Fuel lift pump problems!

[TDI]

Hello All,

I have a 1985 4x4 F250 , 6.9. Its a great truck , relatively new to me. The previous owner installed a "Mr. Gasket" electronic fuel pump, hacked into the wiring and installed a cut off switch in the dash.

I had a small fuel drip and upon closer inspection I see the hack job on the fuel pump install and decide to yank it out and install a new lift pump. The original lift pump was left in place when the PO did the electric pump install.

OK, I rip out the electric pump, install the new lift pump , bend and install a new hard line from the pump to the filter bracket ( old line cut into three pieces by PO)

Fire up the truck and it runs much better than off the electric pump, no leaks. Later that day on a local drive i see smoke, smell diesel and notice a pretty bad leak coming from lift pump area.

I assumed it was the cheap pump i bought but could not clearly see the exact source of the leak, when I removed the pump I noticed that the inlet pipe was bent and I just assumed that was the problem. Leak was bad but not terrible.

Today I carefully install a second lift pump of better quality, checked the install and fired up the truck, one quick drive around the neighborhood and no leaks. Just made a 8 mile run with the truck to the dump, by the time I got there the truck was ******* fuel, this was a much worse leak than the prior leak

I made it home, dried off the fuel from the pump and fuel lines and hoses and let it idle , NO LEAK? OK so I give it some accelerator to see if under speed it will leak, NO LEAK -

I check the fuel lines from the tank up to the pump and notice nothing, a lot of fuel sprayed back and around the lines but still I cant see a leak. . there is a lot of fuel with this leak, its sprayed all over the starter motor, exhaust and frame. I dried off all that I could get to but still cant find a leak. The source still indicates that it is the lift pump or in that immediate area.

It has to be the pump installation???? Is it possible that under load and when the frame motor flex's that something cracks open enough to spray fuel? Does not reusing the factory fuel line to the filter matter ( dont have that line with the electronic sensor or heater any more)

Or maybe there is a reason that the PO installed the electric pump?? Truck has 100K on it, I dont think that the crank is worn out but who knows

I will be grateful for any help on this

 

[icanfixall]

This is an odd issue. Did you replace the short rubber hose from the frame rail to the new lift pump. If not that the first thing I would do. they do wear out and crack. As for running a soft rubber line from the pump to the filter. Thats fine too. That heater was never a good idea on the 6.9 or the 7.3 engines. On the 7.3 engines we are supposed to turn on the ignition switch for 5 minutes before we try to start the engines... Sadly Ford never in any of their owners manuals ever mentioned this. And who really will sit in the truck on a hot or coold morning waiting to warm up the fuel in the filter... Nobody will. Only other possible issues with the new lift pump is getting the arm under the can loge. Some owners get it over the top of the ca lobe and the arm tends to break off and fall into the oil pan.. Not a big deal cause its on the bottom but it can vibrate off the oil pickup tube and wear a hole in it. One member found 3 arms in his oil pan when he rebuilt his engine...

 

[TDI]

Hello ,

Yes I replaced the rubber line and hose clamps, even the second time I replaced the supply rubber line and clamps and i left the loop in the rubber supply line. Truck was just idling away for 1/2 hour and NO leak can be seen. I can grab the rubber inlet hose and feel the fuel pulsing through it, also there is no excessive vibration that I can feel on the pump housing.

I am pretty sure that I got the 2nd pump arm under the crank, and the pump I removed ( first new pump) was worn on the top of the arm indicating to me that it was also installed under the crank lobe.

I cant get it to leak fuel while its sitting in my driveway. I am pretty sure that the leak is directly related to the pump I just dont see where.

 

[TDI]

OK, still no luck with finding the leak but there is a ton of fuel all over ( or inside) the bell housing and frame cross members, clutch fork, etc .The drips are so bad that I think that is either another source or I recently cracked something while looking for the leak, the leak still appears to be ABOVE the hard fuel line that runs from the tanks.


** OK, air cleaner housing off, top of intake manifold flooded with raw fuel, fuel dripping down and back over block and transmission bell housing, source of leak still unknown but hopefully its only a loose injector pump line, possibly at the pump manifold.....truck is too hot to work on now since its was idling in the driveway for past hour !!

OK this is what I think, driveway has an incline, truck was pointed downhill this AM when I changed the lift pump and pointed downhill at the dump when I unloaded a ton of debris, but pointing it downhill fuel leaked forward on to the top of the fuel pump area, when i got home truck is now pointed uphill, fuel on top of intake manifold rolls to the back of the manifold and down all over the bell housing and exhaust

Its quite possible that I never had a leak at the fuel pump (s) at all - it was always the injector lines!!!!

 

[gandalf]

Lets see whether I've got this right. The PO installed a cheap Mr Gasket electric fuel pump. He left the original lift pump in place. In doing so he destroyed the hard line between the stock lift pump and the fuel filter. You've eliminated any/all electric fuel pump(s), and gone back to an original stock lift pump. You're on your second mechanical lift pump replacement, because the first replacement leaked when driving, and now that second replacement is also leaking.

