LF 3400 Stalling till warm Cancel The title field is required!

1. Paul Pritchard

   

   0 posts
   
   5/8/2014 6:05 AM

   We have 2 lf3400 that are doing the same thing. When cold they refuse to run until they warm up. We can find no reason for this to happen. We have tested every switch, connection, and did every test procedure listed in the service manual.
   
   What we have found is that after you release the key, it will run for a while then stall. When it stalls there is a momentary drop of voltage on the hold circuit that allows the fuel shutoff to release. After awhile it stops doing it and runs fine. This occurs while the machine is sitting in one place.
   
   After testing and retesting and speaking with the service dept of our local dist and even the Jac rep for product support it still happens.
   
   Out of desperation / annoyance we borrowed a known working computer and installed. Both machines continued to show the same symptoms.
   
   Does anyone have any suggestion or direct experience with this problem and what did you do to fix it?
   
   Thanks
   pfp

   
   
   
   
2. Henry Heinz

   

   0 posts
   
   5/8/2014 6:05 AM

   I would be looking at a ground. Checking for voltage drop will help you find the source of the problem, but I'm guessing that a bad ground is causing your issues. Check your main cable to the frame and any other grounding cables/wire on the machine.

   
   
   
   
3. Frank McQuiggan

   

   2 posts
   
   5/8/2014 8:05 AM

   Along with the main ground cable Skip mentioned check the Positive main cable also, Had a tractor with both the negative and the positive cables go bad.

   
   
   
   
4. Paul Pritchard

   

   0 posts
   
   5/8/2014 2:05 PM

   Thanks for the replies. We will look at the cables etc. to see how they are. We are also going to contact Jac to see if there is something we can use to clean all the connections to ensure there is no corrosion on any the connections.

   
   
   
   
5. Dinger Greg

   
   5/8/2014 5:05 PM

   I like Skip's thought leaning toward ground. Check the ground on the side of the block closely too. Lots of OEM's put a heavy black goo to protect it and for some reason get it behind the connection all the time. Clean all that off to bare metal, maybe even find a copper washer to crush in there to really get a good bite, and tighten it up good.
   
   A lot of times the fuel solenoid grounds through the block, so if the block isn't grounding good then...
   
   Lastly, make sure you've got a good charged battery. GM is now saying to put a charger on the before you start any diagnostics.
   
   Good luck.