87 6.9 Starts but dies after a second....

[snadj]

I have a 1987 F350 with a 6.9 in it and its giving me starting problems again.

I have so far replaced all return lines, glow plug controller and relay, the fuel pump about 6 months ago, dropped both tanks to clean them out, replaced stock water separator with aftermarket one and now this morning I go to start the truck it kicked over right away but died within seconds.Tried starting it to the point where I almost drained the batteries. I checked both the fuel filter and water separator for fuel but neither were full. Last time I replaced the fuel pump I noticed that the pump pushrod was extremely worn out. Is this a common problem? Would it be advisable to put in an electric booster pump before the mechanical pump? And if I did so would this cause problems? I would assume that the glow plugs wouldnt be the issue if it fired right up.Sounds like a fuel delivery issue


help would be greatly appreciated. I came to this site because I heard the people here know what they're talking about.

thanks guys

 

[sle2115]

I wouldn't put a booster pump in for a couple of reasons, the first being that if your mechanical died, and failed internally, you could quickly fill your crankcase with fuel, washing the bearings and trashing the motor. Why not just pull the mechanical, throw a BB Chevy block off plate on the opening and put an electric pump on it and call it done. The advantages of the electric pump are many, like purging air, filling fuel filters and separators, etc.

You may also be sucking air into your separator. They are prone to this after draining. I would stick a 3/8 bolt in the drain tube and hose clamp it just to see if that is the issue. It's a cheap "fix" if its sucking air past the drain valve in the water separator.

 

[Diesel_brad]

sounds like your return lines are sucking air and allowing you fuel to bleed back to the tanks. It fires off the fuel that is in the injector pump but there is nothing left in the lines. try here http://o-f-i.com/ for return lines,injector caps and o rings. that fixed my exact problem

 

[punkmechanic]

I have an 87 crew cab and mine did the exact same thing. I replace the return lines and installed clear tubing so I could keep an eye on the situation. Everything was good for a week or so then air started appearing in the clear tubing.

after forever and a day of trying to localize the air intrusion I finally found that the heating element on my filter head was allowing air in.

Take some heavy grease (bearing grease or transmission assembly lube) and smear it in and around the heater connector and other electrical connections on your filter head. run a clear line from the nipple on the output of the filter down to the #1 injector cap, start the truck and look for air bubbles.

I change a .23 cent oring and now it starts much better (would be great if the pump was in better shape, oh well)

punk

 

[snadj]

I have an 87 crew cab and mine did the exact same thing. I replace the return lines and installed clear tubing so I could keep an eye on the situation. Everything was good for a week or so then air started appearing in the clear tubing.

after forever and a day of trying to localize the air intrusion I finally found that the heating element on my filter head was allowing air in.

Take some heavy grease (bearing grease or transmission assembly lube) and smear it in and around the heater connector and other electrical connections on your filter head. run a clear line from the nipple on the output of the filter down to the #1 injector cap, start the truck and look for air bubbles.

I change a .23 cent oring and now it starts much better (would be great if the pump was in better shape, oh well)

punk

Im quite certain that the return lines are not the issue being that I replaced them not even a year ago(all o rings, plastic T's, lines and clamps..bought the set). If it is the heating element..is it safe to bypass it? by that I mean can I just bend by own line and hook it up to the filter? I live in S. California so I dont think I would have an issue with the fuel thickening or what have you. Thanks for all your help.