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

Reply to
gerryo
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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

Reply to
James Shackley

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..

Reply to
Tim (Remove NOSPAM.

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.

Reply to
malcolm

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?

Reply to
gerryo

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

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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.

Reply to
gerryo

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.

Reply to
malc

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.

Reply to
gerryo

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

Reply to
malc

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