C5 2.2 HDi 136 Facelift - poor MPG and no bottom end grunt

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unclenewy
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Joined: 29 Mar 2016, 18:40

Re: C5 2.2 HDi 136 Facelift - poor MPG and no bottom end grunt

Post by unclenewy »

Thank you for your early reply and detailed answer cachaciero, much appreciated.
cachaciero wrote:I believe the answer to the question is no as regards being stuck but I am not sure that it is not possible to assemble it 180 degrees out so that closed becomes open. But then the crank arm would be up rather than down. You could disconnect the rod from the crank on the swirl valve and lock it (tie wrap?) in one position and try it then lock it in the other position and try it.

I have done something similar to this whereby I disconnected the little plastic ball joint and then ran the engine, the rod pulled back as it should and the crank stayed forward, so I went for a quick spin with it like that.......exactly the same .........no pick up until just over 2000 rpm. Which suggested to me that the swirl valve is already open and when the incoming air reaches enough force from the revs, the direct air outweighs the swirled air and the fourth inlet valve opens, just as it would if the swirl valve was acting as normal.
cachaciero wrote:You really need a Lexia on it to see what's happening it would be particularly interesting to see what it would tell you about boost pressure and mass flow.
I'm looking at them on ebay right now, any advice on those?
cachaciero wrote:The "foam pipe inside a black plastic bag" puzzles me I have no recollection of anything like that in that area but it's a few years since I last had the front of mine apart. Why would you have air blowing out of a supposed air inlet?. As I recall the complete air inlet filter box can be removed from the top without having to take the front off but I can't remember what the inlet to the box looked like :-(
This is the pipe,https://www.dropbox.com/s/u0rdjahvstfnr ... e.jpg?dl=0, the open end feeds deep into the wing in front of the wheel arch but I can't see what it connects to although I can feel it. It seems to stop right below the battery tray. It baffled me why air would be blowing out of it but i wouldn't have noticed the splits otherwise.
If you send me an e-mail address that will accept large attachments I will send you the info that I have given skycat61 it may help you understand how it's all supposed to work :-)
jacko-1970 at hotmail dot com

One final question.....Whist I'm waiting for more EOLYS fluid to arrive, would it be possible to put a litre of diesel in the EOLYS tank with the litre of PAT fluid that's already in there as a temporary top up? My logic tells me it would only dilute it seeing as it gets injected into the fuel tank anyway.

And again....Thank you for your help

Neil
cachaciero
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Re: C5 2.2 HDi 136 Facelift - poor MPG and no bottom end grunt

Post by cachaciero »

Questions so many questions :-)

Swirl valve the "normal" engine not running position for the swirlvalves is open, when the engine is started the valves are shut until about 2100 rpm when they open so you see your test was with the valves open not closed, suggest you try it again this time with the valves closed :-).

Lexia I can't make any recommendation I've had mine for years and it is a genuine Actia device. However there is a humungous thread on here for Diagbox / Lexia issues and I am sure a post on there will get you some good advice. I would say that if you are going to keep the car a while then you will re-coup the cost of a good Lexia clone. Not that you will use it much when you have got all the initial problems sorted, the 2.2 comes in for some stick because of it's fuel consumption particularly the auto version but apart from that it's a good reliable long distance cruiser. Having a Lexia to hand will enable you to diagnose and fix problems very quickly at minimum cost once you get the hang of using it.

I wouldn't put diesel in the EOLYS tank although as yours is a 2002 car it won't be EOLYS it will be DPX142, why the rush to put something in there? a litre will last a while. Now I will answer that question :-) you want to get rid of the low fluid warning, sorry to tell you that it's not so easy as just putting fluid in and you may well have bigger problems than just resetting the ECU. This is a big topic on it's own so I suggest that maybe you should start a new thread on this subject but first read the docs I have sent you then when you start the thread you will start at a much higher knowledge base line.(This is one area where the Lexia is essential ).
unclenewy
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Re: C5 2.2 HDi 136 Facelift - poor MPG and no bottom end grunt

Post by unclenewy »

Questions so many questions :-)
Ha, sorry mate but you seem to have knowledge and knowledge is power.
Swirl valve the "normal" engine not running position for the swirlvalves is open, when the engine is started the valves are shut until about 2100 rpm when they open so you see your test was with the valves open not closed, suggest you try it again this time with the valves closed :-).
I understand that, I'll give it a bash. I just thought as the actuator is working and supposedly going from closed (pivot back) to open (pivot forward) at 2100 rpm when connected, then disconnected leaves the valve open (pivot forward) permanently (in theory). But I'm getting the same result both ways, nothing until above 2100 rpm then a surge of power.
Lexia I can't make any recommendation I've had mine for years and it is a genuine Actia device. However there is a humungous thread on here for Diagbox / Lexia issues and I am sure a post on there will get you some good advice. I would say that if you are going to keep the car a while then you will re-coup the cost of a good Lexia clone. Not that you will use it much when you have got all the initial problems sorted, the 2.2 comes in for some stick because of it's fuel consumption particularly the auto version but apart from that it's a good reliable long distance cruiser. Having a Lexia to hand will enable you to diagnose and fix problems very quickly at minimum cost once you get the hang of using it.
Thanks, I will search that thread out.
The reason I bought it is precisely to use as a cheap (£395 with fully wired up double socket tow bar and 5 months MOT, It was gonna cost £250 to fit same tow bar on our previous Zafira......no brainer) comfortable touring cruiser to tow our folding camper and have room for our 3 'delightful' kids who love nothing more than sitting next to each other for hours in the back of a car. So I'm planning on doing anything within my capabilities myself......Lexia it is then.
why the rush to put something in there? a litre will last a while. Now I will answer that question :-) you want to get rid of the low fluid warning, sorry to tell you that it's not so easy as just putting fluid in and you may well have bigger problems than just resetting the ECU.

No rush as such, it's just I had a mechanic mate put the fluid in and reset the ECU and now I have no warnings on startup. It was him that discovered the tank was empty and not just low and said I should get it filled before the car starts telling me off again. I'll wait for the PAT fluid to arrive then.
This is a big topic on it's own so I suggest that maybe you should start a new thread on this subject but first read the docs I have sent you then when you start the thread you will start at a much higher knowledge base line.(This is one area where the Lexia is essential ).
Once again thankyou for your kind help, and going out of your way to send me the info, I haven't looked at my emails yet before I responded to this so gonna give that a coat of looking over in a minute.
By the way did you manage to use that link I put to the picture of the pipe with a 'bag' on it? I couldn't figure out how to get the actual picture into the reply.
Cheers
Neil
skycat61
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Re: C5 2.2 HDi 136 Facelift - poor MPG and no bottom end grunt

Post by skycat61 »

Seems that I'm not alone with the 2.2HDi and its problems :) Welcome unclenewy!

Have been playing a bit more. Measured the vacuum level of the EGR valve and it was odd.

I started the engine and ran around to the engine to look at the gauge. It was showing 0.5 Bar gauge. Then something odd happens, The gauge drops to zero as I hear the beep of the "depolution system faulty" message I've got used to over the past few days.

I took the EGR blanking plate out and reset the injection ECU faults.

Running the test again the EGR vacuum was 0.5 Bar gauge at tickover and zero gauge at 2500RPM, exactly as the data you sent. I noticed also that the MPG improvement is not as good as it was at first fitting of the blanking plate, before it threw the "depolution system faulty" message. Would I be right thinking that the ECU falls back to some default mode when it get an fault?
cachaciero
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Re: C5 2.2 HDi 136 Facelift - poor MPG and no bottom end grunt

Post by cachaciero »

As far as I know there are two levels of fault the first is a fault which is not engine life threatening, you will get a warning but as far as I know the injection system will continue to attempt to control to the default engine model, the fact that it can't is what trips the warning.
The second case is where in continuing to try and achieve the default engine model serious damage is likely to occur, in this case the system switches the engine model to "get you home mode" sometimes called "limp mode" which is essential a rev limiter to 2500 rpm. The engine will stay in this state until switched off. When switched back on the warning will remain but the engine will work normally until the fault is triggered again If the fault is rectified and a Lexia is not available to clear the fault the service light will reset after five (as I remember) start run stop cycles with no further occurrence of the fault,
The one fault I know that will cause "limp" mode is turbo overboost I am sure that there are others but I don't know what, not to worry the Lexia will tell you should this happen.

Now back to your "strangeness" my question is does the EGR vac drop to 0 because the EV is controlling it to 0 (Lexia trace should be able to tell you this) or is it dropping to 0 because the vac source has dropped to 0?

On start up the swirl valve is actuated which in itself instantaneously takes a lot of vac but the swirl valve itself can develop holes in the diaphragm which can cause leaks depending on position time of day, temperature, whatever, but the leak and severity of the leak can be intermittent and not obvious, the problem with this is that when this happens the turbo looses its control vac and goes into high boost mode and then depending on other conditions the over boost threshold is reached and viola limp mode!. However you were not seeing a "limp mode" fault and the Lexia said it was a flow type problem.

The test with blanking plate removed apparently no errors but MPG worse, well if the EGR was sticking open then the fuel consumption would be worse particularly when the engine is running above 2500 rpm when the valve should be closed.

Something bothers me when you first fitted the blanking plate it took 15 miles or so before you got a warning. Then on this latest exercise you are getting a warning pretty well immediately after starting the engine.

OK do something I suggested before disconnect the vac control line to the EGR from the EV, blank the open port on the EV, the EGR control line being open to atmosphere if the EGR valve is closing properly then based upon what happened with the blanking plate fitted you should get a warning. When doing this set the Lexia up to record mass flow, turbo calculated turbo pressure and actual turbo pressure, EGR valve position, EGR Throttle valve position and on the FAP page there is a parameter for exhaust mass flow, what we need to see is a trace for the error message and the same trace without.

Thinking about comparison with inlet mass flow comparisons with exhaust flow have you checked around the exhaust filter with the Lexia? whats the pressure across the filter at idle and say 2000 rpm?
unclenewy
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Re: C5 2.2 HDi 136 Facelift - poor MPG and no bottom end grunt

Post by unclenewy »

skycat61 wrote:Seems that I'm not alone with the 2.2HDi and its problems :) Welcome unclenewy!

Have been playing a bit more. Measured the vacuum level of the EGR valve and it was odd.

I started the engine and ran around to the engine to look at the gauge. It was showing 0.5 Bar gauge. Then something odd happens, The gauge drops to zero as I hear the beep of the "depolution system faulty" message I've got used to over the past few days.

I took the EGR blanking plate out and reset the injection ECU faults.

Running the test again the EGR vacuum was 0.5 Bar gauge at tickover and zero gauge at 2500RPM, exactly as the data you sent. I noticed also that the MPG improvement is not as good as it was at first fitting of the blanking plate, before it threw the "depolution system faulty" message. Would I be right thinking that the ECU falls back to some default mode when it get an fault?
Hello skycat

Sorry to hijack your thread like this but I've searched and searched for answers, and although I've found a few stating our same problems, yours is the only one that's up to date and still active, everything else was years old.
I'll keep popping back to follow your activity and I'm gonna go and have a mess with things right now and try to keep updating, so hopefully between us.....and with cachacieros extremely kind and helpful input.....we can get to the bottom of it.

Cheers
Neil
skycat61
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Re: C5 2.2 HDi 136 Facelift - poor MPG and no bottom end grunt

Post by skycat61 »

OK with the blanking plate removed and the vacuum line to the EGR valve disconected and blanked at the electrovalve we get the following lexia trace:-

https://www.dropbox.com/s/tb1dwhtu93ota ... t.bmp?dl=0

Image

I have done 20 miles like this and there is no sign of the "depolution system faulty" message and no engine light. I sort of expected this because if the EGR valve were to close under no vacuum we'd be in exactly same position as we were when the blanking plate was fitted - no EGR flow. I will keep it monitored over the next few days and report back.

Neil:- don't worry your not hijacking the thread, in fact, the more the merrier :) Has anything in here been of use yet?

Donald
cachaciero
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Re: C5 2.2 HDi 136 Facelift - poor MPG and no bottom end grunt

Post by cachaciero »

Object of exercise: Trying to establish why blanking the EGR pipe causes a de-pollution Fault and if the EGR valve is stuck.

Reprise.
1. With the EGR pipe blanked at the manifold? which equates to NO EGR, flow fuel consumption improves BUT there is a de-pollution system faulty message.
2 With the blanking plate removed and the EGR vacuum control line disconnected which should equate to EGR valve closed i.e NO EGR gas flow there is no de-pollution message,

If the fuel consumption in this configuration is improved i.e the same as having the blanking plate fitted then it would imply that the EGR valve is closing fully, however if the fuel consumption is reduced then it suggests that the EGR valve is stuck open or partially open.

