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Ahhhh what’s with the cars emissions?!?! - Ideas Needed
Mr Whippy - 19/9/13 at 02:33 PM

Yes it's my damn Zafira again, seriously doing my nut this car, just failed again on the emissions with no change since last time

I fitted a new CAT, new Lambda sensor, these no exhaust leaks, runs fine and smooth, doesn’t even have the air filter in to rule that out. No fault codes coming up, just can’t get the CO2 reading to come down and only just fails.

What on earth is left?! Could it be a leaky injector? Though I’d have thought it would be cutting back the rest of them to compensate. The MOT mechanic thinks it may be the ECU though he says these are coded to the car and can’t be swapped without an expensive computer job. Engines up to normal temp too.

All I can think of is

a) Leaky injector, how do I even check for that??
b) Airflow meter somehow defective?
c) Excessive engine fumes from crankcase, doesn’t seem smokey inside
d) Crap spark plugs not burning the fuel well hmmm

Have to say all this is really putting me off getting a modern car like an MX5 now, think I should just buy a V6 Capri instead at least they are easy to sort!

Any ideas folks???

Thanks in advance

ianm67 - 19/9/13 at 02:40 PM

I know that simply changing to a cotton filter in my Scooby had an adverse effect on the emmissions so I would suggest that you put a new stanadrd spec' air filter back in the car for starters....... Can you get a set of hotter plugs for it? These may help a little?

Mr Whippy - 19/9/13 at 02:57 PM

Thanks, though the standard filter in or out made no difference to the readings

ianm67 - 19/9/13 at 02:59 PM

Just a thought? Would a tank of super unleaded burn cleaner?

bigrich - 19/9/13 at 03:03 PM

have you got the emmissions readings to post up. all 5 readings. will help to diagnose your fault
co
co2
hc
o2
lambda

or as much info as you have

mcerd1 - 19/9/13 at 03:41 PM

is it just a code reader you've tried - or one that can tell you live data ?

if it can tell you live data it might be worth a look to see if the sensors are all giving sensible values (airflow, TPS.....) and not just stuck at some silly value....



quote:
Originally posted by Mr Whippy
Have to say all this is really putting me off getting a modern car like an MX5 now, think I should just buy a V6 Capri instead at least they are easy to sort!

unless you get a 2.8i capri - the K jetronic setup is a nightmare when it goes wrong

chris-g - 19/9/13 at 04:06 PM

My Audi 80 had an MOT failure due to emissions some years back. It was the engine temperature sensor for the ECU. It did come up as a fault code but if you have the ability to see live data its worth checking the temperature.

britishtrident - 19/9/13 at 04:09 PM

With HC then after basic checks the first thing to change is plugs and coil pack.

Mr Whippy - 19/9/13 at 04:18 PM

Sorry the cars still at the testing station, will collect it a 7 and post the 3 emissions sheets I have

Thanks

Mr Whippy - 19/9/13 at 04:20 PM

quote:
Originally posted by mcerd1
is it just a code reader you've tried - or one that can tell you live data ?

if it can tell you live data it might be worth a look to see if the sensors are all giving sensible values (airflow, TPS.....) and not just stuck at some silly value....



quote:
Originally posted by Mr Whippy
Have to say all this is really putting me off getting a modern car like an MX5 now, think I should just buy a V6 Capri instead at least they are easy to sort!

unless you get a 2.8i capri - the K jetronic setup is a nightmare when it goes wrong


I know what you mean but I'd get a MK 1 like I use to have, carbs you can't beat simplicity

ashg - 19/9/13 at 06:39 PM

airflow sensor sounds like the culprit, the data from that is used to calculate the amount of fuel to put in.

dimlaz - 19/9/13 at 06:40 PM

you should try to clean the EGR valve and the pipes.
....many emmisions issues are solved after cleaning!!!

britishtrident - 19/9/13 at 06:59 PM

The stoneage with carbs and dizzy's with points thank the great pumpkin that's in the past I have not had a car with a carb for 25 years life is so much easier now once you have the proper gear even a cheapo OBD2 scanner that reads and graphs live data is vital, fault codes seldom point directly to a fault but live data shows what the ECU sees coming in from the sensors

Looking at the stream from lambda output will tell you if it is "switching" fast enough and the the downstream lambda output will tell you if the cat is doing anything.
The data from the various sensors should make sense for example the coolant temp should be in the expect range relative to the actual engine temperature.

Mr Whippy - 19/9/13 at 07:15 PM

here's two if the fail sheets, I can't find the first

the difference between them are the top one is with a new cat and todays is one with a new lambda sensor as well, as you can see, its getting worse not better!

seems to be running a bit fast too while cold and the exhaust smells strong



bigrich - 19/9/13 at 08:22 PM

If I was faced with those results I would say eithet you had no Cat or the cat fitted is tired or a cheap replacement with not much in the way of precious metal content to complete the catalyst process. Only other thing would be is it hot enough to turn the cat ""on"". Thats my gut reaction. But we will see what the locost massive say

coyoteboy - 19/9/13 at 08:30 PM

Could be as close as just a sensor slightly out of whack. Coolant temp sensor started to drift with age?


Get a digital meter out and start checking sensors against their correct curve.

Mr Whippy - 20/9/13 at 06:41 AM

Thanks for all the replys.

Hmm where to start, the engine does run a bit cold, new thermostat should cure that seems hot enough though and the tester did make sure he heated it well. Not a clue tbh how to test the sensors with a meter, I can test a light bulb and that's about it

Found the first test sheet and it looks very similar to the last one so everything I have changed so far was a complete waste of time and money

It had started to be quite smokey though that seems to have vanished, but it was blueish smoke so why would that reduce with a CAT?

