Reducing AFR readings ????????

[cameron]

I started at a garage today and thought id check out the AFR readings.

Not a good idea

It stated on the computer that anything over 0.30 is a fail

So 1st attempt was 0.80 2nd attempt was 0.68 then on the 3rd attempt i got the lowest reading of 0.55.

Ive recently changed the oil and filter, the plugs and i only run 99 ron either V power or Tesco super.

Any ideas on how to drop it down any would be appreciated.

Cheers guys

Lee

[Tomcat]

Lee, read your other post....

[Volvostorm]

Wasn't your exhaust blowing at one point?

[BruceT]

Thats your emissions mate.

AFR is Air to Fuel Ratio which Rolling Road/Dyno places do with a similar probe in the exhaust though I believe.

[Tomcat]

Agreed, AFR is Air Fuel Ratio, the emmissions is basicaly measuring the amount of carbons/ Hydrocarbons in the exhaust emmisions. As I said in your other thread, check your vac lines for leaks.

[cameron]

Wasn't your exhaust blowing at one point?

No mate it was my Mrs hearing things :doh:

[pookie]

These are the emmission readings used in a MOT test. Try an italian tune-up before taking these readings, generally they will reduce.

Pookie

An italian tune-up is to take it for a long run and screw the bo****ks off it. Gets the cat really hot.

[cameron]

I'll try pookie but the needle on the temp guage never goes above half way no matter how hard i treat her ;)

Lee

[1996 850 T5]

0.8 lambda is around 8% CO

theres a good conversion chart on page 44 of this link:

http://books.google.co.uk/books?id=CTz2EAp2ua8C&pg=PA43&lpg=PA43&dq=su+carb+setting+des+hammil&source=web&ots=gs0pk8tEgQ&sig=JDtQ4OWu-ZoozUJNNLtINMLYWt8&hl=en&ei=Da6QSbKhIZm1jAeVpujICg&sa=X&oi=book_result&resnum=4&ct=result#PPA44,M1

that should give you a general idea.

[Alan M]

As above get the cat really hot before doing the emissions test. It took my new cat about four tests before it passed.

[timbo_1975]

First job is to get it properly warmed up - 3pm on the gauge. So change thermostat first etc.

I very much doubt it is running closed loop either with those figures.

Get any codes read, and go from there.

Once you get it running lean enough, you may find the o2 sensor still wont switch because its choked with carbon, so you may need a new one.

Tim.

[Wobbly Dave]

Am I being stupid when saying the AFR readings - if taken post cat - will reduce as the cat warms up?

[timbo_1975]

Should do- depends on the fuelling of the engine and general running. The cat can only do so much, and needs certain conditions to work at all.

[cameron]

How can i reduce the emissions, is it best to get a spare ecu for MOT Time ?

Still reading 0.50 after a really good blast :(

Lee

[timbo_1975]

Change the 'stat first and then re-test!

If the o2 sensor and / or cat is buggered, all the ECU's in the world aren't going to help...

[cragmaz]

How can i reduce the emissions, is it best to get a spare ecu for MOT Time ?

Still reading 0.50 after a really good blast :(

Lee


you can do i suppose, but its a hassle in my opinion, besides, you will have to make sure your "spare" ECU is an EXACT match for your car, your best just getting the fuelling sorted on your existing one, you may need it re-mapping, as some files
from some certain people are well dodgy. :hbomb:
i can sort you out a bespoke re-map on the dyno if ya want, so we can get everything bang on. My T5 back on the dyno this sun for a tweak!!!! :B_thumb:
PM me if you want any more info.




BTW are`nt you running a Rica/HLM map on your ecu???

Craig

[cameron]

Yeah mate HLM 304 fitted in October :)

Goes like a friggin train and will probably be even better after the PCV is done and the boost leaks are fixed :B_thumb:

Lee

[Volvostorm]

Yeah mate HLM 304 fitted in October :)

Goes like a friggin train and will probably be even better after the PCV is done and the boost leaks are fixed :B_thumb:

Lee

A blocked PCV can affect the readings, as the engine isn't just burning air and fuel, but other junk to, like oil

[cragmaz]

Yeah mate HLM 304 fitted in October :)

Goes like a friggin train and will probably be even better after the PCV is done and the boost leaks are fixed :B_thumb:

Lee

Right then, in my opinion, (for what its worth), i would def. get the afr`s checked (Air/Fuel Ratio`s) on a dyno, oh, and boost pressure too!

Craig

[AndysR]

An emissions test for mot standards on your car would be testing the following

Co - burnt fuel
Hc - unburnt fuel/oil
Lambda - Oxygen

You co is too high which means you are running to much fuel for the test. This could be something like a blocked air filter or a faulty oxygen sensor. If it was due to an exhaust blow then I would expect your lambda readings to be higher due to the extra oxygen draged into the exhaust through the hole where it is blowing from. You could also check your vacumn lines to make sure they are all air tight from the outside but tbh the lamdba sensor would detect the extra oxygen content in the exhaust and richen the mixture to compensate when on closed loop. So as your car is running too much fuel it probably is more a case of too little air due to poor air flow into the engine or more probable a faulty o2 sensor (lamdba sensor) which isn't unheard of on an 850 ;)If that doesn't work then maybe it may be time to look at the cat :(

At least thats my understanding of the readings for mot's

[Yosser]

Lee, first of all - DON'T PANIC

FWIW I'm running the same ECU as you and my car passed it's MOT no problem in December - the tester actually commented how low the emissions were.

My advice would be service your car: plugs, cap, rotor arm, oil & filter, air filter, fuel filter, get the injectors cleaned, clean the air flow meter (MAF), PCV sorted, vac lines sorted.

Theres probably more that I've missed :)

Just pick away at it bit by bit, it sounds like a lot but it's all diy-able and it's all essential maintenance.

After all that, see how it's going and decide if you still have issues.

[thebadger]

^

Agreed, I had the plugs & filters done (fuel & oil), checked the injectors as well as a good oil change...

Big difference in the feel of the pickup & sailed through the emissions test!

I have no remap yet, but the Ferrita system on my car looks less than 2 yrs old! So I'd say it may be the sensor has clogged, or might need spacing?

Try a bit of this yourself first, as Yosser said, all diy'able!