Hi all, bough my first diesel truck the other day. 1994 F-250 4x4 with the 7.3l IDI. When I got it, the glow plugs weren't working so I replaced them all with genuine motorcraft plugs. The relay and or controller were also suspect and since they looked original I went ahead and replaced them too.

For the first few days the truck started fine in the mornings but now its getting harder and harder to start. Just to be sure I have double checked and tested each individual glow plug with a test light and checked continuity. Tested the relay and controller, including voltage to the relay and voltage from ignition. Glow plugs come on and then cycle as they should, then after the WTS light shuts off I can hear the relay clicking. I also verified I have voltage getting to all 8 plugs.

When I try to start it in the morning I have to crank it for quite a bit after the WTS light goes off before it starts. Once it starts it runs great and once it's warmed up theres no visible smoke.

Is it possible I have injector(s) leaking inside the head and therefor losing fuel pressure and that could be causing the hard start? I have verified that there are no external fuel leaks. I changed all the return lines, o rings and injector caps when I first got it.

Thank you in advance, this truck is now my daily driver so I've gotta get this figured out.

 

Plug the truck in one night and if it fires good in the morning and runs and dosn't stall it s a glow plug issue. if it fires and stall in sbout 5 seconds its a fuel leak down issue

 

Might not be turning over fast enough.

 

both of the above are good things to look at.
if it starts and then dies rite away and takes forever to restart, that is air intrusion.
pull the fuel filter when cold and see if it is full. if not, air intrusion is the culprit.
a always connect a small 12 volt light, or now use a 12 volt led to the output of the glow plug relay. this way i know for a fact whether power is going to the glow plugs or not.
just because the light in the dash goes on, that is not a guarantee the plugs are getting power.

as for the starter not spinning the engine over fast enough, a weak starter will fire a hot engine but sometimes not fire a cold engine.
here are two short videos of a good starter ar 40 degrees, and a bad starter at 70 degrees.
click on the links to play the videos.
bad starter:
http://vid41.photobucket.com/albums/...8/DSCF0070.mp4

good/new starter:
http://vid41.photobucket.com/albums/...8/DSCF0080.mp4

 

I'm not sure if the block heater works. I will try that tonight though and also check before I start it in the morning to see if there is evidence of the block heater working or not. It never stalls after it starts, it just struggles to fire then once it does it runs fine.

Interesting! I don't know why I never thought about that, I've actually seen that be the culprit on Diesel motors before.

How large of batteries should this truck have? How many cranking amps? I should also load test both batteries.

Wow that bad starter video kind of sounds like mine trying to start. The glow plugs are definitely good. I've testing each plug, and the relay with a test light, and each glow plug wire. Everything there checks out, which it should because it's a brand new relay, controller and all new plugs.

Thanks for all the replies! I definitely need to find out if I have big enough batteries, they actually look a little small for this truck, and yesterday morning it was definitely turning over slower than usual and took a lot longer to start.

 

Oh I forgot - in that video I noticed he put the accelerator pedal to the floor while cranking it over. I've always thought that wasn't necessary for a diesel because its injected...

 

I think you will find starting instructions on your sun visor. Sounds like you need to test your batteries, cables and starter. Its usually the starter. Reman ones are hit and miss. Some people have had good luck with db electrical off ebay. Ive got one of theres that is intermittent no crank. Ive been through several autzone ones. At least they are lifetime warranty. Tom has had good luck having them rebuilt locally.

 

Says to depress throttle 1/2 above 32* and fully below 32 when cranking. Doesnt really matter, it helps mine start, others say the opposite, see which way yours likes it.

Couplbe 800CCA batteries should be more than enough, i use a single 950CCA group 31.

I got a new OEM motorcraft at Oriellys, almost 400, but worked great. Some use a cummins starter, cheaper i guess. Local rebuild is probably safest if you can find someone with a good rep.

 

stock batteries are group 65 800CCA or better.
the bad starter video was a DB electrical starter that was only around 11 months old. i put it in to get the dead one i had rebuild mainly because it was free, and i wanted to see if it was any good or not.
it actually left me stranded at a fuel station 5 miles up the road about 3 days after that video was taken.
lucky for me the old wrench puller was kind enough to climb under the truck and smack the starter with a hammer and get it spinning enough to fire it up.
it has since been rebuilt by my guy and is sitting on the shelf in the shop waiting for a truck to go in.

 

Hi,

I had a similar problem with my truck. I replaced the glow plugs, the GP relay, and the starter. That all helped, but on cold mornings the trucks was reluctant to start unless I used the block heater (more on that in a sec). I referenced the owner's manual (yes I was lucky to buy a truck that still had the manual and it detailed a cold weather start up procedure. At temps below 32 degrees, you are supposed to crank the truck with the pedal all the way to the floor. Above 32, you should crank the truck with the pedal half-way depresed. Following these procedures made starting my truck much easier. It starts the first time, every time now. I don't hold the accelerator down after the truck fires up. I just ease off and let the high idle solenoid do its job.

As for your block heater, you can actually hear it working. Just plug your truck up and kneel down next to the passenger side front door. If you listen carefully you should be able to hear the heater working. The heater is just above the starter. If you're having trouble hearing it, you might have an easier time hearing it from under the truck. Just find the starter and you'll see it. Mine wasn't working when I first got the truck. I replaced the cord (most common failure point) and haven't had any trouble sense.

Hope this helps.

Mike

 

Yeah, we've got three of these trucks in my family. None of them like it floored; I've found 1/4 pedal works best for starting.

 

I didn't like the idea either and it still makes me anxious sometimes to press that pedal all the way to the floor when I'm dealing with a cold engine, but the manual was pretty clear on the procedure. And it has worked in helping me start the truck reliably, while reducing cranking time. Still, the best option is to use the block heater to avoid the need for a true cold start. I only rely on the factory cold start procedure when I'm in a place where I can't plug in.

The other thing that seems to have helped my truck is using 5w40 Rotella T6. I write "seems to have helped," beause I can't be 100% sure on this. I started using it shortly after I got my truck as part of a full-court press to improve starting and to reduce engine wear. I was doing a lot of things almost simultaneously to restore the truck mechanically. I can't be sure if synthetic oil made much of a difference, but my sense is that it may have helped and certainly didn't hurt.

 

Thinner oil has to help. Below 20* mine doesnt want to do much of anything.

 

Thanks for all the replies you guys are awesome! I just looked at my batteries and they are both 675CCA and 890CA above 32*. I don't know how old they are though, and as soon as I borrow a load tester I will test them. Of course I can't find mine... I know the truck sat for at least a year before I got it, which is never good for batteries. What do you mean group 65? I guess I've never paid that much attention to specific battery application.

So Sunday morning I started the truck up, it cranked over ok but not wonderful. Drove about 20 min and then parked it. Three hours later I got in and ran the glow plugs and it would barely crank over. It's never been that bad and almost didn't start. But then later in the day after it had sat for another 4 hours or so it started up ok.

I will try that startup procedure, my brother has the exact same truck and I've never had an issue starting it in any temperature. Also, pretty sure my block heater isn't working, I'll check the cord.

 

group 65 is the size of the battery.