4008TAG2A engine’s exhaust manifold & turbocharger turning almost red

[nexuspower]

Genset been installed on March 2007, running hours 3784
We put on load within 5 minutes after start the Genset, load increase gradually, when load goes up to 400Amps to 500Amps, then turbo getting hot and turning almost red color within 10-15 minutes after put on load. Yes, it has silencer, but each exhaust pipe extension is almost 18 feet long , both exhaust pipe diameter is 6”. There is a long extension exhaust pipe (almost 10 feet distance) between flexible bellows and inner end of the silencer box, and more almost 4 feet extension exhaust pipe from outer end of the silencer box. Silencer box size is standard as you supply with this unit (Length 3.9 feet, dia 14”). It is your brand (Welland Power) Genset.

The engine serial number is -DGA080701U0477D.

[garyslator]

Was the turbo running correctly until recently? or has it always glowed red since installation?

It could be be that the turbo has been gradually worn by too much of a restriction in the exhaust pipe which is now causing it to glow or it could be a possible timing/ injector problem.

Has the timing been checked or adjusted recently or have there been any any other problems with the running of the set? I would check the ignition timing and test each injector individually for faults as per the workshop manual.

[nexuspower]

Yes, both turbo running correctly. No, turbo has been glowing red since last 20 days.
Yes, back pressure could be a reason, but the unit has been running in this situation since last 4 years, before that this problem didn't occur.
Yes, we will check timing and each injector individually. Can you send a instruction how do we check timing and injectors? If possible send a copy of workshop manual, which will help us a lot.

[merryengineer]

If the set has been fine for 4 years, the back pressure won't be an issue, unless the exhaust system has been changed in some way.

How did the injector check go?