FNM Marine Diesel Problems: Diagnostics?

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watson1959

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Hi
I posted recently about a possible fuel-related problem on an FNM Marine diesel.

The engine has been checked out again and there's no problem along the length of the fuel system; all fuses have also been checked individually and are working.

Based on what the engineer has seen I need to get someone to carry out diagnostics on the electronic control unit, but as FNM is a less than common engine, this is not so easy.

I am making contact with the manufacturer via an Italian colleague however in the meantime, can anyone recommend a possible contact/agent who would be able to run diagnostics on this make?

I'm in Reading, Berks

Cheers
 
watson1959 said:
I've spoken with Mermaid: they're checking if they still have the kit as they're no longer an FNM dealer.






Is this based of a VAG car/van based diesel power unit or perhaps PSA or mebbe Fiat etc . If so surely somebody with a normal vehicle canbus reader should be able to up get some fault codes via the ODB socket.
If it is an ECU fault will possibly be a modified car unit reprogrammed for marine purposes.?
If water gets into unit all sorts of grief ensures.
If caught early enought sometimes a good drying out can sort intermittant problems.
Normally shiney aluminium box about 250 x 250mm with big plug on side.It may also be all hidden in black plastic protective box.
Just found out its Fiat based.
Click to expand...
 
Last edited:
oldgit said:
watson1959 said:
I've spoken with Mermaid: they're checking if they still have the kit as they're no longer an FNM dealer.

Is this based of a VAG car/van based diesel power unit or perhaps PSA or mebbe Fiat etc . If so surely somebody with a normal vehicle canbus reader should be able to up get some fault codes via the ODB socket.
If it is an ECU fault will possibly be a modified car unit reprogrammed for marine purposes.?
If water gets into unit all sorts of grief ensures.
If caught early enought sometimes a good drying out can sort intermittant problems.
Normally shiney aluminium box about 250 x 250mm with big plug on side.It may also be all hidden in black plastic protective box.
Just found out its Fiat based.
Click to expand...


Cheers OG: Ross also suggested trying a local Fiat dealer to see if there's a mobile engineer with kit to try.
Click to expand...
 
You need the local man known to every small garage in your area.

Cheers OG: Ross also suggested trying a local Fiat dealer to see if there's a mobile engineer with kit to try.[/QUOTE]


In most areas there is going to be a man with a van who will come to you.
He will almost certainly have a knock off of the Fiat software and lots more besides.May probably be prepared to spend an hour or £50.00 for cash money(poss on a no cure no money basis.).
Suspect your local Fiat dealer will not even want to know and if he does it will be £100.00 VAT per hour etc even if he cannot read the codes.

Any small local trading estate with a few small one man garages on site will know this very useful bloke and be happy to give you his details.Very useful to call on to get rid of any dashboard lights one has provoked into illuminating when carrying out a repair on customers cars.:)*
We of course have one in our area and he is a godsend when you just need to get aheads up on a problem and do not want/have to spend main dealer money.
*Not us guv was on when it came in !
 
Last edited:
watson1959 said:
Hi
I posted recently about a possible fuel-related problem on an FNM Marine diesel.

The engine has been checked out again and there's no problem along the length of the fuel system; all fuses have also been checked individually and are working.

Based on what the engineer has seen I need to get someone to carry out diagnostics on the electronic control unit, but as FNM is a less than common engine, this is not so easy.

I am making contact with the manufacturer via an Italian colleague however in the meantime, can anyone recommend a possible contact/agent who would be able to run diagnostics on this make?

I'm in Reading, Berks

Cheers
Click to expand...

Likely Fiat Unijet engine and pretty sure you will have an automotive OBD2 diagnostic socket. Any generic OBD2 fault code reader will work (ELMScan).

Having said that DO NOT EVEN BOTHER WILL TELL YOU SQUAT ALL!

Explain your symptoms in DETAIL, common rail engines are pretty simple to troubleshoot, however you will need some gauges.
 
Latestarter,

I broke the fuel system down as far the HP pump inlet, and with ignition on we had a healthy squirt of good, clean, non-aerated fuel.

