I am fed up with the chronic loss of fuel continuity after my 87 F250 HD 6.9l IDI sits for a few months. I drain the battery bringing the fuel up, then I have to find a way to charge the battery fully after running the engine up to temp. As you can conclude, this wonderful truck is not driven a lot, but I believe strongly in keeping a non-computerized vehicle for use in the event of an emergency.
I am considering adding an electric fuel pump before the mechanical lift pump to ameliorate the drain-down of my batteries. Have any of you attempted this? Do any of you see any show-stoppers here? Do you have any electric fuel pumps you can recommend? I prefer using a non-solid state pump (Like the Holley), because 'solid state' means transistor junctions, and I prefer a simple motor. Thanks in advance for any and all replies. And no, I couldn't find a thread that discussed this...

 

you cant run a electrical pump behind a mechanical, they will be fighting eachother.
now if you can run the electric side by side, meaning that when the electrical pump primes the system, you shut it off and use the mechanical that's not obstructed.


holley fuel pumps will get water in them killing the pump.
a water separator should be used before these pumps.
im on my 3rd, and when this one dies I have a SD pump going in

 

If you can find a cheap 'flow-through' pump like this:
12V Electric Fuel Pump Low Pressure Bolt Fixing Wire Diesel Petrol HEP-02A NEW | eBay
You can just insert it after the mechanical pump and before the fuel filter.

I've done that on one of my trucks as a 'band-aid' until I can fix the real problem, which is a pinhole or something in the fuel pickup.
It works. I've verified that fuel will flow through it just fine when it's off, and it will prime the system by itself when it's on(at least to the fuel filter - nothing will push fuel through the IP without cranking).

You never want an E-pump /before/ the mechanical lift pump - if the diaphragm ever breaks, you can end up pumping fuel into the crankcase.

 

Very true. Not worth running concurrent fuel pumps in series. Just a nightmare waiting to happen.


I switched to duralift e-pumps long ago. Never looking back. The lift pump had too many issues, and it was a hassle to purge the air. Now I just flip a switch, push my custom schrader valve, and purge the air out right up to the IP. (I also run an R&D IDI Performance Stage 1 fuel filter system on my frame rail, so that is great too.)

I highly recommend doing the stock filter delete. The micron rating on these stock filters are awful, plus it wastes space in the engine bay. Plus running the e-pump allows me to purge the air very easily.

 

The only problem I have with this is that if you are /getting/ air into the system, enough to make hard starting a problem in under a week... you have a problem.
No amount of band-aids like an E-pump will fix the fact that something is wrong here - you shouldn't be getting air into the supply side of the system.

I currently have two trucks that will fire right up after sitting for a couple of days. Stock mechanical pump. No issues at all.

I have a third which is definitely getting air in it, is hard to start, and even with an E-pump, you still have to bleed air out occasionally.

What's the difference? There's something wrong with truck #3's fuel system!
(in this case, I'm sure it's tank pickup/line related, which basically requires dropping the tank or pulling the bed... which is why it hasn't happened yet).

The solution is... Fix the problem!
Short term? Sure, throw a bandaid on it. But if you are still having to 'purge air out'... you've still got a problem.

 

I agree with Macrobb, you have a problem,

maybe the diaphragm in the mechanical fuel pump has a pin hole or a crack, you have air intrusion somewhere and i know they are a pain to find at times.

​​​​​​​if you want a band aid fix I vote a check valve right at the tank, cheap, effective

 

I totally agree. He should obviously find the air intrusion issue.

But regardless, once that is fixed, I highly enjoy using an e-pump over the lift pump. With the amount of work I do on my van, I like the luxury of purging air with a flip of the switch.

 

I really like Macrobb's posts, the last one by genscriptor and most of the other posts.
However, note that the factory fuel line on a 1987 6.9L from the mechanical lift pump to the filter header is a solid steel line with a fuel heater on it. (same with some earlier years).

I would hate to cut that steel line to splice in an electric fuel pump because it would be very difficult to find another steel line to bring it back to original and there is nothing wrong with that original design, it's NICE to have the steel line and the fuel heater.As far as moving the fuel filter to another location to provide additional space under the hood, I like that idea for a VAN but in a pick-up the location of the fuel filter assembly is not much a problem. At least with a non-turbo IDI (I have no experience with turbochargers).

Replacing the Thermostat (and possibly the Vacuum Pump) is an exception. Aside from that, I think it is UGLY! However, it's VERY EASY to change filters and fix any leaks in fuel lines/return lines coming in or out.

After carefully replacing my return lines and 'olive' gaskets that came with a return line kit my truck will start on essentially the first revolution every time after sitting for 2 months! That is at outdoor temperatures from 32deg.F to 50deg.F. I haven't let it sit longer than that but it probably would still start up on the first or second engine revolution after sitting for 4 months or more.

It also has new glow plugs (2 years ago) and the solid state controller seems to be working right.

Like others have suggested, My advice is to fix the problem! The SURE way to do that is to carefully REPLACE ALL of the return line components which come ikn a return line kit. (except the copper injector washers) The REASON is because there can be air leaks that you can NOT SEE or easily detect! The only way to cure those is to install the whole return line kit! In my opinion, the worst method for solving air intrusion problems is by hunting and pecking trying to find a single leak or two or three here and there and just fixing them as you find them. REPLACE IT ALL with a return line kit. Then you will KNOW where you DON'T have a problem because you were PATIENT and DID IT RIGHT. That might fix your whole problem. Often it does, but IF NOT you can move on to other parts of the system which will be much easier now that you can forget ALL of those potential air intrusion locations above the engine. There are at LEAST 36 of those! (including the O-rings, olive seals and hose connections). Hoses can APPEAR to be good yet they are old, less flexible and UNDER THE CLAMPS where you can't see the rubber can be cracked and allow air intrusion. I found one or two like that. If there is an air leak at one location there are likely to be several more and you'll be chasing those leaks for a long time. Fix them ALL at one time and be done with it!

