FNM Marine Diesel Problems: Diagnostics?

[rosssavage]

Latestarter, fuel lines / fittings are conventional hose and jubilee clip.
Secondary filter is downstream of pump, so any leak would manifest itself as fuel out, not air in. We have no fuel leaks.

As I say,the engine did run beautifully for 17 mins until we intentionally shut it down, it just won't restart!

15psi switch is an interesting point though.....

 

[vas]

15psi switch is an interesting point though.....

so, it's a matter of finding this 15psi sender, shorting the cables and test starting again
if it works, replace the sender job done.

 

[rosssavage]

Certainly is. Problem is I'm off for hols for two weeks!

Watson1959, got any tech savvy friends who could try this?

Latestarter, would this be the switch on the back of the Bosch HP pump?

 

[Latestarter1]

Certainly is. Problem is I'm off for hols for two weeks!

Watson1959, got any tech savvy friends who could try this?

Latestarter, would this be the switch on the back of the Bosch HP pump?

No that is the Mprop valve, leave well alone!

 

[watson1959]

There's at least one bad electrical connection.

With the ignition turned to position 1 there is no alarm until I move the cables under the ECU at which point the alarm comes on.

I can't get the connector undone however to see if there's muck in it..And reconnect

 

[rosssavage]

Oooh, interesting! Which connector? The one I found contaminated was the lower, bigger plug on the forward edge of the ECU box.

If its that one, wiggle the back (cable entry end) whilst undoing the locking ring. DON'T wiggle the wires, just the metal rear of the plug - that sometimes encourages those type of plugs.

Latestarter, any idea where the LP px switch might be?

 

[watson1959]

the metal connectors appear solid.

This is the plastic connectors where there are two separate 'bundles' of wiring that then come into a single plastic connector under the ECU. When I move the wires the alarm goes of and on depending on position. I cant get the plastic snap-together connectors apart to blow on em.

 

[rosssavage]

Right at the back of the unit....

No, they're not easy, you need two hands on them - one to squeeze the plastic tabs together whilst you pull the two halves apart.

If you can reach, again, wiggling rather than a direct pull can help.

Then flagellate whoever put that control box down there!!

 

[watson1959]

Right at the back of the unit....

No, they're not easy, you need two hands on them - one to squeeze the plastic tabs together whilst you pull the two halves apart.

If you can reach, again, wiggling rather than a direct pull can help.

Then flagellate whoever put that control box down there!![/QUOTE]

probably an italian.....I'll make sure he eats bland food for the rest of his miserable garlic-crunching life ....

Lemme give it a go.

In the meantime what does this '15psi sender' thingummyjig look like in case I spot it whilst fiddling?

 

[rosssavage]

Possibly a connector with two wires coming out of it located at / on the top of the secondary filter housing (the one that's impossible to see, never mind access!). The connector we swapped over at the bottom of the filter is the water-in-fuel sensor.

Hopefully latestarter will come along and tell us...

 

[watson1959]

nope....cant get plastic connectors to separate. I can get a decent grip but nothing seems to budge when I squeeze on what appear to be clips....i think i need a beer and kick the wall

 

[vas]

nope....cant get plastic connectors to separate. I can get a decent grip but nothing seems to budge when I squeeze on what appear to be clips....i think i need a beer and kick the wall

some of the automotive italian connectors are works of art and a pig to pull apart if you don't see them dismantled first (which is rather pointless...)
If it's easy to post a pic maybe someone could help?
Soak them in WD40 or something whilst you have your beer

V.

 

[watson1959]

some of the automotive italian connectors are works of art and a pig to pull apart if you don't see them dismantled first (which is rather pointless...)
If it's easy to post a pic maybe someone could help?
Soak them in WD40 or something whilst you have your beer

V.

Boat in marina..... Beer in hand in garden

WD40 will be applied liberally tomorrow... Thanks for your ongoing input!

 

[watson1959]

Managed to get one connector apart but no obvious muck. Other one couldn't get to separate.

Definitely still getting this poor connection wit alarm cutting in and out.

No luck re fuel pressure yet: will have to wait till back from the US.

Thanks to all so far!

 

[Latestarter1]

Managed to get one connector apart but no obvious muck. Other one couldn't get to separate.

Definitely still getting this poor connection wit alarm cutting in and out.

No luck re fuel pressure yet: will have to wait till back from the US.

Thanks to all so far!

Boat I am dealing with now on its way to the Pagent, you now on the radar.

Still sounds like wiring is a buggers muddle. Please remember you are dealing with PWM 0-5 volt signals.

When you are comfortable that you have electrical continuity have another go.

Let me start with the worst case, you have had water in the system and injectors have excessive back leakage causing a non start. I think that this is highly unlikely.

Look for the PWM pressure sensor on the fuel rail. The ECU applies a stabilised 5 volts to the switch. The resistive value in the sensor creates a change in the signal wire proportional to the rail pressure. If you pull the plug off the pressure sensor engine HAS to start even if injectors have excessive back leakage. Do not be scared when engine makes exciting noises, as if it is full of broken glass, just the injectors banging in fuel at the full monte! If motor still refuses to start with PWM sensor disconnected your injectors are fine. Nobody is telling the pump to let rip.

Made some enquires and the good news is that the Fiat Ducato van is known for dodgy stop solenoids. Failure of stop solenoid will obviously cause your issue and it will not throw up a fault code either.

Nearest Iveco truck and van dealer whom I know is not far away in Aylesbury and he is happy to supply you with parts at truck not marine pricing if your engine # comes up on his system.

PM me if you require contact details.

Good luck.

 

[ulyden]

One thing I don't understand. Why can't you monitor your rail pressure during start on CR engines? Most of starting problems comes from rail pressure don't reach minimum for starting. If you could read it out the trouble shooting had been a lot faster. Boost pressure and fuel flow you can read, why not rail pressure?

If your rail pressure are below start limit you can du a leakage test and replace bad injector, if ok you can check fuel suply like filter, feed and HP pump.

If you have rail pressure and engine don,t start its propably not a mecanical failure in fuel system, but a gear swich or another sensor preventing start.

Wire brake , bad connectors , shortcuts, speed sensors, low voltage and so on gives you problems .

 

[No Regrets]

Just a thought: You said the fuel pump was running, but the engine wasn't starting.

Yet, the engine was running well at one point.

How about a fractured fuel pick-up in the tank? Once running there's enough fuel to make it go, but starting is unlikely?

 

[rosssavage]

Had a few days away from the problem and had a think. The fuel pump was pumping lots of fuel (we dumped a load into Mrs Watson1959's washing up bowl..) with an open output, but when plumbed back in AND with ignition on but engine stopped the pump ran for a few seconds then cut out. This would suggest the 15psi switch has triggered as the LP system has pressurised correctly. Hence, I think this is not the problem.

Unfortunately watson1959's sticky / dodgy plugs are PROBABLY not the issue, as these plugs feed the instrument panel displays only.

When it ran, it was perfect until we turned it off, then it refused to even fire on restart.... Stop solenoid? No idea where that is on this engine though - latestarter, is it obvious like a non-common rail engine, or this integral with the Bosch HP unit?

Testing the common rail px sensor as above is easy - I actually know where that is!

 

[rosssavage]

Does a common rail engine have a stop solenoid?

Doesn't the ECU just stop opening the injectors?

 

[watson1959]

Chaps
Just heading back from the US: looks like an Italian colleague has managed to find me an English-speaker at FNM so I will call on MOnday.

Are there some specific questions I should put to him apart from a UK diagnostics agent? I've a feelIng they're not too helpful from what I've heard so I may get in touch with one of their US partners.
Cheers