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We have a 7.3 in an F350 rollback w/ a 5spd. This truck is smoking white smoke badly. It has a fuel smell to it, not antifreeze or oil smell. We have checked to make sure we are not getting exhaust into the water. Did a compression check, all cylinders 200-250psi. Changed out injectors w/ new injectors, and changed out the pump with one from another truck. We used to think we knew alot about these motors, but this one has us stumped. Any ideas before we pull this motor next weekend to put in another?
 

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I think the minimum compression needs to be 300psi +. You are way low. The fact that its on all the pistons is kinda a wierd syptom. Anybody ever rebuilt that motor before? Maybe they shaved the pistons crazy low to lower compression a ton.

The white smoke is unburnt fuel, because with your compression being so low, its not igniting/burning well at all. The bad idle is just another symptom. Something weird is definatly up here.
 

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Diesels need fuel, air and compression to run. When you changed the injector pump the truck it came from probably had higher compression than the engine now, so it is pumping more fuel than needed. If you have enough power, then turn down the injector pump (approx. one flat) and try it. Its a free fix and dowsn't take a long time. I am not a mechanic, so this is just my ......
 

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when you changed out the injectors did you change the under valve cover wiring harness??? and do you have some type of scanner???
 

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hook up your block heater for an hour befdore starting. After it is running see if the white smoke is diminishing, if it is it is your glow plugs and your engine is too cool to allow complete ignition.
 

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when you changed out the injectors did you change the under valve cover wiring harness??? and do you have some type of scanner???
None of that on a IDI :thumb:
 

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Your compression numbers are way off though...thats your problem right there.
 

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drew 06... he has an idi ... mechanical fuel pump... mechanical injectors that are pulsed from fuel pressure... no wire harness goin to his injectors
 
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