'02 Excursion, 425k miles. I bought it with this problem. Other than the visible REMAN sticker on the HPOP I have no service history on it. All stock as far as I know. I see a cut-out on the ECM box so apparently it had a tuner at one time.

It only does it on the first start of a day. Sometimes it fires right up perfectly, most of the time it fires right up but it sounds like there's two dead cylinders, sometimes just one. Once in a while it acts like half or more are stuck and it worn't start, it crackles and jumps but won't quite fire. The two times that it wouldn't fire it took several minutes of trying, then seemed to have two still stuck.

When it's got the two stuck the only cure seems to be driving it, WOT and it has almost no power. Eventually as the revs climb to around 1500 one clears then around 2k the other clears, then it runs perfectly for the day. Reving it in neutral seems to do nothing, it seems to need to be under load to clear up. No smoke that I've noticed. There seems to be no set of conditions that'll dictate how well it starts, just whatever mood the engine is in apparently.

Is this the common injector stiction? I tried some Archoil 9100 with a fresh load of Rotella 15-40, didn't seem to change. Has around 500 miles since the oil change, mostly short trips and a few 50-80 mile highway runs. Would switching to 5-40 or some other additive possibly help? I'm not ready to dive into injectors yet and would like to buy some time if I can. The mild sticking isn't unbearable, but I'd rather not have to worry about it, the no-starts are a bigger problem.

 

I think you may be on the right track, but first ohm out your valve cover harnesses.

It just might be glow plugs or the UVCHs connections to GPs or injectors. Get enough vibration going and they might be automagically connecting.

And check your glow plug relay too. Whenever there is a cold start problem, I am in favor of ruling out the entire glow plug system first as the checks are easy.

 

5w40 will help, 0w40 will help a little more. Your symptoms are exactly like what I've been living with for over 4-5 years now with my '02 F250, but mine's not as bad as yours (I'm also at only about 299K miles). There are poppet shims available to resolve this, and I've had a set on the shelf in the garage for nearly two years now. In our colder days/months, I might drive the truck a couple extra miles to ensure that all injectors fire off before I shut down the engine (I only live 4 miles, or 10 minutes, from my office). My plan is to install teh shims, drill the poppet spacer plate, install new o-rings, and possibly new cups when I finally get into it.

I run 5w40 full synthetic, and what makes a huge difference for mine is letting the glow plugs run hot for about 10-15 seconds longer than the WTS light, and sometimes I'll cycle the GP's twice before firing off. If I let it idle in the driveway for about 5-8 minutes, that also reduces how long it takes before the sticking injector fires off. At current ambient temperatures, though, I'll let the WTS light turn off, fire up the truck, let it idle until I hear the GPR click off (I can actually HEAR it because I mounted my GPR on the passenger fender wall), and ALL injectors are firing off before I get two houses past mine (less than 1/10th of a mile).

It's all related to oil temperature at this point. Heck, if I plug in the truck overnight, she fires up perfectly the next morning and all injectors are firing before I even leave the driveway, and this works for me all the way down into single digits on the thermometer.

For additional context, though, I have tired batteries which I'm trying to nurse along through this summer before replacing them this coming fall, and I know that conditions does not help my engine startup scenario.

 

Just a note, are you sure your EBPV is all the way open when this happens? That would be your lack of power and then as it warms up it is restored. All good advice above. I had a clicking years back and had to change my #8 injector. You could really here it after a long drive in in a parking structure or next to a wall. Never noticed the things your saying though. Changing the weight of oil, say 5-40 you should notice a difference right away. Won't cure it but a big difference.

 

The 7.3L doesn't suffer from stiction like later engines do.

I would recommend against using oil additives. Our engines are pretty rough on the oil and don't like a lot of extra stuff suspended in there IMO.

Just my .02

 

Pretty sure it's not glow plugs or the EBPV. When it's happening there's a distinct misfire and no exhaust smoke which should indicate no fuel to the dead cylinders. I doubt it could be the harnesses causing the injectors to not fire. I would assume that if the harness has a bad connection that's wiggling on/off I'd have some problems other than only the first start of a day.

Brian42, you're the first I've heard say that 7.3s don't get stiction, lots of people have the problem. Lots of people have cured their injector stick with the additive I used and a few others. The Archoil didn't work, but I give them credit for honoring their guarantee. The guy said it might take a little more than the normal 100 miles and encouraged me to not give up on it, but he was willing to refund me right then.

F250- sounds like we have similar issues. I've never tried plugging it in, the lowest low lately has been 50-something. I've waited 'till late afternoon after it's been baking in the sun for several hours for the first start of the day and it doesn't seem to help, but the problem is a little sporadic so hard to say. Once it clears up I can shut it off immediately and it'll re-start running on all 8.

 

Well Brain is right. Don't know who your talking to but we don't have the spool valve's that cause this either on the 6.0L. Best thing you can do is change the oil to 5/40 and is if that helps. With that mileage you never know. Maybe the guy you bought it from never changed the oil. These things need fresh oil, so 5K changes is best. I'd pull the valve covers and check all electrical, check for oil discharge from each injector. Run a compression test. All that would be first thing for me.

