Changing the Primary Pump on a 6.9 IDI Engine Ford F250 Diesel: A Tutorial

If you are fitting a new diesel primary lift pump on a 1983 Ford 6.9 truck with the Navistar 6.9 or 7.2 diesel engine, then reading this article could save you a lot of work, grief, and big money, not to mention bad language!

1. Removing the Old Primary Lift Pump

OK, so let me start by saying that I am not a qualified mechanic so anyone following this advice does so at their own risk!

The primary lift pump on these engines is located on the right-hand side of the engine block near the front. It has two pipes attached. One is the feed from the fuel tank—it's a rubber pipe—while the outlet is usually a steel pre-formed pipe that goes up to the fuel filter.

• The first task (after removing the keys from the ignition) is to remove the steel bracket that clamps the battery to starter motor cable to the engine cross member by undoing the two nuts. This gives you much better access to the pump.
• Next, you will need to have on hand a suitable receptacle to catch the diesel fuel that will leak out of the open fuel lines.
• Remove the rubber fuel feed pipe and then attempt to loosen the union nut on the steel line going up to the filter. (I must say that this proved unsuccessful in my case, as it had probably never been removed before and was seized solid—so solid, in fact, that I thought that the bottom of the pump would snap off before it came loose. So my solution was to undo the steel pipe from the filter end remove the pump by removing the two retaining nuts, then lifting out the pump, taking care not to damage or distort the steel pipe that was still attached. Once the pump was removed I then clamped the union nut in a vice and unscrewed the pump off the pipe.)
• After removing the lift pump you then you need to clean up the gasket surface on the engine block by removing any old gasket material with a scraper, solvent, or whatever you find works best for you.

2. Fitting the New Lift Pump—Getting It on the Right Side of the Cam!

Now Comes the Important Bit!

You REALLY need to make sure that the cam that operates the lift arm on the new pump is resting in the correct position (cam lobe pointing upwards) BEFORE you fit the new pump with the arm underneath the cam.

It is very difficult to see inside the pump aperture to check the position of the operating cam. My tip is to use a digital camera with flash to see what is what! The correct position is with the cam lobe pointing upwards (see picture above). If you find that the cam is not in this position you can "nudge" it round using the ignition key.

Once you are sure the cam is correctly positioned, you can then proceed to fit the new gasket & pump.

The reason that you take all this care is that if you don`t ensure the cam lobe is pointing upwards it is quite easy to fit the pump operating arm above the cam by mistake. If you do that, then once the engine starts it wrecks the pump and dislodges the pivot pin, which then drops inside the engine sump pan—thus creating a lot of unnecessary work & expense.

The operating arm on the new lift pump may be a different shape (my old one was straight and the new one was shaped) but as long as it is the correct one supplied it will be fine.

Additional Notes!

Because it is not unknown for the operating cam to wear on these engines you may decide to use an electric fuel pump in place of the mechanical lift pump.

You could just cut off the pump operating arm and use the old pump body as a cover, but make sure that you bypass the lift pump with the fuel lines because you don`t want the diaphragm puncturing under pressure and filling the crankcase with diesel.

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Just for Fun: My Old Ford F250 Diesel Truck Videos

Starting Our 1983 F250 Diesel Truck

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.

Did You Find This Helpful? Why Not Leave Your Comment? I Would Love to Hear From You

Wayne pehlwayne@gmail.com on April 17, 2019:

Bubbles in my rusted raidator .

. any thing I can do?

It's a 84 6.9 idi diesel Ford F-250 4+4. Thanks

Wayne (author) from west vancouver BC Canada on May 21, 2015:

I am glad you found my hubpages post helpful and good luck with your truck.

456-sign on May 14, 2015:

I just got my first 84 ,350 with a 6.9 and i love it.it scares me to work on it cause everything is so big and so rusted together.im about to tackle the fuel pump and your advice kinda put me at ease.thanks for the post.also going to yank the orig. tank and use an auxiliary bed mount...since the sending unit is no longer available.northern has a d.o.t. apprvd. 18 gal. aux for 320.00. Thnx agn!

Wayne (author) from west vancouver BC Canada on May 06, 2015:

Hey Bernd...Thanks for your comment that is exactly why I built this webpage I am so pleased that it was helpful to you and I hope you can keep your truck running for many years, My truck has sadly ended up parked up with a blown head gasket.

Bernd on March 24, 2015:

Hi, looks like this site is no longer maintained (last comment 2 years ago).

Anyway, You just saved my life, at least the life of my 1983 6.9 IDI. (fuel lift pump replacement). Many thanks from Germany.

curtmaxwall on January 30, 2013:

Easy to replace after reading this lens. It would be even better if you can add symptoms of a bad fuel lift pump

Wayne (author) from west vancouver BC Canada on January 28, 2013:

@TransplantedSoul: Thanks for checking out my lens!

TransplantedSoul on January 28, 2013:

I love D.I.Y lenses. Well done.

TTMall on March 20, 2012:

Great lens with excellent pictures. Thanks for sharing!

journey103 from USA on December 21, 2011:

Good niche topic!

Wayne (author) from west vancouver BC Canada on December 24, 2010:

@Senora M: Thank you ! I hope that someone finds the info in my lens helpful.

Senora M on December 24, 2010:

Cool lens! I look forward to more lenses from you!

Nimblepins on December 20, 2010:

Oh....so that's how you do it! I wasn't sure!!

This lens is very informative - and you have great step by step instructions (seriously)

Well done, pixelhound

Wayne (author) from west vancouver BC Canada on December 18, 2010:

@thesuccess2: Thank you.

thesuccess2 on December 18, 2010:

People may smile but this type of lens is a life-safer for someone actually has a problem with their 1983 Ford 6.9 IDI Diesel engine. (Good Niche!)

Wayne (author) from west vancouver BC Canada on December 15, 2010:

@anonymous: Thanks for your comment, I love Ford diesels too especially these older trucks they can rack up huge mileages but just keep going & going I doubt that the newer ones will still be rattling round in 27 years time.

anonymous on December 15, 2010:

Welcome to Squidoo. Should I ever need to know how to change a fuel lift pump on on a 1983 Ford 6.9 IDI Diesel engine, I will know where to come for information (love Diesel Fords, btw - partner has many as he is a dealer).