Heya folks. This should be a fun one, intermittent issues are the most fun to track down, huh?

Anyways, my truck usually starts perfectly, no more than ~2-3 seconds of cranking. Once in a while though, it hard starts in one way, and today it found a new way:

Scenario A, the most common kind of hard start it does: the truck will take ~5-8 seconds of cranking, then fire right up. No sputtering before starting, just crank crank crank boom. It'll shudder for maybe half a second to a second, that's it. This scenario usually only happens if I've left the truck alone for a few days.

Scenario B, this happened earlier today for the first time: the truck took about ~15 seconds to start, it sounded like it was cranking a bit slower than usual.

For scenario B, I had originally started the truck perfectly fine, let it run for 3 minutes, drove it 2 miles, shut it off. 15 minutes later, I started it back up (perfectly fine) and drove it 10 miles on the freeway, shut it off. Came back 30 minutes later, and that's when it didn't want to start. After it started, I let it run for about 10 seconds, then shut it off to see if it'd repeat. It took about 5 seconds of cranking to make it restart.

I drove back 10 miles on the freeway and dropped my stuff off (left the truck on this time for ~10 minutes), then went to the mechanic to get the batteries and charging system checked. Batteries and charging system checked out good, and my truck started perfectly every time we tried.

So, theories? For the first one, I'm thinking it's probably a minor case of air intrusion, no biggie. The second one is what I'm worried about though. The truck was already warmed up, so it should've cranked over in a heartbeat. The batteries are good, so I'm hoping it's the starter but fearing it's the IP. Or my truck just has a bad sense of humor.

 

My advice, do what I wish I'd have started with when I had my problems .... change the lift pump. There is all kinds of troubleshooting you can spend all kinds of time on, but unless you KNOW your lift pump is new/good, just replace it. Cheap - easy - and if you still have the problem ,then you at least know that you have a new lift pump and can focus on other areas.

 

I'd say the next time it doesn't start right up to pull the fuel filter to see if it is full. If its not, your lift pump is bad or you are sucking air somewhere between the tank and life pump. Get under the truck and check for leaks, and made sure your tank is at least 1/2 full. If everything up to the filter looks good, you'll need help from someone else.
Good luck

 

The truck has ~35 gallons in the main tank right now (45 capacity). No leaks anywhere that I can see.

The lift pump is pretty cheap, so there's no harm in getting that changed out. If it was only just starting to go bad, would that cause such intermittent issues? The truck can have several weeks of cranking over perfectly, then out of the blue it decides to take ~5 seconds of cranking instead of 1-2. Before yesterday, I've never had it take ~15 seconds to start before, especially on an 80*F day when it was already warmed up.

 

you don't say if you have tried to step on the peddle while cranking..or how long the WTS lite stays on. it should stay on 5 to 8 seconds. if it go's out to soon it's an indicator that one or more glows are bad. if one or more are bad the rest will glow hotter, and blow out sooner, my van will start hard some days to..same symptoms, have got an e pump on it and it make's no difference on or off (my e pump is flow thru type, and is only used to prime if the wife run's it out of fuel etc.). I am not worried, if she stops starting I will hang parts on it.

 

I've never tried stepping on the pedal, I thought that trick was limited to the old carb'ed gas engines. The More You Know™

On first start for the day, the WTS light stays on for the usual 7-8 seconds. If I drive a short distance, shut it off, and come back an hour or two later, it's anywhere from 5-8 seconds. If I drive a good distance (30+ miles freeway) and the truck gets completely warmed up, it's on for about 2 seconds.

For what it's worth, my glow plug controller does start to audibly click on and off once the WTS light turns off. I've done a lot of searching, and I never could find anything definitive. I know it's supposed to cycle the GP's on and off, but apparently some people think clicking = glow plug relay is going bad. Mine usually clicks in a regular pattern, but it likes to be odd sometimes (rapid clicking, strange patterns, maybe my truck speaks morse code?).

Pretty sure the clicking is normal, and to my knowledge the GP's should all be good. I do believe the cold timing advance and cold idle solenoids are defective though, if that helps at all. I've only seen it high idle once (and yes, I know it needs help to get started), 99% of the time it won't idle high. It will also sometimes have a knock on first startup; 3/4 of the time it'll go away after 10-60 seconds, other times it'll go away after being driven a short distance and then restarted (ex., it'll knock on the way to the grocery store, but not on the way home).


Sorry if most of that wasn't very relevant, I'm not really sure what might end up being helpful or not, so might as well throw it all in. Better to give too much info rather than too little, right?

