JD 2240 Runaway engine, resulted from return fuel hose getting disconnected

[fritza2tt]

The fuel to the tank return line got disconnected and sprayed fuel into the air intake. This caused the engine to run away uncontrolably and sever engine knock developed. This happened to me about four years ago with no after effects and then again yesterday, though this time with disastrous results. It is possible to start the engine but this ime the connecting rod bangs furioussly as soon as the engine starts to run. I now must decide whethet to scrap this 34 year old tractor or try to fix it. My thought is that first a compression check needs to be made to see how many cylinders are affected. If it is only one cylinder it should be possible to replace just that piston, hoping that the connecting rod is still ok. Other parts that might need to be replaced are the intake and exhaust valves, the cylinder itself and the upper connecting rod bearing. Has any one out there had any experience doing a repair like this?

 

[Briana03]

Hello, I moved your thread to the John Deere Owning and Operating forum. Best of luck and welcome to TractorByNet.com!

 

[Tx Jim]

In all my years of JD experience I've never heard of that happening. If return fuel sprayed at sufficient PSI to make it to air intake hole then the return line is PLUGGED. I think an engine dis-assembly is in order.

 

[cottermac]

I did rebuild on an engine one time that ran away and the only advice I can give is tear it down and do alot of inspecting. The one I did cracked 2 cylinder sleeves and melted pistons down like candles. If I remember right we used all new part to put it back together. I would also call around or do internet search for salvage engine for a replacement just to compare the cost. Hopefully you got it shut down before to much damage was done and it will be a easy fix. Best of luck

 

[fritza2tt]

Jim, this is a JD 2240 design flaw. The engine running away happened to me twice. Excess fuel from the injectors is routed through a small rubber hose back to the tank filler neck. The hose is attached there and held with a clamp. Over time the connection becomes lose and the hose slips off. Fuel continues to flow with the engine running and the spray is picked up by the fan. The fuel air mixture becomes combustible, gets sucked in by the engine air intake and the first thing you notice is engine ping. When I heard the engine ping, I naturally was concerned, stepped on the clutch and that's when the engine ran away. The proper procedure would have been to stay in gear and throttle down. The engine would then have died quickly and no damage would have occurred. In my case, the engine ran away but quickly died when I stopped the tractor. This was four years ago. The tractor continued to work perfectly until yesterday, when my son in law had the same experience. He hesitated too long and the engine trew a rod and then stopped. I nevertheless was able to to start the engine again. It ran for a few seconds making terrible banging noises. I quickly shut it down. The dealer was notified and I got an estimate for a $2,500 to $2,700 repair bill. :-(

 

[Tx Jim]

If it's a 2240 design flaw it would also be a design flaw on many other Dubuque/Mannheim built JD utility tractors. I worked for a JD dealer from the mid 60's through the late 80's and have been around/owned JD tractors since. As I stated I've never heard of this design flaw you refer to. I curious if YOU have to ever looked inside the diesel fuel tank filler neck while a diesel tractor is running??????? The ones I've looked at dribble fuel from the fuel return line into the tank neck similar to the way an elderly man relieves his bladder, positively NO SPRAYING.

 

[fritza2tt]

TX Jim, you are quibbling! Call it dribbling, call it spraying, the point is that enough fuel gets sucked into the engine this way to take over from the fuel injection pump. The fuel air mixture ready for combustion is compressed and detonates inside the engine! Diesels are not meant to run this way, it's when they "run away". When my tractor gets fixed again, I will make sure that the clamp holding the fuel return line attached to the filler neck, will get a strap to keep it attached so it can never again slide off and dribble fuel, as you call it, over the engine. Heck a fire could have started just as easily, causing the fuel tank to burst! That's why I called it a design flaw. The fuel return line should never be able to slide off from the filler neck. The first time it happened, the tractor was 30 years old. I figured it was my fault and made sure the darn hose was properly secured. Well it happened again anyway and this rime it will cost big bucks to remedy. I think every one should check that hose now and then and make sure that it will continue to stay in place.

 

[Tx Jim]

TX Jim, you are quibbling! Call it dribbling, call it spraying, the point is that enough fuel gets sucked into the engine this way to take over from the fuel injection pump.

There's a difference between quibbling and stating facts from hands on EXPERIENCE. Were you running your 2240 without the 2(two) air cleaner elements? As I stated I doubt if you have ever looked into the fuel tank filler neck of a running diesel engine. I have several times and your return diesel SPRAYING from a return line isn't happening. How long do you think a piece of rubber hose should last??? In your wildest guess why would you think JD engineers put no clamps on the fuel return line hose?? I'll help you out,because there's no real PSI on the hose or line. Look at parts key #15 in the 2nd photo. Have you stopped to think that the governor ring in the injection pump could have gone SOUTH and that's why the engine over sped???????????

 

[AGRIMAN]

I have many years under my belt also and I have never seen or heard of a broken/loose return line causing an engine to run away, mostly just makes a mess. Most of the time a runaway is caused by the rank sticking. I don’t see how the engine fan is going to atomize the fuel enough to get it to combust. It’s the air intake on a 2240 in front of the radiator?

TX Jim, What was the bust pressure on the old pencil injectors? Can’t remember.

 

[Tx Jim]

AGRIMAN
Thanks for the backup. I can't remember since I left a JD dealership as service manager in '87. I think 2750 psi but I will try to find out.