I'll try and check the points you say but I'm a bit out my depth for testing components with the equipment I have. A plug in reader that I can see on my IPad would be fab, not sure how much one of those would be?

Thanks, for the help, much appreciated

[Edited on 20/9/13 by Mr Whippy]

mcerd1 - 20/9/13 at 07:40 AM

the HC count does seam a bit on the high side (even on the ones that passed)
I've never had a count that high even on my cars with carb's
my little carb'd 106 used to get 3 ppm out of 200


so it could just be running a little too rich, trouble is that could be caused by lots of things inc. lamda sensors, temp sensors, airflow sensors....... they often fail without generating a fault code


I'd probably try a temp sensor first (check the live data if you can though) - thats going to be the cheapest one by far (google suggests £10 - £15) and caused similar problems on my brothers car a while back....

[Edited on 20/9/2013 by mcerd1]

britishtrident - 20/9/13 at 10:33 AM

From the numbers it looks to me as if isn't running closed loop, that would fit with a coolant temperature sensor-

Mr Whippy - 20/9/13 at 11:38 AM

quote:
Originally posted by britishtrident
From the numbers it looks to me as if isn't running closed loop, that would fit with a coolant temperature sensor-


Oh

But I get a sensible reading on the dash if a bit cool but it does go up, would there be an additional sensor?

Also read that the exhaust gas recycling valve is an issue on these cars, haven't a clue where that is but will have a look

[Edited on 20/9/13 by Mr Whippy]

mcerd1 - 20/9/13 at 11:58 AM

quote:
Originally posted by Mr Whippy
But I get a sensible reading on the dash if a bit cool but it does go up, would there be an additional sensor?


if the ECU is getting a reading thats cooler than it really is then it might still be running with some warm up enrichment ? (i.e. like leaving the choke on a bit)


also the dash gauges aren't always directly related to the temp - my focus one programed to stay in the middle of the normal bit of the gauge unless its cold or overheating - it stays at 'normal' for quite a wide range of temperatures, but the live data tells you the temp the ECU is really seeing

[Edited on 20/9/2013 by mcerd1]

coyoteboy - 20/9/13 at 12:00 PM

Many cars run an EFI coolant temp sensor and a gauge temp sensor, but I'm not sure on that car.

Mr Whippy - 20/9/13 at 12:32 PM

Hmm interesting will look into that then, thanks

MikeRJ - 20/9/13 at 01:18 PM

Is the idle a bit rough, and does it ever stall at junctions etc? If so then the EGR valve commonly gets stuck open on these which will adversely affect the emissions as well.

Mr Whippy - 20/9/13 at 04:33 PM

No tbh it has none off those issues, if anything it runs too fast when cold but settles down nicely when warm. Seeing how common it is an issue with these engines I'd suspect it is in need of a clean anyway, or blanking off

Cheers

froggy - 20/9/13 at 05:31 PM

Lambda is in on both those emmisions printouts . Looks like the cat is shagged to me , hc is a little high but a new cat will sort it . Cheap cat will be around £50 but might not last for two mots . I see these figures regularly mainly on cars with cheap "half " cat replacements .

Mr Whippy - 20/9/13 at 05:36 PM

quote:
Originally posted by froggy
Lambda is in on both those emmisions printouts . Looks like the cat is shagged to me , hc is a little high but a new cat will sort it . Cheap cat will be around £50 but might not last for two mots . I see these figures regularly mainly on cars with cheap "half " cat replacements .


The cat is brand new from autosave, it is surprisingly small tbh, if anything the emissions have went up not down since fitting the cat an a new lambda sensor

I did pour in cataclean additive on the second test but the results were just the same, hence the new cat. There must be something else I'm missing that hasn't been touch behind it.

[Edited on 20/9/13 by Mr Whippy]

britishtrident - 20/9/13 at 05:47 PM

quote:
Originally posted by coyoteboy
Many cars run an EFI coolant temp sensor and a gauge temp sensor, but I'm not sure on that car.


True .......................also on car with only one sensor the dashboard is driven by ECU generated values and if you disconnect the coolant temperature sensor on a lot of engines the ECU assumes a default value of 75c or so a moves the temperature gauge to "N".

[Edited on 20/9/13 by britishtrident]

froggy - 20/9/13 at 06:46 PM

How hard are they trying to get the cat lit?
I've had half cats from various suppliers and some work a lot better than others , sometimes I have to run the engine at 5000rpm for a minute or two and the co and hc slowly come in .

Mr Whippy - 20/9/13 at 06:59 PM

quote:
Originally posted by froggy
How hard are they trying to get the cat lit?
I've had half cats from various suppliers and some work a lot better than others , sometimes I have to run the engine at 5000rpm for a minute or two and the co and hc slowly come in .


I know what your saying but I know the tester very well and for many years so can trust him to have tried everything he could to get it through, he's not even been charging me to check the emissions but he's just as stumped as me

Do you think exhaust wrap would help get the cat hot? It would be straight forward to wrap the down pipe and cat can.

froggy - 20/9/13 at 07:05 PM

With the lambda being pretty much spot on id be looking at the cat . Hc level is down to the cat not working properly unless you can see any oil related smoke coming out of the back end .
Aftermarket cats are worthless for recycling so could well be a duff item you've got

Mr Whippy - 20/9/13 at 07:09 PM

quote:
Originally posted by froggy
With the lambda being pretty much spot on id be looking at the cat . Hc level is down to the cat not working properly unless you can see any oil related smoke coming out of the back end .
Aftermarket cats are worthless for recycling so could well be a duff item you've got


Well there was some blue smoke, not huge amounts just a whisp coming out the tail pipe when idling which seems to have cleared vastly if not completely since the fitting if the cat and lambda sensor, not sure why that would be