6.9L diagnosis
Thread Starter
|
More Turbo
Joined: Mar 2008
Posts: 658
Likes: 2
6.9L diagnosis
So I have an 86 f250 4x2 blah blah, with the venerable 6.9L diesel in it. The engine smokes a little under load, and hardly has any hp/torque left in it. It even has died a few times while running, and has problems starting when its pointed up hill. I ran a compression test, and everything turned out fine. I think the problem is in the fuel delievery, as thats pretty much the only thing that can kill a diesel when it gets running. I only use the truck for dump runs, and I dont mind really tearing into it to find out whats going on.
Any suggestions on where to start?
I heard that to diagnose the fuel system up to the injector pump you can splice in a piece of clear tubing and check for air bubbles... sound like a good idea?
Any insight/past experience is greatly appreciated.
Any suggestions on where to start?
I heard that to diagnose the fuel system up to the injector pump you can splice in a piece of clear tubing and check for air bubbles... sound like a good idea?
Any insight/past experience is greatly appreciated.
Elder User
Joined: Mar 2006
Posts: 901
Likes: 0
From: North-Eastern, Ohio
Does the truck still have the original gray rubber return lines from the injectors? They go from each injector and back to the tank.
If they are still the original gray ones, replace them, because more than likely, they were disturbed and now allows air to enter the system. That's why it is hard to start when facing uphill, gravity helps push the fuel away and draw in air.
If they are still the original gray ones, replace them, because more than likely, they were disturbed and now allows air to enter the system. That's why it is hard to start when facing uphill, gravity helps push the fuel away and draw in air.
Moderator
Joined: Jan 2001
Posts: 56,984
Likes: 2,738
From: Virginia
You did post in the correct forum for your truck, and F250FarmBoy gave you good advice. Here's an even better forum dedicated to your engine, where you can gain lots of info.
https://www.ford-trucks.com/forums/forum117/
https://www.ford-trucks.com/forums/forum117/
Thread Starter
|
More Turbo
Joined: Mar 2008
Posts: 658
Likes: 2
Originally Posted by F250FarmBoy
Does the truck still have the original gray rubber return lines from the injectors? They go from each injector and back to the tank.
If they are still the original gray ones, replace them, because more than likely, they were disturbed and now allows air to enter the system. That's why it is hard to start when facing uphill, gravity helps push the fuel away and draw in air.
If they are still the original gray ones, replace them, because more than likely, they were disturbed and now allows air to enter the system. That's why it is hard to start when facing uphill, gravity helps push the fuel away and draw in air.
Elder User
Joined: Mar 2006
Posts: 901
Likes: 0
From: North-Eastern, Ohio
http://www.mwfi.com/dieselPage/ford_69.htm
They call it an "Injector Kit" for about $35.
I removed the injector lines to make it easier on me and gave then a coat of paint, but you dont need to, just be careful not to bend them. It took me a good hour or 2 from raising the hood to shutting it.
I'd give it a 1.5/5 difficulty rating.
They call it an "Injector Kit" for about $35.
I removed the injector lines to make it easier on me and gave then a coat of paint, but you dont need to, just be careful not to bend them. It took me a good hour or 2 from raising the hood to shutting it.
I'd give it a 1.5/5 difficulty rating.
Thread Starter
|
More Turbo
Joined: Mar 2008
Posts: 658
Likes: 2
Got one, and I'm currently in the process of doing the replacement. Since I'm not really used to diesel stuff, I pulled an injector just to see what it looked like. The end picture is a little fuzzy (couldnt get the camera to focus...) but its basically got a light black char over the tip. Is this what they are supposed to look like?
Thread Starter
|
More Turbo
Joined: Mar 2008
Posts: 658
Likes: 2
ooh, and just a little update here, I did the whole replacement kit, and the thing runs like a beauty! (relatively speaking, of course...) It takes hills like nobody's business and actually accelerates.... Thanks a bunch for the advice guys!
Trending Topics
Elder User
Joined: Mar 2006
Posts: 901
Likes: 0
From: North-Eastern, Ohio
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Rezvani's Latest Post-Apocalytic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
Thread Starter
|
More Turbo
Joined: Mar 2008
Posts: 658
Likes: 2
well, I'm not exactly a stranger to working on old beat up trucks, just the diesel thing is new to me. I would have never guessed something so small like that could cause so many problems.
One thing that I did noticed, however, is that two of the injectors were covered in metalic gunk from the threads to the copper washer, and another one had some oil on it... Cause for concern?
One thing that I did noticed, however, is that two of the injectors were covered in metalic gunk from the threads to the copper washer, and another one had some oil on it... Cause for concern?
