1983 6.9 Fuel Issues
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1983 6.9 Fuel Issues
Little about the truck. 83 6.9 dually, single cab, 4-speed, 140,000..New fuel filter, rebuilt accelerator pump, new plugs. I picked the truck up Two days ago.
Sympom #1
I noticed on the 2-hour drive home from picking it up that when i was going up long hills at 60MPH that the truck would want to surge with alot of power and try to take off, if i didnt let off, it would then starve off and have no power for 5 seconds, then act normal. This is still happeneing.
#2
Sometimes after driving in town if i pull over and stop the truck would "Cam" out and sound really rough for 5-10 seconds untill i pump the gas alittle bit then all is normal again.
Intertate... Last night i was driving and accelerated up to speed "70 mph" after 200 yards at speed i lost all power and almost pulled over..i was pumping the peddle like crazy for 10 seconds then she was good to go again.
Besides these issues. The truck runs perfect. Starts everytime and drives really well when no load is on the fuel system.
Im not sure what this is a sympom of, it all seems to be related to one component just not sure which one. Any insight would be awesome..Thanks F-T
Sympom #1
I noticed on the 2-hour drive home from picking it up that when i was going up long hills at 60MPH that the truck would want to surge with alot of power and try to take off, if i didnt let off, it would then starve off and have no power for 5 seconds, then act normal. This is still happeneing.
#2
Sometimes after driving in town if i pull over and stop the truck would "Cam" out and sound really rough for 5-10 seconds untill i pump the gas alittle bit then all is normal again.
Intertate... Last night i was driving and accelerated up to speed "70 mph" after 200 yards at speed i lost all power and almost pulled over..i was pumping the peddle like crazy for 10 seconds then she was good to go again.
Besides these issues. The truck runs perfect. Starts everytime and drives really well when no load is on the fuel system.
Im not sure what this is a sympom of, it all seems to be related to one component just not sure which one. Any insight would be awesome..Thanks F-T
Mountain Pass
Joined: Dec 2010
Posts: 148
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From: Holland, VA
Sounds like air intrusion to me. With only 140k it's unlikely it is the injection pump (IP), but it's not impossible. I'd start at the fuel tank/s; are they both full? If not then note the level and fill them up. Did the problem go away? If yes then the pick-ups or sending units are the problem. Next check the fuel filter seal carefully. If you are in the mood, warm the truck up, then replace the fuel filter with a new one. Make sure you fill the new filter with clean diesel fuel before you spin it on. Test it out.
After that you are looking for air leaks on the suction side of the IP, bad lift pump, bad injectors possibly, then a faulty IP.
My opinion.
After that you are looking for air leaks on the suction side of the IP, bad lift pump, bad injectors possibly, then a faulty IP.
My opinion.
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I ran into a guy that had this same 6.9. He told me that the fuel system pressure is unsufficient and requires more fuel pressure. I installed a inline Mr. gasket universal fuel pump. The issue is gone. Runs Flawless.
Post Fiend
Joined: Nov 2005
Posts: 7,437
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From: Charles Town, W bygod Va
You should bypass the mechanical lift pump when adding an electric.
It's not that the pressure isn't sufficient, you most likely have an air leak and the electric pump is masking the problem.
It's not that the pressure isn't sufficient, you most likely have an air leak and the electric pump is masking the problem.
Logistics Pro
Joined: Sep 2007
Posts: 3,739
Likes: 181
From: Western Mass
I'll throw another vote to air leak, or fuel pickup broken off. I accidentally forgot to fill up my truck before a trip this weekend (under estimated the distance and thought I could make it to station on the way back...) Ended up running out of fuel on the highway, it was exhibiting these exact symptoms of surging, then dying, usually when going up hill. Then finally it died for good. (luckily I carry a 5 gallon jug of diesel just in case..)
My point is, I was sucking air, and it was exactly like yours was doing. The electric pump is a band-aid on an arterial bleed. Sure its stopping the problem, but for how long? check out the fuel system and fix the real problem (could actually be a failing lift pump)
My point is, I was sucking air, and it was exactly like yours was doing. The electric pump is a band-aid on an arterial bleed. Sure its stopping the problem, but for how long? check out the fuel system and fix the real problem (could actually be a failing lift pump)
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