New Holland LB75 Thermostart

Does any one have any ideas why my New Holland LB75 Would keep burning out the glow plugs in the Thermostart system. The module and the temperature sensor have been replaced also. Dealer seems to be clueless as to why it happens and the Factory troubleshooting does not help. The only idea that I can come up with is maybe because it is a one Battery system the voltage drops causing it to draw too much amperage. Thoughts??
Steve

Check the voltage at the plug with a meter. It should dropout after the start position on the switch is released and engine is running. Sounds like they are staying on.

The only other check I can think of is to make sure they are the correct glow plugs. Are these aftermarket or right from the dealer? Some glow plugs are designed to stay on for a maximum of 20-30 seconds, others like the Bosch Duraterm vary the current flow to heat for 3 minutes, long after the engine is running. Sometimes with one glow plug out the others seem to follow not long after. If the engine starts with a miss that soon disappears, it's wise to check your glow plugs. Some will bypass the timer and operate them manually. I have found that fuel injection shops seem quite knowledgeable on glow plug problems also and are a good source of info. Phil

Did this problem begin after or before the thermostat and the module were changed? Are all the glow plugs mal-functioning at the same time or only one? When was the last time the glow plugs were changed?

regards
Marlon Khan
Ford Tractor Parts

Actually the Thermostart system has only one glow plug. Actually Glow plug is not the correct term it is really an intake preheater. The New Holland like many of the Fords uses a Preheater that drips fuel and ignites the fuel. The difference between the older ford systems and the new holland is that the new holland is automatically controled. You turn the key on wait for the light to go out. When you crank it over it goes back into heat mode. It will then stay on for a set number of seconds once the Motor starts. I will have to dig out the paper I got that tells the whole cycle.
Probably would not ave even had to have replaced the module, but had already done it before I got my hands on a troubleshoot chart for the machine. The service manual says nothing about the Thermostart system. Thanks SteveC

Most interesting. I have never seen one of these work on the older Ford tractor. I believe as they heat, a valve opens and diesel fuel from a reservoir leaks in. Possibly the wiring has been altered and a resistor was bypassed, a long shot. I would check out Bill's advice first, likely it's just staying on too long.

I question putting a lot of time and money into a heater of that design, not that it isn't a slick idea. Your engine could have other cold start aids added that would be more effective, and reduce wear on the cold engine as well. A manifold heater, probably of comparable output, was used on the old Case diesel engines. It would add 10-15 deg F to the starting range, but was ineffective when it really got cold. Phil

How many hours? Just stab in the dark, could a activation switch be sticking in the on position? What about dirty grounds? That alone can cause havoc.

Another thought, if it were mine I would remove it from the manifold, reattach the ground and watch it work, keeping safety in mind. A device like that may have a longer life if it has to vaporize the fuel, rather than 'burn' dry with no liquid available to cool the element(latent heat). Another long shot. Phil