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Smoke at idle with new injectors

BTWKS1

New member
1979 671 TI. Engine has about 700 hrs since major. Engine would always start well and never smoked. This past season I was seeing a little oil sheen coming from my exhaust after I shut down. A mechanic took a quick look and said that it appeared one of the injectors was out of adjustment and that I should have the engine tuned. This mechanic did not have the time available to work on it. I had another mechanic who was highly recommended and very experienced work on the engine(s). He said he found one or two possibly bad injectors and recommended replacing all while he was in there. After replacing all the injectors, engine ran well for a while. After about 15 hours of running, the engine started to smoke heavy at all speeds. The mechanic re-checked the engine and claimed that one of the new injectors was bad and replaced it. Now the engine constantly smokes at idle even after it is warmend up. The smoke appears to be black and is light but enough to be a nuisance to those around me. The smoke will tend to go away at higher RPM's. Any thoughts would be appreciated. Thanks
 
Did your mechanic offer any thoughts about why the "new" injector went bad? Many injectors are damaged by careless mechanics due to rough handling or "droppage" as I call it. You might ask him if he installed a matched set and see how he responds. The injectors are calibrated for idle fuel delivery and having one or more mismatched in a set could cause some idle and general tune issues. It is not always an easy task to walk into a parts house and find a set of six calibrated injectors sitting on the shelf and a guy in a hurry to finish a job might just say close is good enough....NOT!

One thing you should always keep in mind is that WATER in the fuel is injector death. If a small amount of water gets past the secondary fuel filter and to the injector tip, it can blow the tip right off. So, good fuel system maintenance and fresh, quality fuel is a must.

Good luck.
 
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