QuestionQUESTION: Hi, I have a 1990 L10 Cummins, 270 hp with top stop injectors. The engine smokes fairly good at an idle and pretty bad all the way up to top speed where it then gets tolarable. It is a grey smoke. Last year we had the injectors done and just had the pump tested. The local shop said the pump was fine.
ANSWER: Smoking especially on a turbocharged engine during the commencement of acceleration is normal. It is due to the insufficient air from the turbocharger to burn the excess fuel at that point in time. once the turbocharger can supply adequate air, the smoking disappears. But if your engine is euro 2 or euro 3 emission compatible, and you experience this phenomenon, you may need to recheck your injector travel and valve adjustment.
Kind regards,
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QUESTION: I understand the an engine smokes a little until it gets its full supply of air, but this happened some what quickly and it is not normal for this engine. It smokes enough to possibly get a ticket. It is nor raw fuel like it was before we had the injectors changed 1000 hour ago. It is a grey smoke with a hint of black. The trucks acceleration has decreased noticeably. I do not know if it is a Euro 2 or 3. What would be the rack adjustment specs and procedure just in case?
AnswerOn the persistent smoke, I advice the following:
1. Check and clean out the air filter or replace it.
2. Check the individual cylinders exhaust temp. and note the one with a sharp difference i.e. (lower temp.)
3. Remove the identified injector for checks and repair as necessary.
4. If injector is ok, you may have problem with the valves for the particular cylinder
5. Another possibility is oil leaks from the turbocharger, in this case you will likely have short engine oil.
On the rack adjustment specs,the info is located on the fuel pump dataplate on top of the pump beside the tacho drive. You can not adjust manually rather you should have the pump checked on a test stand (Hartridge 120 or compatibles) for proper adjustment.
Regards,
