I have a '86 f-350 Crew Cab 4x4 with a 7.3 (junkyard motor I know origionaly it had a 6.9) if it is left for more than a couple of hours it will not start without a shot of ether! The glow plugs all work and are on a momentary on switch that was installed before i accuired the truck. It also has a electric lift pump installed as there are two diffrent mechional pumps but I have not found any information as how to tell which one this motor takes. It would seem to me that air somehow gets into the injection pump. It also "rattels" after decending a long hill and you get back on the throttle. I travel through the Rocky mountians a lot! I have not been able to find anyone here in Cheyenne that knows anything about this as it is a old truck I have not tried any diesel truck places yet. Hope that someone out there can help me out.

 

How do you know the glowplugs all work? Diesels do not get addicted to ether. They can get in bad enough shape where they do require it, but if things are fixed, it won't need it anymore.

The diesel engine works on heat. It has no sparkplugs. It's very difficult to start a cold diesel engine. The cold metal of the block sucks all the heat away from the chamber. You need working glowplugs to generate heat, and it needs to crank over fast to also generate heat when it compresses the air.

Do you have a block heater and can plug it into 120v? If so, plug it in for several hours and then try to start it. That will also put heat in the engine and make it start if the glowplugs are not working correctly.

 

I have checked all the glow plugs and they work. It does not matter what the outside temp is... it will not start without ether even in the desert at 100 degrees. It also does not burn any significant amount of oil. Any idea about the hammering rattle? I've had my camper on this truck for seven years and have had all sorts of people tell me "oh its your glow plugs" so I realy get tired of hearing it. If you have know idea what your talking about and don't listen to what is asked why waste your time or mine?

 

You have not answered Dave's question - how do you know they work? What methods and techniques did you use to check them? HOW WELL do they work?

He knows plenty about what he's talking about and is trying to diagnose this but needs your help... but if you won't help him and answer his questions, why should he waste his time on you?

 

Strong reply for a new guy. I am trying to help you. Like I said it needs heat in the chamber to light off. The glowplugs are very important in this and will be needed even in 100 degree weather on the first start of the day.

There is a certain procedure to check them. How did you do it? What brand glowplugs are you using? That's important too, some cheap store brands like to burn out.

 

Keep feeding it ether, and the pre-cups will fall out. Prolly already loose as heck.......

Like Franklin asked, how do you know the glow plugs are working?

Have you had the timing checked lately?

How old is the injection pump? Injectors?

Getting *good* voltage to the fuel shutoff soleniod?

Strong batteries, able to spin it fast enough? Starter in good condition? Battery cables all good and tight/clean?


So many little things can make one of these old IDI engines a bugger to start when "cold", and for them, cold starts are anything under 180F..........

 

Well so far the only "good" info has been voltage at the fuel cut soniold. The battries are new Intrestate 1200 CCA commercial, the starter is a new Napa Gold, the glow plugs are new Autolight checked with a Snap-on inductive amp meter, draw 65 Amps.
Now any thing new to check? Still would like to know why the motor "hammers" after a long deceleration.
I do not have much experence with International diesels. I have a fair amount of experience with Volkswagen diesels but being made by germans they make much more sense than Ford. The camper has been moved to a great diesel truck, '96 Dodge Cummins one ton. a much better engine as Cummins has been making the same motor for years and was smart enough to turbo it from the start. There is room under the hood for a battery isolator and air compressor that there was no room for on the Ford. It would make the Ford easer to sell if it would start without a shot of ether.

 

Sorry to tell you, but your glowplugs should be drawing at least 150-200 amps when they are first fired. Something is not right with your glowplug system. Hope that is something "good" to get you pointed in the right direction.

 

Dave these are the "slow" plugs draw is a little less than 10 amps each. The "fast" plugs (6volt) that were origional equipment have a much higher draw. The "fast plugs were replaced with "slow" plugs as the "fast" plugs will pop like flash bulbs if left on for to long and the "slow" plugs will glow red for a long time before failure. So yes I do know about glow plugs and their operation and understand how a diesel works I have been a professional mechanic for 40 years. I have not checked the fuel cut solinoid yet but would guess that the starter (which draws just over 100 amps) could be "starving" the fuel cut of power. This could be the cause of not firing while cranking and then running when the key is released as the solioned would would then get full power.
Any idea about the "hammering" after a long deceleration?

