Oil & Fuel 7000 series diesel won't start, need help!

[jnelson]

Bob,

I definitely agree with you. My question had more to do with what someone could do in the event of a timer failure than installing a bypass as a preventative.

I would only consider temporarily bypassing the glow plug timer under conditions where the timer has (or appears to have) failed as a way to diagnose the problem and/or to circumvent the problem if the need to use the tractor arises. I'm sure there are times that the tractor could be needed right now to clear snow or other cold weather purposes while it might take days to acquire a replacement part.

One thing that I failed to mention in my timer bypass question is that it would be important to determine if the timer is also a relay. If it is then one needs to use wire and a switch capable of handling the amperage required to energize the glow plugs to prevent creating a different problem.

I hope that I never have to worry about dealing with a balky or broken glow plug timer on my tractor. But with the number of times I have seen them discussed on forums I think it is important to understand them and know what to do if mine should ever fail or become suspect.

Thanks to everyone and HAPPY NEW YEAR to you all!

JN

 

[gammata]

My 7235 cub cadet had 2 pistons in the fuel injector pump break causing the pump to stop pumping. So it wasn't the fuel shutoff selenoid. Strange there was no noise when they broke that I know of and trying to start did not cause any strange noise. So no fuel no start. Sad thing is that fuel injectors are not made by tractor manufacture so must be taken out and sent away to be fixed. Should have tractor back in a couple of days. Fingers crossed; its starting to snow.

 

[gammata]

When I asked the mechanic why the injector pump would fail only after 1100 hours running time; the mechanic said " Have you noticed that diesel fuel is now clear and not coloured". He said the fuel suppliers have taken out the additives for eco reasons and the lubrication is zip now. Anyone else concur?

 

[jnelson]

I am not an expert on diesel fuel and injectors though I designed and built mechanically timed fuel injection systems for racing many years ago. Those systems (the mechanical timed systems) were extremely sensitive to tolerances, temperature, and even the tiniest contamination or dirt because they were gasoline systems and gasoline is a terrible lubricant. We used to talk about how much better diesel injection systems had it because of the better lubricity of diesel fuel. Now (from what I have read) that advantage has been reduced by the new low sulfur fuels.

I am not an additive expert but I have read a lot of good things about Power Service diesel additive Power Service Products, diesel fuel additives, prevent gelling, clean injectors, disperse water, boost cetane, reduce emissions, improve fuel economy. Because I am concerned about both increasing the lubricity of my fuel and reducing the effects of cold and moisture creating a gel problem I have been using the Power Service diesel additive year round. I mix 2 oz of the additive for five gallons of fuel. IE - two ounces of prevention.......

JN

 

[OldMachinist]

I too use Power Service diesel additive year round in the fuel for my skid steer. If you do a internet search for lubricity of diesel fuel you'll find many articles and studies about how since they started reducing the sulphur content in diesel the lubricity has decreased and there have been many reports of component failures. There are no standards in the U.S. for lubricity and fuels can vary greatly depending on the source of the crude and refinery that processes it.

 

[F100Panel]

on the manual operation of the glow plug front... I've done this a couple times.. I pick up a foglight kit at Autozone reasonably cheap. Comes with a 30 amp relay... and a switch that I toss in the drawer & buy a momentary switch. Rather than a long drawn out explanation, just follow the instructions for using the kit on fog lights and run a wire to the glow plugs rather than the fog lights & use the momentary switch... Remembering on a Cub, MAXIMUM 10 seconds... Works like a charm CHEAP.....

 

[kesterl]

F100Panel - Thanks for that advice. Since I started this thread I've gone through 3 sets of glow plugs!! And at $150 a set I'm getting preturbed. I thought about doing this and I actually saw what you're talking about at NAPA. I think for now until I can find the cause I'm going to try this. I think my problem is a short because when I'm using the tractor I'll see the glow plug indicator light come on after the tractor is already hot. But that could take a while to find. The only thing I don't know is can the glow plugs take a straight 12v from the battery? Thanks again for all the great info. I don't know what I'd do without the internet.

 

[jnelson]

Kesterl,

Wow, at $150.00 a pop I can understand why you want to get the glow plugs on their own circuit. By constructing a completely independent circuit using the delay and solenoid switches as described earlier you will eliminate the possibility of the plugs energizing during normal operation and hopefully extending their life. If the modifications work well I can't think of any reason why you would not just leave it at that - no need to run down your troublesome short.

Good luck with it!

JN