The ECU is in a steel control box along with fuses and a proprietary FNM control PCB (mainly populated with fuses and various relays). I found one of the multi plugs to this box mildly contaminated but it cleaned up well with Servisol contact cleaner. The engine battery was isolated during this work, effectively carrying out a soft reset of the ECU. All fuses were physically removed and tested with a multimeter as well as visually - all satis.

On test starting afterwards the engine fired instantly and ran fault free (and watson1959 commented smoother than he's ever heard it.. :) ) until we switched off after approx 17 mins. On attempted restart, the fuel pump could be heard running and the engine turned over, but refused to even fire, never mind run.

My problem is its a common rail injection, ECU controlled engine, and I don't have any manuals or diagnostic equipment for FNM. Ive never even seen one before!

My hunch is an intermittent sensor (eg crank position, fuel rail px etc) fault, or at least one seen to be at fault by the ECU.

The fact we got it to run sweetly is both encouraging (no major mechanical failure) but also a real pain as I have no manual to test sensor impedance values or OBD reader to see what the ECU is unhappy about.

Any advice, anything daft I have overlooked or any 'usual' suspects?

Watson1959 has had a crxxy week one way or another. Any help gratefully received.
 
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Ross,

Thanks Ross you have explained one thing for starters. Two types of Bosch CP3 system.

The first has the mechanical fuel pump driven by a quill shaft off the the back of the actual CP3 eg Volvo D4/6 Cummins ISBe automotive engines, IVECO NEF. Good arrangement which sucks fuel through, however WILL find an air leak if any filter incorrectly fitted.

Second system has an electric primer pump eg Cummins QSB marine engines and Mercedes LDA engines and now I am aware the Fiat Unijet engine also uses this second system.

Fiat motor is pretty good piece of kit, however it is just an automotive engine. Does it have the whacko single use push fit fuel line fittings?

You need to get a gauge on the line to establish what pressure the CP3 fuel pump is seeing from electric pump. I will check my #'s but off the top of my head the common rail pump needs to see around 15 psi. In some cases once the engine has fired it can run with low fuel pressure or even without the electric pump, however unless motor is seeing correct fuel pressure on start up, ECU will not allow engine to fire up.

Does engine actually have OBD2 connection by the way?

I do appreciate what you are up against, some poor sod purchases marine engine from reputable dealer who then dumps the franchise and bang goes their support.

I will see what I can dig out for you.
 
Hi Ross, Latestarter & Mlines & others: thank you all for your input.

This is a real booger of a situation.......really appreciate your help

Cheers

Simon
 
watson1959 said:
Latestarter1 said:
Does engine actually have OBD2 connection by the way?
Click to expand...

This is the connector:-

View attachment 18593
Click to expand...

well, how about a bluetooth obdII adapter off ebay for 10-15quid and torque on an android mobile or another prog on a laptop?
Should be able to get either direct error codes or see what sensors seem to be working and whatnot (err, if you're lucky, I was on a petrol BMW valvetronic engine...)

Useful bit of kit anyway, so I recon you should get one anyhow (if not only for checking car error codes or turning off engine check light if you know what's happened)

V.
 
Borrowed mlines' odb2 meter to give it a try but it won't connect.

Looking at the pin outs on the engine socket there appear to be connectors in 16-8-7-5-4

On the meter plug 8 is missing.

Is the plug pin layout standard?

Can I get one that fits my layout or will I find this to be the engine manufacturers secret sauce?
 
It will be the manufacturers secret sauce.

Pin 16 = Power
Pin 5 = Ground
Pin 4 = Ground
Pin 7 = K Line

Pin 8 is not normally used, but you are missing the "L" Line which should be on Pin 15

As I understand it the data is on the K line (which you have) but the ECU initial handshake (to tell the ECU a diagnostic device is connected) happens on the L line. I wonder if they have swapped Pin 15 to Pin 8 so only their reader tells the ECU that a tool is connected??

Martin
 
' oh dear' ......

Tried maplins, halfords, uni-part, John kleez Hi-fi, Thames valley auto electrics...... Baying degrees of help from droopy lower lip and dribble at maplins through to lots of ideas but no sOlution ...

Blooming proprietary captive market!
 
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