So, my accessory switch got left on overnight

[Igearhed]

I'm Jeff, long time troll, first time posting. My buddy and I went in halves on a 69 multifuel. We are both euro car mechanics, and no stranger to diesels, just on a much smaller scale. We have had her for about 2 years now, and occasionally park her at our shop for a couple weeks, sometimes a month. Never had a problem doing this...till now.

Showed up for work Friday morning and heard my low air buzzer going off. Walked over to find that some upstanding member of my community had crawled through the Deuce. No harm done, except the accessory switch had been left on. Luckily we had installed a starter kill switch for security, but the accessory switch still powers everything up. Including our brand new in-tank fuel pump. Don't know how long the switch had been on, but it was long enough to all but kill the batteries.

After charging the batteries, and long story short (taking runaway precautions, and clearing the cylinders ect.) we got her running.....but with a miss on one cylinder. Being Friday after work, and so mad at the situation we decided to leave it alone for the weekend. Of course we removed battery cables to prevent this from happening again before we can get a chance to work on her. As busy as we both are, who knows how long it will be before we have a free minute to go diagnose our miss.

So with nothing to do but speculate (for now) who wants to help me do just that? What about pumping the cylinders full of fuel for who knows how long will cause a miss? Our fuel tank was full of used motor oil (one of the many perks of being an auto tech, and owning a multifuel ). Of course our crankcase is over full now, on my week old oil change, just to add insult to injury. So, ideas, comments, suggestions, and the never ending hindsight that always ensues, why do I have a single cylinder miss after my accessory switch was left on overnight?

 

[gimpyrobb]

If the fuel pump was left on, and now you have a miss, AND the crankcase is over full, sounds like you have weak rings on a cyl.

I'd change the oil, put a car in the bed for weight, and run her hard on a 2-3 hour drive. If that doesn't help free up the rings so they seat better, its time to re-ring that cyl.

 

[pigpen60]

Yep, what gimpyrobb said!

 

[Igearhed]

I'm smelling what your stepping in, a low compression miss from poorly seated rings. She was running great before this, so just the pressure that the fuel pump put on the rings causing a poor seat? Like a flooded engine loosing compression from washing down the cylinder wall? Usually when I run into this on a gas engine my fix is putting oil in the cylinder to lube the cylinder and rings, regaining compression. It is oil in the cylinder, as thats what the fuel tank was filled with. Apples and Oranges, I know. Absolutely worth a try, have yall had good luck with this before?

 

[gringeltaube]

... What about pumping the cylinders full of fuel for who knows how long will cause a miss?...

How could that happen if only the fuel supply pump was running?



G.

 

[cattlerepairman]

How can this happen? I am unclear on this also. The in-tank pump provides fuel to the auxiliary fuel pump at the injection pump. It is a low pressure affair. Not sure how this would get fuel into the crankcase, unless something else is defective (e.g. a leaking, not bypassed FDC) that would also cause oil dilution during normal operation. Maybe there is a learning moment?

 

[gringeltaube]

Well, we learned already that fuel can get into the crankcase, for example if the booster pump seal is bad. (see this thread...)



G.

 

[Recovry4x4]

Need to specify what type of car to put in the bed there Mr Robb.

 

[Flyingvan911]

Find someone with a Mutt. It will look cool. He, he. We use our deuces to haul our Mutts.

 

[gimpyrobb]

Need to specify what type of car to put in the bed there Mr Robb.

Why, nothing short of the family truckster!

 

[rustystud]

I could see how fuel can get into the oil pan through a bad seal in the booster pump but there is no way it could get into the cylinders without the engine running. The injection lines need high pressure for them to pop the injectors first off. Second the Hydraulic Head will only bypass fuel until it is spinning and at a proper pressure of at least 20 PSI (bare minimum the TM actually says 30 PSI) . The in-tank fuel pumps only put out 10 PSI when new so we know that is not happening. I think you have a few problems here.

 

[brianp454]

I think you need to do a compression check before jumping to conclusions. There is also the possibility that you have an injector issue, broken push rod, rocker arm, flat cam lobe, etc. It might also help to do a cold start and monitor the exhaust temp close to each port to see if one is colder than the others. This could help ID the trouble cylinder.

