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Discussion Starter #1
I recently made a post about mad mileage, but that is not the least of my worries. I smelt the oil that I had drained from my truck and I could smell diesel in it. The truck smokes blue and white on a cold startup, gets around 9mpg, has an intermittened vibration at idle with a slight jump in rpm's (only about 50 tops), and used the whole dipstick reading of oil in under 600 miles.
In confused because the truck always starts right up, doesn't have blow by or any leaks, and does not appear to lack any power. It's an early 1999 f250 7.3l (250,000 miles). I'm on a tight budget, does anyone have anything they would recommend I try? After 2 days of research I still haven't found anything it would be.
Thanks in advance.
 

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Usually diesel in the oil is bad injector O rings or at least a couple of them. The best remedy is to replace all of them. You can get a set for all 8 for around $80.00 for parts if you do them yourself.

https://www.dieselorings.com/1999-2003-ford-7-3l/engine-uvc-and-electrical/14-020-alliant-injector-o-rings-exterior.html

If you would like to make sure that there is a lot of diesel in the oil I would suggest that you pull a sample and send it off to a lab such as Blackstone and have them check it. They are fairly quick on getting the results back to you.

https://www.blackstone-labs.com/?session-id=txlnvrfkojyeazjp2e0quvzt&timeout=20&bslauth&urlbase=https://www.blackstone-labs.net/Bstone/(S(txlnvrfkojyeazjp2e0quvzt))/
 

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Discussion Starter #4
Are the o rings a pain to replace on my own?
I did read that form and one guy talked about how bad o rings can cause oil in the fuel, but I'm expecting fuel in the oil. I'm not sure how to check if there's oil in the fuel but I am definitely burning oil on cold starts and when I rev the engine a decent amount. Someone also talked about nozzle springs. Would I be better off just getting new injectors? Thanks
 

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The way to check for oil in the fuel is to pull your fuel filter. It will be stained black from the soot in the oil. I wouldn't change injectors unless you are having a significant cold start issue combined with rough running when cold. Just change the o-rings. It's not terrible to do at home. Basically, you have to pull the valve covers and pull the injectors. You start in the back because when you pull an injector, all the oil in the oil rail and all the fuel in the fuel rail drains into the cylinder. The motor slants back, so by pulling the back one first, you end up with most of the liquid in the rear cylinder. After pulling all the injectors and swapping the o-rings, you suction all the oil out of all the cylinders that you can. Replace the injectors and then WITH THE GLOW PLUGS OUT - rotate the engine over twice by hand, then bump the starter a few times to expel any residual oil out the glow plug hole. At this point, crank the engine over until you hear the HPOP load up (or see IC pressure come up on a scanner). That will ensure a quicker start once you've buttoned everything up.
 

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Discussion Starter #6
Awesome, thank you, I'm planning on getting new o rings tonight from Ford. I read something about injector springs on another form. Are these springs replaceable or would you recommend I only do the o rings while I'm in there? Also are there any certain tools I should get for the procedure?
Thanks so much.
 

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Discussion Starter #7
Also, can the O rings cause fuel to get into the oil? Or do bad ones only result in oil in the fuel. I Definitely have some diesel in my oil.
 

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There are no "injector springs" - at least nothing serviceable. There are some springs inside the injectors, but that requires rebuilding them. That's not a task for the faint of heart. One of those "screw this piece off and POW - 15 parts are now laying on the garage floor in no particular order" jobs. Don't mess with them. Also, there are better places to get your injector o-rings. Here, for example - https://www.dieselorings.com/1999-2003-ford-7-3l/engine-uvc-and-electrical/14-020-alliant-injector-o-rings-exterior.html

So - when the key is on and the engine is off, there is 60 psi fuel in the rail and no oil pressure. At that point, fuel can push across into the oil rail. When the engine is running, there is 500-2500 psi in the oil rail and 60 in the fuel rail and oil is going to be pushing into the fuel rail. So, the answer to the question is - yes, fuel can get to the oil when the key is on and the engine is off.
 

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Discussion Starter #9
Okay, I just checked the fuel filter and it is completely clean. Not black at all. It looks brand new. I'm not sure if the previous owner would have replaced it when I bought it. I'm not sure if 600 miles and a whole dipstick reading would have blackened the filter, but I would assume it would have. Is the filter not a telltale sign? Could it still be the O rings? I'm wondering if it's maybe something with my piston or the rings.
 

