Air in Fuel Filter after two hours and 70 mph.

[1629dill]

Over the Holladay last week I drove my 1999 Suburban with the 6.5 diesel to Washington D.C. with the family. After filling up with fuel and driving down the highway for about a 150 miles the engine stopped for a moment and started back up. I kept going down the road without problems for about 50 miles then got into some stop and go traffic. Every time I would slow down and the engine would stop. I was now on the side of the road it would not start. I wanted to check to see if the fuel pump was working so I opened the air bleed on top of the fuel filter and had a mist of fuel and air coming out. After a few seconds it started pumping all diesel.
After getting all the air out I started just fine and off we went.
About 50 miles later it did the same thing and I had to bleed air.
At the next stop I topped off the tanks. It was at ¾ before I filled up. With the tank full we sent the next 150 miles without a problem. The next day we did a little driving and had no problems, about 40 miles. On Friday we drove into D.C., about 20 miles, no problems. On the way back to the hotel it started to stall when we would slow down. The tank was back at ¾ and we pulled off and filled up and bleed the air out for the fuel filter. No problems for the rest of the day.
On Saturday we headed home. We stopped in Breezewood, PA and filled up before the fuel gage showed ¾ and all was good. The next time we came off the fuel gage showed ¾ and it stopped as we come off to fill up. We filled up and bleed the air and we were off. Did not have a problem till we slowed down to pay a toll in Indiana. Started back up and keep on going till we hit next toll. My wife just keep on driving and when we got home it was down to ½ a tank. When we pulled up at the house I bleed more air.
My question is why am getting air in the system and how do I start to fix it?
Here are some details about the Suburban.
It has 201,000 miles, the injector pump was new in November of 2012. It has a WALBRO FRC-10 LIFT PUMP and pre filter on it. That is the only changes I have made to the fuel system. On other think that is going on is the fuel gage is all over the place as you stop, go and make turns.
Thanks

 

[Drago]

the erratic gauge is wax or paraffin buildup on the sending unit inside the tank, both my trucks did it. it cleared up when I started using biodiesel. of course it cleaned ALL the crap out of the tank and clogged the sock. You're getting air in there somewhere. I had a dry rot crack in one of my hoses near the fuel manager that caused very similar problems. My other truck's filter gelled up as well so there's that.

 

[ak diesel driver]

you need to put a fuel pressure guage on there to see what is going on. sounds like an intermittent LP. maybe relay? or bad connection

 

[hookedup50]

Check all the fuel connections. My Oem LP like to loosen up among the many things that rattle loose on the truck. I still am getting air in the return and think metal return line is pinholed. Good luck. I'm doing the Leroy Walbro thing this week along with Tank swap.

 

[WarWagon]

I would look at the pickup assembly for a pinhole at the top. The return line is under pressure and only would affect cold starts by allowing fuel to drain out. Look for kinked hoses. Throw away the tank sock and don't use one. Use a separate prefilter or the included screen in the Walbro. Aftermarket tank socks and pickup assemblies do not have the bypass valve in them and are nothing but trouble.

Any restriction in the fuel line can cause the suction from the IP to boil diesel in the fuel line. Looks like air and the lift pump looses prime - literately vapor lock.

Check the fuel from the drain valve for gasoline smell, water, and odd crud that could be diesel bugs. Check the filter for silver streaks that is the tank lining coming off.

 

[Burning oil]

Dirty sock can cause those symptoms.