6.9 not running right.

[Martin0759]

1985 6.9 4 speed 4wd f350 crewcab.

In August I replaced the glow plugs and by late November the motor was getting hard to start so I started to pull the glow plugs and could only get 2 out. 3 broke off and 3 where swollen and wouldn't come out. So during the Christmas shutdown I pulled the heads, knocked out the precombustion Chambers and made everything right again. New head, intake, exhaust gaskets and new copper injector seal, orings and fuel return line.

Be fore I started work I got the engine to TDC and marked to IP.

I bled and it started hard but it is pretty well worn out and slated for replacement, new motor is ready when I have time.

Once started it ran good, I ran it around within a couple mile for a bit and then went to town. I parked it in town for a couple hours doing laundry and it started but on the way home pulling a hill it just died and wouldn't restart. The next morning it started and ran but anything past 1500 rpms sounds like the motor is coming apart and it has no power. It died about 1/2 way home and wouldn't start again.

I have an electric pump in line I can switch on for bleeding to the IP I have good fuel flow all the way to the IP.

In the last 20 years I have had her she has been a great truck but this is baffling me. Sorry if everything is a little bit rambling.

Any thoughts or advice.

Martin

 

[Selahdoor]

You sure you got the IP tightened down?

 

[TahoeTom]

Did you pull the pump with gear cover attached? If so you could be a tooth off on timing gear.

 

[Thewespaul]

What glow plugs did you install after pulling the heads? Any damage on the pistons from the previous glow plugs? You said you have good fuel flow, do you have any fuel at the injectors or smoke out the exhaust when cranking? If non motorcraft glow plugs were installed then it’s possible a tip already broke off and fell into the engine, which would explain the noises above 1500 rpms.

 

[Martin0759]

I thought about being a tooth off but pretty sure it was good, and it ran good for about 2 hours before the problem.

I used Bosch glow plugs I can pull them all and see if anything is missing.

I have an electric fuel pump down stream of the tank switch, I am going to troubleshoot the fuel system by running new fuel line from the electric pump straight to the filter. I capped the fuel line from the lift pump so it won't be a problem. If that works I will plumb from the electric pump to the lift pump and the filter.
Make it work and then add pieces to find the problem. Am I wrong?

 

[Thewespaul]

Throw out the Bosch plugs and get some motorcraft glowplugs. ZD1A for 6.9s with early controller, and ZD9 for late controller setups on 6.9s and 7.3s.

 

[Martin0759]

Right now I am not worried about the glowplugs it will barely run. BTW is was motorcraft glowplugs that went bad so fast start this process.

Does anyone know a good shop in Phoenix that knows a 6.9. We start back at 6 12's Monday.

I am going to check the glowplugs for break-off and IP timing.