Dispatch 1.9d Poor MPG

[burgie]

Hi - I hope someone can help me...

My 03 plate dispatch 1.9d with about 96,000 on the clock, recently had it's heater plugs changed and something called the diesel leak pipes...as they had perforated and were leaking diesel all over the engine. The mechanic ( a diesel specialist) wired the heater plugs to a separate button because he said they were not turning off, hence them burning out. He also bypassed the EGR valve and bypassed the choke, as he said it was constantly running on choke. There is also a solenoid thing that he has disconnected that runs a butterfly valve in the air intake too.

Since this work has been done, the vans mpg has dropped by about 10mpg!!! Previously I was getting 38mpg now I am only getting around 30.

Another thing I have noticed, is that there also appears to be a humming noise from the engine, similar to that you would expect if the exhaust was blowing...

Now, with all the stuff that has been disconnected I would rather have re-connected. To my mind it is there for a reason and that is to make the engine efficient, but this chap says those items are to do with forcing the emissions down and tend to cause more problems than they are worth.

Could anything he has done as described above caused this rather dramatic rise in fuel consumption?

Any help would be appreciated, as it feels I am going out to work to simply put fuel in the van, at the moment!

Chris

[Peter.N.]

Hi Chris

Not having an EGR won't hurt but a diesel engine doesn't have a choke and I have not seen a Citroen engine with a butterfly valve, the only use I have seen these put to in the distant past was to provide vacuum for the brakes. If by chance it does have one and its in the closed position it will be reducing the ammount of air into the engine which will cause increased fuel consumption but it should also be causing black smoke from the exhaust.

Peter

[Sean602]

Perhaps your mechanic has used phrases that are understandable to the mechanically (diesel )nieve.

I'd have thought replacing the relay would have been easier than wiring up a suitable manual system for the glow plugs and sounds like the blanking of the egr has been unsuccessful, "Choke"= cold start cable?, as for the solenoid activated butterfly??

[spider]

I've seen butterflies in the air inlet on a diesel but not on an engine that was made in the last 30 years. They sort of use a strange effect to generate some vacuum for the braking system.

The leaks were probably the leak off pipes, they do wear and leak over time.

The heater plugs, nothing really wrong with having a push button to operate them manually if desired. They won't effect economy though.

Choke, hmm I think as above the fast idle thermovalve maybe as this if stuck on and it had the switch on the control arm could in theory lock the post heating on which may of given teh impression of the heater plugs being on all the time.

If it has either a capsule for advance or a solenoid and that's been wired permanently on (when it should only operate when stone cold via the switch on the control arm on the cable) that may cause a drop in MPG...

[burgie]

Diesel niaeve, I like that.

Well, I understand what you are saying, but the butterfly thing, apparently is to do with the emissions. It the solenoid he referred to is located on the top of the engine bay, sort of attached to the underside of the top of the bonnet area. Great description, I know. It has two pipes going to it. I gave since found out that if I reattach the pipe that is disconnected, I get flat spots and lots of black smoke with those flat spots. Disconnect it again and the flat spots vanish as does the black smoke.

I think I will get him to reattach the choke whatever he disconnected and see what happens then.

Thanks for the replies so far....

Chris

[spider]

The solenoid / pipes are the EGR. To be honest its probably best disconnected anyway. Especially on the DW8 unit you have, they can stick and cause some nice running / smoke concerns as you've noticed. The only thing to watch is to make sure the valve is actually shut. I wonder if that's the 'butterfly' valve you're speaking of.

Quick question: When you start the van from stone cold, does it idle OK ? , as in idle at a sensible speed and when its up to temp does it seem to idle fast or not ?

[burgie]

Well, i took the car back to the mechanic today.

The part that I am referring to is apparently the EGR Solenoid. It is now disconnected and I have disconnected and blanked the pipe to the EGR valve aswell.

The choke.....he kept referring to it as the choke, must be the cold start cable. It was fully open apparently when I bought the van and getting 38mpg. It's now disconnected and I am getting 30mpg! When I told the mechanic I was getting less MPG now than before he started tinkering, he told me that there was nothing he could do, I will just have to live with it, as it is all down to the ECU and can't be altered at all.....

I really can't understand how this situation has occured simply because the heater plugs have been changed, and tbh I am more than a little vexed.

