i bought a 99 f350 7.3 last Saturday. they had it running when i got there and thought that was a little weird. ran great and was a great deal so i bought it. got it home (4 hour drive) with no problems. well i go to start it on Thursday afternoon for the first time since i got it home, and no go. it wanted to, but just couldn't catch. i put the battery charger on it for about 24 hours and plugged it in for about 5 hours. got home from work and the same story, only shorter time since the battery's seemed to still be low. i didn't get a chance to see if white smoke was coming out, as i did not know to look for it until i search on here and now my battery's are to low to test that. i figured it may be the relay, so i tested it and got the same volts on each side. the 2 small wires that go to it had a huge difference, but dont know if that matters. i wanted to check the the GP from the connector, but did not see it, and ran out of daylight. it has been under 30 since i got it and been 0 degrees at night.

my questions are:

should the little wires on the relay have a huge volt difference?
where the hell is the GP connector to check them?
what ohm setting should i check them at? my ohm meter has like 10 different ohm setting.

this is my first diesel and know very litle about them other then searching on here.

 

Read through this, it explains everything.
on your voltmeter, if it has several ohm settings, then you should use the lowest setting.
Hope this helps man.

 

Welcome to FTE.
Take the top off the fuel filter. Pull out the filter and look in there. Dirty? How does the fuel heater look? Do you have a way to check for codes? How about the fuses under the hood? Did you try plugging in the block heater for a while? It could be a lot of things. I guess even a CPS. I'm sure more will chime in with better knowledge than me. Hang in there. There are some real gurus here.

 

Make sure that your batteries are good. Your IDM needs to see a minumum of 10.5 volts to fire the injectors. Your glow plugs run for up to 2 minutes after the WTS light goes off.

Here is a thread that will help you with the glow plug system

https://www.ford-trucks.com/forums/7...pr-system.html

Here is one on the battery system:

https://www.ford-trucks.com/forums/7...y-q-and-a.html

 

Welcome to FTE. When you get in the truck and turn the key on, does the wait to start light come on for a few seconds? When your cranking the engine does the tach gauge bounce? If you take a volt meter and test each battery, what voltage do they read? How much does the voltage drop while cranking?

To answer your questions, the GPR has 12volts coming into it from the batteries on one big post. The second big post will have 0 volts with the key off, and should have around 12 volts as soon as the key is first turned on for 1 - 120 seconds. One of the little posts is a ground wire when the key is first turned on (for the same 1-120 seconds as the power output) The ground signal on the little post is what trips the relay and sends the current through it. The wiring to the glow plugs are on the inboard side of each head near the center. The wires plug in to where the valve cover meets the head. The front 2 and rear 2 wires in each plug are the glow plug wires.

 

http://i233.photobucket.com/albums/e...coverplug2.jpg

The is the plug that you will unplug. You will measure Ohms from were this plugs in to. Not from this plug. So you can see what the plug looks like. It Plugs into the top center of the valve cover gasket. One on each side. I forget the ohms, I think my new ones measured .3 to .6. If i remember.

You can measure GP to Ground(-bat)
Pins go.. GP.GP.INJ.INJ.C.INJ.INJ.GP.GP

On the glow plug relay. Rear most relay.. One big lug is 12v constant. The other lug is 0v key off/12v key on.

Edit. Dang Chris. Your getting fast at typing.

 

Welcome to FTE.
Nothing to add, but it sounds like possibly the glow plug relay is shot and the glow plugs are not getting heated.

 

try un pluging the icp sensor on the front top of the drivers head when it wont start.if it fires up it needs a icp sensor.the sensor needs to see 500 psi before it will operate the fuel injectors.when you unplug the sensor it gives the computer a ficticious 500 psi reading and allows the injectors to operate

 

thanks for the reply's guys. im going to look into it further today. i do not think it is a fuel issue since it was trying to fire, just would not catch. i will test the gp in a little while and see what i come up with. if that test fine then i will move on to fuel.

 

only got a reading on one of them of .002. the rest where .00. the ohm meter would jump up then go down to .00.the one that did read with the front one on the drivers side.

i tested the relay is it stayed on for awhile. i counted 112 seconds, but could of been longer. so im guessing that is good.

 

Welcome to FTE - Make sure your batteries in your meter are good for resistance readings.

 

just got some new battery's today with some motorcraft GP, oil change, trans filter, fuel filter, and air filter. i will check out the harness when i get in there. anything else i should look at while the valve covers are off?

 

Yes, Go ahead and re-torque the rocker arm pedestal bolts (circled in red) to 20 ft-lbs and the lower injector hold down bolt (circled in blue) to 120 in-lbs.



Then closely inspect the connector that plugs into the valve cover gasket on the inside. If it comes loose enough to look like this


Then the truck won't run right. You can buy retainer clips that slip in there to prevent this from happening, or simply fabricate your own shim to keep it locked in place. Many of us here trim down a quarter to use as a shim

 

thanks for the tips

i did see the quarter mod in my deep search for all of this. does the quarter slide in there pretty tight? dont really want something like that flying around in the valve train. i actually work for a newspaper company and have quarter dud's, so it will be a free mod for me.

 

Yes the quarter fits in there very snug. Once you get it in, you'll see there's no chance of it going anywhere. The only way it can move is straight up out of the connector, which the valve cover being installed will prevent.

Stick the blank in there and see how it fits. If you have any doubts, just pull it back out.