Vectra failed emissions test, CO read 0.55%

Hi

My 1998 Vectra failed the NCT (Irish MOT) emissions tests.
Test results.

Engine/Oil temperature 83.3C

Low idle CO: 0.17vol% (above 0.5% = fail) -> result = PASS
810 rpm) HC: 0ppm (above 0ppm = fail) -> result = PASS

High idle Lambda: 1.015 (limits 0.97 to 1.03) -> result = PASS
(3030 rpm) CO: 0.55vol% (above 0.3% = fail) -> result = FAIL
HC: 123ppm (above 200ppm = fail) -> result = PASS

1.8L petrol engine with 82,826 miles on the clock.
Before testing, the air filter, plugs, leads, oil, & oil filter were
changed.

The MAF sensor was cleaned with carb cleaner, as was the throttle
area.
Split hose between MAF & throttle body also renewed.

Tester advised me to get codes read, but dealer says if no engine
management light on, the reader cannot say much.

The car does seem to be reasonably OK, starts fine, a bit chuggy for
the first minute, then OK. No problems with engine management light.

Anybody experienced this before?

I've searched Google, not too many with readings like these, usually
CO is a good bit worse. The exhaust is a bit black round the exit,
probably running a bit rich.

regards
Gerry

 

Very odd, CO2 high could indicate cat failure or possibly dodgy
lambda/exhaust sensors?

What's the MPG like?

I'd also recommend trying one of those fuel cleaner additives - not Redex,
but something stronger...stick it in the car and take it for a nailing - I
find they can make or break the difference but your CO2 is maybe too high
for that to make a dent...

Good luck in getting it sorted!

Cheers,
James

 

Is she warming up properly? By the oil temp I would assume so. Otherwise get
the o2 sensor checked for switching properly. It could well be switching
abit slowly- especially if its the original, and the mixture is swinging
rich for too long. Cat is in good shape from those readings..

Tim..

 

Like some others have said, either cat or O2 sensor. There should be at
least 6 crosscounts every 10 seconds.
Pull the codes to see if a fuel trim problem has been detected.

 

Had a look at the 02 Sensor, it's a 4 wire one, black wire seems to be
the signal wire. This reads 4.6 volts, dropping to 0.2 volts, then
back to 4.6 volts. Does this about 6 times per 10 seconds, but does
not seems to be a clean switch sometimes ( measured with a digital
meter, seems to hesitate on occasion before switching down).

When fast idled, the crosscounts increase to about 8 per 10 seconds.

Found another problem, the auxillary air pump is dead, & may have been
dead for some time. The vacuum operated valve which gates the pump
airflow is leaky, there is significant blowback from the exhaust out
through the air pump motor casing.

Is this is now pointing to a cat problem?
Would the lack of the aux air pump significantly shorten cat life?

Can the codes be pulled using the shorted wire link method, or do I
need to book in for a diagnostic check?

 

(gerryo) wrote in message

***** Stuff deleted about Vectra failing emissions *****

Changed the auxillary air pump & the associated vacuum operated valve
with parts from a breakers. These now work fine.

Also found that if you put a DVM on the 02 sensor signal leads, then
squeeze the auxillary air pump pipe to the vacuum valve,you can see
the sensor switch.
Only works while the air pump is running, but you can gauge the sensor
reaction times by modulating the airflow. My sensor seems to be
switching well

Found the following site with information about ECU codes

http://www.topbuzz1.carenthusiasts.co.uk/info/fault_codes/fault_codes.htm

I have the 16 pin aldl socket(located under a cover beneath the
handbrake)so I tried the "short pins 5 & 6" method, then turned the
ignition key & started up.

The ECU warning light did not flash at all, it just went out as
normal.

I tried again, this time, I left the ignition switch at the position
where the dash warning lights are on, but the engine not running. The
ECU light went out, the oil, battery, etc were still illuminated.
Still no flashed codes.

Either there are no stored codes, or else the procedure does not work
for my Vectra. Anybody seen this before?

Since my original problem was CO emission failure at high idle
(reading 0.55%, limit = 0.3%) & there was an exhaust leak (leaking out
the auxillary air pump), it's possible the car might be OK now, so
I'll get it checked for CO.

Would be good to check for stored codes without bringing it to a
dealer, but maybe that's no longer possible from 1998 onwards.

 

If pin 6 is engaged, then flash codes are available. To retrieve the codes,
all you have to do is ground pin 6. with the ignition on, the MIL will flash
any codes stored. If the MIL extinguishes, and does not flash, then no codes
are stored.

 

Did some more testing.

Pin 6 has 12 Volts when the engine is running, grounding this pin, get
a current flow of about 4.5 mA. Strangely, this pin stays at 12 volts
(if not grounded) for about 30 seconds after the ignition is switched
off.

Still no Flashing MIL, so I disconnected the inlet temperature sendor
leads (the sensor just after the air filter)& started up.

Still no flashing MIL.

I would have thought this was a definite way to get a failure code
stored. I guess it's possible the temperature sensor is already
faulty, but then that should have given me a stored code.

My Vectra just does not want to flash the MIL,guess it will have to be
the Tech2 at the dealers.

 

Flash codes should be retrieved with key on, engine off. If you still don't
get flash codes, I'd suspect the ECU.