My father's old '87 with 6.9 will always fire right up as normal. Problem is it will always run for 8-15 seconds then die requiring a starter laboring cranking session to restart.

I realize this is an air leak in the fuel but hoped to get some hints on where this particular issue may stem from. I have tried in vain to get my dad to build a pair of gas caps with valve stems to pressurize the tanks in hopes of finding leaks.

Thus far we have swapped the seals on the fuel return lines and the bad tank selector valve. I do not remember if I have changed his factory lift pump and am awaiting an email from him to verify if I have.
The valve was was changed yesterday and we had hoped it would solve the problem but no such luck.

The truck did have a third tank but it is no longer there. PO did modify the factory lines in front of the selector valve, adding 16 inches of rubber line.

I have no noticeable leaks, no wet nipples that I can see.

Would an inline electric pump eliminate this issue? Will an electric pump and a factory lift pump work fine together? Can an electric be used momentary and shut off once truck is running? Or will the mechanical pump not draw through the electric if it is off? What electric pump is being used with best results? My last one was from car quest and looked liked a modified in tank pump and it seemed to last plenty long on a gas truck.
Brent

 

Yes an inline fuel pump will fix the problem ..........NO do not leave the manual lift in the engine........ remove it and get a Big Block Chevy block off plate for the hole in the block. This part is available at most AP stores for under $10.

Info.....

Napa Balkamp Universal Fuel Pump Kit: Part #610-1050; ~$36 out the door; 4-6 psi at 35GPH. Put it on the frame rail, just after your fuel selector valve, and let it push the fuel to the Fuel Filter.

Holley red off Ebay or at Summit racing........

This was posted by another member....
The Best Electric Lift/fuel Pump

I have a Facet Dura Lift on mine. Unlike the holley pumps, the Facet is designed for seriously long term continued use, its the factory pump for new Carrier Transcold and Thermoking reefer units and is designed to lift fuel 10feet straight up so you can mount it up high under the hood where it's easy to get to and has a nice filter screen on it that's easy to clean and keep an eye on fuel quality.
http://facet-purolator.com/index.php...d=17&Itemid=37
The Carrier part number is 30-01108-01SV ( Facet # 40223 )

It was a good sign when I went to the Carrier dealer to buy one. The parts guy had to search for quite a while to find it. He didn't know where they were because they'd never had one fail. That's a good sign for pumps that run 24 hours a day .
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The cheapo Facet that autoparts stores keep on the shelf don't last very long. I keep one under the seat just in case my Carter goes belly up. It's been in there for 4 yrs now. OkieGringo

Visit......http://www.intellidog.com/dieselmann/idi.htm

Do some reading on the air leak points and how to do the clear hose test.

 

Okay, so pretty easy swap... Didn't know the chevy pump plate fit the .6.9 though
Brent

 

i use a carter rotory pump on mine ,the big block chevy block off plate fit right on mine

 

PLC7.3 the price on the pump has gone up a little. I need one and checked the price. Now it is $48.49 from the online store. Would the same plate work on the 7.3??

 

Same lift pump, same block off plate on both the 6.9 and 7.3.

 

Anyone familiar with the thread size on the filter body? I do need a barbed fitting? Or is it better to use the old hard tubing to take the new line? I last used a "rotary" (looks like an in tank pump) pump on my last gasser. It is $60 at carquest and worked great... any bad info on these?
TIA!
Brent

 

Sounds like the lift pump is letting fuel back thus causing your loss of prime. You can put an electric pump on and run it through the factory lift pump, but you're setting yourself up for problems down the road. If the seal goes out of the lift pump, the electric pump could fill your crank with fuel. I would not recommend running the electric pump through the factory pump. You can either put a new factory lift pump on, or modify your vehicle by adding an electric pump. This should solve your priming issues if there are not leaks anywhere else.

 

Actually you should install the electric pump right in front of the tank selector valve.

They don't pull fuel as well as they push it.

 

Okay we got a rotary type pump from carquest for 60 bucks. Ran a new line (10') to where I cut the steel line under what may be a water detector or possibly a fuel heater gizmo. Well the job was fairly easy and I tapped into the stereo power wire to have a keyed circuit.

Fired up the truck and the erratic idle was gone. The surge when nearly coasting was also solved. Heck, the truck actually seemed much smoother under power as well.
Thanks again for helpin' me convince pops to bite the bullet.
Brent

 

If the seal goes i think the mechanical fuel pump will also fill your pan up with diesel.

 

you could.
but then you would need two pumps.one for each line,and then have to be sure the correct one starts/stops when the correct tank is selected.
gravity feeds the pump well installed after the FSV i find.this way only one pump is needed and just one simple hot wire when the key is turned forward.

 

The way Dave is telling you to install the electric pump it will pull fuel from whichever tank you have selected. You don't need two pumps.

 

By "in front of", I mean closer to the front of the truck.

Two supply lines behind the fuel selector valve, one in front going to the engine.

 

oh ok.oops my bad!
yeah,this is where i put mine today.(this location kinda sucks lol,the pump sits right behind the transfer case.you can get at the filter pretty easy tho,if you shorten the line the most you can,that comes from the FSV.)
i hooked her up,and am all ready for my new FSV now.

oh,for the original poster,
i must say,that was REALLY cool just turning the key forward,walking up the fuel filter on the motor,and pressing the valve.though i dunno if it would have just pushed the air all out own its own just fine all the way back to the tank? anyway,i just felt like helping it lol.
i replaced all fuel lines tanks to engine.i was primed in just a minute or so.