Hi guys just started work on a Man truck that I’ve recently bought and from first day with the trailer on it the engine red light and malfunction engine control unit came on board. I took it to Man twice and they have replaced all the injectors. It still does that and uses a lot of fuel. I’ve heard that sometime even a fuel cap can cause waste of fuel and the engine light to appear on dashboard.
Did any of had this problem? I need to sort it out
Many thanks
I’d post this in the owners forum as well chap, more spanner types there.
Ignoring the dash warning for a mo, is this an auto, if it is have you tried driving it manually when loaded keeping the revs below 1500 unless for deceleration using the exhaust brake…which is surprisingly good if you keep it at the high end for engine braking in manual.
Driven in manual preferably changing up at 13/1400 rpm and keeping it to 85ks cruising speed makes a surpising difference to fuel consumption, the engine if you let it will lug right down to 1000 rpm quite happily on hills its far more tractable than that useless auto box allows it be, might be worth an experiment for a few days before shelling out more at the dealers.
Several MANs here have ended up with new fuel pumps and/or new ECU’s, i don’t know if thats where your fault is heading but might be worth inquiring whether they can be examined/overhauled by BBA Reman or similar if it throws a wobbly at some point, i suspect a new pump or ECU from the dealer is a serious expense…maybe nothing to do with the problem but might be worth having a plan of action already in place should either fail.
Used to get that when I had an MAN it was a simle case of changing fuel filter…
haggis hunter:
Used to get that when I had an MAN it was a simle case of changing fuel filter…
That normally triggers the message ‘‘check fuel supply’’ on ours, filter changes have been brought forward for that reason.
Just a thought whilst on fuel, Costel do you check for and drain any water in the sediment sight glass?
And speaking of the sediment bowl, it has a filter in the top that is notorious for blocking up.
These MANs seem to have quite a few niggles with their electronics. Used to be a good solid truck but feels a bit cheap these days. I drive a variety of vehicles and it’s nearly always these that have problems.
DrivingMissDaisy:
These MANs seem to have quite a few niggles with their electronics. Used to be a good solid truck but feels a bit cheap these days. I drive a variety of vehicles and it’s nearly always these that have problems.
I don’t think they’re a lorry to let just any steering wheel operative knock about, certainly not the unbreakable machine they once were, but allocated to one or two drivers who look after their equipment and they seem to be fine, it takes time use (and interest) to get the best from one.
I wasn’t chuffed at being issued mine but its proving better than i expected (and i’d have another), the most frustrating thing is the auto gearbox but thats rubbish whether its in one of these, a DAF or even worse an Iveco, however once you eventually work round its idionsyncrasies and learn to drive it full time in manual when loaded then progress, fuel consumption and sheer frustration will improve… 
Mine’s had the fuel filter changed and it has reduced the number of times the message appears. It’s a thirsty old thing, though agree with Juddian that not going above 85kmh helps.
I will try the tip about not going above 1500rpm, the rev counter is a bit misleading in this respect as there’s a great deal of “green zone” beyond 1500. The problem is it’s so sluggish getting away. Block changing loaded will go out of the window.
Muckaway:
Mine’s had the fuel filter changed and it has reduced the number of times the message appears. It’s a thirsty old thing, though agree with Juddian that not going above 85kmh helps.
I will try the tip about not going above 1500rpm, the rev counter is a bit misleading in this respect as there’s a great deal of “green zone” beyond 1500. The problem is it’s so sluggish getting away. Block changing loaded will go out of the window.
Muckaway i tend on the flat to start off in 2nd, then 4,6,8 then up singly from there, if slightly downhill i’ll do 3 5 7 then either 8 or 9 and singly depending on how its performing at the time.
What i have noticed is that by locking it in the gear i want it will pull easily over long motorway climbs all the way in 12th, in auto it drops to 11th or even 10th as soon as it sees the incline with subsequent loss of momentum with each unecessary change.
It took me longer to learn the precise change points than Scania, find Scanny lends itself to manual driving (and is a big improvment for junctions and hill climbing) , the MAN doesn’t and fights you all the way, defaulting back to auto after about 30 seconds unless you tell it manual before starting off is a bind and the one thing i would like programming out…mind you thankful for small mercies, some of the things won’t allow manual input at all…
5.7mpg running from Woodstock to Bicester, loaded both ways all day (10 loads). IMO crap fuel figures. Credit to Juddian though, what he said appeared to send it up from 5.4 though.
I need to average 7 to get any fuel bonus, time to ask for a Scania I think.
Juddian:
haggis hunter:
Used to get that when I had an MAN it was a simle case of changing fuel filter…That normally triggers the message ‘‘check fuel supply’’ on ours, filter changes have been brought forward for that reason.
Just a thought whilst on fuel, Costel do you check for and drain any water in the sediment sight glass?
on all of mine, i get an EDC warning come on the dash, change the fuel filter, all good 
thanks all, it does help to see that other people have same problem. I have notticed that when I go over 85 I get that more often and also the exhaust yellow light underneath the spedometer stays on. Filters been checked at Man, fuel pressure test done, injectors replaced and MAN can not find the fault. to be honest I don’t know if I should take it to MAN anymore as they always find something else apart from the problem and I am fed up.
regarding the fuel consumption, somewhere around 9.5 mpg but that is whit an empty container, it is still an improvement as first days of work on this truck was much much worse.
I will keep you updated on his.
the last one of mine i checked was doing 8.5 over the week on containers doing locals around the Midlands
that is a 57 plate TGA XXL 440 euro4