CAT C18 1150's - High fuel pressure alarm

[vas]

I still get by with words which are actually Italian without resorting to Google, thank you.

oi, Italian, stop stealing our words
although often brits steal a greek word and make a mess on the process, changing the meaning (slightly or even sometimes massively...)

nothing to add to the conversation I'm afraid other than when I relaunched MiToS last summer, I'd forgotten the fuel supply cock to the stbrd engine closed (another muppet!).
So revved in reverse to leave the trolley, engine stalled. Started again, reved a bit stalled again. Let it in idle for a bit, moved to a decent distance from shore, stalled again...
Confused, let my mate on the helm, went down, saw it opened the cock, came up again, started, run no problems, run fine. No air in the system? dunno, managed to disappear, not sure. Just worked.

cheers

V.

 

[MapisM]

oi, Italian, stop stealing our words

Doh! I would have sweared it came from latin, but your comment did make me wonder, and THIS was worth googling for.
Greek it is, guilty as charged! :encouragement:

 

[MapisM]

When the alarms sounded at 1500rpm my instinct was to follow the diagnostic instructions and slow down immediately.
It sounds as though I ought perhaps to have done the opposite!

Possibly.
Btw, I believe that whenever a fault is serious enough to potentially damage the engines, the ECU goes in limp mode and don't allow you to exceed a lowish rpm, no matter how hard you try.
In other words, if by hammering the throttles the engines do rev up, you should be fine anyway.
But whether that sorts the problem or not remains to be seen, of course.

Just one question, do the alarms go off EXACTLY at the same time?
I'm asking because it's very unlikely that the fuel lines length is identical on port and stbd, so even if poorly installed new filters could be the culprit in principle, I would expect the alarms to go off together, but NOT 100% simultaneously.

 

[MedMilo]

Possibly.
Btw, I believe that whenever a fault is serious enough to potentially damage the engines, the ECU goes in limp mode and don't allow you to exceed a lowish rpm, no matter how hard you try.
In other words, if by hammering the throttles the engines do rev up, you should be fine anyway.
But whether that sorts the problem or not remains to be seen, of course.

Just one question, do the alarms go off EXACTLY at the same time?
I'm asking because it's very unlikely that the fuel lines length is identical on port and stbd, so even if poorly installed new filters could be the culprit in principle, I would expect the alarms to go off together, but NOT 100% simultaneously.

Ah okay, that's good to know re limp mode. No, they don't go off at exactly the same time, within a minute or so of each other I'd say, but always at around 1500rpm - so I guess the fuel line length differences etc might explain the slight timing difference, as you suggest. Everything seems to be pointing to clumsily installed filters (or a bad batch, I guess, but they are original manufacturers filters)...

 

[jrudge]

Ah okay, that's good to know re limp mode. No, they don't go off at exactly the same time, within a minute or so of each other I'd say, but always at around 1500rpm - so I guess the fuel line length differences etc might explain the slight timing difference, as you suggest. Everything seems to be pointing to clumsily installed filters (or a bad batch, I guess, but they are original manufacturers filters)...

I can see how a filter can cause low pressure but not high

Also air on fuel. Air is compressible so I would have thought it would drop pressure not increase it

 

[Portofino]

I can see how a filter can cause low pressure but not high

Also air on fuel. Air is compressible so I would have thought it would drop pressure not increase it

See post #4 .

Or think of a train with say 12 carriages.Then think of the tube in London .Then let’s hypothetically remove two carriages say number 3 and 7 , but leave a gap connect with a line .
As the train breaks or the rear accelerates ( pump ) those parcels of “ air “ where the missing carriages are will get compressed by the the closing up of the other carriages.As the real carriages ( fuel in the line ) come closer they will compress the air .
If that compressed air section passes a sensor it unfortunately triggers .

There’s probably an ECU program to know that a few air events of a certain number after a filter change is ok because it’s programmed to kick off say after [ x seconds ]
Where x seconds is the normal time and air events self bleed that filter changes initiate .

How ever it’s kicking off because there’s air leaks on the suction side .
So as every whole train passes somethings removing a couple of carriages and the rest are compressing together - all the time ,
Hence it’s limiting to 1500 rpm as there’s enough fuel to run -sort of ie 10 / 12 carriages ,but gaps keep appearing from the bad seal / gasket / connect / valve or what ever ? .

There’s an outside plausible chance that both senors are indeed faulty now , caused by $hit in the fuel damaging them .
How ever with CR the pump and injector tips are Uber sensitive to $hit in the fuel , so any $hit got that far to irreparably damage the CR fuel pressure sensors I would have thought the pump and injector tips would be compromised too that event .This is the worst case scenario .Its not clear thus far that this can be ruled out I,am afraid .

Could be something simple like even a double o ring on the screw on engine filters , when not running maybe the electronic solinoid stops the flow and the tank level is lower or a combo of these two is such as you don,t see a leak .But air is sucked in when running effectively taking out the odd carriage of the train of fuel .

