Sprinter CDI overfueling?

[Cnics]

Good morning guys. I've just got back from a job 200 miles away without my 52 plate 311cdi.

After driving down to Arundel Friday afternoon fault free i set off from the hotel to the venue where the event was this morning and encountered a severe problem.

The van ticks over perfectly, but on pressing the throttle its very erratic, at times when it appears normal it IS normal, but the other times it's as if it's throwing 10 times the fuel in. It cut out completely and EDC light came on once but a restart cured that. It's clearly not burning this and it's coming out the exhaust but its burning lots of it and going like a rocket*. It is however knocking VERY badly when doing this. Think worse than an old transit 2.5D sound.

I've left the van down there and got a lift back with another one of my engineers putting everything on his van instead of splitting the load. I've got a local company (through green flag) bringing it to me tomorrow. It's 210 miles away.



* Attention all sprinter drivers. Loaded to the weight limit on a very slight incline it pulls from 2000rpm to the limiter in 4th gear in 5 seconds. It would be great to have that all the time that is one hell of an engine. but the massive knocking tells me it's doing damage so i've NOT driven it past the venue i was working at which was only 1 mile from the hotel.


So, my question is..... what on earth could cause this? It had a set of injectors 4000 miles ago (about 6 - 7 weeks)

My thoughts are limited to throttle control if resistance lowers for higher throttle, but this wouldn't cause it to throw any more fuel in than full throttle would allow. Or some fuel sensor for the injectors.

 

[jordyman]

Did you have a new set of injectors fitted or second hand, what is the part numer, should end in 1687 however the date on the top of the injector should be quite late as they were modified many times.

Also a sticking control valve on the rail could be the problem.

Good morning guys. I've just got back from a job 200 miles away without my 52 plate 311cdi.

After driving down to Arundel Friday afternoon fault free i set off from the hotel to the venue where the event was this morning and encountered a severe problem.

The van ticks over perfectly, but on pressing the throttle its very erratic, at times when it appears normal it IS normal, but the other times it's as if it's throwing 10 times the fuel in. It cut out completely and EDC light came on once but a restart cured that. It's clearly not burning this and it's coming out the exhaust but its burning lots of it and going like a rocket*. It is however knocking VERY badly when doing this. Think worse than an old transit 2.5D sound.

I've left the van down there and got a lift back with another one of my engineers putting everything on his van instead of splitting the load. I've got a local company (through green flag) bringing it to me tomorrow. It's 210 miles away.



* Attention all sprinter drivers. Loaded to the weight limit on a very slight incline it pulls from 2000rpm to the limiter in 4th gear in 5 seconds. It would be great to have that all the time that is one hell of an engine. but the massive knocking tells me it's doing damage so i've NOT driven it past the venue i was working at which was only 1 mile from the hotel.


So, my question is..... what on earth could cause this? It had a set of injectors 4000 miles ago (about 6 - 7 weeks)

My thoughts are limited to throttle control if resistance lowers for higher throttle, but this wouldn't cause it to throw any more fuel in than full throttle would allow. Or some fuel sensor for the injectors.

 

[Cnics]

I have no idea what part number the injectors were. I just sent the van to an my usual place and they told me injector 1 was faulty and repeatedly putting up faults but 2 of the others had done so. So i had them put a full set in. Not cheap but it cured the problem.

The van has arrived home this evening and i've driven it from where it was dropped off (end of the road) to outside my house and it never caused issue.

My concern (and it's a big concern) is that nobody will find anything wrong and i'll have a van which could do the same at any time. I'd sooner pay hundreds of pounds and have someone take bits apart and test sensors etc 1 by 1 and eliminate them than it go wrong on me. I can have my van off the road for aslong as it takes as i can just hire one, but i can't have it ON the road and be unreliable. So i need to get it fixed regardless of cost as i can't quite run to a new one just yet.

 

[Cnics]

If it helps, i tried starting it it yesterday evening, and it failed the first time, then took 3 or 4 seconds to start the second time. It appeared to run fine when it started but it's the first time since i've had the van that the engine hasn't started on the first turn. let alone turning over for a few seconds. Could this be an injector issue, or a "how the injectors were fitted" issue?

 

[Cnics]

Hi again, the vans been at the garage since Wednesday morning. They can't get to the bottom of it. It acted up on the way there at first and cut out a couple of times. However, as it warmed up (the garage is 7 miles of winding roads so it takes a while) it got much better, to the point where it would run fine all be it a little sluggish but not knocking and smoking.

I'm wondering if there is a hot and cold issue here. A sensor for when its hot and one for when its cold? and the one for when its cold is acting the blink, telling it it needs more fuel and just going mad with it. It really should be the garage that figures it out but you guys seem to know everything there is to know so i'm wanting input from everywhere.

What has brought me to this suggestion?? 12 months ago i tried a performance chip of a friends off his identical (apart from length) sprinter. Performance increased but so did fuel consumption, i need no performance increase so i gave it him back. However, with it on, under heavy load it would knock a bit and smoke. My current problem seems to be exactly this but on a MUCH MUCH bigger scale, but only when cold.

I can tell you what you need to know about array theory and acoustics, but have ver little knowledge of a CDI engine, is there a sensor that detects cold and fuel level and will throw more fuel in when its cold if the need arises. Surely it must be this that's on the blink or something similar.


Rob

 

[dava]

You realy need it put on the star as it will have loged fault codes. From what you have said my intial thoughts are an injector over fuelling, however, these are electronically controled, so it could be an electronic fault, again the star would show this up. I would not advise running it in this condition as it is obviously over fueling and may wash the bores or burn a valve/piston out. Also I would carry out a spill port test and see if any injectors are greater than others, thus pointing to a faulty injector and then bad starting suggest a faulty one. The control valve on the end of the rail has a seal on it, about .60p, these split and give funny pressure problems, so check that out, two torque screws holds them in and with out eliminating this valve with star I would consider changing it, about £11.00 I think, as they can be prone to going. Failing these I would need more info as ever, as this is always the best form of dianostic.
Hope it helps.

 

[jordyman]

Need to know what part number the injectors are and how old they are as your symptoms are a classic injector fault.

You may have been sold a load of second hand injectors, be carefull of recons as no one can properly overhaul them.

The regulator o-ring, if split will cause a non start fault as there will be a pressure loss in the rail on cranking. You need a minimum of 125 bar for the engine to start and if there is even a slight nick in the o-ring you will have poor starting and eventually a non start situation when it finally splits.

On the other end of the rail is the sensor, which if faulty will cause hunting and possibly over fuelling, however this is doubtfull.

 

[ralphymorison]

i had the very same sort of problem on my 54 plate and when it was put on the computer it showed injector problems but my mechanic knew that the problem was a short in the wiring loom on the right side of the engine apprantly the loom chafs against the engine mounting 1hours labour and a piece of wire fixed the problem

 

[Cnics]

Sadly i no longer have the van, i sold it pretty much for scrap as MB themselves had no idea. The wiring loom was all intact (replaced a little earlier in its life).

It cost me nearly £2000 to NOT fix, not to mention a years tax, insurance, and then i got £1500 for it, with a full tank of fuel.