ford 6.9l diesel hard cold start

[SNOWPUSHER]

One of my plow trucks 87 ford rack dump has a 6.9 litre diesel. It is tough to start cold. It usually starts right away but if you don't race the engine it'll die and I have to use either to start. The glow plugs were replaced but no help. When it's warm it starts fine. I've had some success with directing a heat gun in the intake. Does anyone have any suggestions?
Thanks, TC

[BOUNDS-ELECTRIC]

Has it got a block heater, is it working!!

[sno-mover]

How bout the glow plug relay

[wyldman]

The 6.9's were famous for glow plug control problems.A lot of them would run the glow plugs continuosly,and they burn out in short order.

You can check the glow plugs with a simple test light.Clip it onto the positive battery terminal,and touch each glow plug at the electrical connection (glow plug must be disconnected).The test lamp will light up if the plugs are good.Any bad ones will not light up.

If the plugs check out OK,turn the key on and check for power at the glow plugs.You must do this quickly,as they aren't energized for long.If you have power,then the glow plugs are operating correctly,and it's something else.If not,then it could be the glow plug relay (pass side inner fender),or the controller (drivers side cyl head @ rear).

They also had a lot of problem with fuel lines rusting,and it will suck air through the rust pinholes.This allows air to enter,and some fuel to drain back out of the lines,and into the tank.It will take a while cranking to get it out,and then it fires up.They also had similar problems with the fuel heater assy sucking air (drivers side firewall outboard of brake booster).Same symptoms.

[Pickering Snow]

Very well put Chris that would just about cover it

[capnkel]

If the engine starts and then dies,its not likely a glow plug problem,sounds much more likely you have an air leak in the fuel system,anyone thats owned a 6.9 knows that if you get air in the fuel system it won't run,or will run very rough,a common problem for air getting in the system is the water separator on the firewall next to the master cylinder,another common place is all the rubber lines between the injectors .I would bet that if its starting ,and then dieing,have someone hold the tire valve open on the secondary fuel filter while you crank the engine,there should be steady spurts of fuel coming out while cranking,if not you have air.

[SNOWPUSHER]

Thanks for the info guy's. I'll now be better armed to troubleshoot the problem. I'll let you know how I make out.