Re: Fuel in oil! Why?

[pcmos]

Well I know I posted earlier on this thread and perhaps I spoke too soon! Recently it seems my oil has been pretty well saturated with gasoline, I'm really stumped by this issue. Maybe we can get the discussion started again, I still need to get a pressure gauge on the fuel system and watch the pressure. Unfortunately I'm also battling a major transmission failure right now so this oil contamination issue has to take a back seat for a bit. I am going to check for misfires while driving, using my diagnostic scan tool and also look for anything that would cause the engine to be running too rich.

[maxwedge]

You better get that oil out first, check for high FP naturally, also bad fp reg leaking into the vacuum hose!

[Bassasasin]

The old cars used to have a mechanical fuel pump and the diaphram would rupture and pass gas into the oil..

Otherwise I dont know where they even come close to each other unless you have a hole in your piston. YICK! Boy that would run bad..

What car do you have? Is it the 92' or the 2000...
Thin oil will hurt the engine ... get it attended to .. dont push the throttle down too far.

Possibilities of: Running too rich... O2 sensor, CTS, MAP, IAT. Its still in open loop. ECM thinks the engine or air is cold.

Good Luck

Bass

[pcmos]

This is my 2000 LeSabre with about 117k on it. There's no way I have some major problem like a blown piston, the engine runs too well, it seems perfectly fine aside from having no 4th gear right now (seperate thread). I've been smelling fuel in the passenger compartment at times, particularly when I stop at a light or idle for a few minutes. The last time this happened when I pulled up at my friend's house I jumped out and popped the hood and could smell a strong gas smell coming from the the rear firewall area around the injectors. It looks to me like there is a vacuum connection of some sort back there and I can see a lot of residue on the line and connection, as if its had fuel leaking in/around it. It was dark out and I haven't really had time to do any research in my shop documentation, or to hook up my diag software and check for misfires or open loop status. I had a compression test done on this engine around 90k miles because it seems to consume a lot of oil in general, but the numbers came out pretty good, none of the cylinders were within 2 or 3 psi of one another. I want to see if oil runs through the intake manifolds (upper and lower) at all, if its possible that a warped or poorly sealed intake could be causing evap fuel/vapors to mix with oil, thats a stretch though. All I know is that I have an aweful lot of fuel in my oil, I'll be changing it tomorrow, but I need to fix the source of contamination. Unfortunately with a 12 or 1600 buck tranny repair this week I'm not really going to be in the position to afford a dealer fix on the fuel issue, I'm hoping to resolve this one on my own. I drive this car hard, it has done 6 cross country drives in my time owning it. Probably one more from the previous owners based on where it was purchased originally and where I purchased it. I probably routinely exceed its rated tow capacity hauling my junk and a car load of friends around on my road trips. When it isn't loaded down I'm driving her pretty hard. I could potentially be experiencing blowby if my rings or bores are worn excessively, who knows, only another compression/leakdown test could determine that. My goal is to eliminate other explanations before spending the money to do another test. If it were running in open loop status I'm pretty sure I would end up tripping a code or two, plus my performance should be noticeably different, fuel economy would be terrible. I don't think its in open loop but I can confirm that with my software. Thanks for the advice though, I'll post updates when I have new information.

[Smith1000]

Sure sounds like it is possibly blow by and maybe it's getting sucked back into the evap system. I have an old tractor with a fairly worn engine that does something similar. It consumes quite a bit of oil and winds up fouling the plugs fairly quickly. When the plugs get fouled, it eventually ends up with a lot of unburned fuel mixed with the oil. All of this happens fairly quickly. It still runs good though-lots of power, just have to clean or replace the plugs all of the time to reduce the gas contamiantion and to keep it firing. Ended up running the hottest plug I could find and it really helped the situation out. You might have a leak of some other type though. There is a tube on the old tractorand it vents the crankcase. It will drip severely when the plugs are fouled (blow by).

[Bassasasin]

Very interesting problem you have. Hope your trannie gets fixed.. (TCC?).


