I have a 1986 GMC Ralleystx 1ton van. I recently had some hard starting problems and I replaced the fuel pump. Now after letting it sit for about four hours I can crank it and it will start and run for about 5 seconds and die. During this start there is usually black smoke that accompanies this start up. I must crank on it several times to get it started. Not a whole lot but enough to get the fuel back into the injector pump. I was told I may have an airlock somewhere I service this vehicle regularly. It is a Good wrench engine with about 88,000 on it. I did some head work on it, new vacum pump, alternator, radiator that sort of thing. New Glow plugs. If it is an air lock what could be causing it? What steps should I take to remove air and what steps should I take to prevent it from occurring? The Chiltons is very vague and doesn't cover much. Any help would be appreciated. I might add when it is started it runs very good and strong and starts when warm on the first kick. I get between 18-24 MPG with this vehicle and it has been nearly trouble free and I would sure like to fix it. Thanks and any help is appreciated.:help::help:

which fuel pump did you replace? Mechanical supply pump right?

Open the bleed on the filter base while the truck is idling until you get steady fuel. You might want to attach a rubber hose to the fitting and bleed it into a container and check for air bubbles. This would tell you the supply system is drawing air somewhere and possible sources are the lift pump itself, the tank pickup or the lines from the tank.

I'll give that a try. Thanks. Yes it was the mechanical pump. On the front of the engine.:cool2::cool2:

Did you replace the Rubber hose connecting the pump to the feed line? Its probably 9 years old and dry rotted by now, 3/8" hose I think it is.

Nope I didn't do that but I will. Thanks. You are a veritable storehouse of useful inormation thanks.

Nope I didn't do that but I will. Thanks. You are a veritable storehouse of useful information thanks.:grd: