emission test failure

yellow94uk · Apr 24, 2008

my gt decided to fail it's annual safety inspection,3 tires,2 headlights and 1 bulb. all easily fixed. however the lambda test is saying too much o2 is coming out of the exhaust. can anyone help as i know zero about efi and have 14 days to sort this out or my every day car has to come off the road.PLEASE HELP I HATE BUSES!!!

Venom351R · Apr 24, 2008

What are your mods if any? Do you have an O/R H pipe ( or X ) or cats?

yellow94uk · Apr 24, 2008

i have standard cats (passed cat test) shortys non stock h pipe & tail pipes stock injectors,ported heads & manifold,stock filter & intake,mystery cam(slightly lumpy idle)came with car.

Venom351R · Apr 24, 2008

and you have passed emissions fine before but this time your having trouble?

HISSIN50 · Apr 24, 2008

yellow94uk said:
however the lambda test is saying too much o2 is coming out of the exhaust.

Tell us exactly what was said (the above statement makes no sense) and what the numbers were if you can. Deciphering the O2 nonmenclature can be a little tricky.

If you have a set of codes indicating that both O2's are bad, there's a decent chance there's another issue at hand, so dont rush out and buy new O2's till you do some other things.

Good luck.

Chythar · Apr 24, 2008

The Lambda test is run when a sensor is placed in an exhaust pipe and the emissions are sampled. It samples carbon monoxide (CO), hydrocarbons (HC), oxygen (O2) and carbon dioxide (CO2). Basically, the standard emissions test. I didn't know its name until I looked it up just now.

Too much O2 (and the other values too low) would lead me to believe you have an exhaust leak somewhere in the system. The exhaust system is sucking in air somewhere, thinning out the exhaust mixture. Make sure the exhaust pipes are all clamped tight and nothing is broken.

The O.G. · Apr 24, 2008

i can tell u i passed with the vacuum port under the intake open

the car ran terrible ,lean i think ,but passed

reading limit
hc gpm 01.05 01.20
co gpm 000.00 020.00
nox gpm 01.25 02.50
co2gpm 404.00 n/a

iv heard pull the spout but i dont know

94-302-vert · Apr 25, 2008

Run GTP and pull the spout... This is how I passed with pretty bad cats and an EGR that was blocked but the computer thought it was wide open...

yellow94uk · Apr 30, 2008

hi guys,sorry i did'nt reply sooner.as it turns out everything with the engine is fine.the bad lambda reading is due to my exhaust being too low in back pressure to give a reading.this has been cured (for me) by some local mechanics who removed the h pipe & replaced it with a fabricated y pipe (so currently i only have 1 working tailpipe)and bypassed the smog pump.(good news as now i can delete and bin it!!!).all this for £160(or US$300)including putting the h pipe back after it passes its test & i get to keep the y pipe for next year. thanks for your help & suggestions STEVE.

emission test failure

yellow94uk

New Member

Venom351R

yellow94uk

New Member

Venom351R

HISSIN50

"How long does it take to get help in here?

Chythar

Recently finished repairing my rear

The O.G.

Member

94-302-vert

Active Member

yellow94uk

New Member

Similar threads

emission test failure

New Member

New Member

"How long does it take to get help in here?

Recently finished repairing my rear

Member

Active Member

New Member

Similar threads

Privacy & Transparency

Privacy & Transparency