If that doesn't completely fix it at LEAST you have eliminated 36 potential leaks, ruled those out and there aren't many more locations to examine or test to find additional problems. This makes the whole issue much less complicated and easier to focus on.

I'm very tired and I've probably repeated a few things. My advice again is don't use a "hunt and peck" method to try to locate and fix air intrusion problems in 36 possible locations on top of the engine. Just replace it all and be done with it. IF YOU KNOW WITH CERTAINTY that all of it was PROPERLY and carefully replaced recently then you can probably skip it. Don't rely on someone else, like a previous owner telling you that all of it was properly replaced, like '3 or 4 years ago' could mean 8-12 years ago and maybe it was only part of it that was replaced.

Sorry if I wrote too much, I'm really burned out from working on and posting in the VRV topic. I spent about 9 hours on that today (working behind the scenes). I am emphasizing the things I mentioned in this post in order to make it EASIER for people to solve air intrusion problems. I've seen too often where people hunt and peck to find the problem which could be in any one or more of maybe 50 different locations and they get frustrated and want to resort to a seemingly easy work around which doesn't fix the problems. Those problems will eventually get worse and you might have return fuel lines here and there, leaking fuel until your engine is a dirty mess and you end up having to replace it all anyway.

I feel like I am beginning to write in my sleep so I need to stop here.

GOOD LUCK ON GETTING YOUR TRUCK FIXED! It's like a very nice dream when everything is working right and it starts right up every time! It doesn't take much to do that, just a methodical approach to diagnose and fix a few problems. Note on a return line kit. The length of the fuel line between each cap is exactly 4 Inches. You can cut those in advance and assemble the 4 caps, return lines and clamps for each side in advance. Also, measure, cut and attach the REAR return fuel line that goes between the two rear caps behind the intake to ONE of those 4 cap assemblies (I think I chose the the passenger side - not sure). Whichever side has the more difficult access space is the one where you want to pre-connect that rear fuel return hose. Then you can fish it through to the other side as you install that 4 cap assembly, ONE of the difficult back connections already made.

By the way, there is a long metal return line that runs back, on top of the driver side intake manifold that has an olive gasket in it's connection at the back. Do THAT one before installing the caps and hoses on the injectors for easier access!

You can get a better hose fit-up and clamping by doing all of those connections I mentioned (except for that olive seal) outside of the truck. The remaining ones at the front of the engine will be easy to access in the truck.

Carefully install the 2 o-rings on each injector after applying a bit of clean engine oil = they go on easier and the oil helps to properly seat the caps without disturbing the o-rings. (some people use grease), then just carefully push the caps and hose assembly you made for each side, down onto the injectors, over the now lubricated o-rings until the caps are seated. VERY EASY and it will look great with all of the fuel lines cut to the right length!

I need to sign out and go to sleep! GOOD LUCK WITH YOUR TRUCK! I want to see a post where it is all fixed and you are HAPPY WITH YOUR TRUCK! The 1987 was a great design change year to the 8th Generation (1987-1991) and it had the last and best 6.9L engine with 7.3 style roller rockers and the much better solid state glow plug controller. Further, the 6.9L engine was extremely well engineered specifically as a 6.9L engine. Slightly less power, slightly less torque than the 7.3L non-turbo but it's extremely rugged as originally designed and engineered and will last longer then the bored out 7.3L version. The 7.3L was the "new improved" 'bigger engine/more power' sales gimmick that Ford wanted to further increase sales for 1988. One could legitimately argue that removing a whole 1/5th of the 6.9L cylinder wall thickness to create a 7.3L engine was not a good idea. The whole engine block including stronger webbing was extremely well engineered for a 6.9L, not a 7.3L. Further problems related to longevity are likely to occur when pushing the the 7.3L for more power.

Still everyone seems to say that the 7.3L IDI is a very good engine. I won't disagree with that. I personally want a stronger, more durable and longer lasting engine far MORE than I want more power and more speed. Others surely have different preferences than mine and so be it.

All that said, I honestly believe that the 1987 6.9L trucks as described above are the best and most durable of IH/Navistar Ford IDI's produced. I feel very fortunate to have, by magic and good luck this specific truck, 1987 6.9L Super Cab even though it needed more work and money put into it than I had imagined! (It still needs more). Although it was a 28 year old truck when I bought it, in my eyes at the time IT LOOKED LIKE A BRAND NEW TRUCK! Exactly the 'diesel pick-up' that I had been hoping for and dreaming to find for months! I had no idea which brand of truck it would be. I was looking at Dodges with Cummins diesels too. People asking too high of prices for those and as it turned out the Ford has the better "truck" part of the two brands and I certainly can't complain about the 6.9L for my intended uses. It sucks up more fuel being an IDI with the C6 but that's just part of the expense for the quality work that it will do for me.

I AM typing as I am falling asleep in my chair so I must stop. The reason for that last part is this: radjcw5, you should be HAPPY with your 1987 HD F250! Not frustrated and at the end of your ropes with it. I think it will just take a little more patience and a methodical diagnose and fix approach to solve the problems. I just pointed out one easy and inexpensive way to make a big step toward fixing air intrusion problems. I hope that my suggestion applies, I've never seen your truck and I know almost nothing about it aside from my opinions about the 1987 6.9L trucks.

I need to conk myself out here with a sleep aid pill or I'll keep rambling, so GOOD LUCK with your truck!