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Citroen Saxo 1.1 HDZ 1998 - Emissions query, high CO and HC #

Posted by Shaun Dale on July 14, 2009, 5:26 pm

Year of Manufacture *: 1997
Engine Code or Type *: HDZ
( Optional ) ECU Type: Bosch MA 3.1
( Optional ) Scanner used: ACR4

This car is failing its emissions test with the following results at fast idle
First test:
O2 1.22%
CO2 12.0%
HC 439 ppm
CO 1.26%
Lambda 1.005

Second test (two mins later)
O2 0.84%
CO2 13.3%
HC 329ppm
CO 1.19%
Lambda 0.995

This is the 8 valve single point injection engine so I'm not expecting brilliant results, particularly on HC's.
No fault codes in memory.
Live data shows lambda sensor switches 1-2 Hz at idle, coolant sensor is recording correctly.
No detectable exhaust leaks, particularly upstream of lambda sensor.
Slight misfire (well I thought so anyway) so I fitted new leads, plugs had been changed during a service last week.
I advised customer that the Catalyst has failed.
Customer calls and tells me a new catalyst is £500 genuine, £250 non-gen, how sure am I it is the catalyst.
Now I am concerned that my diagnosis was wrong but I can't see any other reason as the lambda is very close to 1.00. My first thought was airleak upstream of lambda sensor causing the management to richen up but I discounted that early on.
My question is do the gas readings point to a faulty catalyst or me being an idiot?
Another thought, could it be wrong plugs giving poor combustion (BKR6EZ fitted from memory, which according to my NGK book is correct)?
Shaun

Re: Citroen Saxo 1.1 Emissions query

Posted by Aidan birley <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT2879' width='330' height='300' border=0 style='border:none;'> on July 14, 2009, 6:52 pm, in reply to "Citroen Saxo 1.1 Emissions query"
Aiden Birley

Hi Shaun

I would be looking at Cat to, is this the one in down pipe ? or under car ?

Price for non OE, sounds way to much, have you priced one ? The 106 under car one is only about £35, The last down pipe type I had was under £100, Ok wont last long but will get an old car through test.

Cheers Aidan

Cheers Aidan

Re: Citroen Saxo 1.1 Emissions query

Posted by Peter Warman <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=Peter+Warman' width='330' height='300' border=0 style='border:none;'> on July 14, 2009, 7:19 pm, in reply to "Citroen Saxo 1.1 Emissions query"
Peter Warman - Administrator

Hi Shaun

I would say you have more than a cat problem

If the cat has failed I would expect CO to be around 0.5% and HC around 50-100 PPM

The cat may well be dead but I think you have another problem that needs fixing first, rich mixture, misfire etc. Once you have fixed, I would do a pre cat gas test, if the CO is down to 0.5% (or abouts) and the same at the tail pipe, then fit a new cat

I may stand to be corrected, but thats my thinking

Peter

Re: Citroen Saxo 1.1 Emissions query

Posted by Mark Carter <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on July 14, 2009, 7:28 pm, in reply to "Re: Citroen Saxo 1.1 Emissions query"
Mark Carter

Hi is all the live data good? including fuel trims?

regards Mark.

Modern cars, Its all wizardry and witchcraft

Re: Citroen Saxo 1.1 Emissions query

Posted by Aidan <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT2879' width='330' height='300' border=0 style='border:none;'> on July 14, 2009, 9:03 pm, in reply to "Re: Citroen Saxo 1.1 Emissions query"
Aiden Birley

Hi

As pointed out HC is on high side, A basic mechanical check of engine would be good start.

Compressions / intake vac / valve timing. Also Condition of oil (fuel contamination ) and breathers

Cheers Aidan

Re: Citroen Saxo 1.1 Emissions query

Posted by Simon Dean <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5221' width='330' height='300' border=0 style='border:none;'> on July 14, 2009, 10:23 pm, in reply to "Re: Citroen Saxo 1.1 Emissions query"
Simon Dean

Hi
I would agree with peter,you should be seeing around 0.6% co if cat u/s.
Unless you have an engine that is starting to breathe due to its age??Dis the breather and see what happens generally.

Lamda switch 1-2 HZ...from memory 1hz is correct....2hz slow??correct me if wrong there.

correct ecu on vehicle?seen it before on the old ones?
correct throttle body and injector...again seen it before?

whats your inj time at idle......

