Ford diesel question!

In reference to below post. When I got my 7.3 a friend of mine told me make sure you wait for the glow plug light to go out before you start the truck, or you will damage the glow plugs,, true or not i dont know. But I have always done that and have never had any glow plug, or injector problems. After reading the below post about bad glow plugs may be the culprit, and the wire harness on the valve covers, do you need the glow plugs to start it?? I have 2 ford tractors, one has no glow plugs, and I don't think the intake manifold heater works, in winter I plug in block heater and tractor starts right up, my other tractor has both glow plugs and block heater, I use both in winter, so why wouldn't a power stroke start without glow plugs?? Just a thought..

I forgot to say, why won't the 7.3 start with out glow plugs, but with the blockheater plugged in?

Don't see how you could damage the glow plugs by not waiting. Just going to make it harder to start.Glow plugs heat the air in each cylinder.If you have a block heater. It will keep the engine warm enough so that you can start. Without glow plugs.The thing you don't want to do is use starting fluid. On an engine with glow plugs. Unless you can disable the plugs. Starting fluid with glow plugs. Is like throwing gas on a fire.

No it will not hurt the glow plugs just wont start as good. The 7.3 diesel after it starts will automatically poll sate the glow plugs on and off. Look at your amp gauge after start up.

I shouldn't hurt the glow plugs, but Why put
extra load on the batteries, they are trying
heat & now you load the starter motor. Might
be the reason why so many have wiring issue's
melted connectors on 7.3 engines.... I only
know it pays to buy Motorcraft Glow plugs..

When I leave mine plugged in at night I go out and start it right off no problems... In the summer or after its been run I don't wait for glow-plugs... Now in the cold months when it is sitting and not plugged in, I cycle the key on and off 2-3 times... Also if you turn the key and wait for light to go off I'm pretty sure but I think the glow-plugs run for two minutes... I could be wrong but i thought I read that somewhere.. I do this with my 7.3

They operate alot like the old IH diesels, where you had to use the glow plugs on them. I don't know the proper terms, but they have to be preheated.

Block heater doesn't get near has hot as a glowplug.

Some of the powerstrokes don"t actually have block heaters. Alot of them just have an oil warmer in the filter base. This is to warm oil for the injectors to operate properly. This heater system doesn"t warm the head enough for combustion with out glows plugs.

There's no harm to the glow plugs by cranking the engine before the WTS light goes out.

On my '99 I never wait for the light unless the outside temp is under about 55. Further it will start without the glowplugs in temperatures down to near freezing - though in this situation it will smoke and the idle will "romp" a few times before it settles.

That said it is easier on the engine, starter, and batteries to pre-warm with the block heater and mind the WTS light when cold starting.

Incidentally my truck still has the original glow plugs.

Waiting for the glow plug "wait" lite to go out makes starting easier on the starter and battery. The wait light on time is judged by the current flowing to the plugs. The hotter they get the less current they draw. A cold glow plug with draw between 17 and 20 amps, depending on the watt rating of the plug. SO a system with 8 draws 140 to 160 amps cold. Glow plugs do not heat the cylinder. They make a hot point that ignites the mixture when compression pressure doesn't get the mixture hot enough. Glow plugs typically get a tip temperature of 1500 to 1700 degrees.

Starting ether can be used on the older in-direct injection diesels with glow plugs. Though it is not the best of ideas doing so likely will not cause engine damage. The use of starting ether in a direct injection has a high possibility of causing engine damage.

Ford's 7.3, as with modern diesels using direct injection, will start without glow plugs to lower temps than the old engines but takes considerable cranking. When it gets below 25* here we start hearing complaints about "hard starting" and pretty well know the glow plug system isn't up to par. Modern diesels also use the glow plug or preheater systems for emission control so having a working system is just a good idea.

Also, having great batteries and a quality starter will help. Starter's don't get attention until they die but on a diesel they should be replaced "just because" every three to four years on a daily driver. They are like shock absorbers in that they don't seem bad until you get new.

Yes they will start just like Summer, or at least my 99 does, if it isn"t WAY cold and you leave the heater plugged in for a couple of hours. You also get instant heat from the defrosters that way.

Ether should never be used. Unless you know how to use it. It can damage engines. Saw a guy one time. Spray a whole can into the intake manifold. Then tried to start the engine. All he got was smoke and broken parts on the floor.

Yep, I dont even own a can of ether!

On my 1995 7.3 I know the glow plugs are bad so when it's below 40 degs. I plug it in and it starts with no problem. If I should forget to plug it in and it's say 30 degs. I hit the starter for 2 seconds and if doesn't start, I turn the key off and back on and wait 30 seconds. Then I give it just a little throttle and try again. Doesn't start, so I wait another minute or so, then repeat the same. Sometimes it takes 3 or 4 times of doing this but it finally starts. You will see some smoke from under the hood and exhaust. My mechanic told me NEVER to crank and crank on the starter. If it doesn't start in 2 or 3 seconds of cranking, WAIT. With his advice my starter lasted from 95 to 2012 because I have never cranked it for more than 3 seconds. In the summer it's not a problem, will start right up once the wait light goes out.

Hello JayinNY,
Glow plugs are a cold starting aid, so they are not needed above 40 degrees F or so. Sensors will not put them in the circuit, if they are auto wired to come on. Other set-up are manual, and the driver will put the glow plug on manually. But your engine may start well below that. Glow plugs are usually set in the precombustion chamber, to get the combustion mix easily ignited.
Guido.