Important! : New CAT, new Lambda, new water sensor & CO2 levels WORSE than before

15th February 2011, 11:41

I'm starting to get really cheesed off with the VTS

Bought just before Xmas a nice clean example of a 2000 MK2 VTS with 8 months MOT left to run.

Took it for a French MOT (compulsory to get her French registered) just before the New Year and failed on excessive CO2 levels (0.74% & 0.76% - limit is 0.30%)

Following a Citroen Diagnostic and various advice I've put a new CAT on, new (2nd hand) Lambda sensor and even changed the crank speed sensor (showed up as faulty on the diagnostic).

Just got back from another French MOT and the readings are now WORSE than before

Matey tells me that even the old 2CVs with no CAT etc.etc.etc. are better than the VTS

So what now ?????? I'll start with a proper NEW Lambda sensor (don't trust 2nd hand electronic parts anymore) but then what - running out of things to change

15th February 2011, 11:45

Try the new lambda sensor,other than that the only other thing I can think of is a fault with the ecu,or your injector/s are overfueling making the car run rich.

Steve.

15th February 2011, 12:02

Thanks Steve - am trying to locate a new quality but not too expensive Lambda sensor at the mo - any ideas? (It's only a single sensor same as the MK1s)

15th February 2011, 12:05

Quote:

Originally Posted by LVC

Thanks Steve - am trying to locate a new quality but not too expensive Lambda sensor at the mo - any ideas? (It's only a single sensor same as the MK1s)

£60.00 is what I paid for,for a Bosch lambda sensor from eurocarparts.

Steve.

15th February 2011, 16:58

New Bosch Lambda sensor ordered (£70 including postage to France) - fingers and everything else crossed that this solves this chuffing problem

24th February 2011, 17:04

This is really, really pissing me off now - back from another FAILED MOT test

So far the VTS has:

New CAT
New Lambda Sensor (Bosch)
New Crank speed sensor (Citroen)
New Engine Temperature sensor - green connection (Citroen)

and the pollution levels are still too high. The lowest we got was 0.40% COs (maximum is 0.30%) but now the lambda reading is over 1.40 whereas before it was 1.07

Car's booked into Citroen for next Tuesday for another diagnostic (last one only showed up the crank speed sensor as having a problem).

I'm wondering whether she's been chipped.... no oil nor water loss, holds tickover and starts first time , powerformance is impressive with her pulling like a train from 4000 revs - but evidently too much fuel being sent through the system.

For a "cheap" car she's starting to cost me too much - still looks good though

24th February 2011, 17:23

Its obviously running rich from somewhere.. You tried the basics like a full service (air + oil filters)?

Are the injectors standard?

24th February 2011, 17:32

It was serviced not long ago I think (will check) and no idea re. the injectors - will ask the previous owner.

24th February 2011, 18:04

I`m thinking along the lines of a faulty injector,or an ecu problem either the ecu is faulty itself or has been poorly remapped.

Steve.

24th February 2011, 18:09

Quote:

Originally Posted by stevo67

I`m thinking along the lines of a faulty injector,or an ecu problem either the ecu is faulty itself or has been poorly remapped.

Steve.

I guess a possible cure is a new ECU as remapping over here is a lost cause?

Would a faulty injector show up on a diagnostic test?

24th February 2011, 18:25

Quote:

Originally Posted by LVC

I guess a possible cure is a new ECU as remapping over here is a lost cause?

Would a faulty injector show up on a diagnostic test?

Pretty sure that yes a faulty injector would show up.

Steve.

24th February 2011, 18:36

Nothing showed up last time - but you never know

24th February 2011, 18:39

You might have to bite the bullet and give it to Citroen - they will let you know if its remapped or not at least.

24th February 2011, 18:51

Yes that's what I was trying to avoid - she's booked in for next Tuesday morning at the Citroen garage

26th February 2011, 11:44

Been searching on here and see that I can get hold of a 1 plug VTS "unlocked" ECU for not too expensive

I understand that "unlocking" can raise the rev limit but does it do anything else and are ECU's a straight swap between the same type of car or are they "coded" for unique cars?

Working on the assumption that mine might have an issue so wondering about just replacing it or can Citroen just re-set it to standard?

Sorry for the questions but I don't know much at all about ECUs - too electronic for me

The sticker on mine (means zip to me) >>>

26th February 2011, 11:50

I don`t think unlocking should affect the rev limit,as your just effectively removing the security element.(no code etc)the other thing you can try isto have the injectors ultrsonicely cleaned & tested.

Steve.

26th February 2011, 13:41

Exhaust leak?
Is it using any coolant?

26th February 2011, 13:43

Ask the previous owner whats happened within the last 4 month before you bought it because if it passed an mot 4 month before you got it then it must have been running fine and emissions should have been normal.. Ask if they have changed anything in this period. But it just could be a failed part as steve says the injectors (Overfueling) Have you checked the spark plugs tips to see what colour they are ?

26th February 2011, 14:48

The exhaust might leak a little at the CAT joint but apparently this effects only the Lambda reading not the CO2.

