2.0Turbo Diesel - lost power

[AndyB]

Hi all
Sudden fault developed in trusting monty 2.0 TD estate.
On way to B&Q suddenly the power became very intermittent - then worse. Almost like misfiring had it been petrol with a dizzy - that's the best way I can describe it. Just managed to limp home.
Oil and filter recently changed.
This engine had an EGR but doesn't now (found an earlier version without and pinched the 'non EGR bits).
Any suggestions on where to check first ?
Many thanks

[E_T_V]

Check wiring to stop solenoid (can break). Also as it is a monty it could be a duff fusebox (they tend to break down internally).

Also check the union to the fuel lift pump is tight (they can come use in service), and that the fuel filter bleed screws are tight.

[AndyB]

Thank you E_T_V.
What you are suggesting is fuel starvation at the pump is the best place to start - be it from the fuel pump, on the way to the Diesel pump or internally in the diesel pump due to eg solenoid or solenoid intermittent supply.
I'll check out here first.
Be good if I could rig a fuel pressure gauge after the pump to see if it's low or dropping off. I might be able to rig something.
Any idea what the running fuel pump pressure should typically be ?
Andy

[E_T_V]

There are two possibilities really

1. Is fuel starvation, either due to insufficient fuel supply (blocked pickup or filter), or due to air ingress before the fuel pump (e.g., loose union).
2. Is electrical, due to duff wiring on the stop solenoid or a duff ignition switch or duff fusebox.

Fuel lift pumps when they fail typically leak diesel out of the top hole. The unions (and indeed the fixing bolts) are known to come loose, so I'd start with these.

If the symptoms are more lumpy and hesitant running (rather than like someone turning the igntion switch off then on again), then I'd look at fuel supply issues first. Obviously if power is there and then not there like someone turned of the igntion I'd look for electrical reasons.

Fuel pump pressure will be 3-10psi I'd have thought. The injection pump itself has a lift pump built into it to suck the fuel through too.

[AndyB]

Thanks again E_T_V
The union tank side of the lift pump wasn't loose, but not tight. So gave it a nip up.
There is no evidence of a fuel leak from anywhere.
Took the car out locally and all seemed fine.
So went to go to B&Q (about 8 miles) and it did it again. It seems to play up when it gets warm. Wasn't quite as bad as before, but still a loss of power and sometimes lumpy even at tickover.
Every change means something. The water temp was hotter than usual - the gauge reached 'Normal' and the heater actually worked ! It's usually pretty crap.
I don't know if diesels get hotter like a petrol engine with lean mixture ?
Next I am going to rig a pressure gauge after the lift pump, plus wire back a monitor wire from the stop solenoid with a lamp - see if it flickers occasionally.
Does that sound reasonable next step ?
Won't be till the weekend now as I'm back to work tomorrow !!
Many thanks
Andy

[Guest]

Take the screw out on the top of the lift pump lift off the top and check the gauze filter inside.
You will probably find it is choked up with crap.
Sean.

[AndyB]

Thanks Sean - I'll look at that too.

[E_T_V]

Yes sounds a reasonable course of action. Also worth taking out the stop solenoid and looking to see if there are any loose bits of rubber in the hole it leaves as they can occasionally shred the seal and this stops the fuel supply accidentally. Very unusual but then this fault seems to be.

You often find the fusebox when there is issues plays up when hot rather than cold so I'd certainly look at the test lamp as a good next move.

[G Force]

The water temp was hotter than usual - the gauge reached 'Normal' and the heater actually worked ! It's usually pretty crap.

Hi Andy

If the engine temperature being hotter than normal is a consistent feature with the loss of power, I would be investigating this as a probable cause of your loss of power.

The engine can be overheating to the point where the pistons start to seize in the bore.

If there is no fault with the cooling system itself causing overheating the fault can be a problem with the injection pump. I have seen this when the pumps have been tweaked for more power or are faulty. Another symptom associated with this problem is that the engine seems to be especially powerful whilst getting up to temp.

[AndyB]

Hi all
I said I'd have some time at the weekend, so yesterday did some work.
1. Took off the fuel lift pump top cover and removed the gauze filter. It was not clear to see through, plus fair bit of gritty stuff in the 'well' of the pump body. So cleaned it all up, could see much clearer through the gauze when finished.
2. Stop solenoid. I'd had trouble with this about 3 months ago - engine would not start and it turned out this had stuck. So IN CASE this was causing a problem I changed this too.
Did 2 runs to B&Q yesterday (that's about 6 miles away) and it's running normally now ! Temp back to below midway on the gauge which is where it normally sits.
Annoying in a way that I did 2 jobs, so couldn't isolate specifically which caused the fault.
So thanks all for your tips - another job concluded and to add to the register of fault diagnosis.
Many thanks E_T_V, 400convoy and G-Force for your comments and suggestions.
You guys are brilliant !!
Andy