Simon

Re: Citroen Saxo 1.1 Emissions query

Posted by Scott Rayson <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT2962' width='330' height='300' border=0 style='border:none;'> on July 14, 2009, 11:05 pm, in reply to "Citroen Saxo 1.1 Emissions query"
Scott Rayson

I Had a peugeot 106 1.1 that had similar emissions. I checked and scoped everything i could, replaced inlet and exhaust manifold gaskets due to slight leaks, spark plugs and leads due to looking old and still emissions high. New lambda sensor also. In the end as a last resort i fitted a new cat, (cheepo one, £28 i think?) Emissions then were vertually down to zero! Didn't think a cat could bring it down that much but it did. So i'd defently try a new cat 1st.

Re: Citroen Saxo 1.1 Emissions query

Posted by Pete Mutlow <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1569' width='330' height='300' border=0 style='border:none;'> on July 14, 2009, 11:08 pm, in reply to "Re: Citroen Saxo 1.1 Emissions query"
Peter Mutlow

Hi Shaun,

I agree with all the others in that the Cat is faulty plus another problem. If this car had no Cat, then the HC reading would be too high for a pre-cat car. The CO is not high enough to produce this amount of HC therefore there must be an under-lying problem and the fitting of a new Cat may not on its own get it through the MOT. Did the fitting of those ignition parts cure the 'mis-fire'? Afraid its back to basics on this first before any more money is thrown at it.

Regards

Pete M

Re: Citroen Saxo 1.1 Emissions query

Posted by Shaun Dale <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT2719' width='330' height='300' border=0 style='border:none;'> on July 15, 2009, 8:16 am, in reply to "Re: Citroen Saxo 1.1 Emissions query"

Gosh, loads of replies, thanks guys,
No signs of smoke at tailpipe.
Disconnected breather with no change also no discernable smoke coming out of it.
Can't remember what injection pulsewidth was at idle, I think it was about 1.8-1.9mS but like an idiot I did not write it down, anyone got data on what it should be?
The misfire was only a minor wobble at idle, not sure if the leads made any difference, but in my opinion was acceptable for an SPi engine.
I only popped the ACR4 on it to check codes and CTS etc. I should have put something else on to check the fuel trims i suppose.
Car does about 3000 miles a year, was serviced last week, has had no other repairs to the engine recently as far as I know.
I was a bit doubtful about my diagnosis, in my opinion most cats don't die of natural causes, they get killed by something, I just could not find a something.
Had a really busy day on Monday and did not want to make a meal of this one.
Shaun

Re: Citroen Saxo 1.1 Emissions query

Posted by Pete Mutlow <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1569' width='330' height='300' border=0 style='border:none;'> on July 15, 2009, 11:05 am, in reply to "Re: Citroen Saxo 1.1 Emissions query"
Peter Mutlow

Hi Shaun,

That "something" you allude to is the high amount of HC's (unburnt fuel/oil) at fast idle. Needs to be dealt with if you want a 100% certainty the vehicle will pass the MOT.

Regards

Pete M

Re: Citroen Saxo 1.1 Emissions query

Posted by Nigel Bennett <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5463' width='330' height='300' border=0 style='border:none;'> on July 15, 2009, 9:01 pm, in reply to "Re: Citroen Saxo 1.1 Emissions query"
Nigel Bennett

Its going to have poor compression or a leaking valve on at least one cylinder , Or check for inlet mainifold leak !

Re: Citroen Saxo 1.1 Emissions query

Posted by Matt Elliott <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1416' width='330' height='300' border=0 style='border:none;'> on July 17, 2009, 12:37 am, in reply to "Re: Citroen Saxo 1.1 Emissions query"
Mattew Elliott

Hi,
I think if it is the small type in line cat I'd just throw one on for 30 quid, There is no doubt other problems but a cat would probably see it through the MOT .

If it only doing 3k a year it probably never gets hot so has probably got premature engine wear but also the cat has to put up with a cold rich mixture for most of it's life which wouldn't do it much good & these cats are crap, I bet it's already had at least one maybe two so far.

I'd check before & after cat with infared temp gun just to comfirm,fit a non genuine cat,explain to customer shes killed her car by only doing short runs,a new cat is just a mask & that due to above issues there is no warranty on cat,oh & sell car before next years mot.

We all know it's not the right way but it's the cheapest route & the car isn't worth chucking hundreds at or many hours testing.

