hey folks, my 1996 f250, turbo,150K miles, non dually automatic has been running ruff lately and i was told by a mechanic friend it may be a stuck injector or just plain bad injector and to fix it before it washes out that cylinder.

it runs like its on 7 cylinders, and has lackluster acceleration, hard cold starts, and lots of white smoke when cold at startup. the intake air filter is k&n and its clean.

i also have 3.5" non cat, no muffler exhaust with 3" down pipe, so exhaust in not restricted.

is there a way i can check the injectors while they are still in the engine so i could narrow it down to as if it is one of the injectors?

we scanned it in his MAC PRO scanner and it cam up with nuthing except the cam sensor wich i replaced since.

 

on tractors we start it cold and then feel on the exhaust mani for which one is not warming up

 

Do like farmer said, or crank it up and disconnect one of the valve cover connectors while it is running (be careful there is alot of voltage going through them). If the engine stumbles and runs rough, plug that one back in and disconnect another one. When you disconnect the one with the bad injector (or under valve cover wiring) the engine will change very little. Each plug controls two injectors.

Once you isolate which valve cover it is, pull that valve cover and check all of the under valve cover wiring, valve cover connectors (inside & out) and the connectors on the engine wiring harness. Most times it is not a bad injector but bad wiring somewhere. If it was me I would pull both vavle covers and check all of the wiring and connectors.

 

white smoke when cold is typical, especially when the glow plugs are shot (or relay). does it continue to sound like it's only on 7 cylinders after it warms up? does the white smoke go away once the engine gets up to temp? the white smoke would not be an indication of an injector not injecting. if it clears up when it's warm, i would start with the glow plug system.

 

White smoke could be an injector that has a leaky nozzle but that is very rare.

 

the white smoke is only when it starts and only for a few seconds, like a big puff. i would attribute it to bad glow plugs/relay, but it also drives like its missing a cylinder.

its also been surging rpms at idle , it sounds worse than it is, it usually goes from 500-700 and back, like its loosing a cylinder or two for a secod or two, and then it gains them back. it does this always while idleing, cold or hot, dont matter.

 

[QUOTE=phatmanmike]the white smoke is only when it starts and only for a few seconds, like a big puff. i would attribute it to bad glow plugs/relay, but it also drives like its missing a cylinder. you are correct

its also been surging rpms at idle , it sounds worse than it is, it usually goes from 500-700 and back, like its loosing a cylinder or two for a secod or two,icp is causing this and then it gains them back. it does this always while idleing, cold or hot, dont matter.do a hpx mod it will help[/QUOTE]

drive your truck get it warm.
pull vc's and watch oil spouts for oil.

what kind of test did you do with the scan tool? did you just check for codes? did you do a cyl cont test.

 

ok, basics. oil level and quality (how long since changed). fuel pressure. air filter. knock out all the basic stuff. and check the codes. then go from there. those symptoms could be from any number of problems.