Did you build a new hard line between the lift pump and the fuel filter? I think you said you did. The flair on those hard line ends can be critical. Did you put the proper "olives" on that new hard line? The "olive" is a rubber sleeve type gasket which goes on the hard line between the flair and the nut. Those olives are critical. See the picture below. I show the hard line between the filter and the IP, but otherwise they are the same.

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[Brad S.]

If this is in the same location on the 85, check the return line, from the injectors, that Y's together on the back of the engine.(drivers side???)

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[TDI]

yes i reused the fitting from the factory line and slid it on the hard line and then flared it - its perfect

but look at this ....!!!!

** OK, air cleaner housing off, top of intake manifold flooded with raw fuel, fuel dripping down and back over block and transmission bell housing, source of leak still unknown but hopefully its only a loose injector pump line, possibly at the pump manifold.....truck is too hot to work on now since its was idling in the driveway for past hour !!

OK this is what I think, driveway has an incline, truck was pointed downhill this AM when I changed the lift pump and pointed downhill at the dump when I unloaded a ton of debris, but pointing it downhill fuel leaked forward on to the top of the fuel pump area, when i got home truck is now pointed uphill, fuel on top of intake manifold rolls to the back of the manifold and down all over the bell housing and exhaust

Its quite possible that I never had a leak at the fuel pump (s) at all - it was always the injector lines off the injector pump!!!!

THANK YOU FOR the diagram....I will check truck in an hour and hopefully find a loose line, all injector lines are good, injector return lines good, T at rear good, leak looks like its from the pump

 

[icanfixall]

Well because you had not mentioned any work done on top of the engine I felt it did not ned to be mentioned but. you have a supply line or return line leak on top of the engine. Any liquid that spills on top of the engine will only drain out the back and down on the starter. It can't drip or flow off the drivers side of the engine. So look at the injectors and the filter to the injection pump line. That line is 5/16 and has the seals in each end called olives. Mc Master Carr and grainger plus any good quality injection pump rebuild shop has them. I'm betting you need to replace them and the return line kit too. Contact Mel at Conestoga Diesel in Pa. He is a founding member here and a great guy to deal with to.

 

[TDI]

I bought the complete kit from Mel last summer, all the injectors, return lines, filter lines are good. Where I think the leak is coming from is right off one of the supply lines from, unfortunately, the bottom of the injector pump supply manifold, It's possible that it loosened up when I changed the injectors but it looks like its been messed with by the PO and come to think of it he did mention that his "mechanic" son pulled and replaced the IP....should have been the first thing that I checked.

Right now i am absorbing the diesel up with diapers - there seems to be a couple of pints of fuel on the manifold.Its still too hot to get a wrench on the IP lines if I can even fit one in there .



Thank you for your help

 

[TDI]

any ideas on how to tighten the lower fuel lines that come off the pump ??

 

[BioFarmer93]

The injector lines- right? The only way I know to tighten them (and there may be a smarter/easier/faster way) is to take them off the pump, starting at the top, until you can tighten the bottom two really well with a fuel line wrench, and then carefully reinstall and tighten each one, side to side until you have them all back on and are sure of their tightness. It's a PITA, I know, but like I said before, someone may know an easier way- maybe with a bent wrench or something..

 

[TDI]

i think that's the only way....!

Thanks

 

[gandalf]

i think that's the only way....!

Thanks

There IS a special tool, a special wrench, made for that exact purpose, tightening those lower hard lines on the IP. That's the good news!!

The bad news is that they're pretty hard to find. The only one I've ever seen was part of a set of tools made specifically for our trucks. I borrowed the whole set, twice, when I changed out my IP, twice. So NO, I don't own it. I have a friend who owns it.

In the attached picture look at the socket type tool in the lower right corner. That's it. For lack of a better name, I'll call it a deep well socket line wrench. Notice that part of it is cut away, so that it can fit around a hard line, reach in under all those lines coming off the IP. Is it possible to make one of these, duplicate it? I guess so. Start with the proper size deep well socket, 5/8th inch I believe, and grind out enough to make it work. Good project for somebody here.

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[icanfixall]

Well sadly without the special socket wrench your going to need to remove all the lines that are in the way. Now doing all the lines is best to remove the line vibration clamps and the rubber insulaters but.. Be sure to reinstall them or you will break a line from the fuel pulse vibrations from the injection pump. I did not replace them and broke a line going to work one day. What amess it was. If your clune clamps are missing then you have a broken line now. A tip or trick is to replace those short 1/4 inch clamp bolts for a longer bolt. A 3/4 or 1 inch will work great. Use some electrical tape on a box wrench end to hold the nut when you reach under for the bolt.

 

[TDI]

It doesnt matter now....I just ran the truck with the air cleaner off and its the pump housing itself thats ******* fuel. I managed to get a crows foot socket wrench on the lower lines and tightened them all up but now its time for a pump rebuild, its leaking behind the manifold - there is a round part on the line manifold that looks like its pressed into the pump housing, its leaking where those two parts meet.

I havent had a close enough look to see if it can be tightened but I dont see how

so whats next ? a baby moose pump??