Big-Black-Beast

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New member here, first time poster, long time reader. I have a beautiful black '89 f350 long bed single cab 7.3 n/a with the zf5 sitting on 35's that i absolutely LOVE!!!! The past week however has me dangerously close to shoving it off a cliff and walking away.
My problem all started with a bit of blue smoke and surging that got worse and worse to the point where 60mph required having my foot in it all the way to the floor. So I decided to put in a new lift pump, bad idea. Ever since then things have gotten worse and worse to the point where it will only run for about 30 seconds and die. And before anybody says to use the search option I've tried that for hours upon hours.
Here's all that I've done so far; two new lift pumps, the p/o eliminated the rear tank so there's no selector valve/switch, I've eliminated the hose going from the #5(?) Injector to the water seperstor housing, new filter, the Schrader valve was eliminated by the p/o, the injectors are fairly new (p/o), so are the glow plugs, the glow plug controller has been eliminated. I'm sure there's some things I'm missing. Now here's what I know there's definitely pressure at the water/fuel seperator housing and it's not leaking back to the tank because my fuel filter is completely full when I remove it. Which leads me to believe my problem is somewhere between my injection pump and my fuel return line.. and like i said the fuel return connecting the water fuel seperator has been eliminated but prior to it's elimination i had a clear line hooked to it and I did indeed have air bubbles in the line. I went and bought 5 gallons of fuel and dumped it in the tank in hopes of elinating a broken shower head as the culprit. So what I've narrowed it down to is either A: my olives are bad and I have a blocked fuel line or B: somewhere I'm getting air in the system like either the injector o-rings or the fuel return to the tank. My only issue is wouldn't that have been somewhat remedied by my removal of the fuel return being connected to the filter housing. And just so we're all clear here the last thing I want to hear is that I have a bad injector pump. So any ideas or insight would be more than helpful.
 

IDIBRONCO

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First of all, welcome. You're not exactly new since you joined almost a year ago.
Second, to me, it sounds like you've got a BAD air intrusion issue here. Air intrusion ONLY happens while the engine is running and ONLY happens before the lift pump. It is caused by air being sucked into the fuel system so that eliminates all of the return lines, injector o-rings, and everything else after the lift pump including the olives. Everything between the lift pump and the injectors is under pressure so air can't be drawn into the system while the engine's running. The entire return system is under little to no pressure, BUT any air that may possibly be drawn into it goes to the fuel tank where it rises to the top of the tank so that can't affect the running of the engine in any way.
Since you've put two lift pumps on, I'll steer away from that. There's no selector valve so that isn't the issue. This leaves me with two options right off the top of my head. There is an o-ring style seal in the factory suction fuel line where it attaches to the fuel sender on top of the fuel tank. The other option is that there's a small hole in either the steel fuel line that runs along the frame from the tank forward or in a rubber fuel line such as the one that runs from the frame over to the lift pump. Instead of a hole, there could also be a loose clamp on one or more ends of the rubber fuel line(s). You did make sure that they were tight after installing the first lift pump, right? If that rubber line before the lift pump seems to be ok, how about where the selector valve was replaced? Is there any rubber line with clamps in that area? That may be your problem area.
My advice is to ignore any response that talks about fuel drain back at this point. Your issues started while the engine was running and now you can barely keep it running. Yes, if you're drawing air into your fuel system, you will also be having problems with the fuel draining back to the tank. Let's just focus strictly on getting your engine running good again. If you're having problems with the engine starting, running a few seconds, and then dying after sitting overnight after it's running good again, then we can focus on that.
 

Big-Black-Beast

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The only reason I thought that wouldn't be true is because my water fuel seperator is always completely full. Should I try the bucket of fuel straight to the intake side of the lift pump? I'll check everything you suggested first thing in the morning and report back. Thanks for the help
 
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Big Bart

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Well you cannot rule out a bad or plugged IP but that is rare.

Yes run a line from a 5 gallon gas can with diesel directly to the lift pump. If your issue goes away IDIBronco shared where to go look. It’s a issue between the the tank pick up and lift pump. If not you need to look at the fuel pressure pre IP.

