Cold-startin' a 7.3 ...

[Kowboy]

Can it even be done??

This is my first 7.3 and first time she's seen cold weather. On my way to Denver to take deliv'ry of my Hallmark and havin' issues.

Night before last I was in Indiana and it was 20 degrees and I couldn't get 'er to fire off. Consulted the manual and followed the cold-start procedure. Can hear the relay clickin' for the glow plugs. Cycled it as many as 10 times. Engine is stock except for intake, exhaust, and tuner. Tried tuner at dif'rent settin's ... includin' stock. Good thang I got 2 new bat'ries. And fortunately I was fairly close to the lobby. So I ran a hun'erd foot extension cord right into the lobby and plugged in the block heater ... after I unplugged the Christmas tree to free up the outlet. :Wow1:

After an hour of bein' plugged in, she rattled to life.

If the relay or glow plugs are bad, wouldn't that trip the "check engine light"?? Any way the system could be tested by Ford or somethin'??

Ain't no electrical outlets where I wanna take this rig. Hate to have to buy a gen-set just to run a block heater. Any ideas how many amps the block heater draws and if I could plug it into an inverter in the camper??

This is an honest request for help ... not an invitation to bash super duties or 7.3's. Thanks in advance for any assistance.

Last night in Kansas, I chose a hotel with a ground-floor room ... a window that actu'ly opens ... and an open parkin' spot next to the window ...

 

[bulrid8]

Bad glow plugs won't trip a cel. Replace all the plugs and the relay. Will start just fine. Only use motorcraft glow plugs in it. The autolites will break off in the heads. If you are doing this yourself, they can be a pain. If they are not working, they will build carbon up on them. Then they won't come out the hole. Loosen up the plug, spray inside hole with a good carb cleaner and work up and down slowly. This will break up the carbon. Be careful to not break one off in the head. Also check valve cover gasket plugs for any signs of melting. Replace gasket and glow plug harness if there is.

Sent from my ADR6400L using Tapatalk

 

[plainjaneFJC]

My older 5.9's would have to be plugged in around 25F if I wanted them to start. This was a 95 and 97 model. The newer diesels seem to be much more forgiving. Maybe some 7.3 owners can chime in. It may be normal to plug those things in at that temp?

 

[The Grinch]

Sounds like bad glows to me. Especially if you cycled them a few times. Did it cough or sputter or do anything?

Starting fluid can be used in these situations but if you are not confident in how it should be used around a diesel then DO NOT attempt it as with the high compression of a diesel you could do engine damage.

You may have a few glow plugs working and that is why it starts okay in warmer temps but not so well when colder. The glowplug system would be the first place I would look. They can often be tested with a multi meter.

 

[Rot Box]

Check Rock Auto sometimes they have the Motorcraft plugs for a great deal. Again Motorcraft nothing else..

One cycle will get the plugs as hot as they need to be. If it doesn't start after a few cranks cycle them again. I've found multiple cycles before the first crank does more bad than good.

Good luck keep us posted.

Andrew

 

[Buliwyf]

Find your glow plug wire and unplug it. Then with the engine cranking gently feed it starting fluid. You can also gently spray it on the air filter and then crank the engine. But that isn't as safe as an already spinning engine. What you want to avoid is filling the cylinders with starting fluid of a stopped engine. But the glow plugs MUST be turned off, as are any intake heaters.
-
I haven't tried this with a 7.3L Ford. But I allways keep a case of either on my truck for industrial diesel engines. Some engines can handle more either than others. A
DDC 12v92TA, for example, can handle 2 entire cans of the stuff, I hold two cans, one in each hand a hose away while cranking. Works every time. But it's best if a master tech deos it, because we know when it's a lost cause. Some crappy Onan diesels will actually slow down as either is applied. If you see that, STOP right away! The either is lighting off too early and making it harder to start not easier. Compression might be too high for either start, or glowplugs are on, or preheater in the intake.
-
I'd check for voltage to the glowplugs, and make sure they're pulling amperage. With a decent amperage reading, you can calculate wattage. Then compare the wattage requirements of 8 glow plugs. If the number is low, then you have failed plugs.

 

[Rot Box]

Oh and never use starting fluids unless you make sure the gp's are not turning on. Disconnect power to them just to be safe. One whiff of that stuff hitting a hot plug can cause multiple cylinders to fire all at once you can imagine the engine damage.

Edit: -Buliwyf beat me to it

 

[fluffyprinceton]

Ain't no electrical outlets where I wanna take this rig.

If R&R ing the glow plugs doesn't help enough consider a diesel fired coolant heater - you can heat the camper with it too...Moe

 

[truck mechanic]

My 97 starts all summer with out useing the glow plugs, in the winter I have never had to cycle them more than once to get the truck to fire. I would do as others have allready said, replace all the gp, check the relay, and intake heater, and all the under cover wiringing.
Let us know what you find.
Paul

 

[F350]

I'd start with the relay. I've replaced mine 3 times in the 10 years I've owned it. Napa #GPR109. I know guys that short across the studs on the relay with a screw driver in a pinch. For giggles I started mine yesterday morning at 16deg just to see if it would start. Fired right up without being plugged in. My 2 cents...

 

[back woods]

Cant be afraid to turn that starter. My two 7.3s start like a bear.

 

[Kowboy]

Thanks for the info Folks!

It was 5 degrees this mornin' when I pulled outta the hotel in Kansas. Ol' girl fired right off of course since she'd been plugged in all night. I've now migrated over to Brighton, CO and the manager of the hotel was nice enough to let me plug 'er in to a normally locked-up exterior outlet.

I don't like the cold weather no more than the truck does ... so my solution to this deal is to grab my camper tomorrow and then proceed due south until it's warm. :ylsmoke:

Then I'll look into the relay and glow plugs.

1723 miles here from the east coast thru some right nasty weather ... and my first stop was for a beer. :beer:

 

[surlydiesel]

As others have said, replace the glowplugs but I would first replace the GP Relay. It's a 15 minute job start to finish if you take your time. They are crabby in cold weather but can come to life with the right parts working correctly.

Have fun!

-jorge

 

[plainjaneFJC]

That's a nice looking truck. From the pic it looks like the frame is bent? Maybe my eyes are bent!

 

[shortbus4x4]

Check the glow plug relay/controller, they are known to burn out. Check your valve cover harnesses, they are known to burn out too. You can pull the valve covers and ohms test each glow plug, I think 1.5 ohms or less is good. Make sure you have the right oil in it too. One last thing is that the 7.3 powerstroke seems to be pretty picky on getting the right battery voltage to different modules for it to fire. I have fixed quite a few rigs that came in on the hook at the first cold snap that cranked ok but seemed just a little slow. Two new batteries and their cold start problem was fixed. I suspect you probably have 2 or 3 bad glow plugs based on my experience. Of course I think your idea to head south to warmer temperatures is the best fix.