General Failed mot

[Jayw1984]

Recently had a doblo 2015 1.3 90

Fail and mot for emissions / visible smoke

Only thing I can find is its got least 1 glow plug with no resistance, van does start but is slow so assuming it's down to this. And is visible white smoke on start stinks of unburnt fuel and goes after started driving.

Do get smoke out back when engine reaches temp occasionally as tho dpf is trying to regen but heard it can fail regen if glow plugs aren't working properly so could be down to this?
Any ideas ?

 

[Greasytrucker]

It must be smoking all the time when warm, or at least when revved otherwise it wouldn’t have failed the smoke test as vehicles should only be tested once warm. Unless you were really unlucky and it decided to try and regen whilst it was at the MOT centre. Something doesn’t make sense if you say it’s not smoking once warm. Have you used the MOT centre before?

 

[Jayw1984]

Yes it's one I've used before, but have questioned it since as few others have had issues there, I did put some dpf cleaner in day before an morning of mot I took it for a good blast up motorway so unsure if that would of affected it, I took it to an independent garage to have work done as also failed for an oil leak and all he said was that it smokes on start up, and slow starts and almost like it's miss firing on start up but ran fine after but he did say smelt like unburned fuel as in work shop it stung his eyes when started it up and that could be glow plugs or possibly injectors, also said he could see where there was an oil leak as was old oil under the engine but no oil leak was found even after running with a sheet under van to check for any drops, and jusy advised me get some cleaner and give it a good jet wash underneath he engine and that he wouldn't of failed it for thay leak as can't see one, so i arnt overly concerned about that unless the 2 are linked.

surely if was injectors I'd get clouds of white or black smoke from fuel ratio being too rich or starved most the time? Altho I have occasionally had the smell of fuel in the cabin more of on start up. Only thing he suggested was to get some injector cleaner and take it for a good blast and see how it is.
Have noticed tail pipe is sorted up on the inside so would suggest fuel ratio being too rich maybe

 

[Greasytrucker]

Yes, normally faulty injectors will produce excessive smoke so if you don’t believe it’s smoking once warm and if you can rev it on the spot without it smoking i’d be tempted to take it back for a retest. Plenty of Doblo owners on here so see what others suggest. Good luck

 

[Jayw1984]

Will do think be changing glow plugs anyway as one maybe 2 of them is defo knackered as read 36 ohm instead of the usual 1 -2 ohms so I'll see if get any luck with that probs take it for a test at a different garage

 

[Jayw1984]

Just to add if anyone can help retested plugs today and all seem to read between 0.5 and 0.7 ohms by using multimeter on negative terminal but if I then change it and put the negative on a earth bolt 1 glow plug then shoots up to over 30ohms is this right way of doing it ?

Also not started van for emissions days with being holidays, started today after checking plugs, started forst turn but seemed like was going to stall u til increased revs slightly, loads of white smoke that stinks of diesel, did calm down after couple mins but didn't get engine warm just ran for 5 mins or so. Also engine seems to hunt / shake slightly which never noticed before but this does happen usually but once up to temp never happens. Could this be a plug issue or something else?

 

[Greasytrucker]

Just to add if anyone can help retested plugs today and all seem to read between 0.5 and 0.7 ohms by using multimeter on negative terminal but if I then change it and put the negative on a earth bolt 1 glow plug then shoots up to over 30ohms is this right way of doing it ?

Also not started van for emissions days with being holidays, started today after checking plugs, started forst turn but seemed like was going to stall u til increased revs slightly, loads of white smoke that stinks of diesel, did calm down after couple mins but didn't get engine warm just ran for 5 mins or so. Also engine seems to hunt / shake slightly which never noticed before but this does happen usually but once up to temp never happens. Could this be a plug issue or something else?

Not sure about the glow plug readings but the white smoke, shaking when first started are classic symptoms of knackered glow plugs. Once it’s warmed up though the glow plugs will have no part in any excessive smoke so you effectively have 2 separate problems if it fails the smoke test at the MOT retest. You could have an issue with your negative lead if readings are vastly different if a different earth point is used. Was it just 1 plug that was vastly higher reading or all on different earth point?

 

[Greasytrucker]

Just to add, if it is just one plug that was reading high it would explain it starting but running rough as the one cold cylinder needs to warm before it runs correctly

 

[Jayw1984]

Not sure about the glow plug readings but the white smoke, shaking when first started are classic symptoms of knackered glow plugs. Once it’s warmed up though the glow plugs will have no part in any excessive smoke so you effectively have 2 separate problems if it fails the smoke test at the MOT retest. You could have an issue with your negative lead if readings are vastly different if a different earth point is used. Was it just 1 plug that was vastly higher reading or all on different earth point?

Ya was just the 1 plug with fluctuating reading others all stayed at .6ohm no matter where I put the lead

 

[Jayw1984]

Luckily the one with fluctuating reading is the end plug and relatively easy to get to so might just swap that one out if comes out easily enough and see if makes a difference middle 2 look like be a right pain get to as sit right behind the turbo

 

[Greasytrucker]

Luckily the one with fluctuating reading is the end plug and relatively easy to get to so might just swap that one out if comes out easily enough and see if makes a difference middle 2 look like be a right pain get to as sit right behind the turbo

Make sure you blast some decent penetrating fluid round the plug and let it soak for a while first, some swear by doing it when the engine is hot as well although i did all 4 on my 1.9 Multijet with it cold, pre soaked with Plusgas

 

[Jayw1984]

Make sure you blast some decent penetrating fluid round the plug and let it soak for a while first, some swear by doing it when the engine is hot as well although i did all 4 on my 1.9 Multijet with it cold, pre soaked with Plusgas

Ya thats what ill be doing starting soaking today so shall take for a run tomorrow get it hot and spray some more n do it each day not planning on doing it until weekend so has a good 3 / 4 days soaking will probably just change the one with fluctuating ohms to start with to see if makes a difference if does ill do the other 3