1) If you did not replace the rubber hose to the lift pump I suggest doing so.
2) As I recall 6.9‘s used olives but not 7.3’s. So others can confirm if true or I misread that.
3) Too much fuel IP inlet pressure or too little pressure effects the IP. So its to bad the schrader valve is gone. If the hole is still there perhaps put a fitting in it and hook a fuel pressure gauge up. You want 3-5psi. If above 7psi or below 3psi then potentially an issue.
4) The ip fuel inlet port has a small mesh screen in it, they can plug up. Use a flashlight, if clogged, use a small pick to clean it out. But do not damage it or push anything through it.
 
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IDIBRONCO

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2) As I recall 6.9‘s used olives but not 7.3’s. So others can confirm if true or I misread that
Yes and no. The 6.9's do have a couple of olives that the 7.3's do not have. Since I don't remember for sure, even that may not be 100% correct. Whichever engines/years use the hard return line that runs along the driver's side of the intake does have two more olives that the others do no have. Maybe some of the early 7.3's used that set up, but I don't remember right off hand. They all used an olive in the hard line that comes off of the lift pump. There was also two in the hard line from the fuel filter to the injector pump.
 

ROCK HARVEY

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My 89 7.3 NA has the hard return line and uses olives. I replaced them all with viton olives a while back. As for OP’s issue, I agree with IDIBRONCO. I would look real close at the steel fuel line for cracks, especially if it came out of it’s plastic hangers and is allowed to vibrate. That being said, my money is on the area where the selector valve used to be. There are probably rubber hoses and clamps there now, and I bet they’re wet with diesel.
 

FrozenMerc

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I know you may not want to hear it, but your symptoms are very similar to what happened to my '85 when the Injection Pump went down. I was driving from the Knoxville, TN area back to Northern Minnesota. On the north side of Indy, it started missing occasionally and would take progressively more throttle to maintain speed. By the time I pulled off in Lafayette, it would only idle, and if you gave it any throttle at all it would die. Got a tow to a local Ford dealer, and the next morning, it would start, but only run for a few seconds. A few days later, the truck had a new (rebuilt) IP, and was good to go. It amazed me how fast it went from running like a million bucks to nothing, literally within about 50 miles.
 

Big-Black-Beast

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I apologize for the delay, life got a bit hectic the last couple days. So I finally got around to hooking up a hose from my 5 gallon fuel can to the lift pump and "idibronco" is 100% correct. My truck fired up and ran as smooth and smoke free as I've seen her run in quite some time. My problems are definitely a fuel line leak somewhere between my fuel tank and the lift pump. Thanks everyone for the input and especially idibronco. Jesus freak was right you definitely know what you're talking about. I can't thank you enough!!!!

BTW can you post a pic of your idibronco. I love broncos, my first vehicle was a '79 bronco and now that I got mine running I'm fairly fond of idi's again.
 

Big-Black-Beast

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Also I consider myself a new user mostly because I made the profile back when I first got the truck and never returned and actually forgot I even made the profile until I went to post on the forum and it told me I already had a profile
 

IDIBRONCO

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"idibronco" is 100% correct. My truck fired up and ran as smooth and smoke free as I've seen her run in quite some time. My problems are definitely a fuel line leak somewhere between my fuel tank and the lift pump. Thanks everyone for the input and especially idibronco. Jesus freak was right you definitely know what you're talking about. I can't thank you enough!!!!
Thank you. Instead of being super intelligent, I try to use logic, experience, and what I've learned from others. I also tend to retain information on subjects that I'm passionate about fairly well. Other things? It comes and it goes.
I also hate to see someone wasting money on parts without trying to do some diagnosing first. All that usually gets you is a lighter wallet and sometimes hatred for your vehicle.
BTW can you post a pic of your idibronco. I love broncos, my first vehicle was a '79 bronco and now that I got mine running I'm fairly fond of idi's again.
Not at the moment. I got rid of it back in 2016. Any pictures are at least that old and they're stuck on my old computer that's barely functional until I get (pay:puke:) for someone to take them off.
Also I consider myself a new user mostly because I made the profile back when I first got the truck and never returned and actually forgot I even made the profile until I went to post on the forum and it told me I already had a profile
At least you know it now. I hope you don't forget it again. You'd be more than welcome to stay around after this problem is solved.
 

Jesus Freak

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Don't listen to him, he's actually a rocket scientist. I think he's developed a bull nose bronco with an turbo 7.3idi that can go to the moon. Or at least the grocery store.....I mean prices are SKY HIGH!!! LoL!!!
 
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