Previous owner did an oil and filter in Oct 2010 and did not used it much since - so I guess a Spark Plug change is not a bad idea. He changed nothing on the car since the MOT - it's only got about 2000 more miles on it since the MOT in August 2010

Intersted to see what (if anything) Citroen can find but think a Spark plug change wouldn't hurt - what's the recommended make of plugs for the VTS?

I have the emission tests from 2007 and 2008 but nothing more recent. 2008 she ran 0.013% fast and 0.004% idle CO2 with a lambda of 1.016 - this is what I was hoping to see and is on par with my VTR - only 30k miles difference between 2008 and now.

Apparently she ran a 142BHP at the Sax-p rolling road meet in 2009 - would this indicate a modifed/mapped ECU ?

26th February 2011, 15:51

I would fix your exhaust leak (even just a small leak will affect the reading), and fit some new plugs, fuel filter and air filter (if you haven't got a fancy one fitted). Give it a good drive before the MOT, i.e. get the CAT nice and hot.

I always use these plugs: NGK BKR6EZ.

I wouldn't look too much into the RR result - I doubt your ECU is at fault.

26th February 2011, 18:15

Quote:

Originally Posted by LeeumH

I would fix your exhaust leak (even just a small leak will affect the reading), and fit some new plugs, fuel filter and air filter (if you haven't got a fancy one fitted). Give it a good drive before the MOT, i.e. get the CAT nice and hot.

I always use these plugs: NGK BKR6EZ.

I wouldn't look too much into the RR result - I doubt your ECU is at fault.

True but 142bhp over 120bhp would say to me its been remapped.

Steve.

26th February 2011, 19:56

A friends 106 GTI made a figure similar to that on the rollers at Chipwizards with just a filter and cat back exhaust. Make of that what you will.

I very much doubt it's remapped, personally. I could be wrong though.

26th February 2011, 20:19

has it got a resistor in the intake temp sensor, ya can buy them off ebay really cheap, if it has it will always run rich

26th February 2011, 21:36

Quote:

Originally Posted by seddon89

has it got a resistor in the intake temp sensor, ya can buy them off ebay really cheap, if it has it will always run rich

You can buy bargains on ebay mate,but things like sensors its bes to buy the genuine thing either from the main dealer or eurocarparts.

Steve.

27th February 2011, 07:25

Don't think its got any resistors fitted.

Previous owner did not get the ECU remapped but it could of happened before he got the car. Just checked through the paperwork and the 2 years (2007 and 2008) CO2 test reports I have were both done after the current owner had the car - so remapped or not the CO2 figure has jumped up from 0.004% (2008) to 0.74% (2010/11)

Which is good as it proves if is/was remapped then it can still achieve good emission results

However it still doesn't indicate where the problem is

FYI The car has a BMC CDA air filter and CAT-back Magnex system with "empty" mid box (except at the moment as it has a new CAT fitted) - which I believe was the setup when it had the RR test. She now has a Racelend 4-2-1 mani (as I couldn't get the lambda sensor out of the old OE mani so I changed the mani and put a new Bosch lambda sensor on)

I appreciate the ideas and suggestions guys, keep 'em coming - will get this sorted one way or the other - thx

28th February 2011, 12:09

Changed the plugs today - I've put in NGK BKR6EK (Zs weren't in stock and I was too impatient to wait) - the book lists these as suitable for mine and all other Saxos. They're a twin spark (opposite arms) jobbie.

The ones that came out were Bosch Super Plus FR7DC and according to the Haynes Manual guide were "Normal - Grey-brown deposits lightly coated core nose. Plugs ideally suited to engine, and engine in good condition" - They look like this >>

Which is no chuffing help whatsoever

28th February 2011, 14:10

Its a pity you couldn`t lay your hands on(ie borrow)another ECU 1 thats been unlocked fit that and see what the co2 reading is,this would eliminate the ecu.

Steve.

28th February 2011, 14:21

Quote:

Originally Posted by stevo67

Its a pity you couldn`t lay your hands on(ie borrow)another ECU 1 thats been unlocked fit that and see what the co2 reading is,this would eliminate the ecu.

Steve.

No VTS around here I'm afraid - £80 seems to be the going rate including postage for an unlocked 1 plug ECU - which may be the next step.

I'm taking the de-CAT and old CAT with me tomorrow as if there's time I want to test what the CO2 readings are for the three options as I'm not 100% convinced that the cheapie CAT I got is any good. The previous owner said that he'd bought a new CAT, went for a MOT and it failed on emissions took the CAT back and got another and it passed no problems - I've still got the old CAT and am now wondering whether the problem may have been resolved (as the best figures we got were 0.40% CO2 as compared with 0.74% before) with the new lambda and engine temperature sensor but now muddled/masked with a dodgy new CAT.

I find all this most strange as the car runs beautifully with plenty of go, no oil nor water loss and only a little bit more consumption than my VTR (which you'd expect on a 16v) - its doing my head in

Edit: I'm going to end up with enough replacement parts to build another VTS at this rate ... lol

28th February 2011, 14:33

With plugs like that my money is on the CAT. Exchange the one you got if you still can or just buy a new one.

