6.9 not getting fuel to injectors.

[BigBlockTony]

Long time reader and really my first time posting. I am a soon to be mechanical engineer that has a fairly good background in equipment repair, theory, and design.

Recently picked up a non-running 1986 F350 with a 6.9 for its front axle. Most likely the truck only has 75k on it and not 175k or 275k etc. from the looks of it's interior and other parts of it. This was one of those that ran when parked deals.

So I made the choice of trying to start the engine. Pulled all the glow plugs and shot oil down the cylinders before I tried to start it and primed a new fuel filter and made sure the lift pump was moving fuel before I put the glow plugs back in.

Currently getting fuel to the inlet of the injection pump but no fuel to cracked injector lines all 8 or if I pull a line completely off.

I will be the first to say the fss clicks when it is given power. Pulled the top cover of the injection pump off and the the metering valve assembly turns free like it should.

The fuel in the injection pump looks like it was algaed.

I did fill the top of the injection pump with Seafoam after I cleaned as much old fuel out as possible. Still looks pretty dark.

The return lines do leak pretty badly and i figure they are original to the truck(caps seem to have gray paint on them) Ordering a new set and will put them on this next weekend.

Am I doing something incorrect or is it because my return lines leak so badly or the injection pump is bad from sitting?


Ps. I also noticed that the injection pump had a fine stream of fuel squirt out of the inlet while i had the inlet line off and was cranking the engine. From the design of the pump it seems like this should be normal because of the one slide valve on the the transfer pump in the inlet not having in fuel pressure from the lift pump.

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[IDIBRONCO]

If your injector pump has algae in it, then you probably need a new one. The next bit of good news, is that it would be best if you replaced the whole fuel system because the algae probably is through the whole system. That's from the tanks forward, including the lines, tank selector valve, injector pump, and injectors. Sorry if this is the case.

 

[BigBlockTony]

If your injector pump has algae in it, then you probably need a new one. The next bit of good news, is that it would be best if you replaced the whole fuel system because the algae probably is through the whole system. That's from the tanks forward, including the lines, tank selector valve, injector pump, and injectors. Sorry if this is the case.

Sounds about my luck right now. Luckily it's the parts truck and not the truck I am actually putting my time into.

The injectors seem to be dry and the fuel coming out of the fuel filter is not dark like alaged fuel is so it seems like maybe it was just the injection pump that had algae in it

 

[IDIBRONCO]

Hopefully you got lucky. I'm just not sure how you could only have algae in the injector pump and not the rest of the system, it's the same fuel throughout the whole system. If you do have algae in only your injector pump and you do get it to pump fuel to the injectors, then they're now contaminated too.

 

[Joseph Davis]

Don't crack the lines pull them off of the injectors. Then pull and fill the fuel filter with Automatic Transmission Fluid (ATF) put back on and start cranking till you see red at ends of injector lines. Stop let set over night. Next hook lines back up and start cranking till she fires up. worked when I got my friend truck up and running it sat for two years. runs okay, but I own it now, and it needs a valve job. I hope it works like it did on mine. Good luck

 

[Macrobb]

If you /really/ have trouble, pull the IP(by removing the 3 ip-to-gear bolts and 3 ip-housing-to-ip nuts), put it on the workbench, give it fuel with a little electric pump, power to fss and cold advance, floor the throttle and spin it over by hand a bunch. With no injectors making backpressure, you can do this without too much hassle, and once you see fluid out the injector lines/ports on the IP, you can put it back.

 

[frankenwrench]

If you /really/ have trouble, pull the IP(by removing the 3 ip-to-gear bolts and 3 ip-housing-to-ip nuts), put it on the workbench, give it fuel with a little electric pump, power to fss and cold advance, floor the throttle and spin it over by hand a bunch. With no injectors making backpressure, you can do this without too much hassle, and once you see fluid out the injector lines/ports on the IP, you can put it back.