Anyway, in answer to you question, when the van starts up it idles fine - nothing about the way the engine runs or starts suggests there is a problem. There is a bit of a flat spot when driving it, but otherwise ok. No diesel smell, no erratic revving, no black smoke or anything!!!

[Northern_Mike]

Well, i took the car back to the mechanic today.

The part that I am referring to is apparently the EGR Solenoid. It is now disconnected and I have disconnected and blanked the pipe to the EGR valve aswell.

The choke.....he kept referring to it as the choke, must be the cold start cable. It was fully open apparently when I bought the van and getting 38mpg. It's now disconnected and I am getting 30mpg! When I told the mechanic I was getting less MPG now than before he started tinkering, he told me that there was nothing he could do, I will just have to live with it, as it is all down to the ECU and can't be altered at all.....

I can't really understand it either, but I don't claim to be a diesel expert like your mechanic. I'd be tempted to suggest to take it to someone else!

[mendedit]

Try checking the crankcase vent breather pipe- make sure it's not blocked, there might be a valve at it's outlet from the engine- is this clear and working?,
Anyway I would vent the pipe to the open air at least to try for a few days and see MPG difference if any

[Lighty]

Not sure exactly what has been done, but we tend to remove that air flap in the intake, so it cannot run rich by mistake. Everything he has done sounds fine, would need to see the vehicle really.

[Northern_Mike]

Not sure exactly what has been done, but we tend to remove that air flap in the intake, so it cannot run rich by mistake. Everything he has done sounds fine, would need to see the vehicle really.

I'm not sure why you think it sounds fine? It clearly isn't. It went in for a set of heater plugs and leaks off pipes, had work done to it that wasn't requested, and now has a flat spot and poor economy! Not only that, the "specialist" has simply said it's nothing to do with him.

Sent from my GT-I9300 using Tapatalk 2

[spider]

The advance may be stuck on then but I'd expect it to run badly or run fast.

There should not be a drop in MPG on a diesel engine, the fuel if its not leaking has to go somewhere, too much fuel will make it smoke as will a lack of air (blocked air filter or pipework)

Have to be 100% sure the EGR valve is actually closed even though its disconnected as they can coke up and jam which is why people do away with them in the first place. , if its slightly open then MPG will suffer a little bit.

Regarding the idle speed, look at the fuel pump, on the timing belt end (top) of it where the levers are, there's one with a cable attached (not the acc cable) this should be pulling the little arm when the engine is stone cold but when its up to temp it should be slack in the cable. Its not easy to describe but easy to see. Compare it when stone cold / hot.

The only other thing really is the control potentiometer on the acc arm on the pump it will probably have this as its a later DW8 unit although if someone had been playing with this or unplugged that I'd expect the engine management light on (this does work yes?)

[BX]

I cannot add any useful advice on the reasons for the poor economy on the DW8. However I can assure you all that butterfly valves are alive and well in the induction manifold of many modern diesels. The Transit 2.5 had them up to year 2000. I think they were there to restrict intake air at low speed, improve the egr and thus reduce NOx emissions. VW use them on many of the TDI engines. They are there to stop the jump or judder that occurs when a diesel engine is knocked off. They shut when the ignition is switched off to prevent the engine taking in air which gets compressed and then causes the engine to rapidly stop and reverse direction. The Ford 1.6 TDCI uses them to bypass the intercooler whilst DPF regeneration is in progress. Many of the old diesels with inline pumps had pneumatic governors. The RPM was controlled by keeping a fairly constant depression on the engine side of the butterfly. The more the butterfly was opened the higher the revs required to generate the depression e.g. Ferguson 20 diesel.
Just a few useless items of information.

[bill196510]

Not sure exactly what has been done, but we tend to remove that air flap in the intake, so it cannot run rich by mistake. Everything he has done sounds fine, would need to see the vehicle really.

I'm not sure why you think it sounds fine? It clearly isn't. It went in for a set of heater plugs and leaks off pipes, had work done to it that wasn't requested, and now has a flat spot and poor economy! Not only that, the "specialist" has simply said it's nothing to do with him.

Sent from my GT-I9300 using Tapatalk 2

At front of my c5 2.2hdi there is air intake rotating disc, think thats called a butterfly?
controlled by a solenoid, if disconnected makes a flat spot in revs
Reconnect what he disconnected

[Peter.N.]

I think they only use those on the 16 valve engines.

Peter