 

It's tough to figure a hammering problem on a diesel, when they do hammer normally at lot of the time. I know these type diesels are fairly quiet compared to a powerstroke, which hammers most of the time. It could be something with the injection pump and the timing functions inside it. A "cure all" for mystery pump problems is to take the fuel filter off, dump the fuel out, and put fill strength diesel klean or something like that in it, or some people fill it with transmission fluid, run it a for minute to get the fluid in the pump, and then let it sit for awhile to break anything sticky loose inside the pump.

I think we are done on the glowplugs. I personally do not believe you are going to get it to start unless you put the correct glowplugs in it. I have a manual button on my truck also. The only glowplugs to run are the motorcraft or the internation brand. They are made by Beru. The autolites tend to burn out, and when they do they can swell on the end, and when you take them out the tip can break off inside the engine.

Go buy a set of motorcrafts, hold the button in for about 5 seconds, and it should fire off. If it doesn't, hold it for another 5 seconds and it should go unless it's very cold outside. I haven't burnt any of my glowplugs out doing this, and mine starts right up. I only need them on the first start of the day.

 

Thanks Dave, I have tried the Kleener in the fikter already. I still think that there is something else wrong, but I haven't found anyone that knows what the problem is although I believe that it is in the injection pump. no one seams to have the knowledge about what is causing the hammer after a long decel it slowly goes away after the throttle is applyed it goes away faster if full throttle is used. I think that air somehow gets into the system, but no fuel leaks out. Makes no sense. Will be checking the fuel cut soloniod as soon as the weather improves. Thunderstorms today and snow tonight. I'll post again after checking the fuel cut.

 

If I were you, and I was so sure that everything was correct plus good compression, and it was an engine from a junkyard with an unknown history, I would mark where the timing is and try to retard it some to see if it would start. If not then try advancing it and see if it starts. The "rattling" you speak of could be over advanced timing.. If that fails I would just cough up the money on a new pump if I was 100% sure that the glowplugs, starter, compression, battery cables, batteries, and fuel lines checked out.

That being said Oilburners.net is a better site to post this on, but they are going to tell you what we told you.. to start with the glow plugs. If a small shot of ether causes your engine to immediately start and maintain idle, it is not a fuel return leak, otherwise it would likely die after burning off the ether.

 

They claim the pump and the injectors are only good for about 100,000 before they need replaced/rebuilt. I can't bring myself to spend all that money and go through the trouble on my truck. It just runs and starts too good. It has about 140,000 on it.

 

Air can get in a much smaller hole than fuel can leak out of. Adding a short piece of clear hose right at the filter housing can allow you check for air in the system without having to open it up.

I think the injection timing may be off. Hard starts and funky "hammering" on decel can both be caused by timing too advanced. These things do have a cold start advance, so base timing set too far advanced is compounded by the cold start advance. Even the Cummins can be a bugger to start cold, with overly advanced injection timing.

I agree that the Cummins is a superior engine, that's why I have one ready to drop into my ford truck, but these IH IDI engines are tough old engines. They just need a turbo, like almost any diesel engine *should* have.

 

Rouge Wulff,
Thanks for the heads up on the pump timing. Finally a reply with a explanation and no BS! I will be adding a wire from the starter solonid to the fuel cut solonid to make sure that it is open while cranking. and will retard the timing a tad too. I will not be putting the "fast" plugs in as I would have no control over how long some other user of the truck would hold the button. This motor was purchased from a yard with a good reputation, copmression was checked before they pulled it (all around 400PSI as I recall), was clean, sealed and wrapped on a wearhouse rack. Sold with a warnantee. I replaced the rear main seal (from ford) and valve cover gaskets before I installed the motor. It was spotlessly clean inside. It does not leak or burn oil. Fuel millage with the camper and a single axle inclosed trailer with three dirtbikes and gear ranges from 8 to 12 MPG depending on the wind! It just has too many electrical gremlins, to slow and no turbo for me to continue using it and I now have a Dodge xtra cab one ton to use for camper duty.