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Re: Injectors and Fuel issues CAT 3516B and CAT 3408

After reading your discription, this sounds like past experience I have had with sharing fuel lines.



First, I would check the check valves within the line to see if they are faulty or if on engine componet is staving the line and closing the check valve within the system. I would look at the particualliars on the gravity and distance from the fuel source and see if a engineering change needs to happen.


I would say check the specifcations on line sides for equipment to see if they really meet demands for loaded machinery full plant with all equipment resources online.


All else fails, I know you said the test on fuel tanks showed no indication of out-of-the-norm other than condesation. This is a push but have seen it before. The condensation accumulates in one area and the motion of the floating asset moves throughout and causes the pick-up tube to hit the jackpot. Very rare in small qaunities but possible.


Hope you already figured it out, if so! please info solution that worked for you.

Re: Injectors and Fuel issues CAT 3516B and CAT 3408



Thanks for your prompt feedback.


We do have Racor filter double individually per unit, racor SM2020. PS / SB / Gensets 1 / 2 / 3 / Emergency Genset.


As the fuel is here, are change every quarter, and coming out really dirty.


Thanks for the inputs regarding the differential between 3516B and 3406, will discuss with the Technical team.


The FO Filter alarm is set to 105 Kpa.


Another cause also can be the lack of FO flow (keeping pressure) that overheat the injector?? Should be an alarm this??


Thanks and regards,


Fernando Lopez-Ramos 

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Re: Injectors and Fuel issues CAT 3516B and CAT 3408

Cat electronic fuel injectors are really sensative in water.

specially the solenoid part, a little bit of water and they will quit.

where the 3408 injection pressure is around 400bar your 3516 is 1000+.

tolorances are smaller so cleanness is a priority.


Do you have separ or racor fuel water separators between your daytank and engine?

do you have a water detector on the separator filters and how many micron?

this little device costs less then 100$ but saves your injectors.


regarding alarms, the only one you might get is "unexpected engine shutdown".

other then that you will get no alarm since the engine doesnt know what you are supplying it.

injector fault ou will only get if you have a problem in your electrical side.

is your fuel filter differential alarm working on 14psi or 105kpa?


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Injectors and Fuel issues CAT 3516B and CAT 3408


Dear Friends,

I would like to have your suggestion and inputs from your experience in a problem that im facing in some vessels of the fleet.


Currently we have this units in West Africa, Nigeria, the fuel here is not the best, but we do not have options.

Vessels are fitted with CAT 3516B as propulsion and 3408 as Gensets.


As general fuel spec as per lab result, an average result is as follow;

Product AGO

.- Density@15 ºC : 08750 g/ml
.-Flash Point (Proc A) : 94.0 ºC
.- Water by Distillation : ,0.05 %vol
.- Total Sulphur : 0.133 %wt


I have serious doubts on above results are real as the FO look really moody and smells bad, in fact is not a minimal transparency at all.


Anyway, we do not have more option than purifier and burn.


The problem show up since a week ago, when one vessel sailing from our base and received fuel at the same, suddenly one Main engines start losing power and RPM's to the point that engines just stop, no alarms of any type, just lose power - RPM and then stop, several attempts to start again and nothing happens. Couple hours later, then same happen to the other engine, exactly the same. After several attempts to re start them, was no luck.


We brought the CAT computer and connect to each engine and no failure or alarm was registered, checked injectors and no problems registered as well.


Also were serviced the fuel system, filters replaced, feeders lines inspected believing that can be clog, but all was normal.

Meantime, suspecting a Fuel issue, also was check Daily fuel tanks, small traces of water were found, nothing bigger than common condensation.


Additionally as the FO was the main suspicious at that moment, we were waiting the Gensets to shut down at any minute, luckily didn't happen.


Vessel was brought back to port, troubleshooted again, and without any sign or real backup, was decided to replace injectors. Result is that engine start at first attempt. Same was done with the other engine and same, start at first attempt.

Tanks were cleaned again, but in fact were not found any sludge or contaminant that can drive us to think was dirty and/or contaminated FO.


My questions are:

.- Why Gensets didn't stop if the FO lines are the same that supply Main Engines.
.- Why no alarms.
.- Why CAT Computer didn't show us as faulty injectors.


Your comments and feedback will be really appreciatted.


Fernando Lopez-Ramos