OK - Recently bought a 2001 RAM 1500 4x4 Off Road 5.9 gas. Was not able to start or test drive prior to buying (auction) but the price was right. Had the vehicle transported to my shop. Was able to start up there, and it ran fairly decent. Took it for a test drive and it was lacking power and missing occasionally. Found that the oil pan "self fills" - not with coolant, but with gas. Spark plugs are an oily mess. Suspected the typical "plenum gasket/plate failure" so pulled the intake to inspect. There was oil in the intake plenum side. Also found that the PCV was broken and obviously not working. I have put in a new Hughes plenum kit, cleaned up the intake. Also noticed that when I pulled the fuel line from the fuel rails that BLACK yucky gas came out. Checked all the fuel injectors - one was not working at all and one was leaky, so bought 2 new injectors. Thought I better trigger the fuel pump to see what the gas looked like coming from the tank.... yuck! black... looking like a thinned out version of what the oil in the pan looks like. I plan on pumping out all the gas from the tank, but my question is - How does crappy oil get into the gas tank in the first place? I want to be sure I have corrected all the problems on this 5.9 before I go to start it up again.... your suggestions please.

 

The short answer it can't. Not unless someone poured oil in the tank.

 

Either that, or the gas sat for an extended period of time........

I would empty the tank, drop it, and clean it out.

 

I would not think there was any way to screw up the gas, normally - without dumping something into the fill access. Even old gas does not turn black, and if it was really old gas it smells like funky varnish, which this does not.... still smells like gas. The only other connection to the tank is via the vent system... a pretty good sized hose that runs from the tank to the engine compartment, and has a vacuum controlled purge valve there. Is there any way that can go haywire and take oil from the engine (remember the PVC and plenum were screwed up) and send it to the gas tank? Yes - I will flush the tank, but just wondering if that vacuum purge valve stuff might be messed up as well???

 

To my knowledge no. Not unless the intake filled to the top with oil. The purge valve pulls air from the tank, doesn't send air back in.

 

WAG time - I wonder if someone dumped something in the tank thinking it would keep the fuel from going bad. Real fuel stabilizers don't tend to affect the color, but there might be some home-brew recipe out there that would.

Regardless - clean the tank and flush the lines before trying to fire it up again.

 

If I had to guess.... that black yuck coming from the gas tank looks like someone dumped used oil from the oil pan in there... and must have been a fair amount. Today I thought perhaps I could pump the bad crap out of the tank by turning on the electric fuel pump (dont think it had more than 2-3 gallons left in it) and then run some good gas back in the tank - suck that out and repeat a couple of times to clean up the tank.

That did not go very well. When I turned on the fuel pump, the black gas was shooting out of the hose I connected to the fuel rail quick connect just fine, but after about 1/2 gallon pumped out, the flow started to sputter, so I thought the tank was near empty and the pump was losing prime. I let it sputter for a bit and got maybe another 1/2 gallon out. I then put another 2-3 gallons of good gas into the tank and started up the pump again. Did not get a strong stream coming out... just the same trickle with an occasional brief spurt. Putting the end of the hose in the bottom of my bucket showed that the pump was pumping mostly air.
I pumped about 3-4 gallons of black gas out and then put another 4 gallons of clean gas into the tank. Started up the pump again and was getting the same erratic spurts and lots of air coming out. Let that run until I pumped about 4 gallons out of the tank. The gas coming out was still very black - my "rinsing" operation did not appear to be doing much good, as far as getting rid of the black. Now I am wondering if something is wrong with the fuel pump, since I could not get it to output a strong, steady stream except for the first few seconds that I started pumping out the tank. Anyone used this method to empty their gas tank? Is 3-4 gallons not enough to keep the pump primed, or is my pump a goner as well?

 

You need to drop the tank, and clean it out. Then, you are likely going to need to replace the fuel pump module, as I do believe the filter is trashed, and it ain't available separately. Not to mention, who knows what damage that stuff has done to the pump itself.

 

Yea, the only way to properly fix this mess is to drop the tank -- uuuughh, was so hoping I would not have to do that. There seems to be no light at the end of the tunnel in the near future for this RAM.