Matt

Re: Citroen Saxo 1.1 Emissions query

Posted by Peter Warman <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=Peter+Warman' width='330' height='300' border=0 style='border:none;'> on July 17, 2009, 7:56 am, in reply to "Re: Citroen Saxo 1.1 Emissions query"

I would be VERY surprised if a cheap £30:00 cat would reduce HC from 430 ppm to around 10 ppm and CO from 1.2% to 0.0%

I would personally tell them that if you have covered all the basics, rather than taking a chance with customers money and fitting parts that you THINK might get it through an MOT, I would direct them to the nearest breakers

Is a 1997 1.2 Saxo really worth the time, money and hassle?

Peter

Re: Citroen Saxo 1.1 Emissions query

Posted by Mark Mcgrath <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT2806' width='330' height='300' border=0 style='border:none;'> on July 17, 2009, 9:44 am, in reply to "Re: Citroen Saxo 1.1 Emissions query"
Mark McGrath

can of forte in half a gallon of petrol stick in tank
run car for an hour at fast idle
blast up the road and recheck emissions
not a lot of cost and as worked for us before

Re: Citroen Saxo 1.1 HDZ 1998 - Emissions query, high CO and HC #

Posted by Bryan Smith <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5330' width='330' height='300' border=0 style='border:none;'> on July 17, 2009, 11:15 am, in reply to "Citroen Saxo 1.1 HDZ 1998 - Emissions query, high CO and HC #"
Bryan Smith

Hi Shaun
As others have said, the CO and HC's are far to high to be just a cat problem. I reckon its mechanical, so also as previously mentioned go back to basics. Have you done a vac test? I would also do a cylinder leakage test as well as a compression test. My money is on a valve problem but maybe thats why I'm skint

.
Regards, Bryan.

Re: Citroen Saxo 1.1 HDZ 1998 - Emissions query, high CO and HC #

Posted by Pete Mutlow <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1569' width='330' height='300' border=0 style='border:none;'> on July 17, 2009, 10:29 pm, in reply to "Re: Citroen Saxo 1.1 HDZ 1998 - Emissions query, high CO and HC #"
Peter Mutlow

Evening all,

Peter. Not sure why you want CO down to 0% and HC @ 10ppm. The fast idle test is a bit more generous than that. I can also under-stand why people spend money on old motors on the basis of better the devil you know... .

Mark. I assume you mean Forte Gas Treatment. Cracking stuff. Well worth a go.

Regards

Pete M

Re: Citroen Saxo 1.1 Emissions query

Posted by Matt Elliott <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1416' width='330' height='300' border=0 style='border:none;'> on July 17, 2009, 10:56 pm, in reply to "Re: Citroen Saxo 1.1 Emissions query"
Mattew Elliott

The hc's only have to be under 200 ppm & co under 0.20 % (more if not under BETs test) & I don't see having a punt at a cheap cat on a cheap car as wasting money. What's the alternative, spend hundreds diagnosing/fixing what is probably a knackered bore washed engine or telling customer to buy a new car ?

If you take mk3 fiestas with the ohv engine,these were heavy oil burners & were forever destroying their cats(again very cheap cats)you could pretty much be sure a new cat would see it through the mot.Again not exactly the right approach to diagnostics but it does the job on these cars with older style engines designed way before any cats were ever fitted to cars.

We're not talking about guessing at a £400 cat in the manifold set up here, it's a £30 in line cat about the size of a squashed baked bean can(in fact a can full of baked beans would probably do a better job than these things

)You'd save more in wasted time than it would to buy it,fit & test it.

I'm not saying it's the technically the right thing to do but there are times and cars when it makes better sense to have a leap than waste customers money in lenghty tests to comfirm something thats pretty obvious, THE ENGINES SHOT & thats wrecked the cat.

I'm not trying to offend anyone but I certainly don't waste my customers money,if you explain to people your line of thought & give them the choice most would go with the cheap cat gamble."I know my car's a banger & I really need a new one but if you could just get it through this year".... etc etc......you know how it goes

Just my thoughts

Matt

Re: Citroen Saxo 1.1 HDZ 1998 - Emissions query, high CO and HC #

Posted by Scott Rayson <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT2962' width='330' height='300' border=0 style='border:none;'> on July 18, 2009, 2:00 am, in reply to "Re: Citroen Saxo 1.1 HDZ 1998 - Emissions query, high CO and HC #"
Scott Rayson

While i agree with some that yes there maybe or maybe not be another problem with this car a £30 cat would probably sort the emission problem to get another year out of it, but would your customer be happy with a BIG bill for getting this car, which honestly is only worth, what £600?, sorted out "properly".
It's all down to customer satisfaction?

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