 

a 7.3 can have "sticky" injectors that need warmer oil to fire, but it is not nearly as common as the 6.0 and happens in a different way.

archoil is one of the few oil additives that I would trust in a 7.3 or 6.0. It uses boron as a friction reducer and I have seen it work wonders on multiple ailing 6.0s. I've seen/read a few testimonials on the internet, but haven't seen any 7.3 success with archoil in person.

To the OP, it sounds to me like your injectors are simply wearing out. With the miles on them, I'd suspect they at least need shimming. Having them rebuilt wouldn't be terribly expensive and as long as you get your same injectors back, you don't have to worry about getting injectors that don't perform well, due to being rebuilt 2 or 3 times. The best route would be new injectors, but it all depends on what you are willing to spend. Compared to other diesels, even new 7.3 injectors aren't terribly expensive. Take a look at what new injectors on a common rail cummins or a duramax cost.

Of course, getting an obd2 bluetooth adapter and torque pro with the proper PIDs would be an inexpensive way to much more accurately diagnose your issue. Tugly has a write-up somewhere about getting that set up IIRC.

 

Can they be 'worn out' and still appear to work perfectly other than at start-up? It runs smoothly, no smoke, and seems to have good power.

I'd love more info on the Torque Pro. Can it let you see HPOP pressure and all the other stuff that lets one diagnose the condition of their system? I'm somewhat technology tarded so it would have to be fairly simple as far as no programming/modifying for it to work for me.

 

Yep that is typical for worn injectors, they run fine after warming up. First step to nursing them along is a slightly lighter oil as mentioned above. The critical part is the oil needs to be synthetic. I've seen several examples on this forum where a new-to-you truck runs poorly after the first oil change. That's because the OP had synthetic in there and it's replaced by dino. FWIW I run plain Delo since my injectors are fine. The next step is to shim the injectors, and then finally bite the bullet and get new injectors.

Conventional wisdom is no additives in the oil, always additives in the fuel.

Grab your android phone and get the Torque Pro app from the playstore. Only like $5 so might as well pay for it. Then you'll need a bluetooth OBDII adapter. is a cheap one, but the cheap ones have iffy QC so some people step up to a . Then search for a few threads or videos, lots of info out there. Interpreting the info is a steep learning curve but people here can help with that.

Just to cover the bases, there are no codes now, right?

 

I just did injectors. My truck ran like **** cold but was fine warm. 5w40 helped some but now with 15w40 on the new injectors it starts up and runs great right away. I am looking forward to winter to test it out in cold weather.

Nothing on these trucks is cheap, except o-rings... and there are a lot of them that seem to need replaced often...

 

Actually Brian is correct. You aren't suffering from stiction, that's a sales pitch from Archoil. The type of stiction that we best know is only on the 6.0L injectors due to a design flaw.

The injectors that are giving you trouble are flat worn out. Your symptoms exactly describe worn poppet valves. This is the most common type of 7.3L injector wear. Once the engine oil temps start to come up and oil flows easier, it can get through the worn poppet valve and the bad injectors begin firing.

Oil additives like that are simply a band-aid to bypass problems, they don't actually fix anything. They change the properties of the engine oil, which is significant in how the rest of the engine is lubricated and how the HEUI system functions. Change the oil properties to the wrong specs via additives and you could be causing damage elsewhere.

The reason the additives (or thinner oil) work as a band-aid on cold start is because that thin oil can cold flow easier through the worn poppet valve. But there's a downside to this once the oil is warmer. Often times worn poppet valves can't seal properly. Thinner oil escapes easier and you lose ICP through the injector at higher load and RPM, causing a power loss. As the leak gets worse, you'll begin to have problems hot-starting the engine.... basically the reverse problem you have now.

On a cold engine you can remove the valve covers and start the truck. The injectors with the worn poppet valves won't have any oil coming out of the squirters until the engine oil gets warm enough to begin flowing through. Then the bad injectors will begin firing and oil will come out.

Your only solution is to replace the injectors with new or remans.

 

Thanks guys. And thanks for the diagnostic tip on watching the oil squirters to know which ones are causing the issue. I understand how a loose/worn poppet would 'leak' oil, but don't understand how it could stick. If it's worn it has excessive clearance and should be more resistant to sticking. I'll google up some stuff on the poppet valves and hopefully seeing them will bring it together for me.

I'm towing my boat in a few days so I won't have time to down the Ex. Would Rotella 5-40 T6 be safe to tow heavy (13k. lbs) on a warm day? I know that theoretically it'll be a 40 when warmed up just like 15-40, just want confirmation.....or just leave the 15-40 in it for now?

 

You can run 5-40 synthetic year-round with no problem. It's within Ford's spec for oil for what you're doing.

 

As the poppet valve wears the clearance under the armature plate is reduced, not increased. Clearance on a new injector is .004, operational range down to .002, and less than .002 you have trouble with cold operation and the injector needs to be rebuilt/replaced.

People have shimmed the armature but that's just another bandaid since the worn poppet valve isn't addressed and as it continues to wear it can cause other issues down the road.