running rough
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Joined: May 2006
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running rough
Hello, I,m new here so I,ll cut straight to the chase.
I,ve got a 91 f-250 7.3 IDI, automatic that has had zero issues in the last three years. However, in recent days it has begun to idle and run rough. No smoke, except the usual at first start-up after sitting overnight, but it just idles and runs rough. I have replaced the fuel filter and air filter, have run two tanks of diesel kleen through it and have cracked injecter lines one at a time, all seems well. Any ideas as to why this thing is running soo poorly?
I,ve got a 91 f-250 7.3 IDI, automatic that has had zero issues in the last three years. However, in recent days it has begun to idle and run rough. No smoke, except the usual at first start-up after sitting overnight, but it just idles and runs rough. I have replaced the fuel filter and air filter, have run two tanks of diesel kleen through it and have cracked injecter lines one at a time, all seems well. Any ideas as to why this thing is running soo poorly?
Posting Guru
Joined: Sep 2002
Posts: 1,897
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From: Northeastern Pa - USA
when you crack the injector lines, the fuel should be clear and not frothy (air in the fuel on one or 2 injectors). This would be a sign that the injector is getting weak and allowing compression gasses backwards into the system. Basically, the injector isa one way valve that is opened by injection pressure spraying fuel into the pre cup. The spring gets weak or broken and allows the compression pressure to flow backwards OR a piece of dirt got through the filter and into the injector and has scratched/gawled the injector not letting it close properly OR the injection pump has suffered from the same thing (last place to look). You may also be picking up air in the system from a broken pickup tube, but that might show up as white exhaust smoke.
