Eberspacher D4 problems

[Murv]

It fires roughly one time in 5.
When it does light, it runs faultlessly for up to a week (the longest I've run it for)
But, usually, it just blows white smoke.
The burner is clean, it has new gauze, gaskets and fuel pump filter, the only fault code is a time-out, voltage is good (currently running it on the bench straight off a large leisure battery on charge)
Changed the glow pin this morning, no change.
Measured the fuel flow from the pump and found it supplying about half of what it should (2.8 mls in 200 clicks)
Increased the flow until roughly 5.5mls in 200 clicks, connected all back up and it fired straight up. Shut it down again, tried to restart and it's back to normal (white smoke)

Any ideas?

 

[matthewriches]

Have a look at the flame sensor if you haven’t already. I could possibly lend you one to test if needed.

Also still need to sort your lids out of you still require them!

 

[matthewriches]

I th8nk off the top of my head it should read 1,000 ohms there or thereabouts at room temperature.

60,000 ohms on the overheat sensor

 

[Murv]

Thanks for that, the multimeter is on the boat so I'll grab it next time I'm there and test those.One other thing, if I switch it off whilst it's trying to fire (and belching smoke) with the fan ramping up, it frequently fires (can hear the roar) as soon as the fuel pump stops. But, of course, it then quickly runs out of fuel and goes out but the unit is winding down then anyway. That, to me, would indicate over fuelling?? even though it displays the same symptoms whether it's running at 2.5 mls or 5.5 mls/200 clicks. Winding it up higher then that, whilst it's alight produces blue smoke from the exhaust.And, yes please, would certainly still like those lids, just let me know how to pay! Cheers,ChrisEDIT: Forgot to add! Thanks very much for the offer of the loan flame sensor but I'll try the resistance readings first

 

[Murv]

Why is the text all running together?

 

[pcatterall]

How did you increase the fuel flow rate?
As it is trying to start ( going to the pumping white smoke stage) it would seem that the ECU is 'happy' that the components are within spec. although it would not hurt to check them
Of course the ECU may accept that all is good but as the load comes on when the glow pin heats up the thing may not power up.
Several customers have, in the past, been sure that their battery and connections are good but then found that the problem was there. It sounds like you are well aware of this issue but still worth checking volts at the unit on start up.
Is the pump within the correct angle range on your bench set up?
As you have it out and n the bench it is fairly simple to go through everything again following the manual. If you open it up again you might get a clue as to what has been happening.
I recall one particular heater where I changed every thing and de coked the chamber it still misbehaved rather like yours. I eventually opened it up again to find it very sooty inside and the soot was wet from unburnt fuel which was presumably inhibiting start up. Cleaned it again and it was fine but I never found out why it had got so coked up so suddenly.

reading your new post I agree that over fuelling or at least fuel not burning is a possible issue. The firing up happens BECAUSE no extra fuel is being pumped and it can manage to ignite the 'leaner' mix. Sounds even more like my related experience.

 

[Murv]

How did you increase the fuel flow rate?As it is trying to start ( going to the pumping white smoke stage) it would seem that the ECU is 'happy' that the components are within spec. although it would not hurt to check themOf course the ECU may accept that all is good but as the load comes on when the glow pin heats up the thing may not power up.Several customers have, in the past, been sure that their battery and connections are good but then found that the problem was there. It sounds like you are well aware of this issue but still worth checking volts at the unit on start up.Is the pump within the correct angle range on your bench set up?As you have it out and n the bench it is fairly simple to go through everything again following the manual. If you open it up again you might get a clue as to what has been happening.I recall one particular heater where I changed every thing and de coked the chamber it still misbehaved rather like yours. I eventually opened it up again to find it very sooty inside and the soot was wet from unburnt fuel which was presumably inhibiting start up. Cleaned it again and it was fine but I never found out why it had got so coked up so suddenly.

Thanks for that. I actually opened it up at the weekend as I'd left the glow plug removal socket on the boat so easier to separate the burner and get at it from the side, spotlessly clean inside. I increased the fuel flow rate by loosening the small nut on the outlet side of the pump and counting the clicks until it was within spec (according to the numbers on the letokenois site, anyway)

 

[Murv]

reading your new post I agree that over fuelling or at least fuel not burning is a possible issue. The firing up happens BECAUSE no extra fuel is being pumped and it can manage to ignite the 'leaner' mix. Sounds even more like my related experience.

That was my thinking, but I don't get how it displays the same symptoms with the fuel flow at such different rates?

 

[pcatterall]

still interested to learn how you are adjusting the fuel flow rates!
To my knowledge the pumping cycle rate is governed by the ecu with the pump sending a fixed dose per cycle/click. The ECU will choose to alter the pumping/pulse rate depending on the setting activated/fan speed. My manuals all quote the required volume as that which is produced during a start up cycle rather that so many 'clicks'.