If you had fuel dribbling into the engine you could have gotten into a situation where you shortened a connecting rod. If the lift pump is on it slightly pressurizes the system and if you have a leak in the flame heater, FDC, main pump, etc. you could have gotten fuel into the engine. Some potential leaks could get into the crank case, while the flame heater would leak into the intake side of the engine. The cylinder with an open intake valve or the lowest dribble path could have led to having more fuel in the cylinder than the combustion chamber volume. Did you notice anything the first time it was cranked after the unwelcome visitor incident?

 

[brianp454]

The flame heater can leak into the intake manifold.

I could see how fuel can get into the oil pan through a bad seal in the booster pump but there is no way it could get into the cylinders without the engine running. The injection lines need high pressure for them to pop the injectors first off. Second the Hydraulic Head will only bypass fuel until it is spinning and at a proper pressure of at least 20 PSI (bare minimum the TM actually says 30 PSI) . The in-tank fuel pumps only put out 10 PSI when new so we know that is not happening. I think you have a few problems here.

 

[Igearhed]

I don't know for a fact that fuel had gotten into the cylinder, just my first thought and that it leaked passed the rings and overfilled the crank case. I'm the furthest thing from an expert on any diesel, never mind this engine.

After charging the batteries, she would crank about half a revolution and stop, this is with the engine stop pulled. She did this a few times then turned all the way over and eventually started. Didn't runaway, but went to a roughly 2500 RPM idle for a minute before she stopped running. Again all with the engine stop pulled out.

We narrowed it down to a single cylinder miss by cracking the lines to the injectors while she was running. Thats where we stopped. I'm hoping I'll be able to work on her a bit tonight. I need to read up on the FDC bypass and then check and see if its been done. I'm pretty sure it has not. The reason I had ASSumed there was fuel in the cylinders and leaking passed the rings was because we couldnt get a full revolution when trying to crank the first 4 or 5 tries. Thinking a hydro-lock issue.

 

[gimpyrobb]

Wow, 4 or 5 times? I'd have loosened an injector or six after the first time, maybe even right away.

Anyhoo, might not be a bad idea to still do that and crank it over with the fuel stop pulled out. Of course do that after you change the oil! Next I'd run it hard with a load in the bed for a couple hours.

 

[gringeltaube]

The flame heater can leak into the intake manifold.

With only the lift pump running? No way.

Take a look into the elbow, how it is shaped where the spray nozzle is located. If this nozzle was defective, fuel may weep down into the turbo, but not into the intake manifold.

 

[Wildchild467]

With only the lift pump running? No way.

Take a look into the elbow, how it is shaped where the spray nozzle is located. If this nozzle was defective, fuel may weep down into the turbo, but not into the intake manifold.

That is what I always thought. I hear guys saying a bad flame heater can cause a crank case to fill with fuel and I cant for the life of me figure out how it ever could.

 

[gringeltaube]

Well, if- and after the turbo housing (and part of the inlet U-tube) got filled up high enough, fuel may finally get into the crankcase via the turbo bearings and oil return line.
But I've yet to hear of someone actually experiencing this situation. ... Or even managed to start his engine, like that. It wouldn't go unnoticed, for sure!...

 

[The King Machine]

What is described in this thread is almost exactly what happened to my truck. The only difference is....... I left the switch on by accident.

My truck was suffering from oil dilution before I left the pump on over night.
I tried to turn the motor over and it laboured, so I stopped. This incident was the catalyst for my truck. The engine needed work and I knew it. Leaving the pump on highlighted several issues.

I found the following:
My turbo was full of fuel.......leading me to believe my flame heater was leaking. So I deleted that.
My injector nozzles were toast........leading me to believe they were weeping fuel. She smoked white at idle also. Rebuilt the injectors.
The crank case was full to the top of fuel and oil. I believe this is why the truck seemed Hydro locked. Not form the top end but from the bottom. Possible?
I think this because when I removed the heads I didn't find excess fuel in the pistons.
I bypassed the FDC for good measure.
The head gasket was blown between 2 cylinders. There was no symptoms of head gasket issues.