 

[MedMilo]

There’s an outside plausible chance that both senors are indeed faulty now , caused by $hit in the fuel damaging them .
How ever with CR the pump and injector tips are Uber sensitive to $hit in the fuel , so any $hit got that far to irreparably damage the CR fuel pressure sensors I would have thought the pump and injector tips would be compromised too that event .This is the worst case scenario .Its not clear thus far that this can be ruled out I,am afraid .

With apologies for resurrecting this thread but the sensors have now been changed and apparently 'the problem is solved'. To me the chances of both sensors failing simultaneously for no connected reason is too slim to be plausible. So Portofino's explanation of air pockets having damaged both sensors seems a credible possibility. If I've understood this theory correctly, there appears to be a real risk that the injectors have been damaged; is that correct? If so, is the considered view that I need to get the injectors checked? How does one do this and what is one looking for?! Of course I now have a poacher / gamekeeper issue with the local Caterpillar guys checking their own homework, to mix my metaphors!

 

[jrudge]

An injector ( or all of them ) would be removed and sent to a test centre. Volvo use Bosch stuff - I don't know about CAT but there are not that many people who make it. The test places are the same mob who do cars and trucks.

They put it on a reassuringly expensive machine, give you a reassuringly expensive bill ( about £50 per injector but it adds up) to test them and you get a report that says how they are working.

Then you give them more money to fix it.

The process is fast as they are used to fixing trucks that need to be back on the road.

New injectors for a Volvo are ball park £1k each so you don't want to go down that route - unless CAT are paying!

 

[Portofino]

With apologies for resurrecting this thread but the sensors have now been changed and apparently 'the problem is solved'. To me the chances of both sensors failing simultaneously for no connected reason is too slim to be plausible. So Portofino's explanation of air pockets having damaged both sensors seems a credible possibility. If I've understood this theory correctly, there appears to be a real risk that the injectors have been damaged; is that correct? If so, is the considered view that I need to get the injectors checked? How does one do this and what is one looking for?! Of course I now have a poacher / gamekeeper issue with the local Caterpillar guys checking their own homework, to mix my metaphors!

Good news they work now above 1500 rpm without alarming off .

No ,air pockets not running out/ purging were from a leak after a filter change and suction drawing in air .
That was my first arm chair long range Dx sans examination.

Not connected is dirt or some foreign contamination of the fuel actually damaging the sensors .
And then wondering why such contamination has just only damaged those nothing else ?
That was again a theoretical long range Dx sans examination and sans watching over the shoulders of the techs .

Obviously not being present and watching i don,t know what’s exactly been done to get them running as before they touched them ?

How ever if they are running and throwing no other codes then there’s a good chance the rest of the fuel system with CR which relies on Uber clean fuel is not affected, assuming it was contaminated fuel that simultaneously and bilaterally damaged each sensor in each engine .

As far a injector testing they need to be removed and sent away to a ( assume Bosch ) agent .
There will be a service interval in the CAT service book anyhow .With my none CR Bosch MAN s it’s every 1000 hrs ,and usually the tips are replaced ,even though nothing seems wrong, however with newer CR MANs they have removed injector testing alltogether the on board diagnostic system or tech with anup to date laptop can interrogate .So they leave them until they whistle so to speak theses days .

How good a sea trail have you done since the fix ?

Presume you have the old sensors that were removed , they kinda showed you them in a “ honestly look what we have done “ kinda way ??

As opposed to spending time in the ER ( fixing air leaks from last time ) and “ hey presto look they work now “
Sorry for the cynicism.

 

[kashurst]

Good that its all sorted but, I think I might be tempted to talk to CAT in the UK or even the USA for a second opinion. Getting air into your fuel injection system is easily done when servicing etc. Shouldn't bother anything - when the engine is first built it's full of air. Also the pressures inside a fuel injector are enormous! seriously doubt a bit of air is going to harm anything - especially as its compressible.
I am also sceptical that two fuel sensors should fail simultaneously. CAT will have factored into their design a realistic margin to take into account ham-fisted fitters as well. Something doesn't seem right to me.

 

[MedMilo]

Thanks for all these latest replies; much appreciated, as ever. I think it's a good idea to talk to Finning in the UK so will do that this Monday. I fly down to Italy Monday week, so will do a proper sea trial then (also need to seatrial the new Williams 345SJ that arrives in Naples when I'm there Jeremy! ) Am hoping it's just air that cleared through and that the sensor change thing is a bit of a red herring - will press them to give me the 'old' ones to see whether they reveal anything. We'll see...

 

[jrudge]

Have fun with the new Williams. Lovely looking toy

 

[MapisM]

Getting air into your fuel injection system is easily done when servicing etc. Shouldn't bother anything

Positively +1.
Unless required by the maintenance schedule, or suggested by some symptom (typically, engine/s more smokey than usual, or some diesel surfacing around the exhausts upon cold starts), I wouldn't touch the injectors.