Need y'all engine gurus help

[JohnnyReb]

Worked on the deuce this weekend to bring her in good shape for logging, etc.

Here's the problem:
She will not idle under 1500 rpm. Have to pull out the throttle to keep the engine going.
Had a "diesel mechanic" look at it and he said he had no idea.... so I tackled it using the K.I.S.S method:

Changed the air filter and took the air system apart before and after the turbo to make sure there were no obstructions, etc.... none and no help.....

Changed the primary fuel filter even though it wasn't due....NOW SOMETHING INTERESTING #1 opened the draincock and it released pressure!! Fuel did not come out but rather AIR went IN...

INTERESTING #2 Turned on the tank pump to purge air out of the system and then heard a hissing sound at the secondary fuel filters. One of the cannisters was not properly sealed. The gasket is bad so I have to wait until tomorrow to replace it and install the new secondary fuel filters. When I re-seal the secondary fuel filter cannister, will that fix the problem?

Further info: truck runs out great. Plenty of power. will go to redline without a problem so it doesn't act like it is fuel starvation. Just will not idle under 1500.

So....predictions: Will it run correctly? Is it possessed and requires the services of a priest?

Thanks
JR

 

[ah1955]

If your sucking air in the fuel system that could very well throw the idle off.

 

[poppop]

RE: Need y

Fix the air leaks and I think that will fix your problem. I think when the engine trys to idle the leaks are disrupting the fuel supply. When the engine starts to die the governor speeds it up to the point it can overcome the leaks. When you pull the shut off cable to kill the engine the governor pulls the racks wide open trying to keep the engine running.

 

[JohnnyReb]

Thanks for the replys. Just want to make sure I was clear. The truck doesn't try to idle at 1500. I have to pull the throttle to a minimum of 1500 rpm to keep it running. If I do not set the throttle at least this high then it won't crank or idle.
Don't have to use the engine stop.... just release the throttle and she dies...

Thanks
JR

 

[poppop]

I still think thats your problem. Fix the leaks and try it again.

 

[rdixiemiller]

Check your in tank pump. If you didn't get fuel out when you opened the filter, it is not pumping. My in tank pump was running just fine, but the hose had popped off the pump. So, I was pulling fuel with the IP fuel pump rather than pushing fuel to the IP. Darn thing ran out of fuel with over 1/4 tank left, I pulled the pump and found the problem.

 

[JohnnyReb]

Yep, checked the tank pump. While the primary fuel filter was off, I turned on the power and SHOOOSH... (hope the EPD wasn't around).