So the important question:- what's the fuel consumption like?

All the traces seem to be consistent with each other though what the real values of Air Volume should be i really don't know but it increases in step with Inlet Mass flow in some believable proportion.
The EGR recycling throttle valve still seems strange to me, the valve appears to spend as much time closed as open, logic says to me that once the engine is warm this valve should be wide open other wise there isn't much point in having an inter-cooler!.
skycat61
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Re: C5 2.2 HDi 136 Facelift - poor MPG and no bottom end grunt

Post by skycat61 »

Cachaciero:- Your stated objective is sound unfortunately I'm having real trouble deciding! :?

After 32 miles with no blanking plate but with the EGR valve vacuum line disconnected the car has now given me the "depolution system faulty" message and the engine light is on. Over that distance the consumption has been 27-30MPG but this is not on the "work run" as I've been on leave, making direct comparisons difficult.

I'm guessing here but it seems like the EGR might be almost but not quite closed with no vacuum applied. Is it difficult to remove the EGR valve to inspect and clean it? I feel this might be the way forward but am reluctant to tackle the job myself if its difficult as I don't have a garage and a compendium of workshop tools to set about it. The accessibility of EGR looks pretty poor to me.

I will put the lexia on it again tonight, check the faults, and get a trace of the engine parameters you suggested. Many thanks for bearing with me on this one.
cachaciero
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Re: C5 2.2 HDi 136 Facelift - poor MPG and no bottom end grunt

Post by cachaciero »

Without having a feel for the difference of routes viz a viz work and today it is difficult but my impression is that the consumption is lower than it was with the blanking plate so your theory may well be a good one.
The warning message is a mystery in that we don't know exactly what triggers it but that it has a relationship with the EGR seems certain, would be nice to have a Lexia trace of it happening as it were.
EGR valve never had to go there myself, as you say access doesn't look good although removing the head steady bracket may allow rocking the engine far enough forward to improve access.
I think at this stage I would be inclined to try one of the EGR cleaners. I am personally a little sceptical but as we have seen there are people on here who have had good results so I would give it a go, easy to do and doesn't cost a lot.

Rgds
cachaciero
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Re: C5 2.2 HDi 136 Facelift - poor MPG and no bottom end grunt

Post by cachaciero »

Hmm.... Just done a review of where we have got too. In an earlier post there was a reference to a PUG site and article on MAFs that caused me to compare your latest trace with earlier ones where the EGR was in circuit.
Now you said that at idle the Measured air flow was about 188 (as I recall!) which is about the same as mine and indeed the earlier traces show just that with an "average" driving value sitting on the 500 line. Now look at the latest trace and the Measured Air Flow is higher all the way through the range, this would suggest that the EGR valve is closed, however I believe that between the two traces the MAF was changed. So we really need to revisit this like what is the air flow at idle and say 2000 rpm with the current MAF and EGR connected and what it is at the same rev points with the EGR vac disconnected.
I guess that the ECU can detect if the EGR is blanked by looking at the Air Flow, (as claimed on the PUG article) it may be that the detection is only triggered after some time analysing the air flow.
From a recording point of view forget Turbo Pressure Setting but record revs.

I also note that while you have commented on fuel consumption I don't recall anything about pickup / acceleration or have I missed that?
unclenewy
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Re: C5 2.2 HDi 136 Facelift - poor MPG and no bottom end grunt

Post by unclenewy »

skycat61 wrote:OK with the blanking plate removed and the vacuum line to the EGR valve disconected and blanked at the electrovalve we get the following lexia trace:-

https://www.dropbox.com/s/tb1dwhtu93ota ... t.bmp?dl=0

Image

I have done 20 miles like this and there is no sign of the "depolution system faulty" message and no engine light. I sort of expected this because if the EGR valve were to close under no vacuum we'd be in exactly same position as we were when the blanking plate was fitted - no EGR flow. I will keep it monitored over the next few days and report back.

Neil:- don't worry your not hijacking the thread, in fact, the more the merrier :) Has anything in here been of use yet?

Donald
Yes, massive use, in fact all the thread from your first post has been a checklist of jobs done and what to tackle next.