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Well - you'd expect the filter to be black. 9 MPG is pretty horrific mileage. About half of what I get. Are you checking that by the "lie-o-meter" or hand calculated? The most common cause for poor fuel economy is lack of boost. Leaks, bad turbo, etc. That would give you the black smoke and you would definitely have to overfuel to make the truck move. Are you getting any codes? Lack of power? How does it start cold? Smooth idle? Do you have access to a scan tool that can monitor PIDs?
 

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Discussion Starter #11
I hand calculated it, I filled the tank the night before to figure out the mileage, drove it about 70 miles And filled it up again the next day and I fit another 8 gallons in it. I think the previous owner said he has a 50hp tune on it, is there a way I can check? If it truly does have a tune, I would expect some coal when I get on it, because it's not a crazy amount or anything but not horrible either. No light are coming up on the dash, I don't think there's a lack of power and I can definitely hear the turbo when I give it some gas. The truck starts up right away, after about a second of cranking. The truck will have a vibration when it idles that comes and goes randomly every 3-5 seconds if I had to guess. When it seems to vibrate, the rpm's jump very slightly (only 50rpm's tops). I have a tuner that came with the truck that plugs into the ob2. It says Fuego on it, I'm not sure if it would scan codes or anything though, I haven't touched it yet. Also, it will smoke blue if I rev it in park only above around 2400 rpm's I would say. It hasn't ever smokes blue when I drive it.
 

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You need a scan tool to monitor some parameters. Autoenginuity is what a lot of us use, but Forscan with an obdIi adapter works. You can post your location if you want- someone close might have a scanner.


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Discussion Starter #13
I just called my friend's friend's friend who has the exact same truck as me. The guy had the exact same problem as me and his fuel filter wasn't black. He installed new O rings and it fixed his issue. I'm assuming the fuel filter check isn't always right? As of now I think this is my best bet and I'm probably going to order some new o rings to install. Whats your opinion on this? Has anyone heard of bad o rings with a clean fuel filter?
 

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You should get little to no back smoke from a 50 hp tune. Black smoke is hype some programers used to sell there programs as big HP programing. If you have a lot of black smoke you have a poor program for your engine. You are basically overfilling and wasting fuel. Do a search on chips/programers that will tell you how to spot one in your truck.
DENNY
 

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I would go ahead with the o-ring change. For the filter to be black, there has to be such a significant leak that dirty oil backs up out of the fuel rail into the bowl. Your leak may not be that bad.


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One other thing to change if you don't know if they have been changed out are the glow plugs. Since you will have them out when you turn the engine over to get the fuel and oil out of the cylinders it is a good time to do it.

Use only Motorcraft ZD-11's, others tend to cause problems.

As for pulling and reinstalling the injectors I am sure that YouTube has a few videos on how it is done. There are also instructions on most of the suppliers that sell injectors also.
 

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Discussion Starter #17
Thanks everyone for the help! I'm planning on putting new O rings ASAP. I'm eager to get them in, I can get a set for each injector at Ford for $150. I would rather get them sooner than later, are there ones that an autoparts store would sell? Or should I not bother with the off brand ones. I prefer not to wait for shipping if I would order them. Also is there a tool I should get for doing the procedure? We've got more tools than we know what to do with at our house so I would imagine we would be okay. And as for glow plugs, I'll probably replace those as well! I check some auto parts store a around me and they sell the ones you're talking about. Thanks again.
 

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I haven't had to do anything to my injectors yet but I believe that you will need a rubber mallet to seat them properly.

I am away from my computer until later but I'll see if I can find the installation instructions for you, if you don't find them before that

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Take note of the rear valve cover bolts and how you get them out, be careful when you put them back in so you don't strip them (right and left heads are the same just reversed so looking at the front of one will tell you what the back of the other looks like). I use an old brake adjustment tool to help tease the injector out. A small pice of fuel line or vacuum hose slipped over the top of the glow plug makes it easy to get them started (you will see what I mean once you try it) Take a good long look at all the cups and make sure none are cracked.
DENNY
 

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Discussion Starter #20
Sounds good, I'm thinking about just having Ford do this so that I don't mess anything up. Does anyone know what Ford would charge for 8 new sets of o rings and new glow plugs? I called them and the price quote for 8 sets of new o rings cost $150. Obviously there would be labor costs too. Any guesses? Thanks
 
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