AGCO GT 75A tractor-engine running backwards

   / AGCO GT 75A tractor-engine running backwards #1  

Sieg2014

New member
Joined
Nov 21, 2014
Messages
4
Location
Union City,IN
Tractor
GT 75A Agco
I am trying to go to bat for my son. The engine on his 2005 tractor runs backwards and AGCO will not fix it. It started doing this when under warranty. They have done bandaid fixes and it still runs backwards. My son said it is now a safety issue because if something flies off of it some one will get hurt. The dealer put a kick off flapper on it. They put a new governor on it. The regional manager told him to sell it! My son refuses because he said they will just sell it to some one else and they could get hurt. If they don't want to put a new engine in it, it should be scrapped for safety reasons. What does he do?
 
   / AGCO GT 75A tractor-engine running backwards #2  
Diesels can run backwards but there are reasons they will do so. Google "diesel engine runs backwards" and you'll find many instances of it happening and why.

I suspect it's caused by the operator. Releasing the ignition key too early when starting it can allow it to roll over backwards against normal rotation and fire and continue to run backwards. If a cylinder is on the compression stroke it will normally fire before TDC but if it hasn't enough energy to continue normal rotation, the piston may not make it past TDC and will reverse in the bore imparting enough momentum to the engine to continue running in reverse. Lugging the engine to the point that it is within a hair of being killed, then declutching can allow it to do the same thing.
 
   / AGCO GT 75A tractor-engine running backwards #3  
Since the tractor is nearly 10 years old, has running backwards got progressively worse during the time he has owned it? Is there a sequence of events under which it runs backwards i.e. every time it is turned off? What about the engine running backwards makes him think something is going to fly off?

I was evaluating a software update on a developmental engine for Tier 3 emissions and during my testing I encountered a very rare circumstance where the engine started running backwards. The fuel systems team did not believe this could happen but they duplicated the conditions I reported in the test lab and they found out it could happen. The change needed to prevent running backwards was a major engine hardware change that would identify certain parameters and shut down any fuel injection. Fortunately this was discovered well before production as making the change afterward would have been very expensive. This is what I thought of when you described your son's problem. You are correct in saying that selling the tractor will just transfer the problem, but it is not an uncommon retail practice, something I think of when I see a deal too good to pass up.
 
   / AGCO GT 75A tractor-engine running backwards
  • Thread Starter
#4  
Thank you for the comment. Will let my son know.
 
   / AGCO GT 75A tractor-engine running backwards
  • Thread Starter
#5  
MHarryE, you are right. There is a sequence of events that he has told me about. (I am better at nursing than mechanical things!) 2 pushrods were bent the first year, the hydraulics run backwards too, the engine is smoking more, there is a power problem, loader bucket "doesn't stay up". Reading comments on here makes it sound like he is stuck with the problem. It is sad the regional manager at AGCO called my son a liar, since comments here say it does happen. ACGO not standing behind their product is sad. He did find out after persistently talking to the regional manager that AGCO did relace an engine in the same tractor for a guy in Canada. I will let my son know you comments. Thank you.
 
   / AGCO GT 75A tractor-engine running backwards #6  
MHarryE, you are right. There is a sequence of events that he has told me about. (I am better at nursing than mechanical things!) 2 pushrods were bent the first year, the hydraulics run backwards too, the engine is smoking more, there is a power problem, loader bucket "doesn't stay up". Reading comments on here makes it sound like he is stuck with the problem. It is sad the regional manager at AGCO called my son a liar, since comments here say it does happen. ACGO not standing behind their product is sad. He did find out after persistently talking to the regional manager that AGCO did relace an engine in the same tractor for a guy in Canada. I will let my son know you comments. Thank you.

The machine I talked about - engine division sent me new software to evaluate. I flashed the software into the computer and during my testing encountered the condition where it ran backward. I flashed the original software back into the computer and parked the machine where our endurance test drivers would continue running it the next dat. When I arrived for work my right hand guy said he just got a call from the proving grounds - the engine had failed. We drove out and sure enough the side of the block was shattered, oil and parts all over. When engine division did their thing they found that when running backwards some of the injectors did their thing 40 degrees before they were supposed to start injecting and combustion pressures went out of sight. That is why the problem I identified was such a big thing.

The AGCO tractor is actually a SAME Deutz-Fahr branded for AGCO. As far as I can tell it is an Italian engine originating from the SAME part of the merged company. That increases the difficulty getting support because the company that sold it is not the one that built it. I can sympathize. I worked for Allis-Chalmers when Deutz bought the company and we had to switch to Deutz engines. Engine application engineering fell under my group and the project leader I had assigned was always complaining to me that trying to get Deutz to recognize problems was like beating his head against a wall. From what you are telling me the remnants of Klockner-Humbolt-Deutz AG are no easier to work with.
 
   / AGCO GT 75A tractor-engine running backwards #7  
The only flaw in this story is that the engine oil pump would also run backwards & therefore NOT supply lubricating oil to the engine. The engine would not run long without oil pressure.
 
 
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