I never would have thought of that. That's a really good idea.

 

[Thewespaul]

While you have it on the bench it would be a good idea to remove the back of the ip and clean the screen as well. Good call @Macrobb!

 

[BigBlockTony]

Thank you guys! All sound like wonderful ideas! I will report back with results

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[icanfixall]

Just a note about that screen in the inlet of the injection pump. Please look at the u tube videos first. In that area are the smallest springs that holds the very tiny inlet pump vanes in place. You do not want to loose those. The videos also show how to easily remove this rear section too. My suggestion is to do this work in a vice where the rear of the pump is facing upwards.

 

[BigBlockTony]

Just a note about that screen in the inlet of the injection pump. Please look at the u tube videos first. In that area are the smallest springs that holds the very tiny inlet pump vanes in place. You do not want to loose those. The videos also show how to easily remove this rear section too. My suggestion is to do this work in a vice where the rear of the pump is facing upwards.

Thank you very much for the tip! I am pretty excited to do a bit of a tear down on this pump. Luckily it's a parts truck and its something I can just take my time and play with.

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[matt threet]

I'm having nearly word for word your same problem right now. Keep this thread updated on how you resolve it if you dont mind!

 

[BigBlockTony]

I'm having nearly word for word your same problem right now. Keep this thread updated on how you resolve it if you dont mind!

Will do. Right now, since this is the parts truck, I have a lead on a running take off injection pump off a jasper reman engine that threw a rod recently. But I plan on cleaning and bench testing the injection pump when i get time. Working full time and trying to finish an engineering degree leave me with little free time.

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[kent01]

Long time reader and really my first time posting. I am a soon to be mechanical engineer that has a fairly good background in equipment repair, theory, and design.

Recently picked up a non-running 1986 F350 with a 6.9 for its front axle. Most likely the truck only has 75k on it and not 175k or 275k etc. from the looks of it's interior and other parts of it. This was one of those that ran when parked deals.

So I made the choice of trying to start the engine. Pulled all the glow plugs and shot oil down the cylinders before I tried to start it and primed a new fuel filter and made sure the lift pump was moving fuel before I put the glow plugs back in.

Currently getting fuel to the inlet of the injection pump but no fuel to cracked injector lines all 8 or if I pull a line completely off.

I will be the first to say the fss clicks when it is given power. Pulled the top cover of the injection pump off and the the metering valve assembly turns free like it should.

The fuel in the injection pump looks like it was algaed.

I did fill the top of the injection pump with Seafoam after I cleaned as much old fuel out as possible. Still looks pretty dark.

The return lines do leak pretty badly and i figure they are original to the truck(caps seem to have gray paint on them) Ordering a new set and will put them on this next weekend.

Am I doing something incorrect or is it because my return lines leak so badly or the injection pump is bad from sitting?


Ps. I also noticed that the injection pump had a fine stream of fuel squirt out of the inlet while i had the inlet line off and was cranking the engine. From the design of the pump it seems like this should be normal because of the one slide valve on the the transfer pump in the inlet not having in fuel pressure from the lift pump.

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Those inj. Pumps can be hard to get primed, if the truck is a manual trans, pull it with another vehicle and let clutch out I've done that before with my 7.3 it wouldn't start cranking but fired pretty fast pulling it.
The 6.9 is a great engine, they can make good power if you Turbocharge them. And the cylinders are not known for electrolosis like the 7.3 engines are. And electric fuel pump can be of a big help getting primed. One more thing if the glow piug timer goes click click click it's malfunctioning. You can bypass it to put power to the glow plugs for 20/30 seconds.

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[kent01]

If your injector pump has algae in it, then you probably need a new one. The next bit of good news, is that it would be best if you replaced the whole fuel system because the algae probably is through the whole system. That's from the tanks forward, including the lines, tank selector valve, injector pump, and injectors. Sorry if this is the case.

You. Can use starting fluid without the glow system working

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