L3650GST Glow Plugs / Will not start

[dkcobbs]

My L3650GST stalled out and now will not start. It has been getting harder and harder to start. We have cracked the fuel lines and have diesel at all four injectors. With a fresh battery, the engine will fire and almost start but just won't quite make it. When we tried to remove the glow plugs to check them we could not get them completly out because of the intake manifold. The local dealer is not being real helpful other than offering to pick it up (for a substantial fee) and look at it in his shop. I will spend the $100 for a shop manual before I go back to my dealer. No one I talk to can believe that the design would prevent the glow plugs from being replaced without taking off the intake manifold but it sure seems that way to us.
Does anyone have experience with replacing the glow plugs on a L3650? Is there some trick to it that we don't see?
Does anyone have the 3650 shop manual that would confirm you do need to take off the intake manifold?
We have been working on this for quite some time now and have tried everything we can think of with no success - any ideas would be greatly appreciated! Thanks

 

[bmiker]

You can test the glow plugs with out removing them. Can use a ohm meter or you can just touch the electrical contact end with a hot jumper from the battery if it pulls a good arc then the plug is working. The next thing to check is the glow plug controller this can be checked with a volt meter connect your meter to the hot wire that goes to one of the plugs then have someone to activate the glow plug switch if you read voltage the controller is working. Hope this will get you started.

 

[Rockyridge]

The only time glow plugs are used are before you start your diesel on a very gold day to pre-warm the cylinder a little. Other then that they are not used at all.
Your problem is almost certainly fuel or possibly not enough air. Check fuel and air filters. Most likely starving for fuel for some reason, but forget the glow plugs at this point.

 

[art]

The 3650 should start without the glow plugs above 50 degrees without to mcuh difficulty.

 

[dkcobbs]

Thanks for the responses - It was the dealer that told me that the glow plugs had to be working for it to start unless it was really warm - 90+ - and questionable even then. We have tested with a volt meter and do have good voltage to the glow plugs. How do you use an ohm meter to test the individual plugs? Just out of curosity, does anyone know if you do have to pull the intake manifold to replace the plugs?

Fuel has been our number one expectation all along but we have tried everything we know and everything keeps checking out. We first drained the tank and put new fuel in from a different source. We bypassed the fuel pump with an elevated reservoir going directly to the injection pump. We have pulled the fuel line at each of the injectors and made certian we have fuel to each of the cylinders. Any other ideas for what we should try this weekend would be appreciated.

 

[Rockyridge]

It was in the 40痴 overnight here in MN and it痴 now in lower 50痴 and I started my L3400 without using the glow plugs. Probably better to use them now but it still should start without them.

It sounds like you have worked pretty well with the fuel side of the problem, what have you checked for air supply?
You don稚 want to run it to any extent without the air filter, but for trouble shooting, you could try staring it with the air filter removed. If it starts and runs then you know it was a plugged air filter.

When it almost starts are you seeing anything (smoke?) coming out of the exhaust? If so, what color is it?

Let us know what you come up with.

 

[Yankee Clipper]

I think you have a problem with the transfer circuit. Did this just start when things got cold or was it getting harder to start? If when cold weather started, maybe the fuel is gelling in the lines or fitler, but it sounds like you have addressed that.

Take the fuel line loose at the injection pump (banjo fitting) and crank the engine over. You should get a jerking stream of fuel as the engine rolls over. If not, there is a small orifice in the fitting that keeps the appropriate flow to the galley. Be sure the orifice is open.

If you don't get flow, put a gauge between the transfer pump and the injection pump - it should read 3-5 PSI. If not, the transfer pump may be worn out or the filters restricted or the supply line out the bottom of the tank is collapsed/twisted/ aged.

The other note about checking th glow plug at the top post is correct - in the cranking mode, you should see battery voltage at the glow plug - if not find out why. Don't test them out of the tractor as they can explode - they need the heat sink of the bore in the head to function correctly.

One last thing - don't ether the engine or you will break the top ring land and it will have to get pistons and rings.

Good luck.

 

[dkcobbs]

Thanks for everyone's ideas - to answer the questions:
We have unhooked the air intake to bypass the air filter. The engine seems to have good air suction when we crank on it. But of course doesn't start.
When it almost starts the exhaust is dark gray, one of the guys helping me calls it black but I believe it is more of a dark gray. There is a substantial amount of smoke - very close to starting.
Yes we already have taken the fuel line off at the injection pump and we do get the pulsing or jerking fuel flow as you stated.
When cranking we do have voltage at each of the glow plugs - I don't have it here at the office but I it was slightly less than the full 12V - I think closer to 10 but I'm not certian of that off the top of my head.
Once again - I thank everyone for taking the time help me out.

 

[mrwitty_1]

One thing I don't see in any of the post is the number of hours on the machine, is there a chance the compression could at the threshold of low and without the aid of the glow plugs not igniting the fuel ? The way I check glow plugs in everything I have ever owned is much simpler to me, I use a volt test light, remove all the leads from the glow plugs, clip the one end of the test light to the positive post of the battery then touch the probe to the glow plug connector, if the light glows the glow plug is OK. After all a glow plug is only a controlled dead short that makes heat. I think from reading your first post that it stalled out then would not start you are looking at a fuel delivery problem. Good luck keep us posted.

 

[dkcobbs]

The hours on the tractor are slightly under 700 - we will be trying some of your suggestions tomorrow and see where we get.
Thanks