analysis on the one that's been stagnant would still be feasible.

It kind of makes me mad that using the recommended change intervals may have caused damage. It looks like I'll need to make a severe reduction in change intervals until we have some kind of solution.