F250 7.3L Diesel starting quirk

[jmc]

I don't use it much-1999 w/24,000 miles...

Last week cold snap with ice storm coming- parked it down by the road and waited for thaw to (try to) bring it back up to the barn. Weather had turned warm and very damp. Ran the batteries down somewhat without the slightest fire. Road service tried his portable battery and same thing. Jumped it with his truck and after extended cranking, it finally fired and started immediately thereafter. No problem starting after that until several days ago. Parked outside again when warm and damp. Won't fire again.

Id appreciate any thoughts on this.

 

[Botaskinner]

1985 6.9 user here, also occasional use.

Have you checked the soft lines that distribute fuel to the injectors? Any dampness/leaks?

If so they can allow air into the injectors causing a difficult start.

These hoses deteriorate from the inside out and last 5 to 10 years max.

Check back and let us know.

 

[Cataclysm]

Sounds like it needs new glow plugs. How old is the diesel fuel? Do you keep up with fuel filter changes? Did it smoke a lot when it finally started?

 

[rangerfredbob]

Having a used to be cranky PSD 7.3L myself I'll run through the easy things...

Glow plug relay, you probably have two brown relays in front of or beside the fuel filter bowl, one goes to the air heater that is in the aluminum "spider" that has two air passages through it one from the turbo to the intercooler and the other from the intercooler to both intake manifold things. Ignore that one, I'm not sure how much the air heater does, don't have one on my '97... Anyway, the other one controls the glow plugs, it's about 100A load when they are on and that relay goes out fairly often apparently, when I got mine it was $30 on rock auto or amazon, super easy install (2 mounting bolts, two big power wires and two little control wires).

Other than that, oil changes are big on these engines, everything is ran off of oil, the injectors are ran off of oil that has gone through two pumps before the injectors, if the oil is gummy they can get cranky.

Battery voltage is a big issue, the starter is near 5hp on it's own, throw the 100A glow plugs on top of that and you get issues. I was plagued by battery issues where one would kill the other after just a few days but now have two good batteries. The battery connections also have to be clean and good, if you have cheezy repair connectors on one or both batteries they have to go, if the battery terminals are dirty they need to be clean. I know for a fact that it takes about 30 minutes for a small car to jump start a 7.3L with dead batteries!

Oh, valve cover gaskets! they're important! the valve cover gaskets have the control wires for all of the fuel injectors and glow plugs going through them and the connections do go out and need replaced... on my '97 it's a pretty easy job, but on a '99 it's much more cramped under the hood...

My beat to heck '97 F350 with 350k on the clock (not original engine) starts right up now. I did have a bum starter at one point and bought a late '03 starter for it, went right on and is apparently better...

 

[dieselcrawler]

Having a used to be cranky PSD 7.3L myself I'll run through the easy things...

Glow plug relay, you probably have two brown relays in front of or beside the fuel filter bowl, one goes to the air heater that is in the aluminum "spider" that has two air passages through it one from the turbo to the intercooler and the other from the intercooler to both intake manifold things. Ignore that one, I'm not sure how much the air heater does, don't have one on my '97... Anyway, the other one controls the glow plugs, it's about 100A load when they are on and that relay goes out fairly often apparently, when I got mine it was $30 on rock auto or amazon, super easy install (2 mounting bolts, two big power wires and two little control wires).

Other than that, oil changes are big on these engines, everything is ran off of oil, the injectors are ran off of oil that has gone through two pumps before the injectors, if the oil is gummy they can get cranky.

Battery voltage is a big issue, the starter is near 5hp on it's own, throw the 100A glow plugs on top of that and you get issues. I was plagued by battery issues where one would kill the other after just a few days but now have two good batteries. The battery connections also have to be clean and good, if you have cheezy repair connectors on one or both batteries they have to go, if the battery terminals are dirty they need to be clean. I know for a fact that it takes about 30 minutes for a small car to jump start a 7.3L with dead batteries!

Oh, valve cover gaskets! they're important! the valve cover gaskets have the control wires for all of the fuel injectors and glow plugs going through them and the connections do go out and need replaced... on my '97 it's a pretty easy job, but on a '99 it's much more cramped under the hood...

My beat to heck '97 F350 with 350k on the clock (not original engine) starts right up now. I did have a bum starter at one point and bought a late '03 starter for it, went right on and is apparently better...

Ditto... good advice above.

Does it fire up easy when warm? Be it warm weather, or if block heater plugged in?

I've been running 7.3L PSDs for a dozen years or more... great motors, with a few quirks.

 

[Raspy]

Sounds like it needs new glow plugs. How old is the diesel fuel? Do you keep up with fuel filter changes? Did it smoke a lot when it finally started?

Not likely this. The glow plugs don't all fail at once, but the glow plug relay can. Diesel fuel does not go bad in a few weeks.

 

[jmc]

Thank's all, for the ideas. It was always a 5 second (or more) cranking, even when new.

Would the air dampness affect the fuel quality when it's 50F?

It was remarkable when it cranked for several long intervals without the slightest firing and then it instantly started with no sputter or hesitation.

For now, I'm finding enough extension cords to recharge it where it sits. More after that.

 

[rangerfredbob]

I would throw a glow plug relay at it, sounds like it's not turning them on.

Is it low on oil by chance? they're picky on that...

24000 miles in 20 years isn't much. If it's cold outside and you have summer fuel it's possible it gelled and wasn't flowing as well, but the glow plug relay sounds most promising to me.

 

[RoyKing]

Mine got to be erratic about starting, replace the relay driving the ECU. I think I swapped the heater relay, $7 part back in business, also had problem with fan, turned out to be ignition switch on the column, also with age you think your battery's or cables are going but the starter just sort slowly dies.

 

[Btown]

I had to replace my glow plug relay about 2 years ago on my 2001 F-250. It had fallen apart. No issues after replacing. I was using the block heater to start it in cold weather, but that died on me too. Both replaced. I don’t really use the block heater until it gets into the single digits F.