Blow by would smell exhaust comming from the fill cap when running.
The pvc valve sucks out vapors and reburns them.
I think the oil does go through the intake manifold. But the intake is sucking and the oil is at 50 psi. More like you would burn oil or have coolant in the exhaust.
If the gas is leaking into the vaccuum then it is also burned unless the crankcase smaller vaccum is pulling it from where its pooling somewhere like a valve cover.

Good Luck.

Bass

[pcmos]

Upon further investigation I have discovered that the quick connect high pressure line fitting which connects the high pressure feed line to the rear of the fuel rail is leaking significantly. The fuel is running down the fuel rail and puddling directly on the manifold vacuum source. There is an off chance that the damaged rubber fittings are allowing the leaking fuel to be drawn into the intake via the vacuum source connection. One way or another this leak has to be fixed, whether it is the source of the fuel in my oil or not. Theres no question that the leaky connector is the source of the fuel smell I was getting on idle. The problem is that I would like to replace the quick connect itself or even the little O-ring inside of it but I can't seem to find any information on that repair. Has anyone ever replaced one of these fuel line quick connects or installed new O-rings in them? Essentially the dealer wants me to replace the entire line all the way down to the fuel filter at a cost of about 140 bucks for both lines (not sold seperately), I'd rather try to repair the leaky connector if possible.

[BNaylor]

You should get that leaking fuel pressure line repaired as soon as possible. That has been a source of engine compartment fires. Sounds like the o-ring.

I use a fuel line disconnect tool like in the link below to remove the connector from the fuel rail. The o-ring(s) should be available separately from auto parts stores or the dealer. Also, I recall they are part of the fuel injector o-ring kit.

http://www.zzperformance.com/grand_p...ts1.php?id=326

[pcmos]

Just to give an update, I did replace the O-rings with new ones made from HNBR material for use with R-134 refrigerant. HNBR is designed to stand up to just about anything including solvents and fuel, its the same rubber material used to make timing belts. Both quick connect fittings are now tight and leak free. There were two O rings per connector and they required tremendous patience and a set of picks to replace. The rings used on the pressure line are slightly larger than the ones used on the return line. I also discovered a couple of broken vacuum boots that I will replace and a worn out gasket on the MAP sensor on top of the PCV valve cover. I changed out the contaminated oil and filter and cleaned up all of the vaccuum connections. I still have a strong fuelish/exhaust odor when I remove the valve cover cap and smell the oil. Hopefully the work I did will help keep the oil cleaner, as long as it doesn't get any worse than what it was before I'm not terribly concerned. Theres no way I am going to pull a head or have someone pull a head to work on the rings, unless they are physically broken. Most people i know who have attempted work involving the removal of the heads end up with worse problems than what they started with. I may purchase a leak down test kit to determine if any of the cylinders are leaking down excessively.

I'd also check for a leaking injector. Fuel draining down into a cylinder will end up in your oil if it just sits. I've noticed that I have periodic hard starts, and traced it to fuel pressure bleeding off overnight. Which meant either the check valve in the fuel pump was leaking back into the tank, or a leaking injector. By disconnecting the quick connect I was able to determine that it was fuel bleeding out the injectors rather than back to the tank. From what I hear these injectors are notorious for getting fouled. I've started running injector cleaner in every other tank (a great new injector product is avail by the gallon here for a fraction of the price of the little 4 oz bottles) and the problem has gone away.

[pcmos]

Yeah well thats an excellent point, The fuel leak was an obvious problem though that needed to be fixed quickly. Once I deal with my transmission problems and get that sorted out I'm going to come back to the fuel system and do more analysis on the line pressure. I dump injector cleaner in the system about once a month but I also stick to shell gasoline, I won't put anything else in the car. Thanks for all the advice, I'll keep posting updates when I have more diagnostic information on the subject.

There was also a recall on the pressure regulators back in '04. Leaking diaphragms allowed fuel to leak through the vacuum line into the intake manifold.

[Luke.]

Fm pcmos

There were two O rings per connector and they required tremendous patience and a set of picks to replace

That is why I have a full collection of "dental tools" -- the are invaluable.

[pcmos]

Yeah I forgot to mention that I had the fuel pressure regulator replaced by a dealer as a result of the recall, not to say they didn't screw up the design the second time around also but I don't seem to see any sign of fuel in that connection.