28th February 2011, 14:41

Quote:

Originally Posted by outrage_uk

With plugs like that my money is on the CAT. Exchange the one you got if you still can or just buy a new one.

Got a new one

if you're right though I'll go find an exhaust centre and get them to fit and test one - damn things coming off anyway after the stupid test as I want to fit the de-CAT.

Thx for the advice

28th February 2011, 15:10

In the past I've come across cheapo cat that are complete and utter shite. So much so I actually can't be bothered to buy and fit and take off again and get a replacement and refit tha I just buy second hand genuine ones off here now.

2nd March 2011, 12:40

Update:

2 hours at Citroen yesterday - full diagnostic, on ramp, off ramp, this changed and tested, that changed and tested....end result....very healthy engine with no diagnostic errors, it has had an ECU remap (but doesn't effect the emissions negatively) and the 4 mechanics all decided that both CAT's are dead (old one knackered and the new one useless pile of tin crap). The readings the emission test gave when compared with Citroen data point towards failed CATs and the condition of the old plugs confirmed that the fuel mix is fine - no injector errors neither.

So....instead of 680 (nearly £500) for a Citroen part I'm trying to locate a local exhaust centre that can supply, fit and TEST a new CAT cheaper.

All a real pain in the arse for something that will be on the car for only 10mins every 2 years

2nd March 2011, 13:28

Mines doing the exact same thing mate! ive changed the Cat and the Lambda sensor and it didnt change a thing! the place that i had the Mot done recon its been remapped because of how far the revs go when its reved up! so its going into citroen to be put back to the standard MAP, they recon this should sort it out!

2nd March 2011, 14:10

Emissions are never tested at 7,000 rpm though - its idle and fast idle (2-3,000 rpm) so even if it was remapped - I personally think you shouldn't have any problems with over fuelling. + them plugs have come from a healthy engine.

2nd March 2011, 17:17

i cant believe how poor some of those aftermarket cats can be, how they pass quality control i'll never know

2nd March 2011, 18:37

I've proof (printouts from 2007 and 2008) from two MOT/emission controls which were done since the remap - and rather than the CO2 at 0.74% I've got at the moment they both read 0.004% (hell of a difference). The CAT was new for the first one and 1 year old for the 2nd - so I guess that it shows the remap didn't affect the emissions, which is logical if the remap is a good one

When you compare the "weight" of the old worn out Citroen CAT with the new cheapie Ebay one there's a lot of difference so I guess you get what you pay for

2nd March 2011, 19:05

Glad you got it sorted in the end sorry for you though having to shell out a small fortune on parts.

Steve.

2nd March 2011, 19:12

Quote:

Originally Posted by stevo67

Glad you got it sorted in the end sorry for you though having to shell out a small fortune on parts.

Steve.

Cheers Steve - not sorted yet but hopefully will be soon

11th November 2016, 20:07

What was the fix in the end as I have same problem on HDZ engined 106 with readings worst after replacing lambda sensor CO 2.71 HC 224 Lambda 0.988 after putting injector cleaner in the tank and driving the card hard.

11th November 2016, 20:42

Crikey that's a post from the past - if I recall correctly buying a proper named brand CAT brought the reading down to an acceptable level - however I'm now on engine number 3 in this car so can't recall if the "correct" CAT was tested before or after I changed the engine the first time around.

Either way I would recommend trying a "heavy" (not cheap tin/lightweight/ebay) CAT and seeing what gives (I think mine's a "Walker" - it goes on before the test and comes off straight afterwards) - good luck

11th November 2016, 23:50

Quote:

Originally Posted by fdimu

What was the fix in the end as I have same problem on HDZ engined 106 with readings worst after replacing lambda sensor CO 2.71 HC 224 Lambda 0.988 after putting injector cleaner in the tank and driving the card hard.

.988 lambda is close enough to pass so it's the cat at fault, or it's not hot enough to function.

12th November 2016, 10:40

wouldn't that CO 0f 2.71 being a bit high say its running rich?

12th November 2016, 13:51

Where did you get the cat from? I've had issues with new ones not passing before if it's faulty

12th November 2016, 21:03

Lambda is a better indicator of mix ratio and 0.95 to 1.05 are acceptable limits for the cat to function if hot enough. CO can vary depending upon other combustion efficiency factors.

15th November 2016, 15:32

I put cataclean in mine every mot to get through emission's works a treat

15th November 2016, 20:36

To the op are you letting the car warm up enough so that the cat is at optimum operating temperature?

16th November 2016, 08:02

Have you ( or your mechanic) thought about valve stern seal's condition? If they are worn, CO2 values are going high

20th November 2016, 18:24

Quote:

Originally Posted by alfasud

Have you ( or your mechanic) thought about valve stern seal's condition? If they are worn, CO2 values are going high

It would be burning an outrageous amount of oil to affect the gasses that much.