 

X2... It almost sounds like the pressure in the fuel system is bleeding off, even after you just drove it. I believe that the clicking is normal, I think that the 7.3s clicked more rapidly than the 6.9s did. Also might want to check return lines, if they are cracked or brittle, replace them. They will only cause problems.

 

The glow plug relay is just that... a relay. Relays click. Anyone who tells you that a relay is bad just because it clicks is an idiot. They're supposed to click on for about 7-10 seconds when the engine is cold, and then click off and on for another 30 seconds or so. That's the GP's after-glowing. It's normal. Fast clicking is usually a sign of a bad connection, or a bad glow plug. The system can't tell the difference between the two. A bad glow plug creates a bad connection. Since yours is erratic, it's most likely a bad connection. Check your wires and bullet connectors.

The fast idle and cold idle advance are two different things. The fast idle is the little plunger on the passenger side of the injection pump, that activates when you have the a/c on and whatnot. The cold idle advance is internal to the injection pump, and it gets "activated" by pushing the throttle to the floor when the engine is cold. It's in the old Ford owner's manual for starting procedures. It makes an obvious change in engine noise when it turns off. The engine gets a little quieter, and the RPM's drop a little when it turns off.

With 300k on your clock, I'd look into your starter. They're relatively cheap, and pretty easy to get to. You can get a gear reduction starter if you want, but I like the direct drive ones. In my book, the gear reduction doesn't spin any faster like everyone says it does; it just puts a lesser load on the batteries. The direct drive should spin a little faster (think about it... a smaller gear turning a bigger one won't turn the big one as fast), but is more noticeable to spin slower when your batteries get weak.

 

You may have multiple issues but this is where I would start. It needs to crank at a good rate to start quickly. Likely as it is intermittent it's as simple as a lose connection somewhere. For instance the ground for the second battery.

 

So, this morning it only barely started. The WTS light came on for the usual 8 or so seconds, but it wouldnt start. While cranking it would kindof stumble like it was going to, but it didnt go.

Tried cranking again, this time giving it a little gas. No change.

Third time, i ran the glow plugs again. That did the trick, it fired up in about 2 seconds easy. Edit: i should mention, the second it fired up, it revved itself to 1500. I assume thats because i pushed the pedal on the second attempt, right?

So, time for glowplugs?

 

Glow plugs wouldn't explain why you had trouble starting warm the other day. I would look more into air intrusion or a dying IP.

The IP isn't like a carb where the extra fuel from pumping the throttle will sit in the intake and get sucked in when the engine lights off... the fuel system just doesn't work that way. So by revving itself up to 1500 for no reason after you started it is a new development in the problem.

 

I'm going to respectfully disagree that you don't need glow plugs when the ambient temperature is warm.

My truck would need plugged in if it was under 70 degrees when dead plugs and controller. Even then it was a struggle at times especially if I was not parked in direct sunlight.

My .02 batteries can test good but still be junk. Happens all the time at work. Customer drives in, we test the battery, tests good. Go check it later, fails. Sometimes they will hold a surface charge but the cold cranking amps is what gets you moving.

The 7.3 needs a lot of juice to get going in most scenarios.

You have plenty to check out already so I'd do all those things first.

Also FYI when I got my truck the WTS light would function normally and I would hear the relay click. Previous owner disconnected the output side of the controller. I found 4 different types of glow plugs installed when I replaced everything. Ever since I replaced the plugs and controller she starts almost before I hit the key

Good luck and let us know what you find

 

As the engine is cranking and trying to fire, isnt fuel being shot in to the cylinders? I figured something like that would explain the "enthusiastic" start. We'll see if it happens again when i get off work.

I'm getting the batteries tested again, this time i'm pulling them out of the truck. The truck and batteries have been sitting for about 6 hours as i write this, so we'll see how they turn out. Theres no specific date on the batteries, just a trademark bit saying 2005, so they may be 8 years old.

I almost hope it's the GP's. 100 bucks for GP's vs 300 for a pair of batteries, joy of joys.

 

To me this is a sure sign of air intrusion. Air in the IP effects the governor system and will cause it to rev on it's own. But how long did it stay at 1500, if it came down in seconds as soon as the air was worked out then I say air. If it stayed up then after it warmed up suddenly dropped then I guess your fast idle finally worked.

 

It was like if you just quickly mashed the pedal and released it, like revving the engine at the lights. It didnt hold the revs at all, thats why i thought maybe some extra fuel was in the cylinders.

Edit: batteries checked perfect. Back to the drawing board