ebteckx

Hello!! Hope everyone is enjoying the new year so far. Its been a long time since I've been on had a massive computer failure. So I start the new year with a problem...

My truck is still as is in my sig, as soon as cold weather hits I begin to get fuel in my oil again. I have eliminated the lift pump off the engine, the only seal is the injection pump seal and I cannot get it to leak. Truck runs incredible, fires right up, doesnt miss, doesnt smoke on start up, nothing and I am at my wits end.

A couple of weeks ago when it got real cold, I was driving home and I knew it was happening again. I could smell the fuel and it finally started running a bit rough and sure enough by the time I got home i was almost 3 quarts overfull on oil. I really hope nothing was damaged this time. It happened so fast!! Problem only occurs when cold. Went all summer with the same set up and the oil never got thin never lost or gained level. I feel that maybe I just flat out have it too hopped up for cold weather. I change the oil every 25-3500 miles, its plugged in every night and I am just stumped.

I dont mind takiing the bus, I really dont mind driving my 78(minus the 9 mpg 440) but I really miss my truck!!!! Any insight at all would be greatly helpful, I am totally lost on this one... even a starting point would be great. Thank you again I have missed being on the forum!!!

Buddy Stewert

Electric fuel pump could be it.
What is the psi when it is doing it.
Just a idea.

j_martin

What is your water temp?

What are your injectors, and how old are they?

Douglas2

hey-Hey!!!,
I am curious about how exactly you eliminated the front IP seal.

Now on to thinking out loud; there are two paths for fuel into the oil, either through that IP seal or past the rings from faulty injectors. The latter can certainly do some rather spectacular damage to the pistons( due to overfuel-driven overheating ) and also misc nastiness to the rings/cylinders from washing out the oil.
cheers,
Douglas

gyman98

I would get your injectors tested

bobva

Your Injection pump housing has a very tiny itty bitty superfine hairline crack. When conditions are right it opens up in your case colder weather.

You have a warm block on one side of pump and freezing cold air rushing through a ice cold radiator being blown past the pump.

When its extremely cold outside your T-stat is working double overtime keeping the freezing coolant out of the block.

brainfade

I'm thinking along the same lines as Bobva but would look at the pump seal first. If the seal rolled and started leaking it would drop the case pressure and affect timing, hence the poor running and fuel in the oil. When the engine stops the seal perhaps reseats and doesn't leak for a while. This could be temperature related. I'd just replace the seal, it's cheap though a bit of a hassle and at least you'd have that off the table.

On second thought, while you're in there check the side-to-side shaft play as well. It could be that a cold pump and a worn bushing opens up enough clearance to get the shaft off the seal causing a leak.

ChrisLib

Is that 2nd gen elec lift pump regulated and have you checked inlet fuel pressure? Perhaps the cold weather is causing the fuel to thicken a bit, which will drive up the pressure a bit, and cause the front IP seal to leak.....justhinkinoutloud

ebteckx

okay i will check all of the above, fuel pressure on that lift pump is 15 psi before filter. The injectors were "rebuilt" factory injectors about 3 years ago by the previous owner. The truck has never run bad by the way and it has had the current mods for a tad under a year and never has any problems during the summer. The only time its had any running issues was this last time because I believe the crankcase got so full...

ebteckx

Pulled oil filler neck let fuel pump run with a mirror and couldnt get any fuel to leak...

Also radiator gets partially blocked in the winter and the temperature of the truck is great, no overheating on engine temp and also no outrageous egts... no excessive smoke no hard start no extended crank no missfires not loss of power....

deanhinsley1963

As far as I know there are only three places fuel can get in the oil from 1 the lift pump on the eng. not a electric. 2 the fuel pump front seal or housing, probably have to pull the pump run on test stand and observe. 3 fuel injectors or inj. O rings.