Fuel in Oil

[James O’Hara]

I am reposting this in a much easier to read format to hopefully get some insight. This car is in for roughly a 140-200mile trip from PA to NY to a mechanic that specializes in foreign sport cars and also to get some body work done by a body guy that does foreign sport cars.

2004 Acura NSX 3.2L Manual Fuel in Oil

Older Repairs:
Salvage title – Two cars put together to make one (Not by me) Chassis car 32k miles. Engine 66k
Coolant leaks – Every coolant clamp had to be replaced all were oversprung.
Brake Fluid Leaks – 3 Flare nuts tightened rear quarter panels engine compartment side
Evap Leaks – 3 different ones all fixed, fill neck, charcoal case, fuel cap

Latest Repairs:
oil + filter change
Fuel system cleaner
fuel filter
manual cleaning #3 injector
New injector o-rings bank 1 – all 3
oil + filter change

Latest problems:
Vacuum Leak – Fuel Regulator Bank 1 (Not Fixed)

During the removal of the fuel rail the entire rail of fuel was dumped evenly between cylinders 1-3. Smelled fuel in oil and had owner do change. Still fuel smell in oil but, substantially less. I was not able to do a compression test due to time. I ran a noid light test all is fine electrically. it has had an intermittent missfire ever since last winter when he did not put a fuel stabilizer in it. I warned him but… Fuel system cleaner fixed everything but, injector #3. Pulled it and did the manual cleaning. Now no codes but, still intermittent missing. Vacuum leak is barely audible. Could not get the proper size vacuum line to fix it as it is 3.5mm ID.

My main questions are:

Electrical tape then wrapped with aluminum tape over the cracks in the vacuum line a good enough patch to get 200 mi approx?

Is it possible injector #3 is sticking internally still and dumping extra fuel (Ohms fine)?

Is the vacuum leak on the fuel regulator causing both the miss and extra fuel enough to get into oil?

Topic

[Virginia]

On your 2nd question, yes, it is possible to ohm okay but be partially stuck. This is not uncommon. (Even after/despite cleaning.)
On Q1, it depends upon how bad the crack is. It is possible (for your trip), but liquid electrical tape might work much better, and you can coat 2 layers (or even 3) if desired. Have used Star Brite and Permatex brands with success (small 4 oz cans). On the line though, is it flex rubber or rigid plastic? Surprised you can’t get a diameter that will fit snug. It doesn’t have to be perfect – just vacuum-tight. Never have had a problem getting regular flex rubber hosing. In fact, I keep various reels (all sizes) on hand.
On Q3, part a, possibly; on Q3, part b, don’t know, but would tend to doubt that unless there’s a significant ring or seal issue (and doubtful even then). Put your finger in the tailpipe (car cold) and see if there’s compelling evidence of rich burning (abundant universe-black carbon).

Good luck.

[Carlos Garrison]

Yes, Rock climber is right so far, I was asked all questions to my friend a mechanic of Tire mania auto repair shop in Tampa(may know about it by tiremania.net). He replied are some technical solutions of your questions that I can’t remind but the best idea is ask this question to a car expert.

[Mike]

[quote=”MDK22″ post=122586]Electrical tape then wrapped with aluminum tape over the cracks in the vacuum line a good enough patch to get 200 mi approx?[/quote]
Even just the electrical tape should be fine, as long as it’s 3M or something solid.

[quote=”MDK22″ post=122586]Is it possible injector #3 is sticking internally still and dumping extra fuel (Ohms fine)?[/quote]
Yes.

[quote=”MDK22″ post=122586]Is the vacuum leak on the fuel regulator causing both the miss and extra fuel enough to get into oil?[/quote]
This is a little complicated. A small vacuum leak will commonly cause a misfire at idle, but not when the throttle is open more than a crack. If the throttle is cracked while cruising it can misfire then too. It has to be a big leak to for it to matter once intake airflow ramps up, where a small like becomes such a drop in the bucket compared to how much the engine is pumping.

With the fuel, other than the quantity spilled down the intake, there are only few ways to be getting fuel into the oil.

You’re really not going to be getting fuel into the oil while the engine is running unless there is a cylinder with fuel being injected and no combustion is happening. There are plenty of ways of no spark/compression/spark or valve timing to achieve this condition, but make no mistake it will always be a full time completely dead cylinder. On a fairly normal engine like that, even a partial combustion event will burn most or all of the fuel even if it doesn’t explode properly and a misfire is registered/felt. The point being that the cylinder has to be completely dead with fuel being injected in order for there to be liquid fuel running down the cylinder walls. Once the fuel washes all the oil residue off the cylinder wall and rings, a lot can get past and fall into the oil pan.

The other time that a large amount of fuel can get into the oil is when the engine fails to cold start due to flooding, and the operator gets very stubborn and just keeps trying to start it for a long time. The same rinsing of the cylinder walls I mentioned happens to all of them and the unburned fuel will fall into the oil as long as somebody keeps trying. If the oil doesn’t get a chance to be warmed up and the engine driven quite a bit after, the fuel can stay in there for quite awhile before it evaporates.

I’ve seen something else happen with this condition on some very new engines with low friction ring packages that depend on the oil residue on the cylinder wall to make enough compression. I’ve had a couple cars where the engine had been flooded like this and you could tell just from how it cranks that there is low compression (like one or more spark plugs are removed). I’ve had to remove the spark plugs and squirt a little oil down in there to get normal compression. Once it runs for a minute, there is enough oil splashed/smeared back up on the cylinder walls that everything is fine again.

[Author]

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