I've been a bit too busy refurbishing our folding camper ready for our first weekend away in Scarborough next week to get at the car, but after a couple of runs down the motorway I think I may be being a little harsh on the old girl. It's still not exactly a racehorse but it got up to 70 ok and sat there easily on cruise showing 40+ mpg, maybe losing a little puff on the hills but nothing that a bit of right foot didn't sort. It's definitely not 100% as the pull away is still very laboured.....I certainly couldn't get anything close to a wheelspin.......but if I remember to get the revs up a little before engaging clutch, I can get into the traffic flow ok.

It'll be a test next week pulling about 750kg of camper the 160ish miles round trip to the coast and back......Wish me luck.

P.S. a lexia is in the pipeline so updates will be posted when I figure out how to navigate that bugger!
skycat61
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Re: C5 2.2 HDi 136 Facelift - poor MPG and no bottom end grunt

Post by skycat61 »

Well last Friday I gave giving the EGR valve a clean using Wynn's EGR Cleaner, and following the instructions to the letter, including taking it for a gentle 20 mile drive afterwards. On the works run this week I've done 95 miles at an average speed of 19 MPH and the usage is 27.1 MPG. I would conclude that there has been no improvement there. What's remain a disappointment is that is exactly the MPG I got with the old 2L petrol manual C5. The only thing that has given any improvement so far has been blanking off the EGR valve, and from what I've been reading that would in itself automatically improve MPG over the same engine with a correctly functioning EGR system.

Perhaps it's true that diesels give no real advantage over petrol on the urban driving cycle. Perhaps my expectations are too high. It's just a pain as otherwise the car is brilliant.

Anyway, I'm still open to suggestions about the next step. Many thanks for all the excellent help I've had so far.
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Paul-R
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Re: C5 2.2 HDi 136 Facelift - poor MPG and no bottom end grunt

Post by Paul-R »

skycat61 wrote:Perhaps it's true that diesels give no real advantage over petrol on the urban driving cycle.
If that were the case then taxis would not run diesel engines. It's the auto gearbox which is giving an extra twist to the poor consumption compared to a manual gearbox. And a manual gearbox car would be better than a petrol one.
cachaciero
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Re: C5 2.2 HDi 136 Facelift - poor MPG and no bottom end grunt

Post by cachaciero »

Well last weekend I took mine from mid Sussex to Bristol (overnight stop) Gloucester and thence back home, Fuel consumption overall posted at 38 mpg. This as a reminder is an Auto estate and it was not loaded. Interestingly the first half of the journey consumption which starts of as M/Way after a 15 mile warm up stretch cross country looked like it was going to achieve something in the region of 42, however stop start traffic around Heathrow knocked that back to 40 and later on stop / start for about 15 miles around Swindon cemented it at 38 from which number it never recovered.
Having done the same run both with the EGR loop blanked and unblanked I saw little difference in the fuel consumption, however such a run for the most part is high speed and as such the EGR valve would likely be closed much of the time anyway.
The more I look at this the more I find what happens with the EGR inlet throttle valve strange and frankly just plain wrong from a consumption perspective, My next step would be to disconnect the vac lines to the two throttle valves at the front of the intake and see what that does for fuel consumption, my feeling is that it should improve it, maybe by quite a lot around town as the engine would be getting cold air as opposed to warm air. Anybody that tries this needs to be aware that it will likely screw the FAP regeneration but I reckon it should be ok for a couple of hundred miles to prove the point.
Will I do it? maybe not I feel a Lexus RX400H coming on having had a go in one last weekend :-) the C5 could be up for grabs as the number of issues, most minor keep growing :-(

Diesels and Auto Boxes.

The comments by Paul-R are spot on, but interestingly while I have over the years seen many C5' as Taxis I don't recall ever seeing a 2.2 Auto as a Taxi. I have read of many people with manual 2.2's claiming to get mid to high 40's on a run which I feel ought to be obtainable so my gut feel is that an auto should be able to achieve at least 40 on a run and in fact when I first had mine I could achieve that, currently however 37/38 seems to be the norm so something has changed, FAP load maybe. The around town figures have always been poor i.e 30 or less.

Whatever anybody that drives a VAG1.9 based car will know that on a manual box low 50's are easily achievable and the difference between town and motorway is less too which makes the PSA 2.2 look pretty second rate

It is worth comparing the VED for manual and automatic for any given model of car, almost unfailingly the auto will carry a higher rate of tax due too it's higher emissions which of course equate to higher fuel burn.

cachaciero