Hi Everyone,

I have a problem that is driving me nuts. Recently my 96 Powerstroke has become hard to start just from sitting overnight. I let it glow and then crank. It just sort of spins and spins. I never crank it long. I reset the ignition and try it again. After a number of trys, it starts puffing smoke out the exhaust but has yet to try and fire. The only way I seem to be able to get it to start is cycle the ignition off and immediately crank without waiting for the glow light to go out. On top of that...when I do have to crank it several times, I sometimes get fuel dripping of the bell housing underneath. I have just installed two new Interstate MTP-65 batteries. I have also replaced the glow plug relay from Motorcraft. It has a one year old Injector Pressure Regulator as well.
Once the truck is started, it runs like a top and will not give me any more problems the rest of the day. But overnight...same thing.

Any ideas or thoughts? Any help is much appreciated.

Pat in WI

 

as a general rule when it comes to hard starting diesel engines (primarily just when the block is cold anyway) the #1 cause is failed/blown glow plugs.always check these first and replace them with motorcraft plugs if blown (preferably as complete set.)

i don't know your engine enough to know about the fuel leak during excessive cranking.

 

Welcome to the forums.

A couple things to check

The Glow Plug relay..

One large post has a constant 12v
One large post should have 12v when the key is turned to run
One small post will have 12v with the key turned to run
One small post will go to GROUND with the key to run and the ECM calling for the Glow Plugs to be ON

If all that checks out....

Unplug the plugs going to your valve cover gaskets.

You need to ohm out 2 terminals per valve cover gasket.

You are looking for the outer pins.

You want to see .5- 1.0 ohms
If you see more than that you have an issue. it can be the valve cover gasket(VCG), Under Valve Cover Harness(UVCH) or glow plug


As for your fuel leak, it is common to have the little blue hoses that go from the fuel pump to the filter housing to go bad

 

FORDF250HDXLT,

Would one bad glow plug cause the engine not to try and start or would it take more than one? I'm only asking because this is my first diesel. I don't understand either why the engine will finally fire when I quickly cycle the ignition without letting it glow. But with everything I have replaced so far...it sure seems to point to the glow plugs. They are the originals. I have 91,000 miles on the truck.

Diesel Brad,

Thanks for the extra tips. I believe I will be looking at either the glow plugs or the glow plug harnesses next.

Thank you both for your replies.

Pat

 

diesels don't fire up and run like a gas engine (as you know) as there is no "spark" plug used to ignite the fuel.
instead diesel fuel is super compressed and fires up off the heat from the super high compression.

Diesel Engines vs. Gasoline Engines - HowStuffWorks

when the engine is cold,the fuel doesn't want to ignite well.so you warm the cylinders up first using "glow" plugs.
if one of these are not working correctly,then that cylinder isn't going to warm up and aid in igniting the fuel.the more non working plugs you have,the harder the engine is to start.

cranking the engine will in itself begin to warm the cylinders up some.combined with some of the plugs warming as well,if you keep cranking,the engine will eventually fire up.it's just hard on the starter to demand so much over time.

once the engine has been run for the day and up to operating temp (and say it's 60F outside or better) then the heat from the block is pretty much all that's needed and you can fire them up without even waiting for the wait to start light to go out probably for the rest of the day.

im not sure how your engines glow plug system works,but with the diesel engines that i run in my trucks (7.3l idi engines) the glow plug controller doesn't glow the plugs for it's complete duration if a couple of it's plugs are inop,and in fact might just flicker the light without glowing at all.letting you know you've got to test your glow plugs.
they're easy to test as is the rest of the system it looks like as per Brads instructions.so you'll know soon enough if you have any burnt out or other related gp system issues.

 

if you are having fuel run down your bellhousing, youre likely losing prime in the system, allowing air in as well. this will cause one wh0re of a cold start in the 7.3.


other than that, youre dealing with a system that requires glow plugs to start in moderate and especially in cold temps. gotta love HEUI....


for the record, other injection systems don't require any starting aids in anything except the harshest of cold temps. especially the use of glow plugs....HEUI is finicky.

 

Thanks everyone for your informative answers. Now I have a clear direction to move in. I will check those hoses from the pump to the water filter first. Then I will move onto the glow plugs and harnesses.

Pat

 

Air intrusion is NOT an issue on the 7.3 Powerstroke like the 7.3 IDI.

I would start at the relay and work your way to the glow plugs.

One plug will not really effect the starting but 3-4 will

 

GOOD ADVISE GUYS , MINE WAS IN NEED OF G PLUGS ..THANKS

 

Diesel Brad,

I checked the Resistance across the glow plugs from the connector outside the valve cover. 3 cylinders were just under 1.0 Ohm...barely. 5 were over 1.0 Ohm. Looks like I am headed in the right direction. I looked on Amazon and found Motorcraft Glow Plugs for around $12.00 a piece. The valve cover gasket set which includes the UVCG runs around $148.00 for the set. I did see another brand of glow plugs that were cheaper and claimed to get 100 degrees hotter and faster...but I hate to deviate from original unless recommended. Do the above prices sound inline? I may change the whole package since I have to go in anyway.

Pat

 

Yes, that all seams about right. You might be able to save a buck or two. But you are not getting raped at those prices