rapidly accumulating fuel in oil

[Josh]

Do you guys think that an engine, otherwise running well, but that seems to accumulate tons of fuel in the oil pan over a few hundred miles, has an injector problem? Or could it be just a fuel delivery valve that's stuck open? Starting is quick and easy.

[Fatmobile]

I think a delivery valve is just a check valve, keeps pressure from dropping to 0 between pulses. I could be wrong on this.

If it fails, it doesn't pump more fuel into the injector.

I haven't heard of this before and can only refer to the times it has happened on gassers,.. usually due to over fueling,..
So I would have to suspect a bad injector.

Usually over fueling will lead to white smoke.

[Josh]

Thanks, Fat. Thanks also for the education on the function of the check valves!

-Josh

[MizPahPAH]

So you are getting extra oil / Fluid in your crank case? smells like diesel?

The little return lines from the injectors or the little line from the out bolt on the injection
pump isn't going to the vacuum pump is it?

[DanHoug]

that's my guess too.... someone has plumbed the injector overflow line to the nipple on the vacuum pump. i bought a car like this!

-dan

[Josh]

I got to look at this vehicle today. The return fuel line appears plumbed correctly, but it's pinched between the middle rigid fuel supply lines. It could be, in effect, pinched closed. Would that cause the injectors to spray inordinate amounts of fuel such that it would accumulate in the crankcase?

I can't smell, but no coolant is missing, the oil is way too high(again), and the fuel seems to drop quickly.

Should I just try to reroute and unpinch the return line / swap in a replacement? OR is it likely to be injector-related? I'd prefer not to waste an oil change if the injectors are a likely culprit.

Strangest thing I've ever seen; starts and runs fine in any weather, but can smoke like the dickens when warm and as the oil presumably thins with fuel.

(have been draining the crankcase and replacing with new oil as the dipstick rises).

-Josh

[MizPahPAH]

"The return line is pinched between the rigid fuel supply lines.."

Please expalin further,
do you mean that the little rubber return line from the injectors to the out bolt on the pump is pinched by the rigid metal injector lines,

or the small rubber line from the out bolt on the pump to the return to the tank is pinched by the rigid metal lines.

if the small rubber line from the out bolt on the pump going to the tank is pinched yes you could have higher than normal fuel pressure which could cause lots of black smoke and more than likely lots of marbles at Idle and through the rpm range.

Its kind of a streach I would think that if the pressure is high enough to cause that much fuel in the oil that the return lines off of the out bolt on the pump would pop off.

still to double check one injector should have a cap on one barb then a line to another injector then to the third then the fourth and finally the last injector should loop to the out bolt on the pump with one last line off of the out bolt going to the tank.

A picture say a thousand words

[Josh]

Pete, the piping is correct; injector 4 is capped on one side, then the typical cloth piping jumps from injector to injector, and finally the line goes to the OUT bolt on the pump. From that same bolt a semi-rigid plastic line runs back to the tank return, and it's this line which has been sandwiched between a tight spot by the metal lines. So if any pressure is building up within the injector return lines, it is weak enough that the barbed fittings can hold the rubber hoses on without leaking.

-Josh

[MizPahPAH]

I would think that if your return line is pinched enough to raise the internal pressure and cause an excess amount of fuel so that large amounts end up in the crank case, You would also have other symptoms like bad marbles or lots of white smoke at Idle or under load,

You could try getting rid of the pinch in the line. See if that helps

If you get rid of the pinch and find that it doesnt run right you may have to adjust the static pump timing, internal pump pressure, and or full load screw.

Did the apperence of fuel in the oil and the pinch in the return line happen around the same time. Have you maybe had to make some adjustments to try to over come any of the symptoms that I have mentioned

[Fatmobile]

Pretty much said already,.. but if the return line was pinched enough,.. the small lines between the injectors would pop off.
I can't see how it would cause fuel in the oil.

[Josh]

No marbles; lots of white smoke once warm and under load or idling.

I don't know what symptom was first; the car's fresh to all involved. No further background info available, sadly.

So it's really unlikely to be the pinched return line. And nobody's experienced a similar situation with worn or malfunctioning injectors. Should I mess with pump adjustments next?

[Quantum-man]

IMO, the only way to get fuel into the sump is via unburnt fuel passing piston rings.
If an injector is dripping fuel into the prechamber at the wrong time, it could drip onto the piston crown, and past the rings.
When hot engine will make better attempts to burn this fuel, but some may just get turned into 'diesel-steam' ...
Don't ever let buying and inserting a new injector exempt you from injector issues